RESPONSE OF SOYBEAN TO SOIL APPLIED SULFUR AND BORON IN A CALCAREOUS SOIL

A greenhouse experiment with soybean grown on sulfur (S) and boron (B) deficient calcareous soil was conducted for two years in northwest India to study the influence of increasing sulfur and boron levels on yield and its attributing characters at different growth stages (55days, maturity). The treatments included four levels each of soil applied sulfur viz. 0, 6.5, 13.4, 20.1mg S kg(-1) and boron viz. 0, 0.22, 0.44, 0.88mg B kg(-1) at the time of sowing. The highest dry matter yield at 55days after sowing, DAS (19.3g pot(-1)) and maturity (straw yield -25.2g pot(-1) and grain yield -7.3g pot(-1)) was recorded with B-0.44 S-13.4 treatment combination. The combined applications of sulfur and boron yielded highest oil content with B0.44S13.4 (21.7%) treatment level. Chlorophyll a' and b' increased significantly with successive levels of sulfur and boron addition at 55 DAS. The mean sulfur and boron uptake in straw and grains increased significantly with increasing levels of sulfur and boron up to 13.4mg kg(-1) and 0.44mg kg(-1) and decreased non-significantly thereafter. At both the growth stages, a synergistic interactive effect of combined application of sulfur and boron was observed with B-0.44 S-13.4 treatment level for sulfur and boron uptake in straw and grains.