Soil acidification due to crop removal and the use of acidifying fertilisers reduce land productivity in many agricultural systems worldwide. The most common remedy is to apply lime to the soil surface. An alternative approach is to incorporate lime into the sub‐soil. This is a more expensive option, but it substantially reduces the time required to reduce acidity in the sub‐soil horizons. This paper presents a dynamic optimisation model to determine optimal rates, frequency and methods of lime application for a wheat monoculture system in the northern part of the Western Australian wheatbelt. Results show that optimal application rates depend on rainfall levels and soil‐acidity conditions. The net present value of profit is not sensitive to the frequency of lime application. Incorporating lime into the sub‐soil increases the net present value of profit, but only by a small amount: two to four per cent in most scenarios modelled. In the process, sub‐soil lime application reduces both the optimal lime application rate and the time required for the soil pH to increase to a target level.

中文翻译：

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澳大利亚小麦生产中石灰最佳施用量的动态模型

由于农作物的去除而导致的土壤酸化以及酸化肥料的使用降低了全世界许多农业系统的土地生产力。最常见的补救措施是在土壤表面施用石灰。一种替代方法是将石灰掺入地下土壤中。这是一个更昂贵的选择，但是它大大减少了降低土壤下层酸度所需的时间。本文提出了一个动态优化模型，用于确定西澳大利亚州小麦带北部小麦单一栽培系统的石灰施用量，施用频率和施用方法。结果表明，最佳施用量取决于降雨水平和土壤酸度条件。利润的净现值对石灰的施用频率不敏感。在地下土壤中加入石灰可增加利润的净现值，但幅度很小：在大多数模拟情况下为2-4％。在此过程中，下土石灰的施用降低了最佳石灰的施用率，也降低了土壤pH达到目标水平所需的时间。