Effects of nitrogen fertilization on the accumulation and distribution of biomass and plant nitrogen content in intercropped faba beans, together with its impact on the interspecific interactions between faba bean and wheat has not been well studied. Here, we have used a logistic model to analyze the cropping systems (i.e., monocropped faba bean, monocropped wheat, and faba bean intercropped with wheat) by evaluating the effects of different levels of nitrogen application on the dynamic changes in biomass and nitrogen accumulation, along with the interspecific interaction. Using monocropped and intercropped faba beans in field experiments spanning two years, we found that nitrogen application increased both monocropped and intercropped faba bean yields. The yield of intercropped faba beans was greatest at the lower nitrogen input for two consecutive years. Nitrogen application increased the biomass and nitrogen accumulation in both monocropped and intercropped faba beans. The simulation parameters that increased were maximum nitrogen accumulation (A') and maximum accumulation rate (R'_max) while the initial cumulative rate (r') decreased. Compared with monocropping, intercropped faba bean–wheat showed increased yield and biomass accumulation, along with a significantly increased initial growth rate (r) and a maximum instantaneous growth rate (R_max). Intercropping reduced stem and leaf biomass and the nitrogen distribution ratio while increasing the pod content. In the early intercropped faba bean growth stage, there was no competition for nutrients or any kind of yield advantage, while in the later stages, the nutrient competitiveness of intercropping was stronger than the intraspecific competition, showing the advantages of intercropping on biomass and yield (i.e., relative crowding coefficient [K] >1, relative interspecific competitiveness [RC] >0, and relative competition intensity [RCI] <0). In summary, nitrogen application of 45 kg ha^–1 could be the desired amount that maximizes the nutrient competition and interspecific advantages in the middle and late stages of faba bean growth when intercropped, thus contributing to the yield.

中文翻译：

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氮素调控和条带间作对蚕豆生物量、氮素积累与分配及种间互作的影响

施氮对间作蚕豆生物量积累和分布以及植物氮含量的影响，以及对蚕豆和小麦种间相互作用的影响尚未得到很好的研究。在这里，我们通过评估不同施氮水平对生物量和氮积累动态变化的影响，使用逻辑模型来分析种植系统（即单作蚕豆、单作小麦和蚕豆与小麦间作），以及种间相互作用。在为期两年的田间试验中使用单作和间作蚕豆，我们发现施氮增加了单作和间作蚕豆的产量。连续两年间作蚕豆产量在氮输入较低的情况下最高。施氮增加了单作和间作蚕豆的生物量和氮积累。增加的模拟参数是最大氮积累（A ') 和最大累积率 ( R' _max ) 而初始累积率 ( r ') 下降。与单作相比，蚕豆-小麦间作增加了产量和生物量积累，同时显着提高了初始生长速率（r）和最大瞬时生长速率（R _max）。间作减少了茎叶生物量和氮分配比，同时增加了豆荚含量。间作蚕豆生长前期，不存在养分竞争或任何产量优势，而后期间作养分竞争力强于种内竞争，显示出间作在生物量和产量上的优势。即，相对拥挤系数 [K] >1，相对种间竞争力 [RC] >0，相对竞争强度 [RCI] <0）。总之，45 kg ha ^{–1 的}施氮量可能是在蚕豆中后期间作时最大限度地发挥养分竞争和种间优势的理想数量，从而有助于提高产量。