Changes in canopy microclimate of faba bean under intercropping at controlled nitrogen levels and their correlation with crop yield

Background: The relationship between the microclimate of the intercropping faba bean canopy and yield, and its response to nitrogen application, was studied in the crop canopy to clarify that intercropping and nitrogen application changed the microclimate of the faba bean canopy and affected the yield.

Results: In field experiments in Eshan and Xundian, the growth index, light transmittance, interception rate of photosynthetic effective radiation, temperature, relative humidity, and yield of the faba bean were determined using three planting methods (wheat monoculture, faba bean monoculture, and wheat-faba bean intercropping) and four nitrogen application levels, N0 (0 kg/hm² ), N1 (45 kg/hm² ), N2 (90 kg/hm² ), and N3 (180 kg/hm² ). The results showed that the application of nitrogen improved the growth index of monoculture and intercropping broad beans significantly, reduced the canopy light transmittance and temperature significantly, and increased the interception rate and relative humidity of photosynthetic effective radiation significantly. Compared with N0, the yield of broad bean in both places was the highest in N1, which increased by 14% (Eshan) and 15% (Xundian).

Conclusion: Multiple linear stepwise regression and path analysis showed that the decrease in canopy light transmittance during the faba bean pod-setting stage and the interception rate of photosynthetic effective radiation during pod-bulging stage, caused by excessive nitrogen application, were the main climatic and ecological factors limiting the increase in the intercropping faba bean yield in Eshan and Xundian respectively. The optimum nitrogen application rate recommended in production is 45 kg/hm² , to reduce the nitrogen application rate and maximize the productivity of the wheat and faba bean system. © 2023 Society of Chemical Industry.