Dr Gebreyohannes Girmay1, Mr Kazuhisa Koda2, Mr Tesfay Berihu1, Dr Fujio Nagumo3, Dr Keiichi Hayashi2
1Mekelle University, Mekelle, Ethiopia, 2Japan International Research Center for Agricultural Sciences, Rural Development Division, Ibaraki 305-8686 , Japan, 3Crop, Livestock and Environmental Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan, Ibaraki 305-8686 , Japan
Ethiopia has been implementing climate resilient green economy strategy and conservation-based agriculture to reverse impacts of overcultivation, overgrazing and deforestation. Long term experiment has been conducted since 2017 to evaluate the roles of conservation agriculture practices for sustainable production in Tigray, Ethiopia. With split plot design, two tillage depths; (shallow and deep); two tillage frequencies (2- and 3-times); vetch cover (incorporation and mulching), wheat residue maintenance (2/3 and 1/3 residue left) were tested. The soil on the site was hard (e.g. penetrometer test 49kg/cm2 at 15cm depth), low in organic C (0.9%) and total N (0.08). The first year results showed deep-3 times plowing produced higher vetch dry matter (2.8t/ha), wheat dry matter (2.4t/ha) and wheat grain (0.97t/ha) than other treatments. Deep-2times plowing on vetch cover resulted in higher available water (AW, 4mm) and exchangeable K (3.4g/kg). Shallow-3times plowing on wheat enhanced AW (3mm), and K (3.9g/kg). Shallow-2times plowing improved available P (4.5mg/kg on vetch, 3.5mg/kg on wheat plots). Second year, zero tillage was practiced when plots were planted to wheat. Wheat yield increased to 3.4t/ha on vetch incorporation, and to 2.4t/ha on vetch mulching over control (1.6t/ha). Wheat residue maintenance, 1/3 and 2/3 left, produced 1.68t/ha and 1.39t/ha. Vetch cover crop improved soil quality: soil hardness halved (22kg/cm2 at 15cm), AW (10mm) five-fold, organic C (2.1%) and total N (0.24%) contents tripled, and available P (7.76mg/kg) and K (13g/kg) at least four-fold. Decreasing plowing depth and frequency improved P availability. Vetch cover crop enhanced fast soil restoration. Yield benefits after legume cover crops can offset yield penalty of no continuous cereal cropping. Integrating legume cover crops and cereal crop residue management in conservation agriculture strategies can restore soil and crop productivity leading to increased agricultural output for a stable economy in Ethiopia and beyond.
Gebreyohannes Girmay has his expertise in soil fertility management systems focusing on exploring techniques for improving soil quality and health. He teaches and advices post graduate students in the soil science, dryland ecology and resource management, dryland agronomy, sustainable watershed management, and dryland agroforestry and land restoration programmes in Mekelle University, Ethiopia. His current research activities focus on integrated soil fertility management, carbon sequestration in soils, reservoir conservation and sediment use, and land evaluation for irrigation.