Lime and phosphogypsum applications are well‐established practices in weathered soils, and their surface application under no‐till (NT) can affect soil physical attributes and C and N fractions. This study determined the long‐term (10‐yr) effects of lime and phosphogypsum applications to the soil surface on soil C and N fractions of a tropical NT field. The experimental design was a randomized block with four treatments and four replications. The following treatments were applied in October 2002, November 2004, and October 2010, respectively: limestone (2,000 kg ha⁻¹), phosphogypsum (2,100 kg ha⁻¹), and limestone (2,000 kg ha⁻¹) plus phosphogypsum (2,100 kg ha⁻¹). In general, after 10 yr of liming, both alone and when associated with phosphogypsum, the cumulative crop straw inputs were increased at least 20% across the years, and the C fractions increased remarkably at different soil depths. Both treatments improved the SOC stocks by 24% (12.5–15.6 Mg ha⁻¹) at 0.1–0.2‐m soil depths and by 10% (30.6–33.8 Mg ha⁻¹) at 0–0.2‐m soil depths, and in general the soil aggregation at 0–0.4‐m soil depths. However, the particulate C and N fractions were reduced at 0–0.05‐m soil depth, suggesting a slight response to the transitory trend of soil organic C (SOC) depletion. Liming, both alone and when associated with phosphogypsum, overcame the transitory C pool depletion and improved soil aggregation, soil C fractions, and SOC stocks and could be considered an important factor that drives the sustainability of cropping systems under NT.

中文翻译：

---

热带免耕条件下石灰和磷石膏对土壤碳和氮及物理属性的长期影响

在风化的土壤中石灰和磷石膏的施用是行之有效的做法，在免耕（NT）下的表面施用会影响土壤的物理特性以及碳和氮含量。这项研究确定了石灰和磷石膏对热带NT田土壤C和N组分对土壤表面的长期（10年）影响。实验设计是具有四个治疗和四个重复的随机区组。分别在2002年10月，2004年11月和2010年10月进行了以下处理：石灰石（2,000 kg ha ^-1），磷石膏（2,100 kg ha ^-1）和石灰石（2,000 kg ha ^-1）加磷石膏（2,100 kg ha ^-1）。一般来讲，在单独施肥10年后以及与磷石膏联合施肥之后，这些年间，农作物秸秆的累积输入量至少增加了20％，并且在不同土壤深度下，碳含量显着增加。两种处理均在0.1-0.2-m的土壤深度下将SOC储量提高了24％（12.5-15.6 Mg ha ^-1），将SOC储量提高了10％（30.6-33.8 Mg ha ^-1）在0-0.2-m的土壤深度处，并且通常在0-0.4-m的土壤深度处发生土壤聚集。但是，在土壤深度为0-0.05-m时，颗粒碳和氮的含量降低，表明对土壤有机碳（SOC）耗竭的短暂趋势有轻微的响应。无论是单独使用石灰还是与磷石膏一起使用，石灰都克服了短暂的碳库消耗，改善了土壤的聚集，土壤碳组分和SOC储量，可以认为是驱动NT下种植系统可持续性的重要因素。