当前我国蔬菜种植系统氮肥利用率及其驱动因子

  • 摘要:   大量施用氮肥是提高蔬菜产量和质量的重要手段, 然而过量氮投入导致蔬菜种植体系氮肥利用率低下。氮肥利用率是指导作物生产、减少环境污染和开展合理氮素管理的重要指标, 但当前我国蔬菜种植系统氮肥利用率并不清楚, 其驱动因素和提高途径也缺乏综合分析。因此, 通过对2010年至2020年间相关田间试验文献收集整理, 分别分析了我国当前露天菜地系统和温室系统氮肥利用率及其驱动因子等。结果显示, 我国露天和温室系统的当季氮肥用量分别为227.2 kg N ha-1、361.5 kg N ha-1, 氮肥利用率分别为27.8%、23.2%。随机森林分析结果表明露天系统中施氮量对氮肥利用率的贡献度最高, 为24.0%, 其次为生育期日照时长(10.7%), 土壤TN含量最低, 仅为2.9%。温室系统中对氮肥利用率贡献度最高的驱动因子为施氮量(32.6%), 其次为土壤TP含量(15.8%)和土壤SOM含量(11.4%), 最低的是土壤pH, 仅为1.9%。Meta分析表明配施磷钾肥是我国露天菜地系统最有效的氮肥利用率提高途径, 其次为缓释肥, 分别可提升82.4%和53.0%, 而同时施用脲酶抑制剂和硝化抑制剂对温室系统氮肥利用提高效果明显, 可以提高69.9%, 其次为氮肥减量, 可提高57.1%。

     

    Abstract: China is a major producer and consumer of vegetables, the large amount of application of nitrogen fertilizer is a crucial way for enhancing both the yield and quality of vegetables by farmers. However, excessive nitrogen input leads to low nitrogen use efficiency (NUE) in vegetable planting systems, which not only undermines agricultural productivity but also contributes to environmental issues such as soil degradation and water pollution. NUE serves as a key indicator for effective crop production, offering insights into practices that can minimize environmental impacts while maximizing output. Therefore, clarify the current NUEs of vegetable planting systems and its improving ways is imperative for sustainable agricultural practices. Despite its importance, current data on NUE in China's vegetable cultivation systems remains limited. Moreover, the factors influencing NUEs and potential measurement for NUE enhancement have not been thoroughly analyzed. Therefore, by collecting 1, 386 observations (1, 067 were from open-air and 319 were from greenhouse vegetable planting systems) from relevant field experiment literature during 2010 to 2020, we analyzed the NUE and its driving factors in China's current open-air vegetable systems and greenhouse systems, respectively. And a random forest model was applied to identify and rank the importance of different driving factors influencing nitrogen efficiency. Moreover, the effects of various management practices on NUE were quantitatively evaluated by meta-analysis method. Our findings indicated that the current average nitrogen application rates for open-air vegetable systems and greenhouse systems is 227.2(CI: 218.9-235.5) kg N ha-1 and 361.5(CI: 336.8-386.1) kg N ha-1 per growing season. Correspondingly, the NUE d in these two systems was 27.8% and 23.2%, with a range of 26.8-28.8% and 21.6-24.6%. respectively. Over all, the nitrogen application rate in greenhouse systems is 59.1% higher than in open-air systems, but the utilization rate is 16.8% lower. The results of the random forest analysis indicated that in the open-air systems, the nitrogen application rate contributed the most to NUE, at 24.0%, followed by sunlight duration during the growth period (10.7%), with soil TN content contributing the least, at only 2.9%. In the greenhouse systems, the nitrogen application rate was the highest contributing factor to the nitrogen fertilizer utilization rate, at 32.6%, followed by soil TP content (15.8%) and soil SOM content (11.4%), with soil pH contributing the least, at only 1.9%. Meta-analysis showed that combined application of phosphorus and potassium fertilizers is the most effective way to improve NUE in the open-air systems, followed by slow-release fertilizers, these two measures could enhance NUE by 82.4% and 53.0%, respectively. In greenhouse system, using urease and nitrification inhibitors could significantly improve NUE by 69.9%, then followed by reduction of nitrogen application (57.1%). Although current NUEs in vegetable planting systems in China was increased compared with other studies, efforts should continue to optimize nitrogen application rates and select comprehensive nitrogen management strategies based on the type of vegetables to improve NUE and mitigate environmental impacts in the future. The results of our study could provide data support and technical backing for the optimized management of nitrogen in vegetable cultivation systems.

     

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