Nutrient Budgeting, Economics and Energetics of Cowpea under Potassium and Phosphorus Management

P Suresh Kumar,Vk Choudhary

doi:10.3329/sja.v11i2.18408

P Suresh Kumar, Vk Choudhary

Open Access

https://doi.org/10.3329/sja.v11i2.18408

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Abstract

Low availability of phosphorus (P) and potassium (K) in acidic soil is a major constraint for crop production. Cowpea was grown under split-plot design with three levels of K and P (viz., 100%, 75% and 50% of recommended dose). Green pod and stover yield was 20.9 and 16.9% higher with 100% K over 50% K application. Similarly, 100% P had 20.2% higher green pod and 16.6% higher stover yield over 50% P. Production efficiency was found higher with 100% K and P (48.6 and 49.0 kg ha-1 day-1 respectively) followed by 75% K. The actual gain of N, P and K, and balance were higher with the increase of K and P levels but reverse in case of gross and net return, and BCR. The energy productivity and energy use efficiency were higher on 100% K and P. Cowpea on acid soil along with 100% recommended dose of 40 kg K and 60 kg P ha-1 showed highest yield along with soil fertility restoration as well as reduced the cost of inorganic fertilizer, higher BCR (1.89) and energy requirement. DOI: http://dx.doi.org/10.3329/sja.v11i2.18408 SAARC J. Agri., 11(2): 129-140(2013)

Highlights

Cowpea (Vigna unguiculata L.) is an important grain legume in rainfed regions and marginal areas of the tropics and subtropics
Main plots were subjected to potassium with three levels (viz. 100, 75 and 50% of recommended dose (RD)) and sub-plots were subjected to phosphorus with three levels i.e. 40, 30 and 20 kg K and 60, 45 and 30 kg P ha-1
Total dry matter (TDM) was highest with the application of K with 100% of recommendation

Summary

Introduction

Cowpea (Vigna unguiculata L.) is an important grain legume in rainfed regions and marginal areas of the tropics and subtropics. Phosphorus application with 100% P recorded 19.8 and 20.5% higher green pod yield and 11.5 and 19.6% higher stover yield for 2009 and 2010, respectively over 50% P. It can be visualized that among the K levels, 100% of applied K recorded 71.3% higher actual gain of N followed by 75% (39.3%).

Results

Conclusion