HERBICIDE COMPOSITIONS OF EXTENDED SOIL LIFE

Abstract: Herbicidally active thiolcarbamates are employed in combination with a certain thiolcarbamate, thionocarba­ mate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, di­ thiocarbamate or carbamate extender compound, the latter in sufficient quantity to minimize soil degradation and to prolong the soil life of the former. As a result, the herbicidal effectiveness of the thiolcarbamate herbicide is significant­ ly enhanced and prolonged, rendering a single application or multiple applications of the herbicide effective over a longer period of time. Such herbicidal compositions can op­ tionally contain a non-phytotoxic antidotally effective amount of thiolcarbamate herbicide antidote.

Description: Background of the Invention This invention relates to herbicidal compositions and methods of use. In particular, this invention relates to herbicidal compositions comprising an herbicidally effective amount of a thiolcarbamate herbicide in combination with an extending amount of an extender compound. An extender compound is a certain thiolcarbamate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, thionocarbamate, dithiocarbamate or carbamate compound disclosed herein. An extender serves to prolong the effectiveness of single or multiple applications of the thiolcarbamate herbicide in controlling undesired plant growth. Thiolcarbamates are well known in the agricultural art as herbicides useful for weed control in crops such as corn, potatoes, beans, beets, spinach, tobacco, tomatoes, alfalfa, rice, peanuts and soybeans among others. Thiolcarbamates are primarily used in pre-emergence application. They have been found to be particularly effective when incorporated into the soil prior to the planting of the crop. As a herbicide, the thiolcarbamate is most concentrated immediately after its application. How long thereafter the initial concentration is retained depends in large part on the particular soil used. Thus the rate at which the thiolcarbamate herbicide concentration declines following its application tends to vary from one type of soil to the next. This is evident in the observable extent of actual weed control after considerable time has elapsed. The extender compounds of the instant invention extend the soil life of thiolcarbamate herbicides in soil which has been treated one or more times before with a thiolcarbamate herbicide or in soil which has had no previous treatment with a thiolcarbamate herbicide. Soil which has been previously treated with a thiolcarbamate herbicide is termed pretreated soil"; whereas soil which has not been so treated is termed " non-pretreated soil." Under certain environmental and other conditions, thiolcarbamate herbicides are degraded more rapidly in pretreated soil of certain types than in non-pretreated soil. Such pretreated soil is considered conditioned to degrade thiolcarbamates herbicides at an accelerated rate compared to non-pretreated soil. The extenders of the instant invention prevent rapid soil degradation of thiolcarbamate herbicide. Not only do the extenders prevent the rapid soil degradation of thiolcarbamate herbicides in pretreated soil, but also prolong the herbicidally effective soil life of thiolcarbamate herbicides in non-pretreated soil. The soil in many of the examples below showing activity of representative extenders of the instant invention has been pretreated. Such pretreatment is designed to simulate field conditions wherein a field has been repeatedly treated with a thiolcarbamate herbicide. This simulation is effected by retreating the experimental soil, employed herein within weeks of the first treatment rather than seasons later as in the fields. Such a short experimental retreatment period highly conditions the soil. The improvement in the soil persistence of the thiolcarbamate herbicide effected by the extender compound can manifest itself in a variety of ways. Improved soil persistence can be shown by herbicidal efficacy tests, wherein the degree of weed injury is measured after a set period of time following application of the herbicide. In such a test, the extender compound is shown to increase the herbicidal effectiveness of the thiolcarbamate by increasing the persistence of the latter in the soil, and thus prolonging its effective life. Several of the thiolcarbamate extenders within the scope of the instant invention are specifically disclosed as phytocides in Great Britain Patent Specification No. 862,548 (Tilles et al., published March 1961) and as herbicides in U.S. Patent Nos. 2,989,393 and 2,916,370. However, in all three of these references the rates in lb/acre at which the compounds were applied are very high compared to commercial application rates and those employed in the examples herein. Similarly, thiolcarbamates related to the extenders of the instant invention are disclosed as herbicides when applied at very high rates in U.S. Patent Nos. 2,901,498 and 2,916,369. Nowhere in any of the above-cited patent references is the problem of rapid soil degradation of thiolcarbamate herbicides even mentioned nor is the extension of soil life of thiolcarbamates referred to anywhere therein. In EP-A-0 038 945 herbicide compositions of extended soil life are described . In said compositions herbicidally active thiolcarbamates are employed in combination with certain substituted carbamates. The carbamate is included in a sufficient quantity to lessen the rate of soil degradation of the thiolcarbamate. As a result, the herbicidal effectiveness of the thiolcarbamate is enhanced and prolonged, rendering a single application of the herbicide effective over a longer period of time. Also the EP-B-0 100 909 describes herbicide compositions of extended soil life. Said compositions comprise a herbicidally effective amount of a thiolcarbamate and an amount of an allyl amine salt of thiocarbamic acid compound sufficient to extend the soil life of said thiolcarbamate. For a thiolcarbamate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, thionocarbamate, dithiocarbamate or carbamate compound to be considered an extender of this invention, it is highly desirable for there to be a significant difference between the herbicidal activity of the extender when tested alone and the herbicidal activity of the thiolcarbamate and extender composition, when applied at the same rate and by the same method. Summary of the invention This invention relates to a novel herbicidal composition comprising (a) an herbicidally effective amount of a thiocarbamate having the formula wherein R¹ is C₁-C₆ alkyl; phenyl; C₇-C₉ phenylalkyl; C₃-C₆ alkenyl; C₃-C₆ haloalkenyl; or C₇-C₉ phenylalkyl, mono- or poly-substituted on the phenyl ring with halogen; R² and R³ are either selected independently from C₁-C₆ alkyl or C₅-C₇ cycloalkyl or combined to form conjointly C₄-C₉ alkylene; and (b) an extending amount of a compound having the formula wherein Y is oxygen or sulfur; Z is oxygen or sulfur; p is the integer 0, 1 or 2; R⁴ is C₂-C₈ alkenyl; C₂-C₈ alkenyl substituted with one or more halo groups; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with dioxolanyl, cyano or one or more hydroxy or C₁-C₄ alkoxy groups; C₁-C₃ alkyl substituted with one, two or three halo groups; C₁-C₆ alkylthioalkyl; benzyl; benzyl substituted with one or more halo or trifluoromethyl groups; C₃-C₆ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with halo, one or more nitro, C₁-C₄ alkoxy, C₁-C₄ alkyl or C₁-C₄ haloalkyl groups; R⁵ is C₂-C₆ alkenyl substituted with phenyl or one or more halo groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with one or more halo groups; or C₃-C₆ alkynyl; R⁶ is hydrogen; C₂-C₆ alkenyl substituted with phenyl or one or more halo or C₁-C₄ alkoxy groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with C₃-C₆ cycloalkyl or one or more halo groups; C₃-C₆ alkynyl; furfuryl; or benzyl; with the provisos that: (1) when Y is oxygen or both Y and Z are sulfur, then p is zero; (2) when Y is sulfur, Z is oxygen, R⁴ is allyl, 2-methylallyl, 2-butenyl, 3-chloroallyl or n-butyl, and R⁵ is allyl, then R⁶ is other than propyl or butyl; (3) when Y is sulfur, Z is oxygen, R⁴ is either C₁-C₅ alkyl, substituted benzyl, C₃-C₆ haloalkenyl, 2-chloroethyl, methylthioethyl, or propargyl, and R⁵ is C₁-C₅ alkyl, then R⁶ is other than C₁-C₆ alkyl; (4) when Y is sulfur and Z is oxygen, R⁴ is allyl, 3-chloroallyl, ethyl, n-butyl, methoxymethyl or ethoxymethyl, then not both R⁵ and R⁶ are allyl; (5) R⁴ cannot be phenyl unless Y is S and R⁵ and R⁶ are both chloroallyl; (6) one of R⁵ and R⁶ is always substituted allyl unless R⁴ is CH₃SCH₂- or substituted allyl; (7) R⁶ is hydrogen only if Y is sulfur; and (8) when Y and Z are each oxygen, then R⁴ is other than phenyl substituted with one or more C₁-C₄ alkyl or one or more C₁-C₄ haloalkyl. In a preferred embodiment of the invention, the thiolcarbamate herbicides shown above are defined such that R¹ is C₁-C₆ alkyl, allyl or haloallyl; R² is C₁-C₆ alkyl; and R³ is C₁-C₆ alkyl or C₅-C₇ cycloalkyl. In a further preferred embodiment of the invention, thiolcarbamate herbicides are defined such that R¹ and R² are each independently C₁-C₆ alkyl; and R³ is C₁-C₆ alkyl or cyclohexyl. In an even further preferred embodiment of the invention, thiolcarbamate herbicides are defined such that R¹ and R² are each independently C₁-C₄ alkyl; and R³ is either C₁-C₄ alkyl or cyclohexyl. In a more preferred embodiment, thiolcarbamate herbicides are defined such that R¹ is n-propyl or ethyl; R² is n-propyl, n-butyl, isobutyl or ethyl; and R³ is n-propyl, isobutyl, cyclohexyl or ethyl. Exemplary thiolcarbamate herbicides of the invention include S-ethyl N,N-di-n-propyl thiolcarbamate (EPTAM®); S-ethyl hexahydro-azepine-1-carbothioate (ORDRAM®): S-ethyl N,N-diisobutyl thiolcarbamate (SUTAN®); S-n-propyl N,N-di-n-propyl thiolcarbamate (VERNAM®); S-ethyl N-ethyl-N-cyclohexyl thiolcarbamate (RO-NEET®); S-n-propyl-N-n-butyl-N-ethyl thiolcarbamate (TILLAM®); S-(2,3-dichloroallyl) N,N-diisopropyl thiolcarbamate (diallate); S-(2,3,3-trichloroallyl) N,N-diisopropyl thiolcarbamate (triallate); or S-(4-chlorophenyl) methyl N,N-diethyl thiolcarbamate (thiobencarb). In a preferred embodiment of the invention, the extender compounds are defined such that, Y and Z are defined as above; p is 0 or 1; R⁴ is C₂-C₆ alkenyl; C₂-C₈ alkenyl substituted with one, two or three halo groups; C₁-C₄ alkyl; C₁-C₄ alkyl substituted with dioxolanyl, cyano, or with one or two C₁-C₂ alkoxy groups; C₁-C₃ alkyl substituted with one or two halo groups; C₁-C₄ alkylthioalkyl; benzyl; benzyl substituted with halo; C₃-C₄ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with C₁-C₂ alkyl, halo or one or more nitro groups; R⁵ is C₃-C₈ alkenyl substituted with phenyl or one, two or three halo groups; C₃-C₈ alkenyl; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with halo; or C₃-C₄ alkynyl; R⁶ is hydrogen; C₃-C₈ alkenyl substituted with phenyl, or one, two or three halo groups; C₃-C₆ alkenyl; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with C₁-C₂ alkoxy, C₃-C₄ cycloalkyl, or halo; benzyl; C₃-C₄ alkynyl; or furfuryl. In another preferred embodiment, the extender compounds are defined such that, Y, Z and p are defined as immediately above; R⁴ is vinyl; allylic; C₁-C₄ alkyl; C₁-C₄ alkyl substituted with dioxolanyl or cyano; C₁-C₂ alkyl substituted with halo; C₂-C₄ alkylthioalkyl; benzyl; benzyl substituted with halo; C₃-C₄ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with halo or one or two nitro groups; R⁵ is allylic; C₃-C₆ alkenyl substituted with phenyl; C₁-C₄ alkyl; C₁-C₄ alkyl substituted with halo; C₁-C₄ alkyl substituted with halo; or C₃-C₄ alkynyl; R⁶ is hydrogen; allylic; C₃-C₆ alkenyl substituted with phenyl; C₁-C₄ alkyl; C₁-C₄ alkyl substituted with C₁-C₂ alkoxy or C₃-C₄ cycloalkyl; C₃-C₄ alkynyl; furfuryl; or benzyl. wherein allylic in said preferred embodiment for R⁵ and R⁶ refers to the following structure: wherein R⁷ is hydrogen, halo or C₁-C₃ alkyl; R⁸ is hydrogen, halo or C₁-C₃ alkyl; and R⁹ is hydrogen, halo or C₁-C₃ alkyl. In a still further preferred embodiment, the extender compounds are defined such that Y, Z and p are defined as immediately above; R⁴ is vinyl; 2-methylallyl; 2-butenyl; 3-butenyl; allyl; 3-haloallyl; 2-haloallyl; trihalo-2-butenyl; trihalo-3-butenyl; ethyl; methyl; n-propyl; n-butyl; iso-butyl; iso-propyl; 2'-(1,3-dioxolanyl) ethyl; cyanomethyl; 3-cyanopropyl; 2-haloethyl; methylthiomethyl; ortho-halo benzyl; 2-butynyl; propargyl; phenyl; or ortho-halophenyl; R⁵ is allyl; 2-haloallyl; 3-haloallyl, iso-butyl; 2-butenyl; or n-propyl; R⁶ is hydrogen, C₁-C₂ alkyl substituted with halo; or C₁-C₂ alkoxy; C₃-C₄ cycloalkyl; 3-haloallyl; 2-haloallyl; iso-butyl; 2-butenyl; allyl; furfuryl; benzyl; or 2-methylallyl. In a still further preferred embodiment, the extender compounds are defined such that, Y, Z and p are defined as immediately above; R⁴ is vinyl; 2-methylallyl; 2-butenyl; allyl; 3-chloroallyl; 3,4,4-trifluoro-3-butenyl; 3,4,4-trifluoro-2-butenyl; ethyl; methyl; cyanomethyl; 2'-(1,3-dioxolanyl) ethyl; 2-chloroethyl; methylthiomethyl; 2-butynyl; propargyl; phenyl; or 2-chlorophenyl; R⁵ is 3-chloroallyl; 3-bromoallyl; or 2-chloroallyl; and R⁶ is 3-chloroallyl; 3-bromoallyl; 2-methylallyl; benzyl; cyclopropylmethyl; 2-chloroallyl; furfuryl; or methoxyethyl. In an especially preferred embodiment of this invention, the extender compounds are defined such that; Y is oxygen or sulfur; Z is oxygen or sulfur; p is zero; R⁴ is ethyl; methyl; vinyl; allyl; 2'-(1,3-dioxolanyl) ethyl; 2-chloroethyl; 2-butynyl; propargyl; or 2-chlorophenyl; R⁵ is 3-chloroallyl; and R⁶ is 3-chloroallyl; cyclopropylmethyl; 2-methylallyl; or benzyl. Specific extenders which have been found to be effective in the compositions of the present invention include, for example, ethyl-N,N-bis-3-(chloroallyl) thiolcarbamate; n-propyl-N,N-bis-(3-chloroallyl) thiolcarbamate; n-butyl,-N,N-bis-(3-chloroallyl) thiolcarbamate; isobutyl-N,N-bis-(3-chloroallyl) thiolcarbamate; methyl-N,N-bis-(3-chloroallyl) thiolcarbamate; isopropyl,-N,N-bis-(3-chloroallyl) thiolcarbamate; cyanomethyl-N,N-bis-(3-chloroallyl) dithiocarbamate; ethyl-N,N-bis-(3-chloroallyl) dithiocarbamate; methyl-N,N-bis-(3-chloroallyl) dithiocarbamate; allyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 3-chloroallyl-N,N-bis-(3-chloroallyl) dithiocarbamate; n-propyl-N,N-bis-(3-chloroallyl) carbamate; ethyl-N,N-bis-(3-chloroallyl) carbamate; n-propyl-N-allyl thiolcarbamate; ethyl-N,N-bis-(3-chloroallyl) thionocarbamate; ethyl-N,N-bis-(3-chloroallyl) thiolcarbamate sulfoxide; ethyl-N-3-chloroallyll-N-2-methylallyl dithiocarbamate; ethyl-N,N-bis-(3-bromoallyl) thiolcarbamate; vinyl-N,N-bis-(3-chloroallyl) carbamate; allyl-N-3-chloroallyl-N-cyclopropylmethyl carbamate; allyl-N,N-bis-(3-chloroallyl) carbamate; allyl-N,N-bis-(3-chloroallyl) thiolcarbamate; allyl-N-3-chloroallyl-N-2-methylallyl carbamate; allyl-N-chloroallyl-N-benzyl carbamate; 2-butenyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 2-butenyl-N,N-bis-(3-chloroallyl) thiolcarbamate; 2-methylallyl-N,N-bis(3-chloroallyl) thiolcarbamate; 2-butenyl-N,N-bis-3-chloroallyl carbamate; 3,4,4-trifluoro-3-butenyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 3,4,4-trifluoro-3-butenyl-N,N-bis-(3-chloroallyl) thiolcarbamate; 3,4,4-trifluoro-2-butenyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 3-chloroallyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 3-chloroallyl-N,N-bis-(3-chloroallyl) thiolcarbamate; 2'-(1,3-dioxolanyl) ethyl-N,N-bis-(3-chloroallyl) dithiocarbamate; cyanomethyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 2-chloroethyl-N-3-chloroallyl-N-2-methylallyl carbamate; 2-chloroethyl-N,N-bis-(3-chloroallyl) carbamate; methylthiomethyl-N,N-bis-(3-chloroallyl) dithiocarbamate; 2-butynyl-N,N-bis-(3-chloroallyl) carbamate; propargyl-N,N-bis-(3-chloroallyl) carbamate; propargyl-N,N-bis-(3-chloroallyl) thiolcarbamate; propargyl-N,N-bis-(3-chloroallyl) carbamate; 2-butynyl-N,N-bis-(3-chloroallyl) carbamate; 2-chlorophenyl-N,N-bis-(3-chloroallyl) thiolcarbamate; and phenyl-N,N-bis-(3-chloroallyl) thiolcarbamate. The terms "alkyl," "alkoxy," "alkylthio," and "alkenyl" are used herein in their normal meanings intended to include both straight-chain and branched-chain groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, methoxy, ethoxy, isopropoxy, tert-butoxy, methylthio, ethylthio, n-butylthio, allyl, 2-methylallyl, etc. The terms "alkylene" and "alkenylene" are used hereinto denote bivalent hydrocarbon radicals which are saturated or unsaturated, respectively, and are also intended to include both straight-chain and branched-chain groups. Examples are: -CH₂CH₂CH₂-, -CH₂CH(CH₃)CH₂-, -CH(CH₃)CH₂-, -CH=CH=CHCH₂-, -C(CH₃)₂CH₂-, -CH₂C(CH₃)₂CH₂CH₂-, -CH₂CH(C₂H₅)CH₂-, -CH=C(CH₃)CH₂CH₂-, -CH=CH-, -C(CH₃)=CH-, -C(CH₃)₂C(CH₃)₂CH₂-, etc. All carbon atom ranges in this specification and the appended claims are intended to be inclusive of their upper and lower limits. "Haloalkenyl" as used herein refers to alkenyl compounds that are substituted, meaning mono- or poly-substituted, with halogen. Poly-substituted with halogen refers to compounds substituted with one or more halogen atoms, as, for example, 3,3-dichloroallyl or 2,3-dibromoallyl moieties. All carbon atom ranges are intended to be inclusive of their upper and lower limits. The term "halogen atom" or "halo" is used to designate fluorine chlorine, bromine, or iodine atoms, as well as any combination thereof. The term "herbicide," as used herein, means a compound which adversely controls or modifies the growth of plants. By the term "herbicidally effective amount" is meant an amount of compound which causes an adverse modifying effect upon the growth of plants. By "plants" is meant germinant seeds, emerging seedlings and established vegetation, including roots and above-ground portions. Such adverse controlling or modifying effects include all deviations from natural development, for example, killing, retardation, defoliation, desiccation, regulation, stunting, tillering, stimulation, leaf burn, dwarfing and the like. The phrase "to extend the soil life of said thiolcarbamate" is used herein to denote the effect whereby herbicidal effectiveness of the thiolcarbamate is maintained over time. An extended soil life can be manifest in a slower rate of decline of weed killing potency. An "extending amount" means an amount of an extender compound which is sufficient to prolong the soil life of a thiolcarbamate herbicide significantly. The prolongation of the thiolcarbamate herbicide's activity is effected by the extender in both pretreated and non-pretreated soil. The invention further relates to a method of controlling undesirable vegetation comprising applying to the locus where control is desired both a herbicidally effective amount of a thiolcarbamate as described above and an extending amount of an extender compound as described above as well. The invention further relates to a method of extending the soil life of a thiolcarbamate herbicide as described above by applying to the soil containing the said thiolcarbamate herbicide or to which said thiolcarbamate herbicide is to be applied an extending amount of an extender compound as described above as well. Detailed Description of the Invention Many of the thiolcarbamate herbicides within the scope of the present invention can be prepared by the process described in U.S. Patent No. 2,913,327 (Tilles et al., Nov. 17, 1959). Other of the thiolcarbamate herbicides within the scope of this invention can be prepare by methods described in U.S. Patent Nos. 3,582,314; 3,330,821 and 3,330,643. The bis-(3-haloallyl) thiolcarbamate extenders falling within the scope of the present invention can be prepared by reacting bis-(3-haloallyl) amine with an appropriately substituted chlorothioformate in the presence of sodium hydroxide, triethylamine or other appropriate bases and solvents. The method is described more fully in Examples I, II and III below. The preparation of ethyl-N,N-bis(3-chloroallyl) thiolcarbamate is shown below in Example 1 in three steps. A preparation of a symmetrically substituted bis-haloallylamine is therein exemplified in steps (a) and (b). Unsymmetrically substituted amine starting materials can be prepared according to standard textbook procedures, for example, as that disclosed as Method 436, Alkylation of Amines , at page 666 and following of Wagner, R.B. and Zook, H.D., Synthetic Organic Chemistry , New York, John Wiley & Sons, Inc. (1953). The primary, secondary and tertiary amines can be separated by distillation. Other amine starting materials can be prepared by classic syntheses analogous to those described in Chapter 24, Amines of Wagner and Zook, id. at pp. 653-727. EXAMPLE 1 Preparation of Ethyl-N,N-bis(3-chloroallyl) thiolcarbamate Step (a): Preparation of N,N-bis-(3-chloroallyl) cyanamide Sodium hydroxide (120 grams; 20% aqueous solution; 0.6 mole) was added dropwise and stirred into 25.2 grams (g) (0.3 mole) of a 50% aqueous solution of cyanamide (available from American Cyanamide of Canada, Limited). The temperature was maintained at between 0 and 8°C during the addition. After that addition was completed, 55.5 g (0.5 mole) of 1,3-dichloropropene (available from Columbia Organics and Dow Chemical Company) and 3.4 g (0.01 mole) of tetrabutylphosphonium bromide was added dropwise to the mixture. The reaction mixture was then heated slowly to 80°C at which point the mixture turned orange brown. It was heated at 80°C for 40 minutes, and then cooled to room temperature. The product was then extracted with ether and washed three times with water. Conventional techniques of drying over magnesium sulfate, filtering and stripping were then employed. The unreacted starting material was removed in a rotary evaporator at high vacuum. The yield was 87%. The product (41.5 g) was recovered as an orange-brown oil. The product's structure was confirmed as N,N-bis-(3-chloroallyl) cyanamide by mass spectroscopy, nuclear magnetic resonance, and infrared spectroscopy. Step (b): Preparation of N,N-bis-(3-chlorallyl)amine N,N-Bis-(3-chloroallyl)cyanamide (38.2 g; 0.2 mole) was placed in a flask, and 16 milliliters (ml) of concentrated H₂SO₄ in 92 ml of water was added. The resulting mixture was refluxed for four hours under stirring, and then after the mixture was cooled to room temperature, 50 ml of water was added. The mixture was extracted with 50 ml of ether, and the ether extract was discarded. To the water phase, 200 ml of water was added. In an ice bath under stirring, a solution of 47.4 g of NaOH in 92 ml of water was slowly added dropwise. After the addition was completed, the mixture was extracted three times with ether; the ether phases were combined, washed with water twice, dried over magnesium sulfate, filtered and stripped. The yield was 85%. The product (28.2 g) was recovered as an orange-brown liquid. Step (b): Preparation of Ethyl-N,N-di-3-chloroallyl thiolcarbamate Bis-(3-chloroallyl)amine (52.3 g; 0.315 mole) was added dropwise to ethylchlorothioformate (37.4 g; 0.300 mole) in the presence of sodium hydroxide (13.2 g; 0.330 mole), water (100 cc) and ethyl ether (200 cc) in a 500 cc flask. The reaction flask was cooled in dry ice to 5-10°C; the reaction is exothermic. The mixture was phase separated. The ether phase was washed with dilute hydrochloric acid and water; dried over magnesium sulfate and concentrated on a rotary evaporator. The weight of the residual liquid was 73.1 g. The theoretical percentage yield was 95.9%. The refractive index was n D ³⁰ 1.5341. The product was confirmed by nuclear magnetic resonance (NMR), gas chromatography-mass spectroscopy (GC-MS) and infrared spectroscopy (IR). EXAMPLE 2 Preparation of n-Butyl-N,N-bis-3-chloroallyl thiolcarbamate Bis-(3-chloroallyl)amine (1.2 g) was combined with 0.7 g of triethylamine (TEA) and 30 ml of dichloromethane. The mixture was cooled in an ice bath. The temperature was maintained below 18°C. N-Butylchlorothioformate (1.1 g) was added dropwise. The mixture was then stirred at room temperature for two hours. The product was then extracted by conventional techniques. Specifically, the mixture was washed once with saturated sodium bicarbonate; and then once with water. The next day the mixture was dried over magnesium sulfate, filtered and stripped. The product (2.3 g) was recorded as a clear yellow oil. The refractive index was n D ³⁰ 1.5414. The structure was confirmed by NMR, GC-MS and IR. EXAMPLE 3 Preparation of Benzyl-N,N-bis-3-chloroallyl thiocarbamate The same procedures a described in Example 2 was employed to prepare the above-named compound. One and four-tenths grams of benzyl-chlorothioformate was used. The product (2.4 g) was recovered as a clear orange yellow viscous oil. The refractive index was n D ³⁰ 1.5896. The structure was confirmed by NMR, GC-MS and IR. Great Britain Patent Specification 862,548, referred to above, describes the preparation of several of the thiolcarbamate extenders of the instant invention as follows: One may make the compounds for use in the compositions by various methods such as reacting an alkali metal mercaptide with the appropriate carbamyl chloride; by reacting an organic chlorothiolformate with the appropriate amine (using the amine itself as an acid binding agent or using caustic soda as an acid binding agent); by reacting an organic chlorothiolformate with an amine hydrochloride with an acid binding agent or by reacting carbonyl sulfide with an amine and an acid binding agent. (page 3, lines 44-57.) Other exemplary preparations can be found in the patents cited above, including U.S. Patent Nos. 2,916,369 (diallylthiocarbamates); 2,901,498 (lower alkyl N-alkyl, N-allyl thiocarbamates); 2,977,209 (preparation of phenyl N,N-di-n-propylthiocarbamate); 2,989,393 (preparation of compounds relating to the instant thiocarbamate extenders wherein R4 is alkylthioalkyl are disclosed); and 2,916,370 (preparation of compounds wherein R4 is lower alkyl, R5 is chloroalkenyl and R6 is alkyl or alkenyl). The thiolcarbamate sulfone, thiolcarbamate sulfoxide, thionocarbamate, carbamate and dithiocarbamate extenders within the scope of this invention can be prepared by reactions analogous to those described above for the thiolcarbamate extenders. Several ways are known in the art to prepare the carbamate extenders within this invention, which are analogous to those used for thiolcarbamate synthesis. One convenient way is to react an appropriately substituted chloroformate with the secondary amine in the presence of an acid acceptor. The generalized preparation for the dithiolcarbamate extenders of this invention involves reacting the appropriate secondary amine with carbon disulfide in the presence of a base such as sodium hydroxide. Then, the resulting salt of the dithiolcarbamic acid is further reacted with an appropriately substituted organic halide. Compounds which can be prepared by the methods described above or by analogous methods and which were tested by the procedures disclosed herein are listed below by structure in the following Table of Compounds. The objects of the present invention are achieved by applying the thiolcarbamate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, thionocarbamate, dithiocarbamate and carbamate extender compound to the soil at an agricultural field site in conjunction with the thiolcarbamate herbicide. The two compounds can be applied simultaneously in a single mixture or in separate formulations, or they can be applied in succession, with either one following the other. In successive application, it is preferable to add the compounds as close in time as possible. The herbicide extending effect is operable over a wide range of weight ratios of the two compounds. It is most convenient, however, to apply the compounds at a weight ratio of about 0.2:1 to about 30:1 (herbicide/extender), preferably about 0.5:1 to about 20:1, and most preferably about 0.5:1 to about 12:1. Thiolcarbamate herbicides whose soil life is sought to be extended in the present invention include those disclosed in U.S. Patent Nos. 2,913,327; 3,582,314; 3,330,821; and 3,330,643, and preferably include S-ethyl N,N-di-n-propylthiolcarbamate; S-ethyl N,N-diisobutylthiolcarbamate; S-n-propyl N,N-di-n-propylthiolcarbamate; S-n-propyl ethyl-n-butylthiolcarbamate; S-ethyl-N-ethyl-N-cyclohexylthiolcarbamate; S-ethyl hexahydro-1H-azepine-1-carbothioate; S-benzyl N,N-di-n-propylthiolcarbamate; S-(4-chlorobenzyl)-N,N-diethyl thiolcarbamate; S-benzyl N-ethyl-N-1,2-dimethylpropylthiolcarbamate; S-benzyl-N,N-di-sec-butyl thiolcarbamate; S-(2,2,3-trichloroallyl)-N,N-di-isopropyl thiolcarbamate; and S-(2,3-dichloroallyl)-N,N-diisopropyl thiolcarbamate. THIOLCARBAMATE HERBICIDE ANTIDOTES A wide range of chemical substances have been found to be effective as thiolcarbamate herbicide antidotes, and the preferred compositions of this invention may include any one or more of such antidotes. The variety of crops on which the present composition is useful can be significantly broadened by the use of an antidote to protect one crop from injury and render the composition more selective against weeds. Some of the more important types of antidotes are amides of haloalkanoic acids, aromatic oxime derivatives, thiazole carboxylic acids and derivatives, and 1,8-naphthalic anhydride. Amides of haloalkanoic acids have the generalized formula in which R is a mono- or poly-haloalkyl group. The halogens may be variously chloro, bromo or iodo; chloro is the preferred halogen, and the preferred group for R in these compounds in general is dichloromethyl, Cl₂CH-, i.e., the compounds are amides of dichloroacetic acid. In such compounds the nitrogen is further substituted by at least one other functional group. This class of compounds also includes those in which the nitrogen forms a portion of a heterocyclic ring with substituents, as will be described below. Antidotes of this type are described in a number of publications such as U.S. Patents 4,021,224; 4,256,481; and 4,294,764, and British Patent 1,521,540. U.S. Patent 4,021,224 contains a broad disclosure of such types of compounds and indicates a great many possibilities for mono-or di-substitution on the nitrogen atom. One type of antidote disclosed in U.S. Patent 4,021,224 is N,N-diallyl dichloroacetamide, which is included as a antidote in several commercial products containing thiolcarbamate herbicides. Another class of haloalkanoic acid amides is that in which the nitrogen atom is contained in an oxazolidine ring. Preferably R is dichloromethyl, and these oxazolidines have the general formula In this formula, R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are variously independently hydrogen, lower alkyl or phenyl, or R¹⁰ and R¹¹ taken together form an alkylene group, preferably a butylene, pentylene or hexylene group optionally substituted by one or two methyl groups. Compounds of these types are disclosed in a number of patents including U.S. Patents 4,021,224 and 4,256,481. Representative compounds of this type include (where not specifically mentioned the radical is hydrogen): 2,2-dimethyl-N-dichloroacetyl oxazolidine (R¹⁰ and R¹¹ = methyl); 2,2,5-trimethyl-N-dichloroacetyl oxazolidine (R¹⁰, R¹¹ and R¹⁴ = methyl); 2,2-dimethyl-5-n-propyl-N-dichloroacetyl oxazolidine (R¹⁰, R¹¹ = methyl, R¹⁴= n-propyl); 2,2-dimethyl-5-phenyl-N-dichloroacetyl oxazolidine (R¹⁰, R¹¹ = methyl, R¹⁴= phenyl); 2,2-spirocyclohexyl-N-dichloroacetyl oxazolidine (R¹⁰ plus R¹¹ taken together = pentamethylene). Other compounds in which R¹⁰ and R¹¹ taken together are alkylene are disclosed for instance in British Patents 1,512,540 and 2,023,582 and Hungarian Patent 181,621. A third type of haloalkanoic acid amide is disclosed generally in U.S. Patent 4,294,764 and has the general formula in which R¹⁶ may be one of a number of alkyl, alkenyl or alkynyl moieties; R¹⁷, R¹⁸, R¹⁹ and R²⁰ are independently hydrogen or methyl; and n is 0 or 1. A representative compound of this type is the compound N-(1,3-dioxolan-2-yl-methyl)-N-(2-propenyl)-2,2-dichloroacetamide, which has the formula This corresponds to the previous formula in which R¹⁶ is 2-propenyl, R¹⁷ and R¹⁸ are both hydrogen and n is 0. Oxime derivatives which are suitable for use as antidotes with thiolcarbamate herbicides are disclosed, for instance in U.S. Patents 4,070,389 and 4,269,775 and have the general formula in which R²¹ is cyano or a number of other moieties as indicated in U.S. Patent 4,269,775. Representative compounds of this type are those in which R²¹ is cyano and in which R²¹ is 1,3-dioxolan-2-yl. The latter compound has the chemical name O-[2-(1,3-dioxolanyl)methyl]-alphacyanobenzaldoxime. Thiazole carboxylic acids and derivatives suitable for use as thiolcarbamate antidotes are disclosed generally in U.S. Patent 4,199,506 and have the general formula in which R²² is alkyl, haloalkyl or trialkoxymethyl; R²³ is variously hydrogen, agriculturally acceptable cations or various hydrocarbamyl or substituted hydrocarbamyl moieties; and R²⁴ is chloro, bromo, iodo, lower alkoxy or substituted or unsubstituted phenoxy. A representative member of this class is the compound benzyl-2-chloro-4-trifluoromethyl-5-thiazole carboxylate (R²² = trifluoromethyl; R²³ = benzyl, R²⁴ = chloro; m = 1). Another useful thiolcarbamate herbicide antidote compound is disclosed in European Patent No. 0104495 as having the formula wherein R²⁵ represents the group in which R²⁸ represents a C₁-C₃ haloalkyl containing from 1 to 3 halogen atoms or a phenyl group optionally substituted; R²⁶ represents a hydrogen atom, a methyl or a phenyl; R²⁷ represents a C₁-C₈ alkyl group, a C₅-C₆ cycloalkyl group, a cyclohexylmethyl group, a phenyl group optionally substituted, a benzyl group optionally substituted, an allyl or propargyl group; and n is zero or one. A representative antidote of that group would be: The amount of a given antidote to be utilized in combination with the thiolcarbamate herbicide/extender composition of this invention and the manner of its utilization will vary according to the particular antidote to be employed, the crop which is to be protected, the amount or rate of herbicide to be applied, and the soil and climatic conditions of the agricultural environment in which the mixture is to be applied. The selection of a specific antidote for use in the thiolcarbamate herbicide/extender composition, the manner in which it is to be applied (e.g., tank mix, in-furrow application, seed treatment, etc.), the determination of activity which is nonphyotoxic but antidotally effective, and the amount necessary to provide this result, can be readily performed utilizing the test procedures in the cited patents such as U.S. Patent 4,021,224 in accordance with common practice in the art. For other descriptions of antidotes and methods of their use, reference is made to U.S. Patent 3,959,304, issued to Teach on May 25, 1976; U.S. Patent 3,989,503, issued to Pallos et al. on Nov. 2, 1976; U.S. Patent 3,131,509, issued to Hoffman on May 5, 1964; U.S. Patent 3,564,768, issued to Hoffman on Feb. 3, 1971; U.S. Patent 4,137,070, issued to Pallos et al. on Jan. 30, 1979; U.S. Patent 4,294,764, issued to Rinehart on Oct. 13, 1981; U.S. Patent 4,256,481, issued to Gardi et al. on May 17, 1981; U.S. Patent 4,415,353, issued to Pallos et al. on Nov. 15, 1983; and U.S. Patent 4,415,352, issued to Pallos et al. on Nov. 15, 1983. A still further useful antidote is 1,8-naphthalic anhydride. The antidote is applied in conjunction with the thiolcarbamate herbicide and the thiolcarbamate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, thionocarbamate, dithiocarbamate or carbamate extender in a non-phytotoxic antidotally effective amount. By "non-phytotoxic" is meant an amount of the antidote which causes at most minor injury to the desired crop species. By "antidotally effective" is meant an amount of the antidote which substantially decreases the extent of injury caused by the thiolcarbamate herbicide to the desired crop species. The preferred weight ratio of herbicide to antidote is from about 0.1:1 to about 40:1. Another preferred weight ratio range is from about 3:1 to about 25:1. An even more preferred weight ratio range is from about 5:1 to about 20:1. The following examples are offered to illustrate the compositions, methods, and effectiveness of the present invention, and are not intended to limit the invention in any way. EXAMPLE 4 EXTENDER ACTIVITY EXAMPLES Herbicidal Activity Improvement Tests Table 1 below offers herbicidal activity test data for representative extender compounds within the scope of this invention showing their effectiveness in prolonging the herbicidal activity of thiolcarbamate herbicides. The effect is observed by comparing the extent of weed control in test flats treated with a thiolcarbamate herbicide against that occurring in similar flats treated with both the thiolcarbamate herbicide and an extender compound of this invention. The soil used in such tests was a sandy loam soil from Sunol, California, which was pre-treated with the thiolcarbamate herbicide to simulate a typical field which had received previous herbicide applications. In most instances, the tests were run with a thiolcarbamate and antidote formulation (see procedure 2 below), except for those test results marked with a single asterisk indicating that the soil was pre-treated and then treated with a thiolcarbamate herbicide alone. (See Procedure 1A and 1B below). The effectiveness of the extender in minimizing the degradation of the thiolcarbamate herbicide in the soil is then verified by comparing the herbicidal activity of the herbicide or herbicide and antidote when applied alone to the herbicidal activity when those formulations are applied with the extender at varying rates. The herbicide alone or the herbicide and antidote without extender showed negligible herbicidal activity in conditioned soil, that is between 0-5% in conditioned soil. The extender compounds in each instance greatly increased the herbicidal activity in conditioned soil. The last column of Table 1 indicates the nonexistent or negligible herbicidal activity of each extender in non-treated soil at 4 lb/acre. In most instances, the extender was pre-plant incorporated, except where PRE is noted after the test result, indicating that the extender was pre-emergent surface applied at 4 lb/acre. (See Procedure 3A and 3B below.) The procedures below detail the methods used to achieve the results tabulated in Table 1. 1: Tests with S-ethyl N,N-di-n-propyl Thiolcarbamate and No Antidote A. Soil Pre-Treatment A solution was prepared by diluting an emulsifiable liquid concentrate containing 6 lb/gal (0.72 kg/l) (76.8% by weight) of the herbicide S-ethyl N,N-di-n-propylthiolcarbamate in 200 ml of water, such that the resulting concentration of herbicide in the solution was 2000 mg/l. Two hundred ml of this solution was then added to 200 lb (90.8 kg) of soil to which 17-17-17 fertilizer (N-P₂O₅-K₂O on a weight basis) had been previously added to a concentration of 50 ppm by weight with respect to the soil. The mixture was mixed in a rotary mixer for 10 to 30 minutes. The soil was then placed in round plastic containers, 7.5 inches (19.0 cm) in diameter by 7.5 inches (19.0 cm) deep. The herbicidal rate applied was equivalent to 3 lb/acre. The soil was tamped and leveled with a row marker to impress one row across the width of each container. This row was seeded with watergrass (Echinochloa crus-galli). Sufficient seeds were planted to produce several seedlings. The containers were then placed in a greenhouse maintained at 20°C to 30°C and watered daily by sprinkler. About six weeks after treatment, the soil was allowed to dry out and the plant foliage was removed. The soil was then passed through a 0.25 inch (0.64 cm) screen to remove plant roots and clods. B. Herbicide Test A solution was prepared by diluting an emulsifiable liquid concentrate containing 6 lb/gal (0.72 kg/l) (76.8% by weight) of the herbicide S-ethyl N,N-di-n-propylthiolcarbamate in 675 ml of water such that the resulting concentration of herbicide in the solution was 1.14 mg/ml. Five ml of this solution when added to three pounds of soil yielded a quantity in the soil equivalent to three pounds of herbicide per acre. The extender compounds were used in technical form. Each representative extender was dissolved in 5 ml acetone and 14.5 ml water such that the resulting concentration of the extender in the solution was 1.54 mg/ml. Five ml of this solution when added to three pounds of soil yielded a quantity in the soil equivalent to four pounds of extender per acre. Five ml of the extender solution and 5 ml of the herbicide solution were tank-mixed. The resultant mixture of 10 ml was then added to 3 lbs of soil and incorporated into the soil by a rotary mixer. Thus, 10 ml of the mixture and 3 pounds of soil were placed in rotary mixter and incorporated, yielding a quantity of herbicide and extender in the soil of 3 and 4 lb/A, respectively. Some of the extenders, as noted in the table, were tested at varying rates. In those cases, the appropriate ml of the extender solution were tank-mixed with 5 ml of the herbicide stock solution to yield the desired application rates of 0.5, 1.0 or 2.0 lb/acre. The treated soil was then placed in aluminum flats which were approximately 3.5 inches deep, 7.5 inches wide, and 2.5 inches long (8.9 x 19.5 x 6.4 cm). The soil was tamped and leveled with a row marker to impress six rows across the width of the flat. The test weeds were as follows: COMMON NAME ABBREVIATION SCIENTIFIC NAME watergrass WG Echinochloa crus-galli (L.) wild oats WO Avena fatua (L.) shattercane SHC Sorghum bicolor (L.) Moench R-10 milo ( Sorghum bicolor ) was also used as a plant growth indicator. Two rows of watergrass were planted. One row of DeKalb XL-25A corn of species Zea mays (L.) was also planted. Sufficient seeds were planted to produce approximately 20-25 seedlings per row. The flats were then placed in a greenhouse maintained at 70 to 85°F (21 to 30°C) and watered daily by sprinkler. Approximately three weeks after treatment, the degree of weed control was estimated and recorded as a percentage compared to the growth of the same species in a check flat of the same age which had been seeded in conditioned soil but not treated with either an herbicide or an extender The rating scale ranges from 0 to 100%, where 0 equals no effect with plant growth equal to the untreated check, and 100 equals complete kill. 2: Tests with S-ethyl N,N-di-n-propyl thiolcarbamate and the Antidote N,N-diallyl Dichloroacetamide These procedures are essentially the same as that of 1A and 1B except that the antidote N,N-diallyl dichloroacetamide was applied with the herbicide. The stock solutions described in 1(B) were formulated, and additionally a stock solution containing a thiolcarbamate herbicide and an antidote was prepared as follows: An emulsifiable liquid concentrate of S-ethyl-N,N-di-n-propylthiolcarbamate (82.8%) and of N,N-diallyl-dichloroacetamide (6.9%) was diluted in water such that the resulting concentration of thiolcarbamate herbicide in the solution was 1.14 mg/ml. The weight ratio of the thiolcarbamate herbicide to antidote was 12:1. An appropriate amount of the stock solution of each representative extender was applied to yield the desired application rate. The rest of the procedure of 1(B) including the evaluation criteria was followed. Table 1 indicates where unasterisked the test results wherein the thiolcarbamate herbicide and antidote were applied at 3 and 0.25 lb/acre, respectively, by pre-plant incorporation, and the extender was applied at 4.0, 2.0, 1.0 or 0.5 lb/acre by pre-plant incorporation as described above in 1. 3: Herbicidal Screening Tests for Extender Alone The last column of Table 1 as noted above shows herbicidal screening data for the representative extender compounds when tested alone at 4 lb/acre. In most cases, the extenders were pre-plant incorporated except wherein an asterisk indicates that they were pre-emergent surface applied. (3A) Pre-Plant Incorporation Test: The soil used in these tests was sandy loam soil from Sunol, California to which 17-17-17 fertilizer (N-P₂O₅-K₂ on a weight basis) had been added to a concentration of 50 ppm by weight with respect to the soil. The extender compounds were used in technical form. These materials were added to 5 ml acetone and 14.5 ml water such that the resulting concentration of the extender in the solution was 1.54 mg/ml. Five or ten ml of this solution was added to three pounds of soil in a rotary mixer, and mixed thoroughly, yielding a quantity of extender in the soil equivalent to 4 lb/acre. The treated soil was then placed in aluminum flats which were approximately 2.5 inchs deep, 3.5 inches wide, and 7.5 inches long (6.4 cm x 8.9 cm x 19.0 cm). The soil was tamped and leveled with a row marker to impress six rows across the width of the flat. The test weeds were as follows: COMMON NAME ABBREVIATION SCIENTIFIC NAME watergrass WG Echinochloa crus-galli wild oats WO Avena fauta shattercane SH Sorghum bicolor Further, R-10 milo ( Sorghum bicolor ) was also planted as a plant growth indicator, and X-10 corn ( Zea maize ) was planted as a crop sensitivity indicator. Two rows of watergrass were planted. One row of each of the other weeds, plant growth indicator and crop were planted. Sufficient seeds were planted to produce several seedlings per inch in each row. The flats were then placed in a greenhouse maintaineed at 70 to 85°F (21 to 30°C) and watered daily by sprinkler. Two weeks after treatment, the degree of injury or control is determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% is recorded for each species as percent control with 0% representing no injury and 100% representing complete kill. 3(B) Pre-emergence herbicide test . On the day preceding treatment, seeds of eight different weed species are planted in loamy sand soil in individual rows using one species per row across the width of a flat. The seeds used are green foxtail (FT) ( Setaria viridis ), watergrass (WG) ( Echinochloa crus-galli ), wild oat (WO) ( Avena fatua ), annual morningglory (AMG) ( Ipomoea lacunosa ), velvetleaf (VL) ( Abutilon theophrasti ), Indian mustard (MD) ( Brassica juncea ), redroot pigweed (PW) ( Amaranthus retroflexus ) or curly dock (CD) ( Rumex crispus ), and yellow nutsedge (YNG) ( Cyperus esculentus ). Ample seeds are planted to give about 20 to 40 seedlings per row, after emergence, depending upon the size of the plants. Using an analytical balance, 600 milligrams (mg) of the extender compound to be tested were weighed out on a piece of glassine weighing paper. The paper and compound are placed in a 60 (ml) wide-mouth clear bottle and dissolved in 45 ml of acetone or substituted solvent. Eighteen ml of this solution are transferred to a 60 ml wide- mouth clear bottle and diluted with 22 ml of a water and acetone mixture (19:1) containing enough polyoxyethylene sorbitan monolaurate emulsifier to give a final solution of 0.5% (v/v). The solution is then sprayed on a seeded flat on a linear spray table calibrated to deliver 80 gallons per acre (748 L/ha). The application rate is 4 lb/acre (4.48 Kg/ha). After treatment, the flats are placed in the greenhouse at a temperature of 70 to 80°F and watered by sprinkling. Two weeks after treatment, the degree of injury or control is determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% is recorded for each species as percent control with 0% representing no injury and 100% representing complete control. The results tabulated in Table 1 indicate that each of the extender compounds significantly increased the herbicidal activity of the herbicide alone or herbicide and antidote formulations in conditioned soil. These results were unexpected in that as shown in the last column, none of the extenders had any significant herbicidal activity of their own. Example Wherein Herbicide Without Extender in Conditioned Soil Is Other than 0-5% activity Very occasionally in conditioned soil, when the herbicide or herbicide plus antidote compositions are tested alone, that is, without an extender, their herbicidal activity is greater than 0-5%. Using the same procedures as applied in the above Example, the test results in Table 1(b) were obtained. The only difference from Table 1(a) is that the ratings for Eptam® or Eradicane® alone on conditioned soil are tabulated. The extender compound numbers are keyed to the structures in the Table of Compounds. EXAMPLE 5 Delayed Planting Tests in Pre-Treated Soil This example offers further herbicidal activity data for a representative extender compound within the scope of this invention showing its effectiveness in prolonging the herbicidal activity of three different thiolcarbamate herbicidal compositions each contains an antidote. As in Example 4 above, the effect is observed by comparing weed control at a set period after application in test flats treated with an antidoted thiolcarbamate herbicidal composition against that in similar flats treated with such a herbicidal composition also containing the representative extender compound. The thiolcarbamate herbicides employed in this example were as follows: S-ethyl-N,N-di-n-propyl thiolcarbamate = EPTAM® S-ethyl-N,N-di-isobutyl thiolcarbamate = SUTAN® S-n-propyl-N,N-di-n-propyl thiolcarbamate = VERNAM® The antidote employed was N,N-diallyl-dichloroacetamide in a weight ratio with EPTAM® of 12:1 (herbicide/antidote); 24:1 with SUTAN®; and 12:1 with VERNAM®. The representative extender compound employed in this example was ethyl N,N-di-3-chloroallyl thiolcarbamate, Compound No. 1 in the Table of Compounds, supra . A. Soil Pre-Treatment (1st Treatment) Aluminum flats 3 inches deep, 6 inches wide and 8 inches long (7.6 x 15.24 x 20.32 cm) were filled with sandy loam soil from Sunol, California. Ten ml of an aqueous stock solution contains 11.1 mg of EPTAM® and 0.925 mg of the antidote was mixed into each of two flats of soil using a 5-gallon cement mixer. The stock solution was prepared by suspending 134.1 mg of an emulsifiable concentrate containing 6.7 lb of EPTAM® and 0.56 lb of N,N-diallyl dichloroacetamide per gallon in 100 ml of water. The application rate was 3 lb/A of EPTAM® and 0.25 lb/A of the antidote. Two other flats of soil were pre-treated with 10 ml of solution containing 11.1 mg of VERNAM® and 0.925 mg of the antidote. The stock solution was prepared by suspending 132.1 mg of an emulsifiable concentrate containing 6.7 lb of VERNAM® and 0.56 lb of the antidote per gallon in 100 ml of water. The application rate was 3 lb/A of VERNAM® and 0.25 lb/A of the antidote. Two additional flats of soil were pre-treated with 10 ml of a solution containing 14.8 mg of SUTAN® and 0.615 mg of the antidote. This stock solution was prepared by suspending 173.7 mg of an emulsifiable concentrate containing 6.7 lb of SUTAN® and 0.28 lb of the antidote per gallon in 100 ml of water. The application rate was 4 lb/A of SUTAN® and 0.17 lb/A of the antidote. The flats of soil treated with the thiolcarbamate herbicides listed above in combination with the antidote were placed in the greenhouse at 70-90°F for six weeks where they were kept moist by watering lightly by sprinkling. No seeds were planted in the flats for the pre-treatment. B. Herbicide Treatment (2nd Treatment) Six weeks after the first treatment shown in part (A), one flat of soil of each pair of flats that were pre-treated with the same herbicidal compositions was retreated with the same herbicide plus antidote composition by mixing 10 ml of stock solution prepared the same way as described in part A, with a flat full of soil in a 5-gallon cement mixer (PPI application). The other flat of each pair was treated with a tank mix containing 10 ml of the herbicide plus antidote stock solution, prepared as described in part (A), in combination with 10 ml of a stock solution containing 3.7 mg of the extender, ethyl N,N-bis-(3-chloroallyl) thiolcarbamate. The extender stock solution was prepared by dissolving 37 mg of the technical ethyl N,N-bis-(3-chloroallyl) thiolcarbamate in 5 ml of acetone containing 2 drops of a blend of polyoxyethylene ethers of sorbitan mono-laurate followed by adding 95 ml of water. The 20 ml of tank mix containing the 3-way combination of herbicide + antidote + extender was pre-plant incorporated into the soil with a 5-gallon cement mixer as above. The soil was then placed back in the aluminum flat. In each flat of soil, one row of approximately 50 seeds of watergrass ( Echinochloa crus-galli ) was planted 0.5 inch deep immediately (0-days delay). The flats of soil were watered lightly and placed in the greenhouse at 70-90°F. A second row of watergrass was planted in each flat 2 days after the second treatment and other rows were planted 5, 8, 12 and 21 days after the second treatment, respectively. Weed control results for rows seeded at the same time were recorded four weeks after the seeding. Thus, the ratings were made from 28-49 days after the second treatment. Table 2 records those results, which indicate that the herbicidal activity of all three thiolcarbamate herbicides was prolonged dramatically when the extender was included in the herbicidal composition. The extender tested at 1 and 4 lb/A respectively in non-pretreated soil showed no herbicidal activity on watergrass. EXAMPLE 6 Delayed Planting Tests in Non-pretreated Soil The example is similar in all respects to Example 5 above except that the sandy loam soil from Sunol California was not pre-treated according to the procedures of Example 5(A). The procedures of Example 5(B) were followed except that the seedings occurred 0, 7, 14, 21, and 28 days, respectively, after the first and only treatment of the soil. Table 3 indicates again that the extender prolongs the soil life of all three thiolcarbamate herbicides in composition with an antidote. As indicated above, the extender (Compound No. 1) showed no herbicidal activity against watergrass when tested at 1 and 4 lb/A, respectively in non-pretreated soil. EXAMPLE 7 Herbicidal Activity of ORDRAM® with and without Extender in Pretreated Soil This example is similar to Example 6 above except for the following: (a) that the thiolcarbamate employed was S-ethyl hexahydro-1H-azepine-1-carbothioate commercially known as ORDRAM®; (b) that the herbicidal composition was unantidoted; (c) that the soil was pretreated ten weeks, rather than six weeds, before the second treatment; (d) the ORDRAM® stock solution was prepared by suspending 155.7 mg of an emulsifiable liquid concentrate containing 6 lb per gallon (71.3% by weight) of the herbicide in 100 ml of water; thus, 10 ml of the aqueous stock solution contained 11.1 mg of the ORDRAM® yielding an application rate of 3 lb/acre; and (3) the rating was made approximately four weeks after the single seeding. Table 4 indicates that the representative extender significantly prolonged the soil life of ORDRAM® in the pretreated soil. EXAMPLE 8 Herbicidal Activity Tests with ORDRAM® and Extender in Non-pretreated Soil This example is very similar to Example 8 above; however, as in Example 7, an unantidoted ORDRAM® composition was employed. The differences from Example 6 are that yellow nutsedge ( Cyperus esculentus ) as well as watergrass was a test weed and that two rows of yellow nutsedge tubers were planted on the day of soil treatment (0-days delay) whereas a row of watergrass was seeded at 7 and 14 days, respectively after treatment. Table 5 indicates that the representative extender at 1 lb/acre (PPI) prolonged the herbicidal activity of ORDRAM® at 28, 35 and 42 days after soil treatment. EXAMPLE 9 Herbicidal Activity of RO-NEET® with and without Extender in Pretreated Soil This example is very solar to Example 7, above except that the thiolcarbamate employed was S-ethyl N-ethyl-N-cyclohexyl thiolcarbamate, commercially known as RO-NEET®. The differences between this example and Example 7 are as follows: (a) there were eight, rather than ten, weeks between the first and second treatment; (b) two rows of watergrass (WG) were seeded in flats and one row each of the following weeds: green foxtail GF Setaria viridis wild cane WC Sorghum bicolor wild oat WO Avena fatua; (c) the RO-NEET® stock solution was prepared by suspending 149 mg of an emulsifiable liquid concentrate containing 6 lb/gal (74.3% by weight) in 100 ml of water, such that 10 ml of the stock solution again contained 11.1 mg of the herbicide to yield an application rate of 3 lb/Acre. Table 6 shows that in the pretreated soil at 4 weeks after the second soil treatment, the RO-NEET® composition containing the extender had significantly greater herbicidal activity than the RO-NEET® composition without the extender. The extender/RO-NEET® composition also had slightly better or comparable activity to the solely RO-NEET® treatment in non-pretreated soil. METHODS OF APPLICATION The herbicidal compositions of the present invention are useful in controlling the growth of undesirable vegetation by pre-emergence or post-emergence application to the locus where control is desired, including pre-plant and post-plant soil incorporation as well as surface application. The compositions are generally embodied in formulations suitable for convenient application. Typical formulations contain additional ingredients or diluent carriers which are either inert or active. Examples of such ingredients or carriers are water, organic solvents, dust carriers, granular carriers, surface active agents, oil and water, water-oil emulsions, wetting agents, dispersing agents, and emulsifying agents. The herbicidal formulations generally take the form of dusts, emulsifiable concentrates, granules and pellets, or microcapsules. A. DUSTS Dusts are dense powder compositions which are intended for application in dry form. Dusts are characterized by their free-flowing and rapid settling properties so that they are not readily windborne to areas where their presence is not desired. They contain primarily an active material and a dense, free-flowing, solid carrier. Their performance is sometimes aided by the inclusion of a wetting agent, and convenience in manufacture frequently demands the inclusion of an inert, absorptive grinding aid. For the dust compositions of this invention, the inert carrier may be either of vegetable or mineral origin, the wetting agent is preferably anionic or nonionic, and suitable absorptive grinding aids are of mineral origin. Suitable classes of inert solid carriers for use in the dust compositions are those organic or inorganic powders which possess high bulk density and are very free-flowing. They are also characterized by low surface area and poor liquid absorptivity. Suitable grinding aids are natural clays, diatomaceous earths, and synthetic mineral fillers derived from silica or silicate. Among ionic and nonionic wetting agents, the most suitable are the members of the group known to the art as wetting agents and emulsifiers. Although solid agents are preferred because of ease of incorporation, some liquid nonionic agents are also suitable in the dust formulations. Preferred dust carriers are micaceous talcs, pyrophyllite, dense kaolin clays, tobacco dust and ground calcium phosphate rock. Preferred grinding aids are attapulgite clay, diatomaceous silica, synthetic fine silica and synthetic calcium and magnesium silicates. Most preferred wetting agents are alkylbenzene and alkyl- naphthalene sulfonates, sulfated fatty alcohols, amines or acid amides, long chain acid esters of sodium isothionate, esters of sodium sulfosuccinate, sulfated or sulfonated fatty acid esters, petroleum sulfonates, sulfonated vegetable oils, and ditertiary acetylenic glycols. Preferred dispersants are methyl cellulose, polyvinyl alcohol, lignin sulfonates, polymeric alkylnaphthalene sulfonates, sodium naphthalenesulfonate, polymethylene bisnaphthalenesulfonate, and sodium-N-methyl-N-(long chain acid) taurates. The inert solid carriers in the dusts of this invention are usually present in concentrations of from about 30 to 90 weight percent of the total composition. The grinding aid will usually constitute 5 to 50 weight percent of the compositions, and the wetting agent will constitute from about 0 to 1.0 weight percent of the composition. Dust compositions can also contain other surfactants such as dispersing agents in concentrations of up to about 0.5 weight percent, and minor amounts of anticaking and antistatic agents. The particle size of the carrier is usually in the range of 30 to 50 microns. B. EMULSIFIABLE CONCENTRATES Emulsifiable concentrates are usually solutions of the active materials in nonwater-miscible solvents together with an emulsifying agent. Prior to use, the concentrate is diluted with water to form a suspended emulsion of solvent droplets. Typical solvents for use in emulsifiable concentrates include weed oils, chlorinated hydrocarbons, and nonwater-miscible ethers, esters, and ketones. Typical emulsifying agents are anionic or nonionic surfactants, or mixtures of the two. Examples include long-chain alkyl or mercaptan polyethoxy alcohols, alkylaryl polyethoxy alcohols, sorbitan fatty acid esters, polyoxyethylene ethers with sorbitan fatty acid esters, polyoxyethylene glycol esters with fatty or rosin acids, fatty alkylol amide condensates, calcium and amine salts of fatty alcohol sulfates, oil soluble petroleum sulfonates, or preferably mixtures of these emulsifying agents. Such emulsifying agents will comprise from about 1 to 10 weight percent of the total composition. Thus, emulsifiable concentrates of the present invention will consist of from about 15 to about 50 weight percent active material, about 40 to 82 weight percent solvent, and about 1 to 10 weight percent emulsifier. Other additives such as spreading agents and stickers can also be included. C. GRANULES AND PELLETS Granules and pellets are physically stable, particulate compositions containing the active ingredients adhering to or distributed through a basic matrix of a coherent, inert carrier with macroscopic dimensions. A typical particle is about 1 to 2 millimeters in diameter. Surfactants are often present to aid in leaching of the active ingredient from the granule or pellet. The carrier is of mineral or organic origin, and generally falls within one of two types. The first are porous, absorptive, preformed granules, such as preformed and screened granular attapulgite or heat expanded, granular, screened vermiculite. On either of these, a solution of the active agent can be sprayed and will be absorbed at concentrations up to 25 weight percent of the total weight. The second, which are also suitable for pellets, are initially powdered kaolin clays, hydrated attapulgite, or bentonite clays in the form of sodium, calcium, or magnesium bentonites. Water-soluble salts, such as sodium salts, may also be present to aid in the disintegration of granules or pellets in the presence of moisture. These ingredients are blended with the active components to give mixtures that are granulated or pelleted, followed by drying, to yield formulations with the active component distributed uniformly throughout the mass. Such granules and pellets can also be made with 25 to 30 weight percent active component, but more frequently a concentration of about 10 weight percent is desired for optimum distribution. The granular compositions of this invention are most useful in a size range of 15-30 mesh. The surfactant is generally a common wetting agent of anionic or nonionic character. The most suitable wetting agents depend upon the type of granule used. When preformed granules are sprayed with active material in liquid form the most suitable wetting agents are nonionic, liquid wetters miscible with the solvent. These are compounds most generally known in the art as emulsifiers, and comprise alkylaryl polyether alcohols, alkyl polyether alcohols, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol esters with fatty or rosin acids, fatty alkylol amide condensates, oil solution petroleum or vegetable oil sulfonates, or mixtures of these. Such agents will usually comprise up to about 5 weight percent of the total composition. When the active ingredient is first mixed with a powdered carrier and subsequently granulated, or pelleted, liquid nonionic wetters can still be used, but it is usually preferable to incorporate at the mixing stage one of the solid, powdered anionic wetting agents such as those previously listed for the wettable powders. Such agents will comprise from about 0 to 2 weight percent of the total composition. Thus, the preferred granular or pelleted formulations of this invention comprise about 5 to 30 percent by weight active material, about 0 to 5 weight percent wetting agent, and about 65 to 95 weight percent inert material carrier, as these terms are used herein. D. MICROCAPSULES Microcapsules consist of fully enclosed droplets or granules containing the active materials, in which the enclosing material is an inert porous membrane, arranged to allow escape of the enclosed materials to the surrounding medium at controlled rates over a specified period. Encapsulated droplets are typically about 1 to 50 microns in diameter. The enclosed liquid typically constitutes about 50 to 95% of the weight of the entire capsule, and may contain a small amount of solvent in addition to the active materials. Encapsulated granules are characterized by porous membranes sealing the openings of the granule carrier pores, trapping the liquid containing the active components inside for controlled release. A typical granule size ranges from 1 millimeter to 1 centimeter in diameter. In agricultural usage, the granule size is generally about 1 to 2 millimeters in diameter. Granules formed by extrusion, agglomeration, or prilling are useful in the present invention as well as materials in their naturally occurring form. Examples of such carriers are vermiculite, sintered clay granules, kaolin, attapulgite clay, sawdust, and granular carbon. Useful encapsulating materials include natural and synthetic rubbers, cellulosic materials, styrene-butadiene copolymers, polyacrylonitriles, polyacrylates, polyesters, polyamides, polyurethanes, and starch xanthates. E. INJECTION WITH ANHYDROUS AMMONIA The herbicidal compositions of the instant invention comprising a thiolcarbamate herbicide, and thiolcarbamate, thionocarbamate, thiolcarbamate sulfone, thiolcarbamate sulfoxide, dithiocarbamate or carbamate extender and optionally an antidote can be applied to the soil by in-line injection with anhydrous ammonia. For pre-emergence soil injection applications of anhydrous ammonia, on conservation or conventional tilled acreage, the herbicidal composition of the instant invention can be introduced into the anhydrous line using a metering pump which offers a constant rate of the output per acre independent of the anhydrous ammonia output rate. The herbicidal composition discharge hose can tee into the ammonia discharge line between the meter and the manifold. Injection depth can be from 4 to 5 inches. The herbicidal compositions can also be injected with anhydrous ammonia in no-till situations. Other herbicide products can be surface applied and incorporated at the same time the herbicidal compositions of the instant invention and anhydrous ammonia are injected, or post-emergent applications can be used. F. IN GENERAL Each of the above formulations can be prepared as a package containing both the herbicide and the extender together with the other ingredients of the formulation (diluents, emulsifiers, surfactants, etc.). The formulations can also be prepared by a tank mix method, in which the ingredients are obtained separately and combined at the grower site. The herbicide and extender may both be used in the same type of formulation or a different formulation may be used for each, e.g. the herbicide may be in microcapsule form while the extender may be an emulsifiable concentrate, or vice versa. As a further alternative, the herbicide and extender can be applied sequentially, with either being applied first. This is a less preferred method, however, since more effective results are obtained with simultaneous application. In general, any conventional method of application can be used. The locus of application can be soil, seeds, seedlings, or the actual plants, as well as flooded fields. Soil application is preferred. Dusts and liquid compositions can be applied by the use of powder dusters, boom and hand sprayers, and spray dusters. The compositions can also be applied from airplanes as dusts and sprays because they are effective in very low dosages. In order to modify or control the growth of germinating seeds or emerging seedlings, as a typical example, the dust and liquid compositions are applied to the soil according to conventional methods and are distributed in the soil to a depth of at least one-half inch below the soil surface. It is not necessary that the phytotoxic compositions be admixed with the soil particles. Instead, these compositions can be applied merely by spraying or sprinkling the surface of the soil. The phytotoxic compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein. Dust compositions, granular compositions or liquid formulations applied to the surface of the soil can be distributed below the surface of the soil by conventional means such as discing, dragging or mixing operations. The herbicide/extender compositions can also be applied to the soil through irrigation systems. According to this technique, the compositions are added directly to irrigation water immediately prior to irrigation of the field. This technique is applicable in all geographical areas regardless of rainfall, since it permits supplementation of the natural rainfall at critical stages of plant growth. In a typical application, the concentration of the herbicide/extender composition in the irrigation water will range from about 10 to 150 parts per million by weight. The irrigation water can be applied by the use of sprinkler systems, surface furrows, or flooding. Such application is most effectively done before the weeds germinate, either early in the spring prior to germination or within two days after cultivation of the field. The amount of the present composition which constitutes a herbicidally effective amount depends upon the nature of the seeds or plants to be controlled. The rate of application of active ingredient varies from about 0.01 to about 50 pounds per acre, preferably about 0.1 to about 25 pounds per acre with the actual amount depending on the overall cost and the desired results. It will be readily apparent to one skilled in the art that compositions exhibiting lower herbicidal activity will require a higher dosage than more active compounds for the same degree of control.

Claims: A herbicidal composition comprising (a) a herbicidally effective amount of a thiolcarbamate having the formula wherein R¹ is C₁-C₆ alkyl; phenyl; C₇-C₉ phenylalkyl; C₃-C₆ alkenyl; C₃-C₆ haloalkenyl; or C₇-C₉ phenylalkyl, mono- or poly-substituted on the phenyl ring with halogen; R² and R³ are either selected independently from C₁-C₆ alkyl or C₅-C₇ cycloalkyl or combined to form conjointly C₄-C₉ alkylene; and (b) an extending amount of a compound having the formula wherein Y is oxygen or sulfur; Z is oxygen or sulfur; p is the integer 0, 1 or 2; R⁴ is C₂-C₈ alkenyl; C₂-C₈ alkenyl substituted with one or more halo groups; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with dioxolanyl, cyano or one or more hydroxy or C₁-C₄ alkoxy groups; C₁-C₃ alkyl substituted with one, two or three halo groups; C₁-C₆ alkylthioalkyl; benzyl; benzyl substituted with one or more halo or trifluoromethyl groups; C₃-C₆ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with halo, one or more nitro, C₁-C₄ alkoxy, C₁-C₄ alkyl or C₁-C₄ haloalkyl groups; R⁵ is C₂-C₆ alkenyl substituted with phenyl or one or more halo groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with one or more halo groups; or C₃-C₆ alkynyl; R⁶ is hydrogen; C₂-C₆ alkenyl substituted with phenyl or one or more halo or C₁-C₄ alkoxy groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with C₃-C₆ cycloalkyl or one or more halo groups; C₃-C₆ alkynyl; furfuryl; or benzyl; with the provisos that: (1) when Y is oxygen or both Y and Z are sulfur, then p is zero; (2) when Y is sulfur, Z is oxygen, R⁴ is allyl, 2-methylallyl, 2-butenyl, 3-chloroallyl or n-butyl, and R⁵ is allyl, then R⁶ is other than propyl or butyl; (3) when Y is sulfur, Z is oxygen, R⁴ is either C₁-C₅ alkyl, substituted benzyl, C₃-C₆ haloalkenyl, 2-chloroethyl, methylthioethyl, or propargyl, and R⁵ is C₁-C₅ alkyl, then R⁶ is other than C₁-C₆ alkyl; (4) when Y is sulfur and Z is oxygen, R⁴ is allyl, 3-chloroallyl, ethyl, n-butyl, methoxymethyl or ethoxymethyl, then not both R⁵ and R⁶ are allyl; (5) R⁴ cannot be phenyl unless Y is S and R⁵ and R⁶ are both chloroallyl; (6) one of R⁵ and R⁶ is always substituted allyl unless R⁴ is CH₃SCH₂- or substituted allyl; (7) R⁶ is hydrogen only if Y is sulfur; and (8) when Y and Z are each oxygen, then R⁴ is other than phenyl substituted with one or more C₁-C₄ alkyl or one or more C₁-C₄ haloalkyl. An herbicidal composition according to Claim 1 wherein R¹ is C₁-C₆ alkyl, allyl or haloallyl; R² is C₁-C₆ alkyl; R³ is C₁-C₆ alkyl or C₅-C₇ cycloalkyl. An herbicidal composition according to Claim 2 wherein R¹ is C₁-C₆ alkyl; R² is C₁-C₆ alkyl; R³ is C₁-C₆ alkyl or cyclohexyl. An herbicidal composition according to Claim 1 wherein the thiolcarbamate herbicide is S-ethyl N,N-di-n-propyl thiolcarbamate, S-ethyl-N-ethyl-N-cyclohexyl thiolcarbamate, S-ethyl-N,N-di-isobutyl thiolcarbamate, S-n-propyl N,N-di-n-propyl thiolcarbamate, or S-ethylhexahydro-1H-azepinel-carbothioate. An herbicidal composition according to Claim 4 wherein the extender is ethyl-N,N-bis-(3-chloroallyl) thiolcarbamate. An herbicidal composition according to Claim 1 wherein the weight ratio of said thiolcarbamate herbicide to said extender is from 0.2: 1 to 30: 1. An herbicidal composition according to Claim 1 further comprising a non-phytotoxic antidotally effective amount of a thiolcarbamate herbicide antidote. An herbicidal composition according to Claim 1 further comprising a non-phytotoxic antidotally effective amount of an amide of a dihaloalkanoic acid. An herbicidal composition according to Claim 1 further comprising a non-phytotoxic antidotally effective amount of a compound having the formula wherein R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are variously independently hydrogen, lower alkyl or phenyl, or R¹⁰ and R¹¹ taken together form an alkylene group, preferably a butylene, pentylene or hexylene group optionally substituted by one or two methyl groups; in which R¹⁶ may be one of a number of alkyl, alkenyl or alkynyl moieties; R¹⁷, R¹⁸, R¹⁹ and R²⁰ are independently hydrogen or methyl; and n is 0 or 1; in which R²¹ is cyano; in which R²² is alkyl, haloalkyl or trialkoxymethyl; R²³ is variously hydrogen, agriculturally acceptable cations or various hydrocarbamyl or substituted hydrocarbamyl moieties; and R²⁴ is chloro, bromo, iodo, lower alkoxy or substituted or unsubstituted phenoxy; or wherein R²⁵ represents the group in which R²⁸ represents a C₁-C₃ haloalkyl containing from 1 to 3 halogen atoms or a phenyl group optionally substituted; R²⁶ represents a hydrogen atom, a methyl or a phenyl; R²⁷ represents a C₁-C₈ alkyl group, a C₅-C₆ cycloalkyl group, a cyclohexylmethyl group, a phenyl group optionally substituted, a benzyl group optionally substituted, an allyl or propargyl group; and n is zero or one. A method of controlling undesirable vegetation comprising applying to the locus where control is desired both (a) a herbicidally effective amount of a thiolcarbamate having the formula wherein R¹ is C₁-C₆ alkyl; phenyl; C₇-C₉ phenylalkyl; C₃-C₆ alkenyl; C₃-C₆ haloalkenyl; or C₇-C₉ phenylalkyl, mono- or poly-substituted on the phenyl ring with halogen; R² and R³ are either selected independently from C₁-C₆ alkyl or C₅-C₇ cycloalkyl or combined to form conjointly C₄-C₉ alkylene; and (b) an extending amount of a compound having the formula wherein Y is oxygen or sulfur; Z is oxygen or sulfur; p is the integer 0, 1 or 2; R⁴ is C₂-C₈ alkenyl; C₂-C₈ alkenyl substituted with one or more halo groups; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with dioxolanyl, cyano or one or more hydroxy or C₁-C₄ alkoxy groups; C₁-C₃ alkyl substituted with one, two or three halo groups; C₁-C₆ alkylthioalkyl; benzyl; benzyl substituted with one or more halo or trifluoromethyl groups; C₃-C₆ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with halo, one or more nitro, C₁-C₄ alkoxy, C₁-C₄ alkyl or C₁-C₄ haloalkyl groups; R⁵ is C₂-C₆ alkenyl substituted with phenyl or one or more halo groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with one or more halo groups; or C₃-C₆ alkynyl; R⁶ is hydrogen; C₂-C₆ alkenyl substituted with phenyl or one or more halo or C₁-C₄ alkoxy groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with C₃-C₆ cycloalkyl or one or more halo groups; C₃-C₆ alkynyl; furfuryl; or benzyl; with the provisos that: (1) when Y is oxygen or both Y and Z are sulfur, then p is zero; (2) when Y is sulfur, Z is oxygen, R⁴ is allyl, 2-methylallyl, 2-butenyl, 3-chloroallyl or n-butyl, and R⁵ is allyl, then R⁶ is other than propyl or butyl; (3) when Y is sulfur, Z is oxygen, R⁴ is either C₁-C₅ alkyl, substituted benzyl, C₃-C₆ haloalkenyl, 2-chloroethyl, methylthioethyl, or propargyl, and R⁵ is C₁-C₅ alkyl, then R⁶ is other than C₁-C₆ alkyl; (4) when Y is sulfur and Z is oxygen, R⁴ is allyl, 3-chloroallyl, ethyl, n-butyl, methoxymethyl or ethoxymethyl, then not both R⁵ and R⁶ are allyl; (5) R⁴ cannot be phenyl unless Y is S and R⁵ and R⁶ are both chloroallyl; (6) one of R⁵ and R⁶ is always substituted allyl unless R⁴ is CH₃SCH₂- or substituted allyl; (7) R⁶ is hydrogen only if Y is sulfur; and (8) when Y and Z are each oxygen, then R⁴ is other than phenyl substituted with one or more C₁-C₄ alkyl or one or more C₁-C₄ haloalkyl. A method according to Claim 10 further comprising a non-phytotoxic antidotally effective amount of a thiolcarbamate herbicide antidote having the formula wherein R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are variously independently hydrogen, lower alkyl or phenyl, or R¹⁰ and R¹¹ taken together form an alkylene group, preferably a butylene, pentylene or hexylene group optionally substituted by one or two methyl groups; in which R¹⁶ may be one of a number of alkyl, alkenyl or alkynyl moieties; R¹⁷, R¹⁸, R¹⁹ and R²⁰ are independently hydrogen or methyl; and n is 0 or 1; in which R²¹ is cyano; in which R²² is alkyl, haloalkyl or trialkoxymethyl; R²³ is variously hydrogen, agriculturally acceptable cations or various hydrocarbamyl or substituted hydrocarbamyl moieties; and R²⁴ is chloro, bromo, iodo, lower alkoxy or substituted or unsubstituted phenoxy; or wherein R²⁵ represents the group in which R²⁸ represents a C₁-C₃ haloalkyl containing from 1 to 3 halogen atoms or a phenyl group optionally substituted; R²⁶ represents a hydrogen atom, a methyl or a phenyl; R²⁷ represents a C₁-C₈ alkyl group, a C₅-C₆ cycloalkyl group, a cyclohexylmethyl group, a phenyl group optionally substituted, a benzyl group optionally substituted, an allyl or propargyl group; and n is zero or one. A method of extending the soil life of a thiolcarbamate herbicide having the formula: wherein R¹ is C₁-C₆ alkyl; phenyl; C₇-C₉ phenylalkyl; C₃-C₆ alkenyl; C₃-C₆ haloalkenyl; or C₇-C₉ phenylalkyl, mono- or poly-substituted on the phenyl ring with halogen; R² and R³ are either selected independently from C₁-C₆ alkyl or C₅-C₇ cycloalkyl or combined to form conjointly C₄-C₉ alkylene; by applying to the soil containing the said thiolcarbamate herbicide or to which said thiolcarbamate herbicide is to be applied an extending amount of a compound having the formula wherein Y is oxygen or sulfur; Z is oxygen or sulfur; p is the integer 0, 1 or 2; R⁴ is C₂-C₈ alkenyl; C₂-C₈ alkenyl substituted with one or more halo groups; C₁-C₆ alkyl; C₁-C₆ alkyl substituted with dioxolanyl, cyano or one or more hydroxy or C₁-C₄ alkoxy groups; C₁-C₃ alkyl substituted with one, two or three halo groups; C₁-C₆ alkylthioalkyl; benzyl; benzyl substituted with one or more halo or trifluoromethyl groups; C₃-C₆ alkynyl; C₃-C₄ alkynyl substituted with phenyl; phenyl; or phenyl substituted with halo, one or more nitro, C₁-C₄ alkoxy, C₁-C₄ alkyl or C₁-C₄ haloalkyl groups; R⁵ is C₂-C₆ alkenyl substituted with phenyl or one or more halo groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with one or more halo groups; or C₃-C₆ alkynyl; R⁶ is hydrogen; C₂-C₆ alkenyl substituted with phenyl or one or more halo or C₁-C₄ alkoxy groups; C₂-C₆ alkenyl; C₁-C₈ alkyl; C₁-C₈ alkyl substituted with C₃-C₆ cycloalkyl or one or more halo groups; C₃-C₆ alkynyl; furfuryl; or benzyl; with the provisos that: (1) when Y is oxygen or both Y and Z are sulfur, then p is zero; (2) when Y is sulfur, Z is oxygen, R⁴ is allyl, 2-methylallyl, 2-butenyl, 3-chloroallyl or n-butyl, and R⁵ is allyl, then R⁶ is other than propyl or butyl; (3) when Y is sulfur, Z is oxygen, R⁴ is either C₁-C₅ alkyl, substituted benzyl, C₃-C₆ haloalkenyl, 2-chloroethyl, methylthioethyl, or propargyl, and R⁵ is C₁-C₅ alkyl, then R⁶ is other than C₁-C₆ alkyl; (4) when Y is sulfur and Z is oxygen, R⁴ is allyl, 3-chloroallyl, ethyl, n-butyl, methoxymethyl or ethoxymethyl, then not both R⁵ and R⁶ are allyl; (5) R⁴ cannot be phenyl unless Y is S and R⁵ and R⁶ are both chloroallyl; (6) one of R⁵ and R⁶ is always substituted allyl unless R⁴ is CH₃SCH₂- or substituted allyl; (7) R⁶ is hydrogen only if Y is sulfur; and (8) when Y and Z are each oxygen, then R⁴ is other than phenyl substituted with one or more C₁-C₄ alkyl or one or more C₁-C₄ haloalkyl.

Inventors: GRAY, REED ALDEN, PALLOS, FERENC MARCUS
Applicants: STAUFFER CHEMICAL COMPANY
Application year: 1985
Main classification: A01N25
IPC codes: A01N25, A01N47