Soil Properties and Crop Responses to Alternative Tillage Practices on Grazed Pasture and Cultivated Land in Nigeria

Information on the influence of alternative tillage methods on soil properties when imposed on grazed pasture especially in the rainforest agroecological zone of Nigeria remains fragmentary. The study, aimed at evaluating the responses of soil properties and plant growth parameters (PGP) to maximum (conventional) (MXT), conservation (minimum) (CST) and no-tillage (NOT) was conducted on two adjacent but fenced plots: grazed pasture (GP) and cultivated land (CL). The test crop was maize in a 2 x 3 x 3 completely randomized block experiment. Soil samples collected from 0-10, 10-20 and 20-40cm depths were analysed using standard laboratory procedures and PGP was also monitored for two consecutive cropping seasons. On the GP, for instance, after 2 years under CST, soil compaction indicators like bulk density (BD) and cone index (CI) changed from 1.42 to 1.31 and 4.5 to 3.1 respectively while hydraulic conductivity (Ksat) and infiltration rate (Ir) varied from 61.5 to 50.1 and 73.1 to 56.8, gravimetric moisture content (GMC) changed from 15.9 to 12.4%. Soil organic carbon (SOC) under GP was averaged 13.3% before the experiment but reduced to 1.1, 2.1 and 4.1 respectively under NOT, MXT, and CST after 2 years. Furthermore, Maize yield was 4.7. 4.1 and 3.8 tons/ha for CST, MXT and NOT respectively after the first cropping season but reduced significantly at the end of 2nd year to 3.6, 3.3 and 2.5 tons/ha. However, on the CL, no significant changes in either crop or soil were recorded.