Abstract

Two field experiments were conducted on rainfed Spanish groundnut to study the individual and combined effects of P, Ca and S in addition to B and Mo on the yield of unshelled nuts and nutrient uptake. Among the P sources, single super phosphate was superior to dihydrogen sodium phosphate in increasing the yield of un- shelled nuts, Either a farm mixture of CaO+ elemental S or gypsum was equally ef- fective as a source of Ce and S. The synergistic effect of Ca + S was more pro- nounced than their individual effect on yield and nutrient uptake. Application of a farm mixtute of Ca + S or gypsum to NPK increased the yield and nutrient uptake significantly. Maximum nutrient uptake was with DHSP+ NK+ gypsum or with SSP+ NK at the same level of Ca+S. Fertilization of B and Mo neither increased the uptake of nutrients nor yield of unshelled nuts. It was observed that the crop yield was closely related to the nutrient uptake. The nutrients removed for production of one tonne of unshelled nuts and one and half tons of haulm were 71.5, 80, 16.5 27.9, and 5,5 kg of N, P, K, Ca and S respectively.

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