Soil property variation under agroforestry based conservation tillage and maize based conventional tillage in Southern Ethiopia

Abstract

With the objectives of assessing variations in selected soil properties, two tillage types: agroforestry based conservation tillage (AFCST) and maize based conventional tillage (MCVT) under three age categories (5, 10 and 15-years) were selected in Chichu and Haroresa Kebels, Dilla Zuria, Ethiopia. A total of 48 composite soil samples (4 replication×2 tillage types×3 age categories×2 soil depth layers: 0–10cm and 10–20cm) were collected to analyze texture and soil organic carbon (SOC%). Addational undisturbed core samples were also collected to determine soil bulk density (gcm−3). Water infiltration capacity was also measured in the field using double ring infiltrometer. The results showed that clay and sand textural fractions significantly varied (p<0.001, p=0.002, respectively) with age of land management. Soil bulk density, soil moisture content (SMC), total porosity (Pt) and soil organic carbon (SOC) varied significantly with tillage types (p<0.001) and soil depth (p<0.001). Water infiltration (rate and cumulative) significantly varied (p<0.001) with tillage types: higher in the AFCST than in the MCVT. Lower soil bulk density, higher soil organic carbon (SOC) and soil moisture content (SMC) were observed in the top 0–10cm soil layer under the AFCST than in the MCVT. Soil bulk density and soil moisture content (SMC) increased while total porosity (Pt) and soil organic carbon (SOC) decreased with soil depth in both tillage types. Improvement in the soil properties under AFCST was due to higher soil organic matter (SOM) input and less soil disturbance. Thus, reducing the frequency of soil disturbance through application of conservation tillage would help to improve the soil quality.