Tillage and biochar effects on wheat productivity under arid conditions

Abstract

Urea is an important source of inorganic N under wheat (Triticum aestivum L.) production system in Multan, Pakistan. However, the average N loss is high, ranging from 22 to 53% of applied N, which poses adverse environmental impacts. Reduced tillage and combined application of biochar and optimal N fertilizer could improve wheat productivity and reduce N losses. We evaluated the effects of two tillage (conventional and reduced tillage), two biochar (no biochar and poultry waste biochar), and three inorganic N rate (0, 60, and 120 kg ha-1) treatments on productivity and economic profitability of wheat production for two continuous growing seasons (2014-2015 and 2015-2016). Generally, reduced tillage increased wheat grain yield, protein content, and total N uptake by 0.2 Mg ha-1, 3.0 kg kg-1, and 37.0 kg ha-1, respectively, when compared with conventional tillage. Biochar application increased wheat grain yield, protein content, and total N uptake by 0.3 Mg ha-1, 6.8 kg kg-1, and 38.6 kg ha-1, respectively, compared with no-biochar plots. Reduced tillage was economically profitable within the two cropping seasons, but biochar application was not, because of the high price of biochar (US$1.00 kg-1 biochar) and application rate (10 Mg biochar ha-1). Overall, wheat production under reduced tillage, no biochar, and the 60-kg N ha-1 rate resulted in the greatest economic profit in this study.