Yield and economic benefits of peanut intercropping with maize and sesame

Peanuts are an important oil crop in China. Intercropping peanuts with maize or sesame improves the field microclimate and the utilization of light and heat resources and increases yield and income. Different high crops in the intercropping systems have different effects on the canopy light intensity, photosynthetic capacity of the functional leaves, dry matter accumulation, and yield of intercropping crops. The purpose of this study was to optimize the peanut intercropping system and to select suitable crops for peanut intercropping. To assess the effects of different intercropping systems on peanut yield and the economic benefits, a field experiment was conducted in 2018 and 2019 with five treatments: maize intercropping with peanut (maize‖peanut, M‖P), sesame intercropping with peanut (sesame‖peanut, S‖P), monocultured peanut (SP), monocultured maize (SM), and monocultured sesame (SS). The different planting patterns were assessed for their effects on the interspecific competition index, dry matter accumulation, photosynthetic rate response curves to light in the functional leaves, yield, and the economic benefits of peanuts. The results showed that: 1) compared with intercropped peanuts in maize‖peanut, the maximum net photosynthetic rate (P_nmax), yield, and maximum dry matter accumulation of intercropped peanuts in sesame‖peanut increased by 18.0%-20.7%, 64.2%-70.0%, and 26.5%-31.8%, respectively. 2) When the dry matter accumulation of intercropped sesame entered the period of 16-19 days after the slow-growing period, the intercropped peanuts in sesame‖peanut were still in the period of rapid dry matter accumulation. The fast growth periods of dry matter accumulation of sesame and peanut in sesame‖peanut intercropping system staggered each other, however, those of maize and peanuts in maize‖peanut intercropping system were overlapped. At the mature stage, the competitiveness index of peanuts against sesame and maize in the intercropping systems was -2.31~-2.06 and -4.68~-4.34, respectively. This indicates that the competitiveness of intercropped peanuts to sesame is stronger than that to maize. 3) The land-equivalent ratio of sesame‖peanut intercropping system increased by 3.0%-4.0% compared with maize‖peanut intercropping system, and those of both systems were greater than 1. The economic benefits of sesame‖peanut intercropping system significantly increased by 16.7%-50.8% compared with maize‖peanut intercropping system, reaching 23 000-24 000 ¥·hm^-2. Compared with maize‖peanut intercropping system, sesame‖peanut intercropping system improved the land utilization rate, yield, and income. Sesame‖peanut intercropping system staggered the rapid growth periods of dry matter accumulation of two crops, reduced the intensity of interspecific competition between high and low crops, and improved the canopy light intensity and net photosynthetic rate of intercropped peanuts.