Soil erosion from agricultural land use runoff is a major threat to the sustainability of soil composition and water resource integrity. Sugarcane is an important cash and food security crop in South Africa, subjected to an intensive soil erosion, and consequently, severe land degradation. This study aimed to investigate soil erosion and associated soil and cover factors under rainfed sugarcane, in a small catchment, KwaZulu‐Natal, South Africa. Three replicated runoff plots were installed at different slope positions (down, mid and upslope) within cultivated sugarcane fields to monitor soil erosion during the 2016–2017 rainy season. On average, annual runoff (RF) was significantly greater from 10 m² plots with 1163.77 ± 2.63 l/m/year compared to 1 m² plots. However, sediment concentration (SC) was significantly lower in 10 m² (0.34 ± 0.04 g/l) compared to 1 m² (6.94 ± 0.24 g/l) plots. The annual soil losses (SL) calculated from 12 rainfall events was 58.36 ± 0.77 and 8.84 ± 0.20 t/ha from 1 m² and 10 m² plots, respectively. The 1 m² plot, SL (2.4 ± 1.41 ton/ha/year) in the upslope experienced 33% more loss than the midslope and 50% more loss than the downslope position. SL was relatively lower from the 10 m² plots than the 1 m² plots, which is explained by high sediment deposition at the greater plot scale. SL was negatively correlated with the soil organic carbon stocks (r = −0.82) and soil surface cover (r = −0.55). RF decreased with the increase of slope gradient (r = −0.88) and soil infiltration rate (r = −0.87). There were considerable soil losses from cultivated sugarcane fields with low organic matter. These findings suggest that to mitigate soil erosion, soil organic carbon stocks and vegetation cover needs to be increased through appropriate land management practices, particularly in cultivated areas with steep gradients.

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南非夸祖鲁-纳塔尔省雨养甘蔗下的土壤侵蚀评估

农业土地利用径流造成的土壤侵蚀是对土壤组成和水资源完整性可持续性的主要威胁。甘蔗是南非重要的经济和粮食安全作物，遭受了严重的水土流失，因此土地严重退化。这项研究的目的是调查南非夸祖鲁-纳塔尔省一个小流域的雨养甘蔗下的土壤侵蚀及相关土壤和覆盖因子。在甘蔗田中的不同坡度位置（下坡度，中坡度和上坡度）安装了三个重复的径流图，以监测2016-2017年雨季的土壤侵蚀。平均来说，年径流量（RF）为10个显著大于²重复与1163.77±2.63升/米/年相比1米²情节。但是，与1 m ²（6.94±0.24 g / l）样地相比，10 m ²（0.34±0.04 g / l）中的沉积物浓度（SC）明显较低。在12个降雨事件中，从1 m ²和10 m ²地块算出的年土壤损失（SL）分别为58.36±0.77和8.84±0.20 t / ha 。上坡的1 m ²地段SL（2.4±1.41吨/公顷/年）的损失比中坡高33％，比下坡高50％。从10 m ²地块来看，SL相对低于1 m ²地块，这可以通过更大的地块规模上的高沉积物沉积来解释。SL与土壤有机碳储量（r = -0.82）和土壤表面覆盖（r = -0.55）呈负相关。RF随坡度（r = -0.88）和土壤入渗率（r = -0.87）的增加而减小。有机物含量低的甘蔗种植地造成了相当大的土壤流失。这些发现表明，为减轻水土流失，需要通过适当的土地管理做法来增加土壤有机碳储量和植被覆盖度，特别是在陡坡的耕种地区。