Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Provincial Key Laboratory of Eco-circular Agriculture, South China Agricultural University, Guangzhou, 510642, China; Soil Science Department, Faculty of Agriculture, Zagazig University, 44519, Zagazig, Egypt; Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Technology Research Centre of Modern Eco-agriculture and Circular Agriculture, Guangzhou, 510642, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Provincial Key Laboratory of Eco-circular Agriculture, South China Agricultural University, Guangzhou, 510642, China; Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China; Guangdong Engineering Technology Research Centre of Modern Eco-agriculture and Circular Agriculture, Guangzhou, 510642, China.
J Environ Manage. 2022 Nov 15;322:116018. doi: 10.1016/j.jenvman.2022.116018. Epub 2022 Sep 5.
Managing reactive nitrogen (Nr) in agricultural production is crucial for addressing the triple challenges of food security, climate change and environmental degradation. Intensive work has been conducted to investigate the effects of mitigation strategies on reducing Nr losses by ammonia emission (Nr-NH), nitrous oxide emission (Nr-NO) and nitrate leaching (Nr-NO) separately. This meta-analysis evaluated the efficiency of each strategy in mitigating Nr losses coupled with grain yield responses. The results indicate that producing one Megagram (Mg) of wheat grains caused higher Nr losses, twice that of rice and 17% that of maize. The Nr-NH and Nr-NO were the dominant sources of Nr losses of the three crops (96%), while Nr-NH only presented 86% of the total Nr losses for rice. Reducing the N rate strategy decreased the yield by 33% and the Nr losses by 62% compared with the conventional rate (150-250 kg N ha) as an average of the three crops. In contrast, increasing the N rate higher than 250 kg N ha amplified the yield by 15% but also caused a 71% increase in Nr losses compared with the conventional rate. Although subsurface application decreased Nr losses by 5%, this study rejected this approach as an effective strategy due to a 4% yield decline on average of the grain crops. Slow-release fertilizers decreased Nr-NH and Nr-NO losses by 41-58% and 54-89%, respectively, of the highest losses under urea in the three crops, but also led to yield reductions. Organic amendments achieved the highest drop in Nr-NO loss by 66% in maize coupled with yield declines. Biochar increased wheat and maize yields by 0.3 and 0.1 Mg, respectively, coupled with 1 kg reduction in Nr losses. On average, inhibitors augmented the grain yields by 0.2 Mg ha for each 1 kg decline in Nr losses. In conclusion, for sustainable agricultural intensification, biochar (for wheat only) and inhibitors (for the three crops) are strongly recommended as mitigation strategies for Nr losses from grain crop production systems in China.
管理农业生产中的活性氮（Nr）对于应对粮食安全、气候变化和环境退化的三重挑战至关重要。人们已经进行了大量研究，以调查各种缓解策略对减少氨排放（Nr-NH）、一氧化二氮排放（Nr-NO）和硝酸盐淋失（Nr-NO）的Nr 损失的效果。本荟萃分析评估了每种策略在缓解 Nr 损失与谷物产量响应方面的效率。结果表明，生产 1 兆克（Mg）小麦籽粒会导致更高的 Nr 损失，是水稻的两倍，是玉米的 17%。Nr-NH 和 Nr-NO 是这三种作物（96%）Nr 损失的主要来源，而水稻中仅占总 Nr 损失的 86%。与常规用量（150-250kg N ha）相比，减少氮用量策略使三种作物的产量降低了 33%，Nr 损失降低了 62%。相比之下，将氮用量增加到 250kg N ha 以上会使产量提高 15%，但也会使 Nr 损失增加 71%，高于常规用量。尽管地下施用可使 Nr 损失减少 5%，但由于平均谷物作物的产量下降 4%，因此本研究不推荐这种方法作为一种有效的策略。控释肥料使三种作物中最高尿素用量下的 Nr-NH 和 Nr-NO 损失分别降低了 41-58%和 54-89%，但也导致了产量的降低。有机改良剂使玉米中的 Nr-NO 损失降低了 66%，达到最高，同时产量也有所下降。生物炭使小麦和玉米的产量分别提高了 0.3 和 0.1 Mg，同时使 Nr 损失减少了 1kg。总体而言，抑制剂使每减少 1kg Nr 损失，谷物产量增加了 0.2 Mg ha。总之，对于可持续的农业集约化，生物炭（仅适用于小麦）和抑制剂（适用于三种作物）强烈推荐作为减少中国粮食作物生产系统中 Nr 损失的缓解策略。
