The soil's variable capacity to store water, known as plant available water capacity (PAWC), may mitigate the adverse effects of drought on crop yields. Nonetheless, the extent to which this mitigation can decrease the probability of crop productivity loss under various drought scenarios, as well as the specific thresholds at which drought begins to restrict crop growth, remains unclear. In this study, we used the Agricultural Production System sIMulator (APSIM) model to simulate wheat growth and plant available water for 10 different soils with different PAWCs in the New South Wales (NSW) wheat belt, southeastern Australia. By combining copula functions, we estimated the probability of wheat biomass loss under various drought scenarios. We found that simulated wheat yield and biomass were elevated in areas characterized by soils with high PAWC. The probability of biomass loss decreased by 20–50 % as the PAWC of soil increased under various drought conditions. Moreover, the drought mitigation capacity of soils with higher PAWC demonstrated a more pronounced effect in high-rainfall areas compared to arid regions. We identified that the drought mitigation effects became weak when the PAWC threshold exceeded 207 mm. Adopting sustainable farming strategies is required to enhance soil water retention in the high-rainfall regions of the NSW wheat belt, thereby minimizing the risk of crop biomass losses. The framework presented in this study is intended to offer valuable guidance to stakeholders seeking to improve management strategies for sustaining wheat production in dryland agricultural regions.

中文翻译：

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在澳大利亚东南部，植物可用水容量高的土壤可以减轻小麦在干旱条件下生长的风险


土壤的可变储水能力，称为植物可用水容量 （PAWC），可以减轻干旱对作物产量的不利影响。尽管如此，在各种干旱情景下，这种缓解措施在多大程度上降低了作物生产力损失的可能性，以及干旱开始限制作物生长的具体阈值，仍不清楚。在这项研究中，我们使用农业生产系统 sIMulator （APSIM） 模型来模拟澳大利亚东南部新南威尔士州 （NSW） 小麦带 10 种具有不同 PAWC 的不同土壤的小麦生长和植物可用水。通过结合 copula 函数，我们估计了各种干旱情景下小麦生物量损失的概率。我们发现，在 PAWC 土壤高的地区，模拟小麦产量和生物量升高。在各种干旱条件下，随着土壤 PAWC 的增加，生物量损失的可能性降低了 20-50%。此外，与干旱地区相比，PAWC 较高的土壤的抗旱能力在高降雨地区表现出更明显的效果。我们发现，当 PAWC 阈值超过 207 mm 时，抗旱效果变弱。需要采用可持续农业策略来增强新南威尔士州小麦带高降雨地区的土壤保水能力，从而最大限度地降低作物生物量损失的风险。本研究中提出的框架旨在为寻求改进管理策略以维持旱地农业地区小麦生产的利益相关者提供有价值的指导。