Simple and quick determination of the optimum water content for tillage (θ_OPT) is helpful to guide tillage operations. Based on the definition of θ_OPT that is the water content at the inflection point of the soil water retention curve, a simple method was established to estimate the θ_OPT from saturated water content (θ_s) (θ_OPT = 0.75θ_s). The validation results on 132 soils with varying texture showed that the root mean squared error and mean error were 0.021 and 0.009 g g⁻¹, respectively. These results confirmed that the θ_s was valuable information for estimating θ_OPT and the proposed method could give a reasonable estimation for θ_OPT.

中文翻译：

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一种估算耕作最佳含水量的简单方法

简单快速地确定最佳耕作含水量 ( θ _OPT ) 有助于指导耕作作业。根据土壤保水曲线拐点处的含水量θ _OPT的定义，建立了一种从饱和含水量（θ _s）（θ _OPT  = 0.75 θ _s ）估计θ _OPT的简单方法。对 132 种不同质地土壤的验证结果表明，均方根误差和平均误差分别为 0.021 和 0.009 g g ^-1。这些结果证实了θ _s是估计θ _{OPT的有价值的信息，并且所提出的方法可以对}θ _OPT给出合理的估计。