Nitrogen use efficiency and productivity of barley as affected by nitrogen and sorghum mulching in different cropping systems

Nitrogen losses from the agricultural systems not only reduce crop yields, but could also impose adverse effects on environment. Although there is no quick fix to immediately reduce these losses; however, improving nitrogen use efficiency (NUE) through controlled mineralization would be helpful for sustainable management of the losses. This study was conducted to evaluate the influence of nitrogen (N) application and sorghum mulch on the performance and NUE of barley under different cropping systems. Barley was planted in fallow, maize and alfalfa vacated fields. Nitrogen was applied at 0, 50 and 100 kg N ha^-1 with or without sorghum mulch under maize-barley, alfalfa-barley and fallow-barley cropping systems. The contribution of soil N from the preceding crop had a considerable influence on the productivity of barley. Barley grain yield was higher in maize-barley cropping system than fallow-barley and alfalfa-barley cropping systems. Application of N at 50 kg ha^-1 had the highest agronomic NUE, which declined with further increase in N, indicating its potential loss to the environment. However, production efficiency, sink capacity, and economic profitability were higher from N application at 100 kg ha^-1. Although there was no significant influence of sorghum mulch on the barley productivity, it helped to reduce the nitrification rate, as more NH₄ ⁺ and less NO₃ ^- contents were noted with mulch application. The study reports useful information about the potential use of sorghum mulch for suppression of nitrification. However, high cost associated with mulch may render it unacceptable to farmers, unless favorable price policy is devised.