Method for desalination and rehabilitation of irrigated soil

Soil conditioning and method for desalination and reclamation of irrigated soil.

BACKGROUND OF INVENTION 
This invention relates generally to soil conditioning and particularly 
pertains to a method for desalination and reclamation of irrigated soil. 
Soils irrigated with water of a high total dissolved solids (salt) content 
(500 ppm or greater) typically accumulate salts and/or alkalis that 
inhibit crop growth. Salts, mainly chlorides, carbonates, and sulfates or 
sodium, potassium, calcium, and magnesium are typically measured as the 
electrical conductivity (mmhos./cm..sup.2) of a saturation extract of the 
soil. An electrical conductivity greater than 4.0 mmhos./cm..sup.2 
indicates that a soil is saline. In saline soils the effect of salts on 
plants is mainly indirect; that is, the effect of the salts on osmotic 
water potential, and the resultant reduced uptake of water by germinating 
seeds and roots of established plants. An alkaline solid (sodic) is a soil 
that has accumulated large amounts of sodium and is determined by 
calculating the sodium absorption ratio (SAR) of the saturation extract of 
the soil. An SAR greater that 15 indicates that a soil is alkaline. In 
alkaline soils crop growth is inhibited by sodium toxicity. Typically, 
alkaline soils are also saline compounding toxic sodium levels with 
reduced plant water uptake ability. Therefore, alkaline-saline soils are 
particularly deleterious to seed germination and plant growth. It becomes 
advantageous to remove sodium from the alkaline soils and calcium from 
calcareous saline soils. 
Soil salinity/alkalinity is highly influenced by physical characteristics 
of the soil such as, the hydraulic conductivity and infiltration rates. 
Climate, as it affects the evapotranspiration rates from the soil and 
plants, also plays an important role in the extent of salt and/or alkali 
accumulation in the soil. Finally, agricultural irrigation practices have 
an important part in determining whether salts and/or alkalis will 
accumulate in soils. Known techniques and practices for removing salts 
and/or alkalis are often expensive and relatively ineffective. One such 
technique is to add cattle manure and/or green manures into the top soil 
to maintain a porous condition that will induce infiltration of water into 
the soil. In high temperature climates, typical of irrigated arid regions, 
these organic additions decay rapidly and their influence on soil physical 
properties is lost. Another technique involves the application of gypsum, 
sulfuric acid, or elemental sulfur to facilitate the removal of sodium. 
This technique requires large quantities of materials (typically on the 
order of tons/acre), considerable manpower and fuel, and is only 
temporarily effective. Yet another technique previously employed is the 
mechanical practice of chiseling, deep plowing, and slip plowing to 
improve water movement into and through the soil profile. This practice is 
of a relatively short-term benefit because the soils tend to slake down 
and close up after being irrigated requiring reworking on a yearly basis. 
It is therefore desirable to have a method for desalination and reclamation 
of irrigated soil which is relatively inexpensive, easy to perform and 
effective to remove the salts and/or alkalis in order to enhance crop 
yield. 
SUMMARY OF THE INVENTION 
It is the primary object of the present invention to provide an improved 
method for desalination and reclamation of irrigated saline and/or 
alkaline solids. 
In accordance with the present invention, soil in which salts and/or 
alkaline components have built up from irrigation water is treated with 
anionic low molecular weight synthetic polymeric compounds and/or 
organophosphorous compounds to inactivate or remove the salts and/or 
alkaline components and to improve the crop yielding ability of the soil. 
The compounds are added to the soil in a number of different ways. The 
compounds may be (a) added directly to the soil in a dry or semi-dry 
condition and when water is later added, the soil is conditioned. Water is 
necessary to my process. Water permits my compounds to combine with or 
carry the salt in the soil away from the germinating seed and/or roots of 
the plants. The compounds may be added with water, i.e., the irrigation 
water, water supplied directly to the germinating seeds or to roots of the 
plants. (c) Also, the plant seeds may be coated with our compounds so that 
when the seedlings are planted and then watered, my compounds treat the 
soil surrounding the seedlings. (d) Further, the coating may be an 
appropriate time-release coating with the benefits provided thereby. (e) 
The compounds themselves may be prepared as time release compounds so that 
their beneficial aspects are released into the soil each time soil is 
watered. 
The soils are treated with phosphoric acids and their neutral salts and 
anionic compounds having threshold properties selected from: anionic 
compounds and their salts of the formula: 
##STR1## 
wherein: 
R.sup.1 is hydroxyl, COOH, C.sub.6 H.sub.5 COOH, NHC(O)R.sup.9 COOH, 
phenol, COOR.sup.9, COOR.sup.9, SO.sub.3 H, C.sub.6 H.sub.5 SO.sub.3 H, 
R.sup.9 SO.sub.3 H, COOR.sup.9 SO.sub.3 H, OSO.sub.3 H, C.sub.6 H.sub.5 
OSO.sub.3 H, OR.sup.9 SO.sub.3 H, OR.sup.90 SO.sub.3 H, OP(OH).sub.2, 
R.sup.9 P(OH).sub.2 O, or phenyl; 
R.sup.2 is hydrogen or COOH; 
R.sup.3 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sup.4 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sup.5 is hydrogen, COOH, C.sub.6 H.sub.5 COOH, NHC(O)R.sup.9 COOH, 
phenol, COOR.sup.9, COOR.sup.9, SO.sub.3 H, C.sub.6 H.sub.5 SO.sub.3 H, 
R.sup.9 SO.sub.3 H, COOR.sup.9 SO.sub.3 H, OSO.sub.3 H, C.sub.6 H.sub.5 
O5O.sub.3 H, OR.sup.9 SO.sub.3 H, OR.sup.9 OSO.sub.3 H, OP(OH).sub.2, 
R.sup.9 P(OH).sub.2 O, or phenyl, OR.sup.10, hydroxyl or pyrrolidone; 
R.sup.6 is hydrogen or COOH; 
R.sup.7 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sup.8 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sup.9 is C.sub.1 -C.sub.4 alkyl; 
R.sup.10 is C.sub.1 -C.sub.4 alkyl; 
R.sup.11 is hydrogen or CH.sub.3 ; 
R.sup.12 and R.sup.13 are hydrogen; 
R.sup.14 is hydrogen or CH.sub.3 ; 
R.sup.15 is hydrogen, hydroxyl or C.sub.1 -C.sub.4 alkyl; 
R.sup.16 is hydrogen or C.sub.1 -C.sub.4 alkyl; 
R.sup.17 is N, NR.sup.19 N, NR.sup.9 NR.sup.9 N; 
R.sup.18 is C.sub.1 -C.sub.4 alkyl; 
R.sup.19 is C.sub.1 -C.sub.6 alkyl; 
R.sup.1 and R.sup.2 when taken together are anhydride; 
R.sup.5 and R.sup.6 when taken together are anhydride; 
n and m are independently 3-100; 
p and q are independently 0-3.

DETAILED DESCRIPTION 
I have found that certain anionic materials or their substantially neutral 
water soluble salts applied to a soil in minute amounts are effective to 
reduce the harmful effects of salts and/or alkalis which had accumulated 
in the soil from irrigation water. Thus, soil in which such salts and/or 
alkalis have reached the concentration that whitish deposits appeared on 
its surface and on which growth was unacceptably low is restored to useful 
fertility level through the action of these materials. 
Specific compounds which are useful in our invention are listed as the 
following. Of course, their acceptable salts are included as part of the 
following list. 
polymaleic acid; 
polyacrylic acid; 
polymethacrylic acid; 
poly(4-vinylbenzoic acid); 
poly(N-vinylsuccinamidic acid); 
poly(ethylene sulfonic acid)poly(ethylene sulfuric acid); 
poly(4-vinylphenyl sulfonic acid); 
poly(4-vinylphenyl sulfuric acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid); 
poly(3-methacryloyloxypropane-1-sulfonic acid); 
poly(3-(vinyloxy)propane-1-sulfonic acid); 
poly(4-vinylphenol); 
poly(ethylenephosphonic acid); 
poly(acrylic acid-co-methacrylic acid); 
poly(acrylic acid-co-methyl acrylate); 
poly(acrylic acid-co-ethyl acrylate); 
poly(acrylic acid-co-maleic acid); 
poly(acrylic acid-co-4-vinylphenol); 
poly(acrylic acid-co-4-vinylbenzoic acid); 
poly(acrylic acid-co-n-vinylsuccinamidic acid); 
poly(acrylic acid-co-ethylene sulfonic acid); 
poly(acrylic acid-co-ethylene sulfuric acid); 
poly(acrylic acid-co-4-vinylphenyl sulfonic acid); 
poly(acrylic acid-co-4-vinylphenyl sulfuric acid); 
poly(acrylic acid-co-2-methacryloyloxyethane-1-sulfonic acid; 
poly(acrylic acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(acrylic acid-co-3-(vinyloxy)propane-1-sulfuric acid); 
poly(acrylic acid-co-vinyl alcohol); 
poly(acrylic acid-co-ethylenephosphonic acid); 
poly(acrylic acid-co-vinyl ethers); 
poly(acrylic acid-co-ethylene); 
poly(acrylic acid-co-propylene); 
poly(acrylic acid-co-isobutylene); 
poly(acrylic acid-co-styrene); 
poly(acrylic acid-co-vinylpyrrolidone);; 
poly(methacrylic acid-co-methyl acrylate); 
poly(methacrylic acid-co-ethyl acrylate); 
poly(methacrylic acid-co-maleic acid); 
poly(methacrylic acid-co-4-vinylbenzoic acid); 
poly(methacrylic acid-co-n-vinylsuccinamidic acid); 
poly(methacrylic acid-co-ethylene sulfonic acid); 
poly(methacrylic acid-co-ethylene sulfuric acid); 
poly(methacrylic acid-co-4-vinylphenyl sulfonic acid); 
poly(methacrylic acid-co-4-vinylphenyl sulfuric acid); 
poly(methacrylic acid-co-2-methacryloyloxyethane-1-sulfonic acid); 
poly(methacrylic acid-co-3-methacryloyloxyethane-1-sulfonic acid); 
poly(methacrylic acid-co-3(vinyloxy)propane-1-sulfonic acid); 
poly(methacrylic acid-co-vinyl alcohol); 
poly(methacrylic acid-co-4-vinylphenol); 
poly(methacrylic acid-co-ethylenephosphonic acid); 
poly(methacrylic acid-co-vinyl ethers); 
poly(methacrylic acid-co-ethylene); 
poly(methacrylic acid-co-propylene); 
poly(methacrylic acid-co-isobutylene); 
poly(methacrylic acid-co-styrene); 
poly(methacrylic acid-co-vinylpyrrolidone); 
poly(maleic acid-co-methyl acrylate); 
poly(maleic acid-co-ethyl acrylate); 
poly(maleic acid-co-4-vinylbenzoic acid); 
poly(maleic acid-co-n-vinylsuccinamidic acid); 
poly(maleic acid-co-ethylene sulfonic acid); 
poly(maleic acid-co-ethylene sulfuric acid); 
poly(maleic acid-co-4-vinylphenyl sulfonic acid); 
poly(maleic acid-co-4-vinylphenyl sulfuric acid); 
poly(maleic acid-co-2-methacryloyloxyethane-1-sulfonic acid); 
poly(maleic acid-co-methacryloyloxypropane-1-sulfonic acid); 
poly(maleic acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(maleic acid-co-vinyl alcohol); 
poly(maleic acid-co-4-vinylphenol); 
poly(maleic acid-co-ethylenephosphonic acid); 
poly(maleic acid-co-vinyl ethers); 
poly(maleic acid-co-ethylene); 
poly(maleic acid-co-propylene); 
poly(maleic acid-co-isobutylene); 
poly(maleic acid-co-styrene); 
poly(maleic acid-co-vinylpyrrolidone); 
poly(4-vinylbenzoic acid-co-methacrylic acid); 
poly(4-vinylbenzoic acid-co-methyl acrylate); 
poly(4-vinylbenzoic acid-co-ethyl acrylate); 
poly(4-vinylbenzoic acid-co-n-vinylsuccinamidic acid); 
poly(4-vinylbenzoic acid-co-ethylene sulfonic acid); 
poly(4-vinylbenzoic acid-co-ethylene sulfuric acid); 
poly(4-vinylbenzoic acid-co-4-vinylphenyl sulfonic acid); 
poly(4-vinylbenzoic acid-co-4-vinylphenyl sulfuric acid); 
poly(4-vinylbenzoic acid-co-2-methacryloyloxyethane-1-sulfonic acid); 
poly(4-vinylbenzoic acid-co-3-methacryloyloxyethane-1-sulfonic acid); 
poly(4-vinylbenzoic acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(4-vinylbenzoic acid-co-vinyl alcohol); 
poly(4-vinylbenzoic acid-co-4-vinylphenol); 
poly(4-vinylbenzoic acid-co-ethylenephosphonic acid); 
poly(4-vinylbenzoic acid-co-vinyl ethers); 
poly(4-vinylbenzoic acid-co-ethylene); 
poly(4-vinylbenzoic acid-co-propylene); 
poly(4-vinylbenzoic acid-co-isobutylene); 
poly(4-vinylbenzoic acid-co-styrene); 
poly(4-vinylbenzoic acid-co-vinylpyrrolidone); 
poly(vinyl sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(vinyl sulfonic acid-co-vinyl sulfuric acid); 
poly(vinyl sulfonic acid-co-4-vinylphenyl sulfonic acid); 
poly(vinyl sulfonic acid-co-4-vinylphenyl sulfuric acid); 
poly(vinyl sulfonic acid-co-2-methacryloyloxyethane-1-sulfonic acid); 
poly(vinyl sulfonic acid-co-3-methacryloyloxypropane-1-sulfonic acid); 
poly(vinyl sulfonic acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(vinyl sulfonic acid-co-vinyl alcohol); 
poly(vinyl sulfonic acid-co-4-vinylphenol); 
poly(vinyl sulfonic acid-co-ethylenephosphonic acid); 
poly(vinyl sulfonic acid-co-vinyl ethers); 
poly(vinyl sulfonic acid-co-ethylene); 
poly(vinyl sulfonic acid-co-propylene); 
poly(vinyl sulfonic acid-co-isobutylene); 
poly(vinyl sulfonic acid-co-styrene); 
poly(vinyl sulfonic acid-co-vinylpyrrolidone); 
poly(vinyl sulfuric acid-co-n-vinylsuccinamidic acid); 
poly(vinyl sulfuric acid-co-4-vinylphenyl sulfonic acid); 
poly(vinyl sulfuric acid-co-4-vinylphenyl sulfuric acid); 
poly(vinyl sulfuric acid-co-2-methacryloyloxyethane-1-sulfonic acid); 
poly(vinyl sulfuric acid-co-3-methacryloyloxypropane-1-sulfonic acid); 
poly(vinyl sulfuric acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(vinyl sulfuric acid-co-vinyl alcohol); 
poly(vinyl sulfuric acid-co-4-vinylphenol); 
poly(vinyl sulfuric acid-co-ethylenephosphonic acid); 
poly(vinyl sulfuric acid-co-vinyl ethers); 
poly(vinyl sulfuric acid-co-ethylene); 
poly(vinyl sulfuric acid-co-propylene); 
poly(vinyl sulfuric acid-co-isobutylene); 
poly(vinyl sulfuric acid-co-styrene); 
poly(vinyl sulfuric acid-co-vinylpyrrolidone); 
poly(vinylphenyl sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(4-vinylphenyl sulfonic acid-co-4-vinylphenyl sulfuric acid); 
poly(4-vinylphenyl sulfonic acid-co-2-methacryloyloxyethane-1-sulfonic 
acid); 
poly(4-vinylphenyl sulfonic acid-co-3-methacryloyloxypropane-1-sulfonic 
acid); 
poly(4-vinylphenyl sulfonic acid-co-3-(vinyloxy)propane-1-sulfonic acid); 
poly(4-vinylphenyl sulfonic acid-co-vinyl alcohol); 
poly(4-vinylphenyl sulfonic acid-co-4-vinylphenol); 
poly(4-vinylphenyl sulfonic acid-co-ethylenephosphonic acid); 
poly(4-vinylphenyl sulfonic acid-co-vinyl ethers); 
poly(4-vinylphenyl sulfonic acid-co-ethylene); 
poly(4-vinylphenyl sulfonic acid-co-propylene); 
poly(4-vinylphenyl sulfonic acid-co-isobutylene); 
poly(4-vinylphenyl sulfonic acid-co-styrene); 
poly(4-vinylphenyl sulfonic acid-co-vinylpyrrolidone); 
poly(4-vinylphenyl sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(4-vinylphenyl sulfuric acid-co-2-methacryloyloxyethane-1-sulfonic 
acid); 
poly(4-vinylphenyl sulfuric acid-co-3-methacryloyloxypropane-1-sulfonic 
acid); 
poly(4-vinylphenyl sulfuric acid-co-3-(vinyloxy) propane-1-sulfonic acid); 
poly(4-vinylphenyl sulfuric acid-co-vinyl alcohol); 
poly(4-vinylphenyl sulfuric acid-co-4-vinylphenol); 
poly(4-vinylphenyl sulfuric acid-co-ethylenephosphonic acid); 
poly(4-vinylphenyl sulfuric acid-co-vinyl ethers); 
poly(4-vinylphenyl sulfuric acid-co-ethylene); 
poly(4-vinylphenyl sulfuric acid-co-propylene); 
poly(4-vinylphenyl sulfuric acid-co-isobutylene); 
poly(4-vinylphenyl sulfuric acid-co-styrene); 
poly(4-vinylphenyl sulfuric acid-co-vinylpyrrolidone); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(2-methacryloyloxyethane-1-sulfonic 
acid-co-3-methacryloyloxypropane-1-sulfonic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-3-(vinyloxy) 
propane-1-sulfonic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-3-(vinyloxy) 
propane-1-sulfonic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-vinyl alcohol); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-4-vinylphenol); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-ethylenephosophonic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-vinyl ethers) 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-ethylene); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-propylene); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-butylene); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-isobutylene); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-styrene); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-vinylpyrrolidone); 
poly(3-methacryloyloxyethane-1-sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-n-vinylsuccinamidic acid); 
poly(2-methacryloyloxyethane-1-sulfonic acid-co-3-(vinyloxy) 
propane-1-sulfonic acid); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-3-(vinyloxy) 
propane-1-sulfonic acid); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-vinyl alcohol) 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-4-vinylphenol) 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-ethylenephosphonic acid); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-vinyl ethers); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-ethylene); 
poly(3-methacryloyloxyethane-1-sulfonic acid-co-propylene); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-isobutylene); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-styrene); 
poly(3-methacryloyloxypropane-1-sulfonic acid-co-vinylpyrrolidone); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-vinylsuccinamidic acid); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-vinyl-alcohol); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-4-vinylphenol); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-ethylenephosphonic acid); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-vinyl ethers); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-ethylene); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-propylene); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-isobutylene); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-styrene); 
poly(3-(vinyloxy)propane-1-sulfonic acid-co-vinylpyrrolidone); 
poly(vinyl alcohol-co-n-vinylsuccinamidic acid); 
poly(vinyl alcohol-co-4-vinylphenol); 
poly(vinyl alcohol-co-ethylenephosphonic acid); 
poly(4-vinylphenol-co-n-vinylsuccinamidic acid); 
poly(4-vinylphenol-co-ethylenephosphonic acid); 
poly(4-vinylphenol-co-vinyl ethers); 
poly(4-vinylphenol-co-vinylpyrrolidone); 
poly(ethylenephosphonic acid-co-vinylsuccinamidic acid); 
poly(ethylenephosphonic acid-co-vinyl ethers); 
poly(ethylenephosphonic acid-co-ethylene); 
poly(ethylenephosphonic acid-co-propylene); 
poly(ethylenephosphonic acid-co-isobutylene); 
poly(ethylenephosphonic acid-co-styrene); 
poly(ethylenephosphonic acid-co-vinylpyrrolidone); 
1-hydroxyethylidene-1-diphosphonic acid; 
nitrilo trismethylene triphosphonic acid; 
ethylene bis (nitrilo dimethylene)tetraphosphonic acid; 
diethyltriamine penta(methylene phosphonic acid); 
ethanolamine N.N-di(methylene phosphoric acid); hexamethylenediamine 
tetra(methylene phosphoric acid). 
The material(s) is/are applied suitably by incorporation in irrigation 
water to insure uniform distribution in the soil in depth. Alternative 
applications involve spraying, injecting, "flying on" the material(s) 
directly to the ground. The material can be supplied directly to the 
seedlings, the roots of plants by direct watering systems, may be planted 
with the seeds, used to coat the seeds, the seed coating may be a time 
release coating, and also the materials of my invention may have a time 
release coating thereon so that their effect can be used to treat the soil 
over a preselected time period. 
The amount of active material(s) required per unit area will depend on the 
extent to which salts and/or alkalis have accumulated, but the amount is 
not in stoichiometric relation to the salt and/or alkali concentration in 
the soil. No exact figures can be given since the nature of the soil also 
affects the amount of active material(s) required, but for moderate salt 
and/or alkali accumulation, useful effects have been obtained by 
application of from 0.1 pound to 15.0 pounds per acre over a 4- to 48-hour 
period, while for heavy accumulation, from 1.0 to 25.0 pounds per acre 
over a 12- to 96-hour period may be needed. The material(s) is/are 
preferably applied in a plurality of spaced treatments to insure 
improvement of the soil in depth, and the treatments may continue in 
extreme cases until the soil is fully saturated. 
Anionic materials having threshold activity suitable for use in the present 
soil treatment process include low molecular weight, water miscible 
synthetic polymers, organosulfuric acids, organophosphorous acids, and 
substantially neutral salts of these. Threshold activity refers to 
sub-stoichiometric chemical processes of which dispersancy and calcium 
carbonate stabilization are important factors. As described in Journal Of 
The Cooling Tower Institute, Vol. 3, No. 1, Winter 1982, page 17 et seq., 
in the article of Leonard Deubin entitled "The Effect of Organophosphorus 
Compounds And Polymers on CaCO.sub.3 Crystal Morphology," calcium 
carbonate stabilization is understood to involve an increase in average 
particle size and a change in the gross shape of calcium carbonate 
crystals, and dispersancy involves surface charge effects. 
Anionic polymeric materials for use in the present process include 
polymers, copolymers and sulfonated polymers and copolymers of acrylic 
acid, methacrylic acid, hydrolyzed polymers and copolymers of maleic 
anhydride and substantially neutral water soluble salts of these. The 
commercially available material known as "Belclene 200," a product of 
Ciba-Geigy Corporation, of Ardsley, N.Y., which is understood to be a 
water soluble hydrolyzed maleic anhydride polymer having low molecular 
weight, e.g. from 300 to 5000, or salt of such polymer, has been found 
particularly useful. 
Organophosphorus agents for use in soil treating include phosphonic acids 
as hydroxyethylidene diphosphonic acid, amino tri (methylenephosphonic 
acid), and nitrilo trismethylene triphosphonic acid, phosphonic acids such 
as phosphinocarboxylic acid, and substantially neutral salts of these 
acids. 
These anionic polymers, organophosphorus acids, and/or substantially 
neutral water soluble salts of these may be used alone or in combination 
of two or more. 
High molecular weight polymethacrylates are used as ion exchange 
fertilizers as described in U.S. Pat. No. 4,396,412. The form of the 
polymethacrylate is a solid to which various fertilizer constituents are 
bound. These ion exchange fertilizers are useful in soils that are 
subjected to waters with a low salt content such as in hydroponic 
agriculture. It is an intent of this invention to use low molecular weight 
liquid polymethacrylates on soils subjected to irrigation with high salt 
waters and is not intended as a means of introducing fertilizers to crops. 
To those versed in the art it is understood that applying to soils various 
species of organophosphorus compounds is common for the addition of 
micro-nutrients such as iron, manganese, and other essential metals as 
described in U.S. Pat. No. 3,958,972. This invention relates to the use of 
these compounds to lower harmful salts and/or alkalis and to improve a 
crops ability to absorb water. 
U.S. Pat. No. 4,098,814 describes a method for manufacturing several 
species of organophosphorus compounds and suggests their use in the 
manufacture of liquid fertilizers to prevent mineral deposits from forming 
in the manufacturing equipment. It is not the intent of this invention to 
prescribe a method for manufacturing these compounds or the use thereof in 
the manufacture of liquid fertilizers. 
Our invention relates to a new use or method of using known compounds to 
achieve unexpected results. These compounds as described above in detail 
increase the solubility of sodium, potassium, calcium, and magnesium salts 
by dispersing these salts found in the soil pore spaces. These salts when 
dispersed have a large increase in surface area that is available to be 
wetted, effectively shifting the equilibrium from the solid phase to the 
dissolved liquid phase. I believe that the precipitated salts are 
dispersed because the Helmholtz double layer model for dispersancy is 
satisfied by the presence of the high negative charge density of these 
compounds. Additionally, the precipitation of dissolved sodium, potassium, 
calcium, and magnesium salts present in the irrigation water is inhibited 
as the soil drys. This is a result of crystal distortion effects at the 
surfaces of forming crystals. The net effect of both mechanisms 
(dispersancy and crystal distortion) in calcareous saline soils is the 
removal of precipitated calcium salts from the soil pore spaces. The net 
effect of both mechanisms (dispersancy and crystal distortion) in sodic 
alkaline soils is to provide excess calcium and magnesium cations to 
displace sodium from the colloidal clay surface resulting in 
sub-stoichiometrically induced cation exchange, facilitating the removal 
of sodium from the soil. The action of these compounds forces the mineral 
salts deep into the soil or discharges them through the field tile drains, 
resulting in an improved drainage and percolation rate, reduction of soil 
salts and/or alkalis, improvement in the crops ability to absorb water, 
and increase germination and yield. 
It is to be understood that this proposed mechanism is advanced only as a 
possible assistance in understanding the invention and that patentability 
is based on the novelty and utility of the process and not the correctness 
of the mechanism proposed. 
The following examples are given to aid in understanding the invention, but 
it is not limited to the particular procedures, condition s or materials 
of the examples. In each case there was noted an increase in the percent 
of seeds germinated as well as an increase in the rate of germination, 
that is the seeds began to grow more rapidly and in greater numbers. Also, 
there was noted an improvement in the percolation of the soil as evidenced 
by a marked increase in salinity and flow of water through drain tile. 
Furthermore, there was a very evident removal of encrusted salt on the 
soil surface. Each example is representative of other experimental 
treatments performed on Imperial Valley agricultural land in Imperial 
County, Calif. 
EXAMPLES 
Example 1 
A commercially producing alfalfa field in Imperial Counta, Calif, newly 
planted with 40.0 lbs. per acre of alfalfa seed was selected as a test 
plot. The field consists of several border irrigated lands. Four lands 
were used for the test: 2 controls and 2 treated with a low molecular 
weight, anionic, maleic acid based copolymer (Belcline 283, a commercially 
available product of Ciba-Geigy Corp, Ardsley, N.Y.). 
The soil survey report of the USDA's Soil Conservation Service shows that a 
soil type in these lands is representative of many irrigated farms in the 
U.S. desert southwest. It is a medium textured silty clay loam which is 
moderately saline-alkaline, and slowly permeable. 
The treated lands received 3.0 lbs. per acre of the co-polymer solution 
(50% Active Ingredient: 50% water) in the germination irrigation and two 
subsequent irrigations. Following harvesting, (cutting and baling), the 
treatment was reduced to 2.5 lbs. per acre in each irrigation. In all 
applications the soil desalination agent was added to the irrigation water 
through a constant head drip siphon at the time of irrigation for the two 
treated lands. 
The field was allowed to grow and establish through the winter months with 
harvesting beginning in early May and then monthly through the summer an 
diminishing through the fall and winter. The desert temperatures increased 
to 105.degree. F. on average from May until early October. 
Compared to controls the treated lands maintained an average yield 
improvement of 27%. 
EXAMPLE 2 
Simultaneously, using the same procedure as described in Example 1, another 
field was treated with a soil desalination agent as described in Example 1 
using a low molecular weight, anionic, homopolymer salt of sodium 
polyacrylate (P-70, a commercially available product of American Cyanamide 
of Wayne, N.J.). 
The results were similar to that in Example 1. The yields of the treated 
lands maintained an average 22% improvement over controls. 
EXAMPLE 3 
Using the procedure of Example 1 and, at the same time, yet another field 
was treated with the phosphonic acid, a soil desalination agent, 
1-hydroxyethylidene-1-diphosphonic acid (Tecquest 360, a commercially 
available product of BRJ Industries, Wheeling, IL.) 
Similarly to the Examples 1 and 2 the yields of the treated lands 
maintained an average 12% improvement over the controls. 
EXAMPLE 4 
Undisturbed soil cores from the surface where taken in the Imperial County, 
Calif. area. The cores were obtained by using a backhoe to press eight 
inch diameter, twenty inch length fiberglass pipes twelve inches into the 
soil. Three control and three treated cores were set up to receive 
irrigations and to collect leachates from the bottom of the cores for 
analysis. 
The control cores were irrigated with 843 ml. (equivalent to 1.0 acre-inch) 
of Colorado River water (700 ppm TDS). 
The treated cores were irrigated with the same amount of Colorado River 
water with the dissolved equivalent of 3.0 lbs. per acre of maleic acid 
based co-polymer of Example 1. 
All cores were irrigated as above every 7-10 days and leachates were 
collected for analysis. The experiment was terminated at day 120. 
The results showed (1) an improvement in the rate of sodium removal for 
each irrigation and (2) an accumulative removal of 40% more sodium when 
compared to the controls. 
EXAMPLE 5 
Another undisturbed solid core experiment according to the procedure 
described in Example 4, was performed with sodium polyacrylate of Example 
2 as the soil desalination agent. 
The results also showed (1) an improvement in the rate of sodium removed 
from each irrigation and (2) and accumulative removal of 31% more sodium 
when compared to the controls. 
EXAMPLE 6 
Yet another undisturbed soil core experiment according to the procedure 
described in Example 4 was performed with the phosphonic acid, soil 
desalination agent 1-hydroxyethylidene-1-diphosphonic acid. 
Similar results were achieved with an accumulative removal of 18% more 
sodium when compared to the controls. 
EXAMPLE 7 
To demonstrate improved early development of salt sensitive seeds and 
seedlings, the following was performed. 300 gms. each of a saline-alkaline 
soil as described in Example 1 were placed into two styrofoam containers, 
one controls and one for treated seeds. The container bottoms had six 
holes of equal size for drainage. To each container twenty lettuce seeds 
(a salt sensitive crop) were carefully placed one quarter of an inch below 
the surface. The control was irrigated with 150 ml. of Colorado River 
water. The treated soil was irrigated with 150 ml. of 100 ppm maleic acid 
based copolymer. The containers were then watered every other day with 150 
ml. of water for the control and 150 ml. of 100 ppm soil desalination 
agent for the treated seeds. The experiment was terminated after 20 days. 
After twenty days, 80% of the control seeds germinated with 40% surviving 
and 85% of the treated seeds germinated with 75% surviving. 
EXAMPLE 8 
Example 7 is repeated using sodium polyacrylate as the soil desalination 
agent. 
Similar results as in Example 7 were obtained. After 20 days, 75% of the 
control seeds germinated with 40% surviving and 90% of the treated seeds 
germinated with 80% surviving. 
EXAMPLE 9 
Example 7 is repeated using the phosphonic acid, 
1-hydroxyethylidene-1-diphophonic acid as the soil desalination agent. 
The results were for the control a 75% seed germination with 45% surviving 
and for the treated a 75% seed germination with 60% surviving. 
EXAMPLE 10 
Example 7 is repeated using poly (4-vinylbenzoic acid as the soil 
desalination agent. The results were for the control 80% seeds germination 
with 50% surviving and for the treated 80% seed germination with 65% 
surviving. This soil desalination agent did not appear to have quite the 
dispersing action as other agents.