Residual Effect of Biochar on Soil Properties and Yield of Maize (Zea mays L.) under Different Cropping Systems

A field experiment was conducted to examine the residual influence of biochar applied previously to an established experiment at the Agriculture University Research Farm, Peshawar on soil properties and yield of maize crop during summer 2016. The experiment was established in RCB design with split plot arrangements having cropping systems (CS) in main plots and biochar (BC) in sub-plots. Cropping systems were: 1) wheat-mung bean; 2) wheat-maize; 3) chickpea-maize; and 4) chickpea-mung bean. During the past three seasons, each cropping system received biochar at 0, 40, 60 and 80 t·haǃ along with recommended dose of NPK in each season. For this study, maize was planted after chickpea and wheat in summer 2016. The results showed that grain yield, cobs weight and total N uptake of maize was significantly greater for chickpea-maize than for wheat-maize cropping system. Soil organic C was also significantly higher in soil under chickpea-maize than under wheat-maize cropping system. However, other yield components such as stover yield, harvest index and N concentration in grain and stover of maize and soil properties such as pH, EC and mineral N were non-significantly affected by cropping systems. With respect to residual effect of biochar grain yield of maize and bulk density of soil were maximum for treatment receiving biochar at 40 t·haǃ whereas cobs weight soil pH and mineral N were highest receiving biochar at 60 t·haǃ. Moreover, N concentration in stover, N uptake and soil organic C were maximum for treatment receiving biochar at 80 t·haǃ. However, stover yield, harvest index, N concentration in grain, and soil EC were non-significantly affected by biochar treatments. However interactions between CS × BC were significant for yield and yield parameters of maize and for soil properties (bulk density mineral N), while non-significant for harvest index, soil organic C, pH and EC. It was concluded that chickpea-maize cropping system performed better in terms of improving yield and yield components of maize and in improving soil properties. Application of biochar to previous crops also improved yield and yield parameters of the following maize as well as soil properties. Thus we recommend that legumes must be involved in cropping system for sustainable and higher productivity and improved soil properties. However, further studies are suggested to find out suitable dose of biochar for sustainable and economic crop productivity and soil fertility.