Direct and Residual Effect of Molybdenum and Sulphur on Yield and Quality of Indian mustard and Pearlmillet in Typic Ustochrept Soil of Gujarat

A field experiment was carried out during 2003–04 to study the effect of molybdenum (Mo) and sulphur (S) on yield, quality, nutrient content and change in soil properties. Interactive direct effect in Indian mustard (Brassica juncea L.) and residual effect in subsequent pearlmillet (Pennisetum glaucum L.) was studied on loamy sand (Typic Ustochrept) soil of Anand. Four levels of S (0, 20, 40 and 80 kg ha⁻¹) through gypsum (14.5% S) and three levels of Mo (0, 1 and 2 kg ha⁻¹) through ammonium molybdate (52% Mo) were evaluated. The grain and straw yields of Indian mustard were higher with application of S₂₀Mo₀ by 14 and 25% over S₀Mo₀. However, residual effect of S on grain and straw yield of pearlmillet was not significant, but the residual effect of Mo significantly decreased the crop yield. The antagonistic effect of S and Mo was seen at higher levels only. Application of 20 to 40 kg S ha⁻¹ enhanced S contents of Indian mustard as well as grain and straw of pearlmillet and thereby uptake. The highest S content of grain and straw (0.78% and 0.32%, respectively) of Indian mustard were recorded under S₂₀Mo₀. Similarly, Mo application increased Mo content in Indian mustard as well as pearlmillet grain and straw. Although the oil content of Indian mustard grain was not affected considerably by application of S and Mo, protein content was significantly increased due to S application up to 40 kg ha⁻¹ over S₀. The Mo and S application significantly improved the available Mo and S content of soil.