Soil erosion is among the foremost causes of declining soil resources in Ethiopia, which in turn affect agricultural productivity. To limit this problem, for the last two decades in Gumara watershed, soil and water conservation measures have been practiced through free labor community mass-mobilization. However, their effect on soil fertility has not been evaluated. This study investigated the impact of implemented soil and water conservation measures on fertility improvement in the Gumara watershed. Both composite and core soil samples were taken from upstream, midstream, and downstream adjacent conserved and non-conserved cultivated and grazing plots. Selected soil fertility indicators were analyzed using standard laboratory procedures. Soil and water conservation practices have resulted in a statistically significantly higher mean values of total nitrogen, exchangeable Na+ and Mg2+ at p < 0.01, and of soil organic carbon and organic matter at p < 0.05 in the watershed. The clay content, soil reaction, cation exchange capacity, and exchangeable K+ showed non-significant, but higher mean values in conserved plots. Furthermore, the effects of conservation practices on soil properties were found more effective in cultivated land uses as compared to that of grazing land uses. This is because conservation treatments had significant effects on organic carbon, total nitrogen, exchangeable Na+ and Mg2+ in cultivated land uses but only on exchangeable Na+ in grazing land uses. The interaction effect of treatments and land uses did not reach a statistically significant result for any of the soil properties considered in this study. Conservation measures have important implications for improving soil fertility in the Gumara watershed. Therefore, proper guidance and follow-up, use of agro-forestry and grass strips, and maintenance are required for the watershed’s sustainability and good soil conditions.

中文翻译：

---

水土保持方式对埃塞俄比亚上尼罗河上游古玛拉流域土壤理化性质的影响

水土流失是埃塞俄比亚土壤资源减少的最主要原因，这反过来又影响了农业生产力。为了限制这个问题，在古马拉（Gumara）流域的最近二十年中，通过自由劳动社区的大规模动员采取了水土保持措施。但是，尚未评估它们对土壤肥力的影响。这项研究调查了已实施的水土保持措施对古马拉地区的肥力提高的影响。复合和核心土壤样品均来自上游，中游和下游的邻近的保守和非保守耕地和放牧地块。使用标准实验室程序分析了选定的土壤肥力指标。水土保持措施导致流域中的总氮，可交换的Na +和Mg2 +在p <0.01时以及在土壤中的有机碳和有机质在p <0.05时具有统计学上显着较高的平均值。黏土含量，土壤反应，阳离子交换容量和可交换的K +均显示不显着，但在保守区中均值较高。此外，与耕地相比，保护措施对土壤性质的影响在耕地中更为有效。这是因为保护性处理对耕地用途中的有机碳，总氮，可交换的Na +和Mg2 +具有显着影响，而对放牧地用途的仅可交换Na +具有显着影响。对于本研究中考虑的任何土壤特性，处理与土地利用的相互作用均未达到统计学上显着的结果。保护措施对改善古马拉地区的土壤肥力具有重要意义。因此，为流域的可持续性和良好的土壤条件，需要适当的指导和跟进，农林业和草条的使用以及维护。