Conventional surface-application of agricultural lime takes many years to increase pH deeper in the soil profile, which is a barrier to increased adoption of liming. We conducted a series of experiments to measure the rate of vertical movement of alkali and identify the factors that determine this movement into the subsurface, to evaluate the feasibility of ameliorating acidic subsurface soil using residual (undissolved) lime (CaCO3) at Wongan Hills (30.85°S, 116.74°E) and Merredin (31.48°S, 118.21°E) and to test whether deep tillage and lime incorporation can significantly speed up the amelioration of subsurface soil acidity at Kalannie (30.42°S, 117.29°E). Multiple applications of lime to the surface of the soil at higher rates (total 6–8.5 Mg ha–1) significantly increased subsurface soil pH but only in the 0.10–0.20 m depth by 0.049 pH units per year over 10–24 years. A large proportion of the surface-applied lime was stratified in the top few centimetres of the soil and incorporation of this undissolved lime with a rotary hoe to a depth of 0.25 m significantly increased soil pH (by 0.63 units) within a year in the Wongan Hills field experiment. Deep incorporation of 6 Mg ha–1 lime to a depth of 0.45 m through excavation and spading with a small rotary hoe also increased soil pH by more than a unit and decreased Al concentration to below the toxic level within two months in the Kalannie experiment, allowing wheat (Triticum aestivum L.) plants to produce root systems up to 0.59 m deep compared with 0.26 m for the control. Our soil column leaching experiment indicated that surface incorporation of lime in higher rainfall regions can be useful to treat subsurface soil acidity but that the rate of improvement in subsurface pH was slow. Therefore, deeper incorporation of lime using cost-effective strategic deep tillage is likely to be necessary.

中文翻译：

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表面施用石灰中碱的缓慢移动需要引入战略性耕作以快速改善澳大利亚西南部的地下酸度

农用石灰的常规表面施用需要多年才能增加土壤剖面中更深的 pH 值，这是增加采用石灰的障碍。我们进行了一系列实验来测量碱的垂直移动速率并确定决定这种移动到地下的因素，以评估在 Wongan Hills (30.85) 使用残留（未溶解的）石灰 (CaCO3) 改善酸性地下土壤的可行性°S, 116.74°E) 和 Merredin (31.48°S, 118.21°E) 并测试深耕和石灰掺入是否可以显着加快 Kalannie (30.42°S, 117.29°E) 地下土壤酸度的改善。以更高的速率（总共 6-8.5 Mg ha-1）在土壤表面多次施用石灰显着增加了地下土壤 pH 值，但仅在 0.10-0.20 m 深度增加了 0。10-24 年间每年 049 个 pH 单位。大部分表面施用的石灰分层在土壤的顶部几厘米处，用旋转锄将这种未溶解的石灰掺入 0.25 m 的深度，在一年内，Wongan 的土壤 pH 值显着增加（增加了 0.63 个单位）希尔斯现场实验。在 Kalannie 实验中，通过挖掘和用小型旋转锄铲铲将 6 Mg ha-1 石灰深度掺入 0.45 m 也使土壤 pH 值提高了一个多单位，并将铝浓度降低到低于毒性水平的两个月内，允许小麦 (Triticum aestivum L.) 植物产生深达 0.59 m 的根系，而对照则为 0.26 m。我们的土柱浸出实验表明，在降雨量较大的地区，石灰的地表掺入可用于处理地下土壤酸度，但地下 pH 值的改善速度缓慢。因此，可能需要使用具有成本效益的战略性深耕来更深地掺入石灰。