Growth, Nitrogen Fixation and Nutrient Uptake by Chickpea (Cicer arietinum) in Response to Phosphorus and Sulfur Application under Rainfed Conditions in Pakistan

A field experiment was conducted at Barani Agriculture Research Institute Chakwal Punjab, Pakistan to assess the seed yield, nitrogen fixation and nutrient uptake by chickpea (Cicer arietinum L.) in response to application of different levels of phosphorus (P) and sulfur (S). The treatments comprised three levels (0, 40 & 80 kg P2O5 ha(-1)) of P and three levels (0, 15 & 30 kg S ha(-1)) of S from two sulfur S sources (gypsum & ammonium sulfate) in different combinations. The trial was laid out according to randomized complete block design with split split plot arrangement. Application of P and S resulted in significant increase in seed yield by 21 and 12% over control, respectively. Effect of combined application of P and S was synergistic at nutrient application rate of P40S15, while antagonistic at P80S30. Sulfur application had significant effect on percent nitrogen derived from atmosphere (% N-dfa), while effect of P was non-significant. There was significant increase in protein content of chickpea seed due to application of S. Application of both P and S resulted in increase in nitrogen (N) fixation by 16%. Value cost ratio was less than 2 for higher level of P either sole or in combination with S. A fertilizer combination of P40S30 is more economical and cost effective for chickpea production under rainfed conditions. (C) 2011 Friends Science Publishers