Zhang Liqiang, Feng Yudi, Zhao Zehang, Cui Zhengguo, Baoyin Bate, Wang Hongyu, Li Qiuzhu, Cui Jinhu
College of Plant Science, Jilin University, Changchun, China.
Soybean Research Institute, Jilin Academy of Agricultural Sciences, Changchun, China.
Front Plant Sci. 2024 Sep 3;15:1437631. doi: 10.3389/fpls.2024.1437631. eCollection 2024.
Intercropping practices play a crucial role in enhancing and maintaining the biodiversity and resiliency of agroecosystems, as well as promoting stable and high crop yields. Yet the relationships between soil nitrogen, microbes, and yield in maize cultivated under maize/soybean intercropping systems remain unclear.
To fill that knowledge gap, here we collected maize rhizosphere soil at the staminate stage after 6 consecutive years of maize/soybean intercropping, to investigate how intercropping and nitrogen application rates affected nitrogen utilization by crops and soil microbial community composition and function. We also examined correlations of those responses with yields, to clarify the main ways that yield is enhanced via intercropping and by nitrogenous fertilizer gradient changes generated by different nitrogen application rates.
The amount of applied fertilizer was 240 kg N ha was best for obtaining a high maize yield and also led to the greatest nitrogen-use efficiency and bacterial diversity. Under the same N application rate, intercropping increased the maize yield by 31.17% and soil nitrogen (total, ammonium and nitrate nitrogen) by 14.53%, on average, in comparison to monocropping. The enrichment of and significantly increased the soil nitrogen content, and a greater relative abundance of and increased the maize yield, whereas enrichment of and decreased it. The benefits of intercropping mainly arise from augmenting the abundance of beneficial microorganisms and enhancing the efficiency of N use by crop plants.
This study's findings are of key importance to bolster the stability of agro-ecosystems, to guide the scientific rational use of nitrogen fertilizers, and to provide a sound theoretical basis for achieving the optimal management of intensive crop-planting patterns and green sustainable development.
间作措施在增强和维持农业生态系统的生物多样性与恢复力以及促进作物稳定高产方面发挥着关键作用。然而，玉米/大豆间作系统下种植的玉米，其土壤氮素、微生物与产量之间的关系仍不明确。
为填补这一知识空白，我们连续6年进行玉米/大豆间作后，在雄穗期采集玉米根际土壤，以研究间作和施氮量如何影响作物对氮的利用以及土壤微生物群落组成和功能。我们还研究了这些响应与产量的相关性，以阐明通过间作和不同施氮量产生的氮肥梯度变化提高产量的主要途径。
施氮量为240千克/公顷时最有利于获得较高的玉米产量，且氮肥利用效率和细菌多样性也最高。在相同施氮量下，与单作相比，间作使玉米产量平均提高31.17%，土壤氮素（全氮、铵态氮和硝态氮）平均增加14.53%。 和 的富集显著增加了土壤氮含量， 和 相对丰度的增加提高了玉米产量，而 和 的富集则降低了玉米产量。间作的益处主要源于增加有益微生物的丰度和提高作物对氮的利用效率。
本研究结果对于增强农业生态系统的稳定性、指导氮肥的科学合理施用以及为实现集约化种植模式的优化管理和绿色可持续发展提供坚实的理论基础至关重要。
