Wide-strip intercropping of cotton and peanut combined with strip rotation increases crop productivity and economic returns

Cotton/peanut intercropping and their rotation have been widely studied and adopted in many cotton and peanut growing countries including China. However, it is impossible to harvest two crops in the same year under the cotton/peanut rotation. And continuous cropping constraints as indicated by inhibited crop growth and development as well as yield decline remain under continuous cotton/peanut intercropping. We hypothesized that a combination of intercropping and rotation can resolve these constraints or challenges. In a preliminary experiment, the traditional intercropping (TIC) of cotton and peanut was established and studied using monocultures of cotton (MC) or peanut (MP) as the control. Field experiments were then conducted to develop an alternate intercropping (AIC) of wide-strip cotton/peanut intercropping in combination with strip rotation (strips of the two crops were grown inter-annually in an alternate manner). Crop productivity, leaf photosynthesis, dry matter accumulation and partitioning, and main nutrient uptake as well as input-output and net returns of the new system were evaluated as compared with TIC, MC and MP for two consecutive years. Results showed that crop productivity varied significantly with cropping systems. On average, the TIC increased seed cotton yield by 16.9% and decreased peanut yield by 5.6%, while the AIC increased cotton yield by 21% without sacrificing peanut yield. The AIC increased the biological yield of peanut by 3.8% and harvest index by 2.4%; it increased the biological yield of cotton by 3.8% compared to TIC. AIC increased uptake of N, P and K in peanut by 6.3, 11.5 and 7.3%, as well as net photosynthetic rate, chlorophyll content and maximum leaf area index of peanut by 7.2, 8.9 and 4.4%, respectively, relative to TIC. Crop output value under AIC was 4.5% higher than that under TIC but the input value was the same; thus the net return under AIC exceeded that under TIC by 10%. The AIC increased crop productivity and economic return without additional input compared to traditional intercropping, thus is a promising alternative cropping system in the Yellow River valley and other areas with similar ecology.