bluuebunny/crossref_metadata_2025 huggingface dataset:
Diversity and Suitability for Hybrid Production of Different Sources of Cytoplasmic Male Sterility in Maize1
Authors: Gracen V. E. , Grogan C. O.
Published: July 2010

The epiphytotic of Helminthosporlum maydis, race T, in 1970 on the Texas male sterile cytoplasm demonstrated the dangers of using a uniform cytoplasm for hybrid corn production. Resistance to H. maydis, race T, was obtained by switching to non‐male‐sterile cytoplasms. This shift increased cytoplasmic diversity but necessitated the return to detasseling female parents. Sources of male sterile cytoplasms resistant to H. maydis, race T, are known and are being substituted for non‐male sterile cytoplasms in the production of commercial corn hybrids. We have proposed that a return to male sterile cytoplasm is practical if precautions are taken to ensure that cytoplasmic diversity is maintained. It was our objective in this study to determine the extent of diversity as measured by differential fertility restoration reactions within most of the known sources o[ cytoplasmic male sterility and to evaluate the suitability of each male sterile cytoplasm for hybrid production in various inbred backgrounds. We, therefore, examined the fertility restoration of 38 sources of cytoplasmic male sterility in 28 inbred backgrounds. The sources of male sterility could be divided into three groups (C,S, and T groups) with similar fertility restoration patterns within groups by 11 of the inbred lines. Cytoplasmic sources B, CH, D, EP, LF, NT, OY, SG, 181, and 234 did not fit the fertility restoration pattern of any of these groups. Although three groups of cytoplasms were distinguished, the fertility restoration reactions with some inbred lines indicated diversity within the groups. Sixteen inbred lines restored certain members of a group of cytoplasms but failed to restore others. Most of the inbreds tested formed fully male sterile combinations with several cytoplasmic sources. The feasibility of producing hybrid corn utilizing a physical mixture of male sterile cytoplasms (multiplasm) to insure cytoplasmic diversity is discussed.
Effects of Nitrogen Levels and Row Widths on Kenaf1
Authors: Massey John H.
Published: July 2010

Kenaf (Hibiscus cannabinus L.), a potential annual crop source of paper pulp, was grown to determine the effects of nitrogen levels and row widths on yield and other characteristics. Nitrogen level, up to 112 kg/ha, did not affect dry matter yield of plant height but at 90 kg/ha, N increased stem diameter. In 1 of 2 years, kenaf in 36 cm rows outyielded 71 cm rows. Basal stem diameter was greater in 71 than in 36 cm rows, but row width did not affect plant height.
Fate of 15N‐Labeled Anhydrous Ammonia under Simulated Fall and Spring Conditions1
Authors: Chalk P. M. , Keeney D. R.
Published: July 2010

Many farmers have found that Fall application of anhydrous NH3 has economic advantages over Spring application. Differences of opinion exist, however, and previous investigations at this station have shown that higher losses of N fertilizer occur when applied in Fall. Precise evaluation of the mechanisms involved are difficult in field studies, and therefore a greenhouse experiment was conducted in which the major variable was application of 15N‐labeled anhydrous NH3 before or after a freeze‐thaw cycle, simulating Fall and Spring applications, respectively. Three soils were used. One, a Pella sil, was high in organic matter (4.44% organic C). The other two soils were the same soil type (Plano sil), but differed in that one was acid (pH 4.9) and the other was close to neutral (pH 6.3). Three or 4 crops of ryegrass (Lolium multiflorum) were grown, and the amount of 15N in the plants and in the soil was determined.

Only small losses of fertilizer N (<5%) occurred in the acid Plano soil that was left fallow or cropped to ryegrass. Similar N recoveries were obtained in the pH 6.3 Plano soil and the Pella soil cropped to ryegrass, but losses increased substantially in fallow pots. The magnitude of the losses were directly related to the organic matter content and initial pH of the soils. We found that freezing and thawing of soil significantly increases the rate of denitrification. Fall application of NH3 may lead to significant fertilizer losses by denitrification, since other studies have shown that substantial nitrification will occur in Fall and early Spring.
Simultaneous Uptake of Water and Solutes by Plant Roots1
Authors: Dalton F. N. , Raats P. A. C. , Gardner W. R.
Published: July 2010

A theory describing the hydraulic and osmotic transport of water and the diffuse, convective and active transport of solutes across root membranes is formulated. The theory predicts the dependence of the ratio of the osmotic pressures of the nutrient and xylem solutions and of the solute flux upon the rate of water uptake. The theory also predicts a nonlinear relationship between the flux of water and the pressure difference across root membranes. The results are shown to be in good qualitative agreement with a variety of observations on simultaneous uptake of water and solutes.
Diurnal Fluctuation of Leaf‐water Potential of Corn as Influenced by Soil Matric Potential and Microclimate1
Authors: Reicosky D. C. , Campbell R. B. , Doty C. W.
Published: July 2010

Water stress during critical growth periods is frequently the limiting factor in crop production. However few data are available on the variation of plant water status under field conditions. The object of this work was to quantify the effect of soil matric potential on plant water status. Sweet corn (Zea mays L.) was grown on a Varina sandy loam soil to determine the effect of the microclimate and irrigation on leaf water potential. Soil water stress was imposed naturally and by use of automated portable shelters that covered the plots during rainfall.

Leaf‐water potential was closely related to the diurnal change of incoming energy. A maximum leaf‐water potential of −1.5 bars occurred just prior to sunrise. The minimum value, which occurred during the peak radiation load or stress, was dependent on soil matric potential and stage of plant development. Before tasseling, soil matric potentials of −0.08 and −0.60 bar at the 15‐cm depth in irrigated and nonirrigated plots resulted in minimal leaf‐water potentials of −12 and −18 bars, respectively. After tasseling, soil matric potentials were −0.07 bar at the 15‐cm depth in the irrigated and −3.0 bars in the nonirrigated plots, and the same minimal leaf‐water potential of −18 bars developed for both. Under the same radiation load, minimal leaf‐water potential of irrigated plants was −12 bars before tasseling and − 18 bars after tasseling. The results demonstrate the need to evaluate the influence of environmental stresses and soil water deficits on leaf‐water potential and associated physiological processes.
Correlation Between NaHCO3‐extractable P and Response to P Fertilization in Pot Tests1
Authors: Matar A. E. , Samman M.
Published: July 2010

Pot tests were used to estimate potential fertility of major Syrian soils. Soil samples were collected from 270 sites throughout Syria.

The relative increase in dry weight yield of wheat (Triticum vulgare L.) seedlings due to the addition of P was calculated. The response of soils to addition of P varied widely among soil groups, depending upon the parent material, degree of weathering, age of the soils, and other factors.

The degree of response to P fertilization by the pot test method was calibrated with the response in 20 field tests giving a correlation coefficient of r = 0.81.

The NaHCO3‐extractable P in soils studied in pot tests was correlated with the relative increase in wheat yield due to the addition of P fertilizers to soils. The correlation coefficient was poor, when all soils were considered as one group, with r = −0.03. Correlation was improved when the soils were grouped according to its genetic origin, into four major groups. Correlation coefficients (r) between the NaHCO3‐extractable P and the yield response to P addition were: −0.69, −0.87, −0.89, and −0.64 for basaltic, Euphrates Valley, Khabour Valley, and limestone soils, respectively.

It was concluded that the pot technique used was satisfactory to estimate the potential fertility of soils and that estimation of the available P in soils by the NaHCO3 method is adequate for soils of diverse genetic origin.
Soil Temperature Increases Induced by Subsurface Line Heat Sources1
Authors: Rykbost K. A. , Boersma L. , Jarman G. D.
Published: July 2010

Generating electricity using the steam cycle produces large quantities of waste heat. Conversion efficiencies range from 32 to 38% which means that for three units of energy input about one unit of electrical energy is produced and two units of waste heat must be disposed of.

Circulating the condenser cooling water through a network of underground pipes would result in warming the soil. The present study was initiated to evaluate the effect of increased soil temperatures on crop growth, the energy balance of the proposed system, and the economic feasibility of the system. This report presents results of the energy balance studies.

The proposed system was simulated by electrical heating cables, 92 cm deep with 183 cm spacing, maintained at temperatures ranging from 35 to 37 C. Soil temperatures were measured at hourly intervals over a 2‐year period at points forming arrays in planes perpendicular to the heat sources. The temperature measurements were recorded on magnetic tape and later processed to obtain desired information, such as daily averages at various depths. Energy input was measured with watt‐hour meters. With a bare soil surface the average daily soil Temperature at the 5 cm depth increased about 1.0 C during the summer and 1.5 C during the winter. At the 25 cm depth temperature increases were about 4.0 C and 5.5 C, respectively. The average daily temperature of the profile to a depth of 220 cm was increased about 10 C in the summer and 13 C in the winter. The rate of energy dissipation varied from about 0.012 cal/cm2/min in the summer to about 0.030 cal/cm2/min in the winter. During summer months heat flow from the soil to the atmosphere accounted for less than half of the total flux. During the winter the heat flux to the atmosphere accounted for most of the energy dissipation. Very large surface areas would be required to dissipate the waste eat generated by a power plant with an electrical output of 1,000 MW. The proposed system of soil warming is not an efficient primary heat sink. The rate of heat dissipation could be increased by placing the pipes closer to the soil surface and closer together.
Nitrate Contents of Sudangrass and Barley Forages Grown on Plots Treated with Animal Manures1
Authors: Pratt P. F. , Davis Sterling , Sharpless R. G. , Pugh W. J. , Bishop S. E.
Published: July 2010

In areas of high concentrations of domestic animals, such as the Chino‐Corona Basin in southern California, there is a tendency to use large amounts of manures on adjacent croplands. In these situations, there is a need to know the upper safe limits of manure use for protection of animals from excess nitrate (NO‐3) in forage and for the protection of groundwaters from NO‐3 and soluble salts. A field trial on the Moreno Farm of the Univ. of California, Riverside was conducted to respond to these needs. This paper presents the results of this experiment relative to the upper safe limits for NO‐3 in barley and sudangrass forages used by the dairy industry.

Barley grown in the winter of 1972–73 and sudangrass grown in the summer of 1973 were analyzed for NO‐3. These crops represented the third year of an experiment with two manures (dry dairy corral manure and liquid manure from a feedyard) and two irrigation treatments (ET and 1.33 ET) on a Hanford sandy loam. Nitrate concentrations in barley decreased progressively as the crop grew, were higher with liquid than with dry manure, and were not affected by irrigation level. The NO‐3 concentrations in sudangrass generally increased as the crop grew until just prior to emergence of flower heads from the boot and then decreased, were higher with liquid than with dry manure, and were higher with the lower water level.

Based on the NO‐3 content of sudangrass the safe annual rate of liquid manure, which had 4.8% N on a dry weight basis, for the particular management system in which half of the manure was applied at the time of planting of barley in the fall and the other half at time of planting of the sudangrass, was about 8.6 metric tons of dry weight/ha/year. The safe limit of dry manure, which contained 1.8% N on a dry weight basis, for the same croppingmanagement system was about 29 metric tons of dry matter/ha/year.
Growth and Element Accumulation by two Single‐cross Corn Hybrids as Affected by Copper in Solution1
Authors: Dragun James , Baker Dale E. , Risius Marvin L.
Published: July 2010

Increased use of land for “disposal” of industrial wastes and animal wastes such as poultry and swine manure from flocks and herds fed high levels of trace elements will require soil monitoring methods to maintain safe levels of these elements with respect to both crop production and the food chain. The objectives of this investigation were to: 1) measure Cu ion potentials, pCu, associated with minimum and maximum Cu ion activities for growth of corn (Zea mays L.) seedlings; 2) evaluate the influence of the chelator DTPA (diethylenetriaminepentaacetic acid) on plant uptake of Cu; and 3) relate pCu to uptake of Cu and other elements by single‐cross corn hybrids selected for genetic controlled accumulations of relatively high and low concentrations of leaf Cu.

Two corn hybrids were grown in the greenhouse using solution cultures of varying pCu. Other essential elements were held constant in solution or supplied by frequent application to 100 g of soil supporting the plants above the solution. For the constantly aerated solutions, pCu, as calculated from formation constants of Cu‐DTPA complexes and pH and as measured with a Cu specific ion electrode, was biologically equivalent to those obtained for solutions devoid of DTPA. For both hybrids, root and top growth were reduced due to Cu toxicity when pCu was ≤ 5.78. A deficiency of Cu was associated with a pCu > 13. While Cu concentrations in plant tops increased with decreasing pCu for both hybrids, the hybrids were different as predicted from the performance of the parental inbred lines. At high levels of Cu (pCu of 5 to 7) hybrid differences and changes in plant concentrations of Cu with pCu in solutions indicated that plant composition could not be used to indicate toxic substrate levels of Cu.
Abnormal Color Response of Turf Ryegrass to Top‐Dressed Isobutylidene Diurea1
Authors: Volk G. M. , Dudeck A. E.
Published: July 2010

Isobutylidene diurea (IBDU) is an excellent source of controlled‐release N for turfgrasses, but certain reports imply a generally low toxic potential not completely supported by recent Florida work. To evaluate toxicity, IBDU (0.7 to 1.4 mm diam. pellets) was used in single applications at 1 to 7.3 kg N/are rates on winter ryegrass (Lolium perenne L.) and at 1.5 to 5.9 kg N/are on bermudagrass (Cynodon sp.), the latter in all combinations with 0, 0.25, and 0.50 kg urea‐N/are every week, and of 0 and 2.4 kg Ca(OH)2/are at initiation of tests. A 2.2 kg N/are rate of IBDU resulted in chartreuse green ryegrass when soil pH was above 7.0. At 3.3 to 7.3 kg IBDU‐N/are the ryegrass was chartreuse‐yellow at 1 month after application, regardless of soil pH. Tissue analysis showed an excellent inverse correlation with Mn content. There was no off‐color response to sulfur‐coated urea or ureaform applied at N rates equivalent to those above. Color assessment by chlorophyll extraction with methanol supported visual observations. There was no toxic response of bermudagrass to IBDU at soil pH 5.1 to 7.3 or at any combination of IBDU with Ca(OH)2 and/or urea. Application of IBDU “fine” to ryegrass apparently should not exceed 2.0 kg of N/are if visual toxicity symptoms are to be avoided.
Seed Coating, Precision Planting, and Sprinkler Irrigation for Optimum Stand Establishment1
Authors: Robinson Frank E. , Mayberry Keith S.
Published: July 2010

The legal prohibition of the short handled hoe in California has forced a change in the conventional practice of surplus‐seedling and subsequent thinning to achieve optimum stands with lettuce (Lactuca sativa L.) and sugar beet crops (Beta vulgaris L.). Precision placement of coated seed was evaluated as an alternate method of stand establishment with five crops grown on Meloland sandy clay loam with sprinkler irrigation. Germination was compared to emergence of coated seed. Emergence was: carrot (Daucus carota L.) 86%, onion (Allium cepa L.) 85%, and sugar beet 71%. Single lettuce seeds 38 cm apart had 89% stand, paired seeds 2.5 cm apart on 38 cm intervals and thinned had 97%.
Water‐soluble Carbohydrate Accumulation in Soybean Plants1
Authors: Dunphy E. J. , Hanway J. J.
Published: July 2010

Because metabolic processes in plants are dependent on water‐soluble carbohydrates (WSC), information concerning the effects of different factors on the WSC contents of plants should be useful in the development of improved practices. Soybean [Glycine max (L.) Merrill] plant samples from field fertility experiments on Webster soil (Typic Haplaquoll) were collected and analyzed during two growing seasons to study the effect of different variables on WSC contents of different plant parts at various stages of plant development. WSC in dried plant samples were extracted with hot water and determined using a phenolsulfuric acid colorimetric method with glucose as a standard. The WSC content of leaves and petioles increased between 0900 and 1300 hours daily. WSC contents generally were higher in 1971 than in 1972. Differences in WSC among cultivars and fertility levels were relatively small. Percentages of WSC in leaves increased throughout the growing season, but in stems and petioles increased only until seed development became rapid. WSC contents of stems, petioles, and pods decreased as the seeds developed. This decrease may indicate that soluble CHO (metabolically active carbohydrate) becomes a limiting factor for seed production during the seed‐filling period.
Herbicides for Seasonal Weed Control in Turfgrasses1
Authors: Johnson B. J.
Published: July 2010

Commercially available preemergence herbicides do not consistently control weeds in turfgrasses satisfactorily in the Southeast. New herbicide tests to determine if weed control could be improved were conducted on several soil types over a 3‐year period. Several herbicides were applied in early spring and evaluated for the control of large crabgrass (Digitaria sanguinalis L. Scop) in bermudagrasses [Cynodon dactylon (L.) Pers.] and Kentucky bluegrass (Poa pratensis L.) turf or they were applied in early fall and evaluated for the control of annual bluegrass (Poa annua L.) and other winter annuals in a bermudagrass turf. Soil types were Cecil sl and Cecil scl (Typic Hapludult), Appling loamy sand and Appling scl (Typic Hapludult), Madison scl (Typic Hapludult), Hatboro 1 (Typic Fluvaquents), and Davidson scl (Rhodic Paleudult). Oxadiazon [2‐tert‐butyl‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐ Δ2‐1,3,4‐oxadiazolin‐5‐one] applied in early spring at 4.5 kg/ha was better than with other herbicides tested for large crabgrass control. Oxadiazon was the only herbicide that consistently controlled large crabgrass at all locations. Parsley‐piert (Alchemilla microcorpa Boissier Reuter), a broadleaf winter annual not previously reported, was controlled satisfactorily when oxadiazon was applied preemergence in the fall. No other herbicide controlled parsley‐piert as well as oxadiazon.
Vegetative‐fruiting Development and N Concentrations of a Dwarf Determinate Cotton Cultivar
Authors: Wanjura D. F. , Sunderman H. D.
Published: July 2010

The lack of information needed to verify a nitrogen submodel for a cotton (Gossypium hirsutum L.) plant simulation model suggested the need to measure the effect of N level on a broad spectrum of vegetative and fruiting development characteristics in a single field study. The effect on plant N accumulation and growth of 0, 90, and 180 kg N/ha applied to Amarillo loam soil, Aridic Paleustalfs, was measured on the cultivar ‘Paymaster Dwarf’ grown in 25 and 100‐cm rows. Increasing soil N application rate from 0 to 90 kg/ha increased per plant dry matter production in 100 but not in 25‐cm rows. Application of soil N increased plant N concentrations in leaves‐petiole‐squares and bur fractions. Plant N concentration was unaffected by row spacing. Stem, leaves‐petioles‐squares, and bur fractions decreased in N concentration from first square to maturity, while seed N concentration increased between peak bloom and maturity. The time of fruiting was unaffected by N application rate but there was a trend of increasing per plant square and boll numbers at higher application rates. Peak boll shedding showed two peaks in 25‐cm rows where soil N was applied compared to a single peak for 100‐cm rows. Collectively, the data describe plant‐N status and dry weight at three stages of growth and fruiting weekly for two row spacing and population levels.
Relationship between Potato Yield and Oxygen Diffusion Rate of Subsoil1
Authors: Saini G. R.
Published: July 2010

Numerous studies in the past have been made of the effects of soil compaction on potato yield by deliberately packing the soil in small experimental plots. Since information obtainable from such experiments has limited value in the economic assessment of crop production of an area, a study was conducted on 10 different farmers' fields to find out which soil physical property (or a combination of properties) may best define the prevailing productive capacity of a soil for potatoes (Solanum tuberosum L.).

Various soil properties (stones, sand, silt, clay, bulk density, penetrometer readings, and organic matter) were measured according to the methods given by Black (1965) at a depth of 20 to 28 cm (8 to 11”) where the compact soles usually occur. Oxygen diffusion rate (ODR), however, was determined at a moisture content of field capacity by the platinum microelectrode method (Lemon and Erickson, 1952) using a rate meter manufactured by Jensen Instruments, Tacoma, Wash.

Stepwise multiple regression analysis of potato yields of cultivar ‘Netted Gem’ and the soil properties indicated that ODR of subsoil was one single factor which highly correlated with marketable yield (r = +0.82). The correlation coefficient was significant at the 1% level of probability. Further addition of other properties did not improve the r value significantly.

The study indicates that the ODR of subsoil is a useful criteria to diagnose the prevailing physical condition of the soil which, in turn, could be related to the relative productive capacity of soil for potato production in New Brunswick, Canada.
Reflectant Induced Modification of Soybean Canopy Radiation Balance IV. Leaf and Canopy Temperature1
Authors: Baradas Maximo W. , Blad Blaine L. , Rosenberg Norman J.
Published: July 2010

Potential water‐savings and increased water use efficiency may result from reflectant‐induced modification of the canopy radiation balance. This report is the fourth in a series of papers describing reflectant treatment effects on the radiation balance. The purpose of this study was to determine the effect of reflectant treatment on the leaf and canopy temperature of two soybean [Glycine max (L.) Merr] cultivars which display contrasting types of canopy architecture. ‘Amsoy’ and ‘Beeson’ which have erectophile and planophile canopies, respectively, were used. Leaf temperature was measured with leaf thermocouples and canopy temperature with an infrared thermometer.

Near solar noon, the reflectorized Amsoy canopy was 1 to 2 C warmer than the untreated canopy. Smaller but qualitatively similar differences were observed in the Beeson cultivar. Whether reflectorized or not, the Amsoy canopies were warmer than the corresponding Beeson canopies. The increased temperature of the treated plants was corroborated by thermal imagery from an airborne scanner.

The unexpected temperature increase of the reflectorized crop was due to two major factors. The first, and probably most important, was a decrease in the longwave emissivity of the treated crop. This, in turn, caused reduced cooling rates and also caused the absorptivity to emissivity ratio (α/ε) to be increased. The second factor was reduced transpiration rates which were observed for the reflectorized crop.
Plant Population Effects on the Seed Yield of Phaseolus vulgaris L.1
Authors: Crothers S. E. , Westermann D. T.
Published: July 2010

Seed yields of Phaseolus vulgaris L. have not increased under the current production systems even with more precise management inputs. Recent studies of snap beans grown for processing suggested that yields could be increased by high density planting. Our study was made to evaluate the effects of plant populations on the seed yields of four representative field and snap bean cultivars grown under sprinkler irrigation on a Portneuf silt loam (Xerollic Calciorthid).

Two cultivars each of bush snap beans and semivining field beans were grown in plant populations of 107,600 to 968,700 plants/ha in nearly equidistant plant arrangements. The optimum plant population for seed yield for the bush cultivars was approximately 400,000 plants/ ha and less than 300,000 plants/ha for the semivining cultivars. At smaller plant populations, seed yields decreased for the bush cultivars and remained constant for the semivining cultivars. The harvest index (seed weight/ total plant weight) increased slightly for the bush cultivars as their plant population decreased, but remained constant for the semivining cultivars up to 300,000 plants/ ha, then increased rapidly. The production index (seed yield/amount seeded) increased curvilinearly as plant population decreased for all cultivars. Plant maturity was advanced 7 to 10 days at the highest plant populations for all cultivars. Pods were located at upper nodes on the plants as the populations increased. These results suggest that greater seed yields could be expected with the equidistant plant arrangements as compared with conventional row plantings for the bush cultivars, but not for the semivining cultivars, primarily because of the ability of the semivining cultivars to compensate for the increased area/plant at smaller plant populations.
Solution Culture Evaluation of Sweet Potato Cultivar Tolerance to Aluminum1
Authors: Munn D. A. , McCollum R. E.
Published: July 2010

A technique was desired that would permit screening of sweet potato [Ipomoea batatas (L.) Lamarck] cultivars for differential tolerance of Al in the root environment. Such a technique would be desirable to identify cultivars which would be adapted to acid soils where AI toxicity was a problem, or to identify A1 resistant cultivars for use in a plant breeding program. A solution culture technique was developed using a solution 0.25 mM CaCl2 14μM H3BO3, and 0 to 25μM Al2(SO4)3 at a pH of 4.5 to assess the relative Al damage to root initiation and root growth by stem cuttings of sweet potato. The technique was used to evaluate the Al tolerance of six sweet potato cultivars representing a spectrum of the cultivars grown in the southeast US. Root growth was assessed by measuring root weight, root length, and root length relative to the zero Al treatment (RRL). The six cultivars were ranked according to their ability to sustain root growth in the presence of Al (RRL) in the following order: ‘Australian Canner’ > ‘Centennial’ > ‘Pelican Processor’ > ‘Nugget’ > ‘White Star’ > ’Jewell.’ There were significant differences between cultivars in ability to sustain root growth in the presence of low levels of Al.
Onion‐Seed Yield and Quality as Affected by Irrigation Management1
Authors: Brown M. J. , Wright J. L. , Kohl R. A.
Published: July 2010

The effects of soil moisture, sprinkler irrigation, and misting (5 min at 30‐min intervals) on hybrid onion‐seed (Allium cepa L.) production were evaluated at Kimberly, Idaho. Sprinkling and misting treatments were included to determine if sprinkler irrigation could be used for onion‐seed production, and if evaporative cooling (misting) would alleviate the scalding of umbels at excessively high temperatures. Results showed that reasonable onion‐seed yields could be obtained with sprinkler irrigation in spite of anticipated adverse effects on pollination. In areas with high daytime temperatures, misting could be used to cool the umbels, as much as 15 C for about 20 min, although it does not seem necessary for the low 32 to 35 C daytime temperatures at Kimberly. The highest onion‐seed yields were obtained with the furrow‐irrigation treatment where water was applied when tensiometers at 20‐cm depth read about 0.5 bar soil moisture tension (furrow adequate). The addition of misting to furrow irrigation decreased seed yields 19%. Furrow irrigating at 0.4 bar decreased yields 26% below those obtained with irrigation at 0.5 bar. While overirrigation adversely affected yield, irrigation treatment had only a slight effect on seed weight and vigor.
Evaluation of an Evapotranspiration Model for Corn1
Authors: Rosenthal W. D. , Kanemasu E. T. , Raney R. J. , Stone L. R.
Published: July 2010

Many empirical evapotranspiration models, used for scheduling irrigation, require meteorological measurements not routinely compiled by the National Weather Service. Thus, difficulties and expense are incurred in obtaining the needed measurements. Therefore, an empirical evapotranspiration model, requiring few meteorological measurements was developed and tested for corn [Zea mays (L.) cv. ‘Dekalb XL72A’] at two sites in Kansas. Daily inputs required by the model include leaf area index, solar radiation, effective precipitation, and maximum and minimum air temperatures. Daily outputs include transpiration, evaporation, advective contribution, and soil water content. Model estimates of soil moisture in the 150‐cm profile were compared with neutron attenuation estimates. Model estimates were within 6% of neutron attenuation estimates during the growing season, and since the meteorological measurements can be routinely obtained at the field site, the model has potential for scheduling irrigation on a regional basis in Kansas.
Time, Magnitude, and Quality Estimates of Forage Consumed by Deer in Woodland Clearings1
Authors: Kalmbacher R. S. , Washko J. B.
Published: July 2010

Forages are seeded in woodland clearings by state and federal agencies to provide herbage for deer (Odocoileus virginianus). Such plantings can supplement the diet, but the quantitative and qualitative means by which agricultural forages supplement the food base are not known. The purpose of this study was to measure time and magnitude of use, and nutritional quality of a birdsfoot trefoil (Lotus corniculatus L.) — orchardgrass (Dactylis glomerata L.) mixture, a birdsfoot trefoil — bluegrass (Poa pratensis L.) — quackgrass (Agropyron repens (L.) Beauv.) mixture, and a mixture of native herbage (Danthonia spp., Festuca ovina L., Andropogon spp., Panicum spp., Rumex spp., Solidago spp., and Achillea millefolium L.) in order to establish guidelines for management of forage for deer in woodland clearings.

Significant forage utilization occurred primarily in late April and May when only the grasses grown in association with birdsfoot trefoil were available. Annual consumption of these cool season grasses averaged 500 kg/ha or 8% of average annual production. The cool season grasses averaged 250%, crude protein during peak utilization. Significant utilization was not measured on the native herbage. Most of these species did not resume growth until after consumption of the cool season grasses declined.

Management of forages for deer in woodland clearings should aim at producing forage during the early spring. Selected forages should be managed as a high protein supplement to bridge the gap between winter and summer foods. There appears to be little need to manage clearings as summer Led sources for deer.
Use of Paraquat in Establishing Dallisgrass and Bahiagrass1
Authors: Evers Gerald W.
Published: July 2010

Plantings of warm season perennial grasses from seed are slow to establish and often fail because of competition from fast growing weeds. Paraquat (1,1′‐dimethyl‐4,4′‐bipyridinium ion), a fast acting contact herbicide, has been used successfully in establishing cool season grasses from seed for seed production. Purpose of this study was to determine if the application of paraquat after planting, but before the desired grasses emerged, would reduce weed competition and promote rapid establishment of the desired grasses. In the spring of 1974 and 1975 ‘Pensacola’ bahiagrass (Paspalum notatum Flugge) and dallisgrass (Paspalum dilatatum Poir.) were planted on a prepared seedbed on a Morey fine‐silty loam [Typic Argiaquolls, fine‐silty, mixed (noncalcareous), thermic]. Experimental design was a split, split plot with four replications for each of the two grasses. Main plots were paraquat applied at 0.56 kg in 154 liters of water/ha at random time intervals after planting. Subplots were 12 fertilizer treatments consisting of a four by three factorial of 0, 22.4, 44.8 and 67.3 kg/ha of phosphorus and 0, 33.6, and 67.3 kg/ha of nitrogen applied on the day of planting. Plant densities were determined at two or three locations in each plot by randomly throwing a 0.09 m2 quadrant on to the plot. Dry matter yields were determined by cutting a 1 × 4.2 m area from the center of each plot to a 4 cm height. Paraquat was most effective when applied as late as possible but before bahiagrass and dallisgrass plants emerged. Dry matter yields of bahiagrass were tripled and dallisgrass doubled. Under the climatic conditions and soil type in this study, optimum time for applying paraquat to dallisgrass plantings was 10 but no later than 14 days and to bahiagrass plantings 14 to 21 but no later than 28 days after sufficient rainfall for grass seed germination. No consistent benefit was produced by any of the fertilizer treatments.
Chemical Tests to Evaluate Plant Sandblast Damage1
Authors: Armbrust D. V.
Published: July 2010

Plant sandblast damage is currently evaluated by decreases in dry weight, survival, plant height, or yield. A laboratory method would be desirable to decrease the time required to determine plant damage and it might be used to predict plant yields. The objective of this study was to evaluate assays for exosmosed amino acids, exosmosed electrolytes, internal conductivity of plant stems, trypsin inhibitor, and chlorophyll content for their ability as predictors of yield decrease due to wind erosion damage. Greenhouse gown tomatoes (Lycopersicon esculentum Mill. ‘Bonnie Best’) and soybeans (Glycine max (L.) Merr. ‘Wayne’) were exposed to 5 amounts of blowing sand ranging from 0 to 30 kg. Exosmosed amino acids and exosmosed electrolytes can be used to predict fresh and dry weights for up to 20 days after tomatoes and soybeans are damaged. However, final yields cannot be predicted by any of the five assays because of the plants' ability to recover from the damage.
Glyphosate as a Postemergence Treatment for Johnsongrass Control in Cotton and Soybeans1
Authors: Banks P. A. , Santelmann P. W.
Published: July 2010

Johnsongrass (Sorghum halepense (L.) Pers.) is a troublesome weed on cropland in the southern U. S. It is difficult to control due to its ability to reproduce from both rhizomes and seed. Glyphosate (N‐(phosphonomethyl)glycine) has demonstrated phytotoxicity to johnsongrass, so experiments were conducted to evaluate its use in cotton and soybeans for Johnsongrass control. Glyphosate was applied postemergence to ‘Lankert LX 571’ cotton (Gossypium hirsutum L.) and (‘Lee 68’ or ‘Bragg’ soybeans (Glycine max L.) in the field. Applications were made either over‐the‐top of the crop plants (topical) or directed to the base of the stems. Glyphosate controlled Johnsongrass best when treatments of at least 3.4 kg/ha were applied to plants 60 cm or greater in height. Discing the Johnsongrass 4 or 8 days after treatment had no effect upon control. Chlorflurenol (methyl 2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate), when used as a tank mix with glyphosate, did not influence the degree of Johnsongrass control. Glyphosate at 0.8 kg/ha used postemergence topically on cotton and soybeans caused significant visual injury and crop yield reduction. When directed to the basal 2.5 cm of the crop stem, glyphosate at 3.4 kg/ha provided season‐long control of Johnsongrass with the least amount of crop injury or yield reduction. The crops were least affected by the directed treatments at the taller crop heights. Thus, selective control of this perennial weed in cultivated crops was demonstrated with directed applications applied to the basal 2.5 cm of the crop stem.
A Simple Laboratory Approach to Test and Estimate Seed Germination Performance Under Field Conditions1
Authors: Hadas A.
Published: July 2010

A simple laboratory procedure for testing seed germination under simulated field conditions, and the utilization of these data in predicting the seed's performance under field conditions is presented.

Sorghum, pea, chickpea, and vetch seeds were germinated in P.E.G. (polyethyleneglycol) solutions of different osmotic potential levels in the laboratory. The collected data were used to predict germination of sorghum and chickpea seeds in outdoor plots. A good agreement was found between the observed germination in field plots and predicted germination from laboratory data time period needed to attain germination. A comparison between this suggested simple seed testing method and the ISTA method is made and the merits of the presented method are discussed.
Control of Italian Ryegrass and Wild Oats in Winter Wheat with HOE 234081
Authors: Brewster B. D. , Appleby A. P. , Spinney R. L.
Published: July 2010

Italian ryegrass (Lolium multiflorum Lam.) and wild oats (Avena fatua L.) are widespread and competitive weeds in winter grain fields of western Oregon and Washington. A new herbicide, HOE 23408 {methyl 2‐[4‐(2,4‐dichlorophenoxy) phenoxy] propanoate}, has shown promise for selective control of both species. Field studies were conducted at 12 locations in 1974–75 and 1975–76 to evaluate the effectiveness and consistency of weed control with HOE 23408 in winter wheat (Triticum aestivum L.) and to measure the influence of removing ryegrass and wild oats on wheat grain yields. HOE 23408 was applied preemergence, early postemergence (two to three‐leaf stage), and late postemergence (tillering stage) at rates from 0.84 to 2.24 kg/ha. When applied preemergence, HOE 23408 gave adequate control of ryegrass when the seedbed was relatively free of clods and plant residues but wild oat control was erratic. Nearly complete control of both species was obtained from all postemergence treatments at rates as low as 0.84 kg/ha. Increases in wheat grain yield were often dramatic; in one case, the increase over the untreated control was 6,000 kg/ha from treatment at 1.12 kg/ha applied early postemergence. Average yields from this treatment exceeded yields from plots treated with diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea], barban (4‐chloro‐2‐butynyl m‐chlorocarbanilate), and triallate [S‐(2,3,3‐trichloroallyl) diisopropylthiocarbamate] by 2,170, 1,280, and 1,580 kg/ha, respectively. Results indicate that HOE 23408 has considerable potential for control of ryegrass and wild oats and that large increases in yield of wheat grain can be expected when severe infestations of these weeds are controlled.
Correction of Mn Deficiency of Soybeans1
Authors: Alley M. M. , Rich C. I. , Hawkins G. W. , Martens D. C.
Published: July 2010

The objective of this study was to compare rates of Mn application and methods of Mn application to correct Mn deficiency of soybeans (Glycine max L.) in planting systems where no starter fertilizer is utilized. Field experiments were conducted at three locations in the Coastal Plain region to evaluate broadcast and foliar applications as well as band placement of granular Mn fertilizer in the row with seed. The latter application was accomplished by utilizing a conventional granular insecticid applicator. Soils studied in this investigation included two aquic hapludults and one typic quartzipsamment.

Applications of 5.6, 11.2, and 16.8 kg Mn/ha bandplaced in the row with seed produced yield increases of soybeans on both limed and unlimed areas at one location. Soybean yield increases were obtained at this location from broadcast applications of 11.2, 22.4, and 44.8 kg Mn/ha on the unlimed soil, and from the 22.4 and 44.8 kg Mn/ha on the limed soil. A foliar treatment of 2.2 kg Mn/ha also produced grain yield increases. Only the 11.2 and 16.8 kg Mn/ha band‐placed with seed, and the 11.2 kg Mn/ha broadcast treatments on the limed soil gave soybean yield increases at a second location. Drought conditions prevailed at the third site and no soybeans emerged on the 11.2 and 16.8 kg Mn/ha bandplaced with seed treatments.

In planting systems where conventional band placement of fertilizer is not practical, band placement of Mn in the row with seed can increase yields on soils supplying insufficient Mn for plant growth. Plant populations can be reduced by band placement of Mn in the row with seed under adverse moisture conditions. Broadcasting high rates of Mn or repeated foliar applications of Mn will also correct Mn deficiency of soybeans.
Water and Nutrient Response of Semi‐dwarf Wheat under Improved Management in Pakistan: Agronomic and Economic Implications1
Authors: Eckert J. B. , Chaudhry N. M. , Qureshi S. A.
Published: July 2010

‘Chenab‐70’ cultivar of semi‐dwarf wheat (Triticum aestivum L.) was grown under improved management conditions with several levels of N, P and irrigations. An incomplete factorial design included N levels of 0, 56, 112, 168, and 224 kg/ha and 1, 2, 3, 4, 5, and 6 irrigations. Each irrigation consisted of 7.6 cm applied water. Irrigations were optimally sequenced with crop growth stages as indicated by prior research in India and Pakistan. The resulting quadratic production functions indicate that yield levels now obtained by the best farmers can be obtained with one‐third to one‐half of the water currently being applied if irrigations are timed and controlled appropriately. Fertilizer response also exceeded that obtained by progressive farmers. Economically optimum application rates for water and N were rather restrictive with little opportunity for substitution. Finally, soil moisture measurements coupled with concurrent physiological and morphological observations are used to rationalize the persistence of indigenous cultural practices and to suggest new cultural practices to further enhance irrigation efficiency.
Role of Anthracnose in Stand Thinning of Alfalfa in Delaware1
Authors: Jones E. R. , Carroll R. B. , Swain R. H. , Bell K. W.
Published: July 2010

Anthracnose, caused by Colletotrichum trifolii Bains, is widespread on alfalfa (Medicago sativa L.) in Delaware and thinning of alfalfa stands is believed to be at least partially due to anthracnose. The purpose of this field study was to determine the effect of C. trifolii on winter survival of alfalfa. Alfalfa plants growing on a Typic Haplueults soil, with and without symptoms of anthracnose, were tagged prior to winter dormancy to determine the effects of C. trifolii on winter survival. Other factors affecting winter survival of alfalfa were evaluated by removing another group of plants with and without anthracnose symptoms from the experimental site before winter dormancy. The following parameters were evaluated: root and crown rot, insect feeding on root and crown tissues, presence of new crown buds, root and crown tissue weights, and total nonstructural carbohydrate levels. Soil surrounding the roots of removed plants was analyzed for soil acidity, P, K, Ca, Mg, and B. Colletotrichum trifolii‐infected plants had 22 to 85% lower winter survival values when evaluated the following spring. Colletotrichum trifolii‐infected plants evaluated prior to winter dormancy had 7% smaller root systems and 29% fewer plants with new crown buds, but did not have significantly different levels of crown and root rot or root insect damage. Soil tests, indicated no relationship between soil parameters measured and anthracnose. It is concluded that anthracnose was the principal factor responsible for stand thinning of alfalfa during the winter dormant period.
Short‐statured Rice Response to Seeding and N Rates1
Authors: Wells B. R. , Faw Wade F.
Published: July 2010

Research on response of direct seeded rice (Oryza sativa L.) to interactions of seeding rate and N rate is very limited, although considerable work has been done in the tropical countries with transplanted rice. Understanding responses by U.S. rice cultivars to these factors is important not only for optimizing management, but also because it provides information concerning the need for further improvement of plant type. Therefore, our objective in this study was to determine what factors might limit performance of ‘Starbonnet’ rice when subjected to a range of seeding and N rates. This study was conducted in field plots for 2 years on a Crowley silt loam soil (Typic Albaqualf) at the Univ. of Arkansas Rice Branch Experiment Station, Stuttgart, Ark. A split plot design was used. Time of N application (preplant or topdress) was the main plot and all possible combinations of seeding rates of 67, 135, and 303 kg/ha and N rates of 67, 135, and 202 kg/ha were the subplots. All treatments were replicated four times. The following measurements were taken: grain yield; stand counts prior to tillering and at maturity; blanks per panicle; florets per panicle; dry weight at heading and maturity; percent N in the flag leaf at heading; leaf area index (LAI) at heading

Excessive vegetative growth before anthesis limited grain yield from dense plant populations. This was evidenced by high LAI at heading, reduced dry matter accumulation after heading, and adequate N levels in the flag leaf under conditions of dense population. Further indication of the effect of excessive vegetation prior to anthesis was shown by the fact that number of florets per panicle had more influence on grain yield than did blanks per panicle.

Increasing the N rate from 135 to 202 kg/ha increased grain yield only for the 67 kg/ha seeding rate in 1972. Time of N application (preplant or topdress) did not influence grain yield.

Under the direct seeding conditions of this study initial plant population, rather than tillering, accounted for the number of panicles per unit area. As seeding rate and plant population increased, number of florets and blanks per panicle decreased. Increasing the N rate increased both florets and blanks per panicle. Both increased seeding rate and N rate resulted in increased LAI.

Under the conditions of this test the major factors that limited yield under dense population appeared to be light and CO2, since extra N fertilizer was ineffective.