Long-term cultivation of steppe soils in a nonsustainable way caused severe soil degradation and reduced agricultural productivity in Eastern Europe, one of the world's most important areas for cereal production. In order to combat soil erosion and maintain yields, a widespread system of tree windbreaks was introduced in the 1950s, accompanied by improved agricultural practices in recent years. However, information on the effectiveness of such measures to rebuild soil organic carbon (SOC) is scarce. The objective of this study was to estimate the OC storage potential of the fine mineral fraction of degraded arable steppe soils in Moldova and to quantify SOC sequestration rates under (a) windbreaks, (b) cropland with improved crop rotation/manure application, and (c) cropland with cover cropping. Natural grassland relicts served as a reference to estimate the SOC saturation potential. Our results revealed a low SOC saturation of 50% under conventional agricultural use due to high SOC losses, indicating a high potential for SOC sequestration. Relatively high SOC sequestration rates were determined for topsoils (0–30 cm) under windbreaks (0.9 t ha−1 yr−1), improved crop rotation/manure application (1.3 t ha−1 yr−1), and cover cropping (1.9 t ha−1 yr−1). In this regard, sequestration rates derived from OC changes of the fine fraction may be more reliable than total SOC-based rates, particularly for windbreaks with high proportions of labile SOC. We conclude that implementation of improved agricultural management together with the maintenance of windbreaks is a promising strategy to rebuild SOC, reduce widespread soil erosion and compaction, and secure Moldova's agricultural productivity.

中文翻译：

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在东欧退化草原土壤中重建土壤碳：防风林和改善农田管理的重要性

以不可持续的方式长期耕种草原土壤导致东欧严重的土壤退化和农业生产力下降，东欧是世界上最重要的谷物生产地区之一。为了对抗水土流失并保持产量，1950 年代引入了广泛的树木防风林系统，并伴随着近年来农业实践的改进。然而，关于这些措施重建土壤有机碳 (SOC) 的有效性的信息很少。本研究的目的是估计摩尔多瓦退化可耕草原土壤中细矿物质部分的 OC 储存潜力，并量化 (a) 防风林、(b) 改善作物轮作/施肥的农田和（ c) 覆盖作物的农田。天然草地遗迹作为估计 SOC 饱和潜力的参考。我们的结果显示，由于 SOC 损失高，传统农业使用下 SOC 饱和度低，为 50%，表明 SOC 封存的潜力很大。对于防风林下的表土（0-30 厘米）（0.9 吨公顷-1 年-1）、改进的轮作/施肥（1.3 吨公顷-1 年-1）和覆盖作物（1.9 t ha−1 yr−1)。在这方面，源自精细部分 OC 变化的封存率可能比基于总 SOC 的速率更可靠，特别是对于具有高比例不稳定 SOC 的防风林。我们得出的结论是，实施改进的农业管理以及维护防风林是重建 SOC、减少广泛的土壤侵蚀和压实、