Effect of liming and fertilization on sulfur availability, mobility, and uptake in cultivated soils of south carolina1

We studied the sulfur status of 32 Coastal Plain and 34 Piedmont soils (Ultisols) under cultivation in South Carolina to assess the impact of changing patterns of sulfur input into the soil system. Through growth-chamber and field research we reevaluated the influence of liming and fertilization on soil and plant sulfur performance, with emphasis on the effect of time on soil sulfur movement and availability and on plant sulfur concentration, total uptake, and rate of uptake.The available sulfur content of these soils appeared to be sufficient for crop needs. The acetate extractable SO4-S varied from 19 ppm in the A horizon to 139 ppm in the B horizon of Coastal Plain soils and from 23 ppm in the A horizon to 126 ppm in the B horizon of Piedmont soils. Soil sulfur increased with increasing clay content and decreasing pH values, which explains why sulfur accumulated in the acid and clayey B horizons of these soils. A 1% clay increment was associated with an SO4-S increase of 1 ppm in the A horizon and 3.1 ppm in the B horizon of Coastal Plain soils and 1.4 ppm in the A horizon and 4.2 ppm in the B horizon of Piedmont soils. A pH unit increment was related to an SO4-S decrease of 15 ppm in the A horizon and 72 ppm in the B horizon of Coastal Plain soils and 23 ppm in the A horizon and 117 ppm in the B horizon of Piedmont soils.The growth-chamber study with corn (Zea mays) showed that in the unlimed soil, dry weights of shoots and roots were highest with a sulfur rate of 40 kg/ha, 8 ppm of SO4-S in the soil and sulfur concentrations of 0.19% in the shoots and 0.41% in the roots. Root length doubled with sulfur application. In the limed soil, shoot growth peaked with a sulfur rate of 20 kg/ha, 8.4 ppm of SO4-S in the soil, and a sulfur concentration of 0.13% in the shoots and 0.16% in the roots. Soil sulfur, plant growth, and sulfur uptake by soybeans increased significantly when liming with the recommended amount. Overliming had a detrimental effect on all these parameters.The field study with soybeans (Glycine max) demonstrated that while sulfur concentration decreased and then increased with plant age, total sulfur uptake increased, and the rate of sulfur accumulation in the shoots also increased, peaking between the 12th and 16th weeks in the limed soil and between the 16th and 20th weeks in the unlimed soil. Overliming soybeans in the field did not have the detrimental effect on soil sulfur and sulfur uptake observed in the growth-chamber study.