滴灌下氮肥减量配施生物炭对玉米大豆间作系统光合特性和产量的影响OA北大核心CSTPCD

To study the effects of nitrogen fertilizer reduction combined with biochar on photosynthetic characteristics and yield of maize and soybean intercropping populations,we used the orthogonal experimental design method to test the three factors of different planting patterns(maize mono-cropping Y,soybean mono-cropping D,maize and soybean intercropping J),biochar(2,4 and 6 t·ha-1)and nitrogen reduction(165,210 and 255 kg·ha-1).To explore the appropriate amount of nitrogen reduction combined with biochar in different planting patterns.The results showed that the appropriate amount of nitrogen fertilizer was 210 and 255 kg·ha-1,respectively,and the amount of biochar was 4 t·ha-1 in both mono-cropping and intercropping modes.The yield of intercropping system reached 13395 kg·ha-1,which was 20.13%lower than that of mono-cropping maize,and the yield of intercropping maize and soybean was 35.69%and 56.39%lower than that of mono-cropping maize,respectively.The low number of effective plants was the main reason for the decrease of intercropping maize yield.The reasonable control of plant number per unit area and seed number per plant is the key factor to determine the yield of intercropping soybean.The Pn of IN3C2(nitrogen fertilizer 225 kg·hm-2 and biochar 4 t·hm-2)corn in intercropping treatment continued to increase from the opening stage to the filling stage and reached the peak value at the filling stage,and the Pn of soybean continued to increase from the flowering stage through the podding stage to the drumming stage and reached the peak value at the drumming stage,showing a significant photosynthetic advantage compared with other treatments,and soybean showed a significant marginal advantage at the podding stage and the drumming stage.In conclusion,under drip irrigation,nitrogen reduction combined with biochar application,the optimal nitrogen dosage of maize was 210 and 255 kg·ha-1 and biochar was 4 t·ha-1,respectively.