Effects of Crop Rotations on Selected Soil Properties and Maize (ZEA MAYS) Yield Under Coservation Farming

Crop rotation is known to affect the physical, chemical and biological soil properties. This farming system has shown to be effective at reducing the farmers’ costs while increasing the yields in the long run and improving the fertility of their land. This study investigated selected crop rotations and their impact on selected soil chemical, physical and biological properties and maize (Zea mays) yield over time in conservation plots. Although crop rotations have positive effects on the soil, many of the rotation factors, processes and mechanisms responsible for increased yields and other benefits are not clearly understood and quantified. This study aimed at testing the impact of crop rotations on selected soil physical, chemical and biological properties and maize yield. The study was conducted in two phases: 1) A greenhouse experiment. 2). Sampling and characterization of soil samples collected from two sites at Golden Valley Agricultural Research Trust (GART) in Chisamba district of the Zambian agro-ecological zone II, GPS coordinates S14o 57.488’, E028o 06.085’. The treatments were maize-cowpea and maize groundnut rotations and the fields were 4 and 10 years old respectively. Changes in soil properties due to crop rotations over time were determined. The results indicated significant differences in soil pH, potassium, soil organic carbon and microbial biomass in the older rotation (10 years old) of conservation farming practice. Micronutrients zinc and sulphur were significantly affected by crop rotation in both sites. The physical parameters porosity, bulk density, infiltration and plant available water were not affected in the four years old rotation. The study also showed no correlation among the number of nodules, nodule weight and the amount of nitrogen fixed. The maize-cowpea rotation however had the highest yield. Similar studies should be conducted in other agro-ecological zones of the country to validate these findings