An improved fallow experiment was established in 2013 to examine the contribution of shrub legume species, Tephrosia vogelii and Cajanus cajan, in improving the productivity of a degraded tropical soil and crop yields compared with traditional fallow. The study was conducted on five farmers’ fields in southwestern Ethiopia laid out in randomized complete block design with farmers as replicates. After 2 years, the amount of aboveground biomass produced was 5–8 t ha−1 for Tephrosia and 3–5 t ha−1 for Cajanus. Maize grain yield was 80% higher for Tephrosia and 41% for Cajanus compared with the traditional fallow. The legume species significantly increased soil pH, organic carbon and total nitrogen levels compared with the natural fallow but there was no significant effect for available phosphorus. The magnitude of fallow benefit from Tephrosia in terms of yield advantage and nitrogen availability could be related to its high biomass production capacity compared to Cajanus. Fallowing with Tephrosia has the potential for improving productivity of degraded tropical soils. Farmers’ responses to the improved fallows were in general positive and their preference was Tephrosia fallow. Farmers can therefore use Tephrosia to enhance soil fertility by increasing N-levels, soil pH and organic matter of the soil. However, phosphate fertilizer is required as basal application to enhance N-fixation by legumes.

中文翻译：

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Tephrosia vogelii 和 Cajanus cajan 的短期休耕提高了埃塞俄比亚西南部退化休耕地的玉米生产力和土壤化学性质

2013 年建立了一项改进的休耕试验，以检查与传统休耕相比，灌木豆科植物 Tephrosia vogelii 和 Cajanus cajan 在提高退化热带土壤生产力和作物产量方面的贡献。该研究在埃塞俄比亚西南部的五个农民农田中进行，这些农田采用随机完整区组设计，农民作为复制品。2 年后，产生的地上生物量对 Tephrosia 为 5-8 t ha-1，对 Cajanus 为 3-5 t ha-1。与传统休耕相比，Tephrosia 和 Cajanus 的玉米籽粒产量分别高出 80% 和 41%。与自然休耕相比，豆科植物显着提高了土壤 pH、有机碳和总氮水平，但对有效磷没有显着影响。与 Cajanus 相比，Tephrosia 在产量优势和氮可用性方面的休耕收益程度可能与其高生物量生产能力有关。休耕山毛榉有提高退化热带土壤生产力的潜力。农民对改良休耕的反应总体上是积极的，他们的偏好是黑麦草休耕。因此，农民可以使用 Tephrosia 通过增加土壤的氮含量、土壤 pH 值和有机质来提高土壤肥力。然而，磷肥需要作为基础施用来增强豆类的固氮。农民对改良休耕的反应总体上是积极的，他们的偏好是黑麦草休耕。因此，农民可以使用 Tephrosia 通过增加土壤的氮含量、土壤 pH 值和有机质来提高土壤肥力。然而，磷肥需要作为基础施用来增强豆类的固氮。农民对改良休耕的反应总体上是积极的，他们的偏好是黑麦草休耕。因此，农民可以使用 Tephrosia 通过增加土壤的氮含量、土壤 pH 值和有机质来提高土壤肥力。然而，磷肥需要作为基础施用来增强豆类的固氮。