Impact of farm exclosure, tillage practices, and cropping patterns on soil and teff grain nutrient status in Semiarid Ethiopia

Abstract

Land degradation is a critical issue globally, particularly in sub-Saharan Africa. Agroecological practices in northern Ethiopia have been implemented to address this, but the combined effects of these practices on soil and grain nutrient status remain underexplored. This study examines the impact of farmland management, cropping patterns, and tillage systems on soil properties and the availability of soil and grain micronutrients in teff-growing areas of semiarid regions in Ethiopia. This study examined the impact of two farmland management systems (farm exclosure vs. unmanaged), two cropping patterns (mono-cropping of teff vs. rotation with legumes), and three tillage frequencies (2-3, 4-5, 6-7 plows) on soil and grain nutrients in teff-growing sites. A Randomized Complete Block Design was employed across 10 sites, resulting in 360 observations. Results showed that management, cropping pattern, and tillage frequency significantly affected bulk density, pH, available phosphorus, total nitrogen, soil organic carbon, spore density, root colonization, and soil and grain micronutrient content (P<0.05). Farmland exclosure combined with teff-legume rotation and a tillage frequency of 2-3 times per year reduced bulk density by 45% and increased soil organic carbon (206%), nitrogen (263%), soil zinc (379%), iron (200%), selenium (291%), and grain zinc (221%). These findings suggest that optimal farmland management, particularly farmland exclosure, crop rotation, and moderate tillage, improves soil quality to support crop growth, and crop nutritional quality. Enhancing land and crop management is crucial for soil health and crop nutrition, especially in arid and semiarid regions with limited micronutrient availability in cereal-based systems, highlighting a strategy to combat soil degradation and malnutrition. • Soil nutrient decline reduces teff productivity in semiarid Ethiopian farms • Farm exclosures improve soil traits and teff grain nutrient status • Tillage practices under exclosures enhance key soil quality indicators • Cropping patterns in exclosures increase teff grain Zn, Fe, and Se levels • Mycorrhizal colonization relates strongly to teff grain micronutrient levels