Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China.
School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia.
J Econ Entomol. 2020 Aug 13;113(4):2035-2038. doi: 10.1093/jee/toaa112.
The intensive use of nitrogen fertilizer has been a common approach for pursuing higher crop yields. However, the ecological effects of such use on the tritrophic interactions (crop-insect pest-natural enemy) and on the ecological and economic benefits of such use are poorly understood. Here, we investigated the effects of low, medium, and high levels of nitrogen fertilizer inputs (70, 140, and 280 kg/ha/yr) on cereal aphid (Sitobion avenae Fabricius [Hemiptera: Aphididae], Schizaphis graminum Rondani [Hemiptera: Aphididae], and Rhopalosiphum padi L. [Hemiptera: Aphididae]) abundance, primary parasitism rates, crop yield, and net income in winter wheat (Triticum aestivum [Poales: Poaceae] cv. Zhou 22) for 2 yr. A higher input of nitrogen fertilizer significantly enhanced the abundance of cereal aphids, while their primary parasitism rates (26.9 ± 3.5% in 2018 and 24.9 ± 4.5% in 2019) were highest at the medium nitrogen level. The performance of participants in the wheat-aphids-parasitoids system was likewise mediated by the nitrogen fertilizers. Meanwhile, wheat yield significantly increased with moderate increases in the nitrogen level, although overuse of nitrogen fertilizer did not significantly further enhance wheat yield. Finally, we found either low or overuse of nitrogen fertilizers resulted in lower net income than did medium nitrogen fertilization. These results demonstrate the need to reevaluate and adjust fertilizer use to optimize the eco-economic and sustainable management of agroecosystems.
氮肥的集约化使用是追求更高作物产量的常用方法。然而，这种使用方式对三营养级相互作用（作物-害虫-天敌）的生态影响以及这种使用方式的生态和经济效益还知之甚少。在这里，我们研究了低、中、高氮肥投入（70、140 和 280 kg/公顷/年）对冬小麦（Triticum aestivum [禾本科：禾本科] cv. Zhou 22）中麦长管蚜（Sitobion avenae Fabricius [半翅目：蚜科]、禾谷缢管蚜（Schizaphis graminum Rondani [半翅目：蚜科]和禾谷缢管蚜（Rhopalosiphum padi L. [半翅目：蚜科]）数量、初级寄生率、作物产量和净收入的影响，为期 2 年。较高的氮肥投入显著增加了麦长管蚜的数量，而初级寄生率（2018 年为 26.9±3.5%，2019 年为 24.9±4.5%）在中氮水平下最高。小麦-蚜虫-寄生蜂系统中参与者的表现也受到氮肥的调节。同时，随着氮水平的适度增加，小麦产量显著增加，尽管过度使用氮肥不会显著进一步提高小麦产量。最后，我们发现低氮或过度使用氮肥导致的净收入低于中氮施肥。这些结果表明需要重新评估和调整肥料使用，以优化农业生态系统的生态经济和可持续管理。
