Sharkey Silty Clay Research Articles

Estimating the Impact of Delaying Irrigation for Midsouth Cotton on Clay Soil

In many years, cotton producers in the Midsouth delay the first irrigation to allow time for other field operations such as pesticide and fertilizer application. This practice is especially common on clay soils that require several days to dry after furrow irrigation. However, the cost to the producer of delaying irrigation is not well understood. The objective of this research was to estimate the impact of delaying the first irrigation for cotton on clay soil to help producers make more informed decisions regarding irrigation timing. Cotton irrigation studies were conducted at the University of Arkansas Northeast Research and Extension Center at Keiser during the 2001 through 2003 growing seasons, with the cultivar PM 1218 BG/RR planted on a Sharkey silty clay (Chromic Epiaquerts) precision graded to approximately 2 mm m-1 slope. All plots contained four rows approximately 180 m long with a 97 cm row spacing and four-row border area left between each pair of plots. A well watered treatment was irrigated at a 50 mm estimated soil water deficit (SWD) based on the Arkansas Irrigation Scheduler. Irrigations for two delayed-irrigation treatments were initiated on the date of the second irrigation or third irrigation of the well watered treatment and then irrigated at a 50 mm estimated SWD. A nonirrigated check was included. Irrigations were ceased when open bolls were observed. Three-year-average yields decreased with delaying irrigation. There was a consistent trend for lower yield for each delay in the first irrigation; however, in 2003, the differences among all four treatments were not significant. The three-year-mean irrigation water use efficiency was higher for the well watered treatment than for either delayed-irrigation treatment; however, in two of the three years (2001 and 2003), the differences among the treatments were not significant. Gross revenues for the well watered treatment were numerically greatest each year; however, when the costs of irrigation were included, estimated net revenues for the well watered treatment were not always highest. A number of scenarios were investigated (e.g., different water sources, rented land), and even though two of the three years were wetter than normal, the delayed-irrigation treatments always had significantly lower estimated net revenues than the well watered treatment. Furthermore, the estimated net revenues for the delayed-irrigation treatments in each case were not significantly different from those of the nonirrigated treatment. When all other factors were held constant for rented farmland, the well watered treatment had higher estimated net revenues than the nonirrigated treatment for diesel cost < $0.65 L-1 ($2.47 gal-1). A treatment with a delayed first irrigation, a fairly common practice on Midsouth cotton farms, was only more profitable than the nonirrigated treatment when diesel cost < $0.19 L-1 ($0.74 gal-1).

Runoff losses of cyanazine and metolachlor: effects of soil type and precipitation timing

The effects of time of precipitation and soil type on runoff losses of cyanazine and metolachlor were studied using a tilted-bed, microplot system. Two silt loam soils, Bosket and Dubbs, and a Sharkey silty clay were evaluated. Rainfall (22 mm h−1) was simulated at 0, 2, and 14 days after treatment (DAT). Time of precipitation did not impact herbicide losses or any of the runoff parameters evaluated in this study. Water runoff occurred sooner and in greater quantities from the surfaces of Bosket and Dubbs silt loam soils than from the surface of Sharkey silty clay. Runoff losses of cyanazine did not vary by soil type. Soil drying produced large cracks in Sharkey silty clay, which greatly reduced runoff in this soil. Combined runoff and leachate losses were highest from Dubbs silt loam. Runoff losses of metolachlor were not affected by soil type. However, regression analyses indicated that time of precipitation and soil type interacted to affect initial metolachlor concentration. At 14 DAT, initial metolachlor concentration was highest in runoff from Sharkey soil. Time of precipitation ranked with respect to initial metolachlor concentration in runoff from Bosket and Dubbs silt loam soils were 0 &gt; 2 &gt; 14 DAT and 0 = 2 &gt; 14 DAT, respectively.

Sorption–desorption of cyanazine in three Mississippi delta soils

Sorption and desorption of cyanazine with three Mississippi Delta soils (two silt loams and one silty clay) were studied under laboratory conditions. Cyanazine sorption calculated using the Freundlich equation was greatest for the Sharkey silty clay soil. Partition coefficients (Kd values) for cyanazine sorption ranged from 1.67 to 1.82, 1.92 to 2.15, and 3.65 to 3.96 ml g−1 for the Bosket silt loam, Dubbs silt loam, and Sharkey silty clay soils, respectively. Differences in sorption and Kd values were attributed to clay content. At a given initial cyanazine concentration, cyanazine was desorbed more readily from the silt loam soils than from the Sharkey clay after the first 4-h desorption cycle. Desorption from the Sharkey clay continued for a longer period than that from the silt loam soils, with up to 6% cyanazine desorption from the Sharkey clay after a 16-h desorption cycle compared with 0% for the silt loam soils. Cyanazine losses increased with decreasing clay content, Dubbs = Bosket &gt; Sharkey. This implies a potential relationship between cyanazine desorption and surface runoff losses of cyanazine.

Comparison of flooded and furrow-irrigated rice on clay

In some situations, potential water savings or relatively steep slopes make furrow irrigation a useful management practice for rice (Oryza sativa L.). Furrow-irrigated and flooded rice were compared in a field study conducted during three growing seasons: 1990, 1991, and 1992, at the University of Arkansas Northeast Research and Extension Center, Keiser, Ark., USA on a Sharkey silty clay soil. Excessive levee seepage greatly affected the water-use data for flooded rice production; however, there appeared to be potential for water savings on the Sharkey soil with furrow irrigation. Yields for flooded production consistently exceeded those for furrow-irrigated, with 3-year averages of 7.04, 6.02, and 5.88 Mg ha–1 for flooded and two furrow-irrigated treatments, respectively. The yield difference appeared due to greater individual grain weight for the flooded treatment. Attempts to compensate for the yield reduction through additional nitrogen applications were unsuccessful. These results are consistent with findings of reduced rice grain yield associated with sprinkler irrigation. Furrow irrigation at an estimated 19 mm soil water deficit had a 3-year average of 11 kg ha–1 of rice produced per mm of irrigation water applied.

Analysis of Seedbeds and Maturity Groups for Dryland Soybean on Clayey Soil

Soybean [Glycine max (L.) Merr.] production systems on clayey soils are difficult to manage. With improvements in no‐till planting equipment and herbicide technologies in the early 1990s, no‐till production has become a viable alternative to the traditional tilled seedbed. Therefore, the relative economic performance of tilled and no‐till seedbeds with respect to profitability, sensitivity to input price changes, and risk is assessed for maturity group (MG) IV, V, and VI soybean. Field experiments using split plots (main plots were MG and subplots were seedbeds) and a randomized complete block design with four replications were conducted from 1992 to 1994 at Rohwer, AR and from 1990 to 1997 at Keiser, AR on Sharkey and Sharkey silty clay, respectively. The importance of weather conditions is highlighted in the varied seedbed preparation effect on grain yields, with no clear advantage to either method. On average, yields were higher for MG IV at Rohwer and MG VI at Keiser. The breakeven price and yield analysis suggested that MG selection had a larger economic impact than seedbed preparation, regardless of location. This analysis also showed the extent of production cost differences and associated risk of loss by location. Risk analysis revealed that optimal production strategies changed when input costs were added to yield information and further confirmed that MG selection affects profitability more than seedbed preparation. Production practices that better exploit the yield potential of various MG cultivars (as related to weather conditions) therefore deserve further research attention.

Economic assessment of irrigated and nonirrigated soybean cropping rotations on a clay soil

Experiments were conducted in Keiser, Arkansas on a Sharkey silty clay soil for three years to examine soybean, wheat, and grain sorghum rotations. Treatments also included selected variation of conventional versus no till and alternative wheat residue management. Both irrigated and nonirrigated strategies were investigated. Agronomic results show that irrigated soybean yields average about 1,344 kg ha‐1 (20 bu A‐1) higher than comparably treated nonirrigated soybean treatments. Economic analysis using enterprise budgets reveals three top rotations regardless of irrigation: continuous monocropped soybean, wheat fallow followed by monocropped soybean, and wheat‐soybean double‐cropped with burned wheat stubble. Statistical analysis demonstrates the profitability of irrigation and the dependence of the most economical crop rotation upon weather conditions.

An Economic Analysis of Alternative Cropping and Row Spacing Systems for Soybean Production

Conflicting results have been reported in the literature concerning the effects of narrow row spacings on soybean [Glycine max (L). Merr.] production in the southern USA. The objective of this study was to revisit the issue by evaluating some economic implications of alternative row spacing arrangements on soybean performance under both irrigated and nonirrigated conditions. Data from 3-yr continuous soybean experiments conducted at the Northeast Research and Extension Center, Keiser, AR, between 1990 and 1992 were used for this purpose. Enterprise budgeting was employed to determine the nature of costs and returns associated with alternative production systems. Simple variability and break-even analyses were used to provide preliminary insights into the probable sensitivities of alternative practices to fluctuations in production and economic environments. The results indicated that narrow row systems (usually between 10 and 20 in.) could enhance yields and net returns either under nonirrigated or irrigated conditions. A yield increase of between 15 and 30% was obtained under nonirrigated conditions, while an improvement in yields ranging from 10 to 17% was obtained under irrigation. Furthermore, results from break-even analysis supported the use of narrow row systems for enhancing net returns relative to wide row arrangements under a production environment that is characterized by fluctuations in yields and output prices.

Nitrogen fertilization and plant development of cotton as determined by nodes above white flower1

Abstract Early maturation is very beneficial in successfully harvesting a high‐quality, high‐yielding cotton (Gossypium hirstum L.) crop. If harvest is delayed until inclement weather patterns are established, both yield and fiber quality may be lost. The objective of these studies was to determine the maturity differences that occur in cotton differentially fertilized with nitrogen (N). Field experiments with irrigated cotton were conducted in 1990 and 1991 in three locations to study the effects of soil applied N rates on cotton maturity as estimated by nodes above white flower (NAWF) measurements. The test sites and soils were a production field near Manila, AR, on a Dundee sandy loam (fine‐silty, mixed, thermic Aeric Ochraqualfs), the Southeast Branch Experiment Station (SEBES) near Rohwer, AR, on an Hebert silt loam (fine‐silty, mixed, thermic Aeric Ochraqualfs), and the Northeast Research and Extension Center (NEREC) near Keiser, AR, on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic Vertic Haplaquepts). Criteria used as indicators of crop maturity and earliness in these studies were the time in days after planting (DAP) and the accumulated heat units (HU) for the crop to reach NAWF=5. Increasing N rates delayed maturity at SEBES both years and at Manila in 1991 but not at NEREC either year. Differences in maturity between N treatments of 168 and 224 kg N/ha were minimal at all locations both years. Smaller differences in time for the plants to achieve NAWF=5 were observed in the cotton grown at Manila in 1990 and at NEREC both years. The smaller differences at Manila are assumed to be due to high levels of residual N from previous crops. Early‐season vegetative growth was indicated by NAWF extrapolated to first flower (60 DAP or 945 HU). A trend of higher NAWF at the extrapolated first flower stage with increasing N rate was observed, but generally differences were minimal. The NAWF values at DAP=60 were lower in 1991 than in 1990 for all locations.

Wheat production on raised beds on clayey and silt loam soils

Abstract Winter wheat (Triticum aestivum L.) production commonly occurs on poorly‐drained soils of the Mississippi River Delta region in Arkansas. Wheat has historically been planted on a conventional flat seedbed (CFS); however, the use of raised beds may improve drainage, grain yield, and nitrogen (N) fertilizer efficiency. Wheat production on (76 inch) wide raised crowned beds (CB) and raised flat beds (FB), were compared to the CFS in seven experiments. The more conventional 38 inch wide CB was compared to the CFS in four additional experiments. The eleven experiments were conducted from 1986 to 1991 at Keiser on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquepts) and at Colt and Marianna on a Calloway silt loam (fine‐silty, mixed, thermic, Glossaouic Fraqiudalfs). Wheat grain yield was measured. Wheat in the center of the raised beds had higher yields than wheat near or in the water furrows. Increases in the number of spikes and kernels per spike is the source of ...

Using cotton petiole nitrate‐nitrogen concentration for prediction of cotton nitrogen nutritional status on a clayey soil1

Abstract Soil and petiole nitrate‐nitrogen (NO3‐N) analyses have been used to monitor the nitrogen (N) nutritional status of cotton (Gossypium hirsutum L.) in Arkansas. The basis for in‐season N fertilizer additions has been NO3‐N monitoring for the most recently matured leaf petiole. In this manner N fertilizer can be adjusted so that N is not limiting during growing seasons conducive to high yields. The objective of studies reported herein was to determine petiole NO3‐N levels that define deficient, adequate, and excessive N nutritional status of irrigated cotton growing on a clayey soil. Experiments were conducted on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquept) located on the Northeast Research and Extension Center at Keiser, AR. The experimental design was a 5 by 5 Latin Square with a split plot arrangement of treatments. Subplots were cultivars of cotton, and main plots were N rates of 0, 56, 112, 168, and 224 kg/ha applied as 56 kg/ha splits beginning just ...

Dissipation of Fluometuron and Trifluralin Residues After Long-term Use

Existing long-term cotton experiments established in 1976 with minimum and intensive herbicide programs were subdivided in 1985 and 1986 to determine the longevity of fluometuron and trifluralin soil residues after discontinuing herbicide application. In monoculture cotton, seed cotton yield increased when herbicide use was discontinued in 1985 and 1986 after 9 and 10 yr of continuous use, respectively, on a Sharkey silty clay and a Dundee silt loam soil. Yield increases coincided with reductions of fluometuron and trifluralin soil residues. Fluometuron dissipated from the Dundee silt loam soil by 10 mo after the last application but was present in the Sharkey silty clay soil at 0.20 ppmw after 28 mo. Trifluralin did not totally dissipate from either soil, and low levels were present in the Dundee (0.05 ppmw) and Sharkey (0.13 ppmw) soils 30 mo after the last application. Visual injury to fall-seeded wheat and vetch decreased as herbicide residues dissipated. Fall tillage had no significant effect on the rate of fluometuron or trifluralin dissipation from either soil but reduced seed cotton yields.

Carryover of DPX-PE350 to Grain Sorghum (Sorghum bicolor) and Soybean (Glycine max) on Two Arkansas Soils

Field experiments were conducted to determine carryover potential to grain sorghum and soybean of DPX-PE350 applied POST at 0.05, 0.1, and 0.2 kg ai ha−1to cotton the previous year. DPX-PE350 did not injure soybean or affect yield adversely. Grain sorghum was injured and maturity delayed on a Sharkey silty clay but not on a Calloway silt loam. Grain sorghum yield was reduced on both soils 16 and 22%, respectively, by residues from the 0.1 and 0.2 kg ha−1rates of DPX-PE350. In an incubation study, dissipation of DPX-PE350 was greater at 35 C than at 5 C., and did not differ between the two soils.

Response of Fast Fruiting Cotton Cultivars to Nitrogen on a Clayey Soil

The present cotton (Gossypium hirsutum L.) N recommendations for Arkansas were developed primarily on silt loam and sandy loam soils, but interest in cotton production on clayey soils has increased. The objective of this study was to determine the appropriate quantity of N for the new faster fruiting cotton cultivars grown on clayey soils. Experiments were conducted from 1988 to 1990 on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquept) at Keiser, AR. The response of cotton cultivars 'Deltapine 20', 'Deltapine 5O', 'Stoneville 453', and 'Stoneville 506' were evaluated at five N rates (O, 50, 100, 150, and 200 lb/acre). Cultivars were found to respond similarly to increasing N fertilizer. These cultivars yielded differently each year but averaged the same across years []

Evaluation of manganese inorganic fertilizer sources and Mehlich‐3 extractant for prediction of manganese deficiency in soybeans on a Sharkey silty clay

Abstract A greenhouse experiment was conducted on two Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquept) soils (SharkeyA and‐B) to compare MnSO4 and two Mn‐oxysulfatc sources (oxysulfate‐A and‐B) and to evaluate the Mehlich‐3 extractant. Soils were collected from a soybean [Glycine max (L.) Merr.] field with (Sharkey‐A) and without (Sharkey‐B) a history of Mn deficiency symptoms. Treatments consisted of two lime treatments, O and 2000 mg kg‐1, and three Mn rates, 0, 20, and 40 mg kg‐1. Each source was broadcast in granular form. Manganese sulfate was also applied in solution. Soybean plants were grown for 40 days. Dry weight, whole‐plant Mn concentration, and total Mn uptake were measured. Extractable soil Mn was determined using the Mehlich‐3 extractant. Dry weight was increased by applied Mn only on the Sharkey‐A soil, especially for the limed treatment. The Mehlich‐3 extractant delineated between the responsive (2.3 mg Mn kg‐1) and non‐responsive (6.0 mg Mn kg‐1) Shar...

Late spring nitrogen applications on wheat on a poorly drained soil

Abstract Many of the poorly drained clayey soils of the Mississippi River delta region in Arkansas are used for soft red winter wheat (Triticum aestivum L.) production. Oftentimes, excessive rainfall occurs between the last N application and physiological maturity, resulting in soil conditions conducive to denitrification. Studies were conducted in 1989 and 1990 to evaluate late N applications on five wheat cultivars on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquepts) at Keiser, AR. A linear‐move irrigation system was used to maintain excessive soil moisture conditions throughout the spring growing season to best insure denitrification conditions. After the recommended spring N was applied, N as urea was applied at rates of 0, 34, and 68 kg ha‐1 at growth stage (GS) 9 in 1989 and GS 10 in 1990. Ammonium nitrate was also evaluated at the 34 kg N ha‐1 rate. Grain yield, yield components, whole‐plant N concentration, grain N content, and whole‐plant N uptake were evalu...

Nitrogen efficiency of grain sorghum grown on flat and raised seedbeds on poorly drained soil

Abstract Grain sorghum (Sorghum bicolor L. Moench) production commonly occurs on poorly drained clayey soils of the Mississippi River delta region inArkansas. Raised, wide seedbeds may improve grain yield and fertilizer N efficiency for narrow‐row sorghum production on these soils. The influence of individual row positions on raised, wide seedbeds was compared to conventional flat seedbed for grain yield, yield components, dry weight, and N uptake. A 193‐cm wide and 15 cm high crowned seedbed (CB) was compared to the flat seedbed (FB) in 1987 and 1988 on a Sharkey silty clay (very fine, mont‐morillonitic, nonacid, thermic, Vertic Haplaquepts) at Keiser, AR. Three rows were planted on each seedbed treatment; one in the middle of the bed and one row 48 cm to each side of the row in the middle. Nitrogen rates of 0, 56, 112, and 168 kg/ha were applied at planting. In addition, two split applications at the 168 kg/ha N rate (56 kg N/ha at planting and 112 kg N/ha at either four‐leaf or eight‐leaf growth stage)...

Protecting Cotton (Gossypium hirsutum) from Fluometuron Injury with Seed Protectants

Field experiments were conducted in 1986 and 1987 to evaluate the potential of growth regulators mepiquat chloride and chlormequat chloride as seed treatments to protect cotton from fluometuron injury. Fluometuron at two and three times the recommended use rate reduced cotton stand and height on Taloka and Convent silt loam soils both years. Cotton grown on a Sharkey silty clay soil was not injured by fluometuron. Mepiquat chloride and chlormequat chloride increased cotton stands on a Taloka silt loam soil when averaged over rates and years. In general, fluometuron injury to cotton was not reduced by treating seed with 1000 ppmw concentrations of chlormequat chloride or mepiquat chloride. Chlormequat chloride reduced chlorosis and necrosis of cotton treated with fluometuron, but neither growth regulator eliminated cotton injury or yield reduction caused by fluometuron at two or three times the recommended rates.

Microbial and Photolytic Dissipation of Imazaquin in Soil

Microbial degradation of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} was monitored by measuring14CO2evolution for 7 months under controlled laboratory conditions. Up to 10% of the14C chain-labeled imazaquin that was applied to a Crowley silt loam was evolved as14CO2in 7 months. Less evolution of14CO2occurred on a Sharkey silty clay, a soil with higher clay and organic matter content, than on silt loam soils. The loss of 66 to 100% of the imazaquin applied to a Crowley silt loam incubated for 8 months at 18 C or 35 C, respectively, suggested that metabolic changes in addition to CO2evolution were occurring. Rapid loss of imazaquin phytotoxicity occurred when soils were held at warm-moist (35 C and −33 kPa) conditions conducive to microbial growth. Imazaquin was more persistent in soils stored under cool, dry (18 C and −100 kPa) conditions. Imazaquin on a soil surface dissipated rapidly when exposed to ultraviolet light or sunlight. Photodecomposition could be a major mode of imazaquin dissipation if this herbicide is allowed to remain on the soil surface.

Imazaquin Persistence and Mobility in Three Arkansas Soils

Field persistence of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} applied preemergence as high as 16 times the 0.14 kg ai/ha recommended rate was studied at two locations in Arkansas in 1984 and 1985. Rapid dissipation of these high rates occurred on the Taloka silt loam under hot, dry field conditions in 1984 when no rainfall occurred for 2 weeks after application. In 1985, when furrow irrigation was applied 7 days after application, imazaquin phytotoxicity was greater and dissipation was delayed. Imazaquin persistence and soil adsorption were greater on Sharkey silty clay than on Taloka silt loam. Following 3- and 8-cm irrigation, 84 and 78%, respectively, of the14C-labeled imazaquin remained in the surface 5 cm, but in plots covered between rainfalls and receiving 8 cm rain, 74% leached out of this top layer. Since nonincorporated imazaquin dissipated rapidly under hot, dry field conditions, carryover into the next growing season or leaching below the plow layer would not be expected. However, in cool, wet conditions immediately after application, the weakly adsorbed imazaquin molecule was readily bioavailable and mobile in the soil profile.

Effect of Cotton (Gossypium hirsutum) Herbicide Carryover on Subsequent Crops

The residual effect of three cotton (Gossypium hirsutumL.) herbicide programs, including the use of no herbicides, a minimum program consisting of fluometuron {N,N-dimethyl-N′-[3-(trifluoromethyl)phenyl] urea} and MSMA (monosodium salt of methylarsonic acid), and an intensive program consisting of trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine], fluometuron, MSMA, and linuron [N′-(3,4-dichlorophenyl)-N-methoxy-N-methylurea], were evaluated from 1976 to 1982. Herbicide injury to wheat (Triticum aestivumL.) and hairy vetch (Vicia villosaRoth.) on three soils showed carryover effects in the following sequence: Sharkey silty clay &gt; Dundee silt loam &gt; Loring silt loam. The intensive program was the most injurious on the Sharkey silty clay. The effects of the two herbicide programs were nearly equal on the Dundee and Loring silt loams. Possible replacement crops for cotton, such as grain sorghum [Sorghum bicolor(L.) Moench.] and corn (Zea maysL.) suffered the least damage from carryover; rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.] and cucumber (Cucumis sativisL.) suffered severe damage. Greenhouse bioassays generally confirmed field results, and fluometuron appeared to be the major component of carryover.