The primary aim of this work was to assess the effect of rates of gypsum used alone and in combination with limestone on (a) soil nutrient contents and acidity, and (b) soybean and maize yields, on a subtropical coarse-textured Ultisol with a low cation exchange capacity (CEC) under no-tillage (NT). For this purpose, a field experiment using different rates of gypsum (0.0, 0.5, 1.0, 2.0 and 4.0 Mg ha⁻¹) with or without limestone at 2.0 Mg ha⁻¹ was started in August 2013. The experimental design was completely randomized blocks with three replications. The soil was sampled in five different layers (0–5, 5–10, 10–20, 20–40 and 40–60 cm) after 52 months, and crop yield was assessed in the seasons 2014/2015 and 2016/2017 for maize, and 2015/2016 and 2017/2018 for soybean. Surface application of limestone increased soil pH and base saturation in the 0–10 cm soil layer without exceeding the critical levels or having a significant effect on crop yield. Gypsum only altered the concentration of exchangeable Mg²⁺ in the soil, which decreased with increasing Ca²⁺/Mg²⁺ ratio in the subsurface layers as the amendment rate was increased. As a result, gypsum reduced maize yield in the first harvest after application, possibly by making the soil deficient in Mg²⁺, and the negative effects on microbial biomass. No similar effect was observed in the subsequent years. Applying gypsum to soils with low CEC and acidity in the subsurface layers not only fails to increase crop yield but also may induce Mg deficiency.

这项工作的主要目的是评估在亚热带粗质地Ultisol上，单独和与石灰石结合使用的石膏用量对（a）土壤养分含量和酸度以及（b）大豆和玉米产量的影响。免耕（NT）下阳离子交换能力（CEC）低。为此，在不同的石膏（0.0、0.5、1.0、2.0和4.0 Mg ha ^-1）下使用或不使用2.0 Mg ha ^-1的石灰石进行田间试验实验设计始于2013年8月。实验设计是完全随机的区块，重复了3次。52个月后，在五个不同的层（0–5、5–10、10–20、20–40和40–60厘米）中对土壤进行了采样，并在2014/2015和2016/2017两个季节对作物产量进行了评估。玉米，2015/2016年和2017/2018年的大豆。石灰石的表面施用增加了0-10 cm土壤层的土壤pH值和碱饱和度，而没有超过临界水平或对作物产量没有显着影响。石膏仅改变土壤中可交换Mg ²⁺的浓度，随Ca ²⁺ / Mg ^2+的增加而降低随着修正率的增加，地下层中的比率增加。结果，石膏可能会导致土壤中的Mg ^2+含量不足以及对微生物生物量的不利影响，因此在施用后的第一次收获期降低了玉米的产量。在随后的几年中没有观察到类似的效果。在地下层CEC和酸度较低的土壤上施用石膏，不仅不能提高农作物的产量，而且还可能导致镁缺乏。