Uwiragiye Yves, Ngaba Mbezele Junior Yannick, Yang Mingxia, Elrys Ahmed S, Chen Zhujun, Cheng Yi, Zhou Jianbin
School of Geography, Nanjing Normal University, Nanjing 210023, China; College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China; Department of Agriculture, Faculty of Agriculture, Environmental Management and Renewable Energy, University of Technology and Arts of Byumba, Rwanda; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, China.
College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Plant Nutrition and the Agri-Environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shaanxi, China.
Sci Total Environ. 2024 Jan 15;908:167989. doi: 10.1016/j.scitotenv.2023.167989. Epub 2023 Oct 31.
Acidic soils cover over 30 % of Sub-Saharan Africa cropland. Acidic soils deprive crops of calcium, magnesium, potassium, molybdenum, and phosphorus due to aluminium (Al), manganese, and iron toxicities. Thus, liming is required to adjust the level of exchangeable Al to the desired level of Al saturation of the crops grown. Lime requirement (LR) was quantified using soil dataset from Africa soil information service (AfSIS). Spatial variations of LR of cereals, pulses and cash crops were predicted using random forest algorithm. Our results revealed that mean of LR Mg CaCO (1 Mg = 10 g) ha for cereal crops were 6.34, 6.35, and 4.41 for maize, sorghum, and upland rice, respectively. Mean of LR (Mg ha) for pulses were 6.28, 5.19, and 4.90 for common beans, soybeans, and cowpeas, respectively. Mean of LR Mg CaCO (1 Mg = 10 g) ha for cash crops were 3.41 and 6.29 for coffee and cotton, respectively. Spatial variation showed that LR in croplands was higher in tropical humid regions than in semi-arid and arid regions and ranged from 0 to 8.8 Mg ha. The results of 10-fold cross validation for high model performance of LR for tested crops were coefficient of determination (R) of 0.61, a root mean square error (RMSE) of 0.5, and a mean absolute error (MAE) of 0.31, maize LR with RMSE = 0.9, MAE = 0.24, and R = 0.51, and cotton LR with RMSE = 0.5, MAE = 0.31, and R = 0.60. We recommend predicting lime requirement in acidic soils of Sub-Saharan Africa by adjusting Al saturation up to the tolerance of the grown crop, updating soil surveys in Sab Saharan Africa, and using digital soil mapping to monitor soil acidity and lime requirement.
酸性土壤覆盖了撒哈拉以南非洲超过30%的农田。由于铝（Al）、锰和铁的毒性，酸性土壤会使作物缺乏钙、镁、钾、钼和磷。因此，需要施用石灰将可交换铝的水平调整到所种植作物所需的铝饱和度水平。利用来自非洲土壤信息服务（AfSIS）的土壤数据集对石灰需求量（LR）进行了量化。使用随机森林算法预测了谷类作物、豆类作物和经济作物的LR空间变化。我们的结果表明，谷类作物的LR（Mg CaCO₃，1 Mg = 10⁶ g）/公顷均值，玉米为6.34，高粱为6.35，旱稻为4.41。豆类作物的LR（Mg/公顷）均值，普通豆为6.28，大豆为5.19，豇豆为4.90。经济作物的LR（Mg CaCO₃，1 Mg = 10⁶ g）/公顷均值，咖啡为3.41，棉花为6.29。空间变化表明，热带湿润地区农田的LR高于半干旱和干旱地区，范围为0至8.8 Mg/公顷。对测试作物的LR模型高性能进行10倍交叉验证的结果为，决定系数（R）为0.61，均方根误差（RMSE）为0.5，平均绝对误差（MAE）为0.31，玉米LR的RMSE = 0.9，MAE = 0.24，R = 0.51，棉花LR的RMSE = 0.5，MAE = 0.31，R = 0.60。我们建议通过将铝饱和度调整到所种植作物的耐受水平来预测撒哈拉以南非洲酸性土壤的石灰需求量，更新撒哈拉以南非洲的土壤调查，并使用数字土壤制图来监测土壤酸度和石灰需求量。
