Precipitation-optimised targeting of nitrogen fertilisers in a model maize cropping system
Precipitation-optimised targeting of nitrogen fertilisers in a model maize cropping system
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模型玉米种植系统中氮肥的降水优化目标
DOI：
10.1016/j.scitotenv.2020.144051
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发表时间：
2021
影响因子：
9.8
通讯作者：
McKay Fletcher D
中科院分区：
文献类型：
--
作者：
McKay Fletcher D
通常，施用于农田的氮（N）肥料有一半会流失到更广泛的环境中。这种低效率是由土壤过程造成的，如反硝化、挥发、地表径流和沥滤。降雨在调节这些过程中起着重要的作用，最终决定了氮肥在土壤中移动的时间和位置以及对气体损失的敏感性。然而，降雨，植物氮素吸收和氮素损失之间的相互作用仍然知之甚少。在这项研究中，我们使用数值模拟来预测最佳施肥策略的降雨模式，并提供机械的解释所产生的差异，在最佳的时间施肥application.We开发了一个模型框架，描述了水和氮在土壤中的运输在一个生长季节，并评估氮的利用效率（NUE）的分割施肥的背景下，不同的降雨模式。我们使用了90种降雨模式，以确定其对最佳氮肥施肥时间的影响。研究了根系生长、根系吸氮、微生物对氮素转化的影响以及土壤水分饱和度和土壤流量对氮素在土壤剖面中运移的影响。平均而言，我们表明，与平均吸收量相比，天气优化施肥策略可以提高作物氮吸收量20%。在干旱年份，天气优化的氮肥施用将作物氮回收效率提高了35%。进一步的分析表明，最大植物氮吸收量是最大的干燥条件下，由于减少淋溶，但它是很难找到最大值，由于低氮流动性。该模型可以捕捉到对比的趋势，在以前的耕地种植田间试验中看到的NUE。此外，该模型预测，NUE在现场看到的变化可能与降水驱动的N淋溶和流动性的差异。总之，我们的研究结果表明，在种植系统的NUE可以显着提高同步施肥时间与作物氮需求和当地的天气模式。
Typically, half of the nitrogen (N) fertiliser applied to agricultural fields is lost to the wider environment. This inefficiency is driven by soil processes such as denitrification, volatilisation, surface run-off and leaching. Rainfall plays an important role in regulating these processes, ultimately governing when and where N fertiliser moves in soil and its susceptibility to gaseous loss. The interaction between rainfall, plant N uptake and N losses, however, remains poorly understood. In this study we use numerical modelling to predict the optimal N fertilisation strategy with respect to rainfall patterns and offer mechanistic explanations to the resultant differences in optimal times of fertiliser application.We developed a modelling framework that describes water and N transport in soil over a growing season and assesses nitrogen use efficiency (NUE) of split fertilisations within the context of different rainfall patterns. We used ninety rainfall patterns to determine their impact on optimal N fertilisation times. We considered the effects of root growth, root N uptake, microbial transformation of N and the effect of soil water saturation and flow on N movement in the soil profile. On average, we show that weather-optimised fertilisation strategies could improve crop N uptake by 20% compared to the mean uptake. In drier years, weather-optimising N applications improved the efficiency of crop N recovery by 35%. Further analysis shows that maximum plant N uptake is greatest under drier conditions due to reduced leaching, but it is harder to find the maximum due to low N mobility. The model could capture contrasting trends in NUE seen in previous arable cropping field trials. Furthermore, the model predicted that the variability in NUE seen in the field could be associated with precipitation-driven differences in N leaching and mobility. In conclusion, our results show that NUE in cropping systems could be significantly enhanced by synchronising fertiliser timings with both crop N demand and local weather patterns.