Effect of sources and levels of phosphorus on productivity, economics, nutrient acquisition and phosphorus-use efficiency of groundnut (Arachis hypogaea) under hilly ecosystems of North-East India

A field experiment was conducted at the ICAR Research Complex for North Eastern Hill Region, Tripura Centre during 2013 and 2014, to study the effect of Godawari phosgold (organic source) and single supperphosphate (inorganic source) at varying rates of application on yield, economics, nutrient uptake, and phosphorus (P) use efficiency of groundnut (Arachis hypogaea L.). Phosphorus supplied through Godawari phosgold (GPG) gave significantly more pods/plant (60.7), pod yield (1.89 t/ha) and haulm yield (3.22 t/ha) than single supperphosphate (SSP). This resulted in 10.5% and 9.9% increment in pod and haulm yields, respectively, over SSP. Among the P levels, application of 27 kg P/ha recorded significantly higher pods/plant (70.8), kernels/pod (2 kernels/pod), pod (2.09 t/ha) and haulm (3.58 t/ha) yields over rest of the P levels. With respect to nutrients acquisitions, groundnut plot treated with GPG resulted in higher NPK uptake (108.3, 15.8 and 64.0 kg/ha, respectively) over the SSP treated plots. Among the rate of application, 27 kg P/ha recorded highest NPK uptake. The lowest cost of cultivation was recorded in SSP-treated plots. However, the net returns and benefit: cost ratio was higher under GPGtreated groundnut plots. Although the highest net returns (65.45 × 103/ha) and benefit: cost ratio (2.54) were noticed in groundnut plots, where 27 kg P/ha was applied. Application of P through GPG significantly increased the partial factor productivity (98.1 kg grain/kg P applied), agronomic efficiency (19.9 kg grain yield increase/kg P applied), recovery efficiency (20.4%) and utilization efficiency (2,185.5 kg biomass/kg P uptake) as compared to SSP. The maximum agronomic efficiency, recovery efficiency and utilization efficiency were recorded with application of 27 kg P/ha.