Effect of sunflower stover and nutrient management on productivity and nutrient uptake pattern of pigeonpea (Cajanus cajan) in pigeonpea–sunflower (Helianthus annuus) cropping system

A fixed plot field experiment was carried out during kharif and spring seasons of 2008–2009 and 2009–2010 at New Delhi, to study the effect of sunflower (Helianthus annuus L.) stover and nitrogen + phosphorus management on pigeonpea (Cajanus cajan (L.) Millsp) –sunflower cropping system. Effect of treatments on the on yield attributes, productivity, economics and nutrient uptake pattern of pigeonpea has been given in this paper. Kharif season experiment was laid out in split-plot design, assigning sunflower stover incorporation (8 tonnes/ha) and no stover incorporation (control) to main plots and combinations of P levels and bio-fertilizers (Control, 15 kg P/ha, 15kg P/ha+PSB and 30kg P/ha) to sub-plots. Spring season experiments was laid out in split-split plot design, in which NP doses to sunflower crop (Control, 50% recommended dose (RD) of NP and RD of NP (80 kg N+15 kg P/ha) were applied in sub-sub plots. Kharif season experiment in second year was laid out in split-split plot design to investigate the residual effect of NP doses applied to spring season sunflower on pigeonpea crop. Sunflower stover incorporation reduced the yield attributes (number of pods/plant, number of grains/pod, grain yield/plant, 1,000-grains weight), grain yield, nutrient uptake and gross returns, net returns and B:C ratio of pigeonpea. Adverse effect of sunflower stover incorporation was more pronounced during second year. Reduction in pigeonpea grain yield was 4.9% and 25.8% in the first and second year respectively. Effect of P levels on pigeonpea was significant and the highest number of pods/plant, number of grains/pod, grain yield/plant, 1,000-grains weight and grain yield (1.63 and 1.32 t/ha), nutrient uptake, gross and net returns and B:C ratio were recorded with the application of 30 kg P/ha, followed by 15 kg P/ha+PSB. Marked effect of PSB integration with 15 kg P over 15 kg P alone was significant only during first year. Residual effect of RD of NP applied to preceding sunflower crop also improved the yield attributes, yields, nutrient uptake and gross and net returns and B:C ratio of succeeding pigeonpea crop under pigeonpea-sunflower cropping system. Significant interaction between P applied to pigeonpea during second year and residual effect of P applied to sunflower during first year was recorded, indicating saving of 15 kg P in pigeonpea due to residual effect.