A field experiment was conducted for two years to determine the effects of four sulfur (S) sources applied at various rates on the elemental composition of Coker 747 3 wheat and on the soil S concentration. The concentration of S in plants increased by all sources of applied S. Increased S in the soil from S application decreased P concentrations in plants regardless of the S source used. Sulfur additions did not significantly affect the concentrations of Cu, Ca, Mg, or N in plants. The concentrations of Mn, Zn, and Fe in plants either increased or decreased depending on S source used.Analysis of the silt loam soil to a depth of 90 cm revealed that applied S moved readily from the surface to the lower depths and that the elemental form of S moved less rapidly than the more soluble forms of applied S. 653

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The changes in nitrate-nitrogen during routine handling of soil samples was investigated for samples taken from profiles (0 to 90 cm) of eight soils used in cotton production. Variables included holding soil samples in the field-moist condition for from 2/3 of a day to 8 days, and drying times of 0 to 7 days from unpacking to testing.Only the one soil that had recently received ammonium-nitrogen showed an appreciable change in nitrate-nitrogen when held in a moist condition. Holding of the other samples in a moist condition for 8 days tended to give slightly lower results.The time of testing after unpacking modified the nitrate level only slightly in all samples except the one soil that had been recently fertilized with anhydrous ammonia. Minor variations in nitrate-nitrogen content during processing of samples taken from unfertilized soils were not great enough to appreciably affect nitrogen fertilizer recommendations for cotton.

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 SO’, ‘Stoneville 453’, and ‘Stoneville 506’ were evaluated at five N rates (0, 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. Nitrogen requirement was most affected by year. On this clay soil, the higher N rates increased yield of both first‐ and second harvest cotton. The high N rates of 150 and 200 lb/acre did not reduce total lint yield for this clayey soil. Economic analysis showed that lint yield changes resulting from different growing seasons could offset those changes resulting in a twofold price change in lint and N fertilizer. Break even N rate ranged from 105 to 160 lb N/acre depending on year and price of lint and fertilizer. Research Question Cotton (Gossypium hirsutum L.) acreage has increased in Arkansas in recent years. Most of this acreage increase has been on sandy‐loam to silt‐loam textured soils. More cotton is also being grown on finer‐textured, clayey soils, however. The present Arkansas N fertilizer recommendation is partially based on soil texture. The objective of this study was to determine the appropriate quantity of N for the new faster fruiting cotton cultivars grown on clayey soils. Literature Summary Little N fertility research has been conducted on clayey soils of the Mississippi River Delta region in Arkansas. Generally, in these studies more N was required on the clayey than the silt loam soils. Rank growth and subsequent yield reductions, resulting from high N rates, were less of a problem on the clayey soils. Earlier research also indicated a significant cultivar × N rate interaction, suggesting that N requirement depended on cultivar. Cotton cultivars evaluated in these earlier studies are no longer commercially available. Study Description Five N rates and four new fast fruiting cotton cultivars were evaluated from 1988 to 1990 at the Northeast Research and Extension Center at Keiser, Arkansas. Soil: Sharkey silty clay Experimental Design: 5 by 5 Latin‐square with a split‐plot arrangement of treatments Chemicals: Recommended cultural practices including the application of harvest aids Irrigation: Furrow irrigation using tensiometers for scheduling N treatments: 0, 50, 100, 150, and 200 lb/acre Cultivar treatments: ‘Deltapine 20’, ‘Deltapine 50’, ‘Stoneville 453’, and ‘Stoneville 506’ Applied Questions How do four new fast fruiting cotton cultivars respond to increasing rates of N fertilizer? Culti...