Effect of sunflower stover and nutrients management on energetics, nutrient acquisition and soil nutrient balance of pigeonpea (Cajanus cajan)–sunflower (Helianthus annuus) cropping system

A fixed plot field experiment was carried out during rainy (kharif) and spring seasons of 2008–09 and 2009–10 at New Delhi, to assess the effect of sunflower stover and nutrients management on energetics, nutrient acquisition and soil-nutrient budgeting of pigeonpea [Cajanus cajan (L.) Millsp.]–sunflower (Helianthus annuus L) cropping system. Direct effect of sunflower stover incorporation had negative impact on pigeonpea productivity; however; it excreted positive effect on productivity of succeeding sunflower crop in system mode. With respect to energetics, sunflower stover incorporation in pigeonpea under pigeonpea–sunflower cropping system reduced the gross and net energy output, energy-use efficiency and energy intensity in economic terms. Among the various levels of P imposed to pigeonpea only, an application of 30 kg P/ha recorded significantly higher values of gross energy output (160.02 × 10³ MJ/ha), net energy output (144.88 × 10³ MJ/ha), energy-use efficiency (10.56) and energy intensity in economic terms (5.61MJ/) of pigeonpea-sunflower cropping system. Significantly higher values of gross energy output (146.24 × 10³ MJ/ha), net energy output (128.36 × 10³ MJ/ha) and energy intensity in economic terms (4.86 MJ/ lower values of energy use efficiency (8.17%) were recorded with the recommended dose of NP (80 kg N+15 kg P/ha) applied to sunflower crop in pigeonpea–sunflower cropping system. With respect to nutrient acquisition, sunflower stover incorporation in pigeonpea only recorded the higher nutrients uptake by the pigeonpea–sunflower cropping system compared to the control. Among the P levels applied to pigeonpea and NP to sunflower, application of 30 kg P/ha and recommended dose of NP to pigeonpea and sunflower, respectively, recorded the maximum N, P and K uptake by pigeonpea–sunflower cropping system. With regards to NPK balance in soil, direct and residual effect of sunflower stover, N and P management exerted positive impact on NPK balance sheet at the end of experiment.