Global studies, generally, and Brazilian studies, specifically, on soil organic carbon (SOC) in experimental research plots, support conservation agriculture (CA) as a tool to partially or totally restore SOC stocks depleted by conventional tillage agriculture. In response, the Brazilian Government implemented in 2010–2030 a “Low Carbon Agriculture Plan” (ABC Plan) program centered on large-scale CA adoption. However, the projections of SOC recovery based on long-term research trials may not adequately portray farm level high-yield operations. The objectives of this study were: (a) quantify and compare SOC stocks to a 1-m depth in long-term CA at the farm scale (>20 years) with paired native vegetation and nearest available long-term research experiments (>30 years) in Southern Brazil; (b) explore the role of oilseed radish (Raphanus sativus L.) as a cover crop to enhance SOC accumulation. In general, farm level CA systems restored SOC at an equal or higher level than the paired research plots. For the farm level CA systems, average SOC recovery was 92% (0–0.30 m) and 97% (0–1.0 m) in the soil profile relative to native vegetation. Moreover, compared to research scale CA, farm level CA average SOC recovery was 91 and 86%, for the same soil layers. Recovery of SOC in research scale CA can be scaled up to farm level systems in Southern Brazil. The main characteristics for SOC recovery (0–1.0 m) were high inputs of plant biomass, lack of soil disturbance, and diversification with oilseed radish cover crop.

中文翻译：

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巴西南部保护性农业土壤碳回收的农场和长期研究实验比较

总体而言，全球研究和巴西研究，特别是关于试验研究地块中土壤有机碳 (SOC) 的研究，支持保护性农业 (CA) 作为部分或完全恢复传统耕作农业耗尽的 SOC 储量的工具。作为回应，巴西政府在 2010-2030 年实施了以大规模采用 CA 为中心的“低碳农业计划”（ABC 计划）计划。然而，基于长期研究试验的 SOC 恢复预测可能无法充分描绘农场水平的高产运营。本研究的目标是：(a) 量化和比较农场规模（>20 年）长期 CA 中 1 米深度的 SOC 储量与配对原生植被和最近可用的长期研究实验（>30年）在巴西南部；（二）探究油菜萝卜的作用（Raphanus sativus L.) 作为覆盖作物以增强 SOC 积累。一般来说，农场级 CA 系统恢复的 SOC 水平等于或高于配对研究地块。对于农场级 CA 系统，相对于原生植被，土壤剖面中的平均 SOC 回收率为 92% (0-0.30 m) 和 97% (0-1.0 m)。此外，与研究规模 CA 相比，对于相同的土层，农场级 CA 平均 SOC 回收率分别为 91% 和 86%。研究规模 CA 中 SOC 的回收可以扩大到巴西南部的农场级系统。SOC 恢复（0-1.0 m）的主要特征是植物生物量的高投入、没有土壤干扰以及油菜萝卜覆盖作物的多样化。