Soil management for conservation and sustainable rice production in an irrigated area of eastern Nigeria

An comparison of soil management techniques in the different irrigation zones of Lower Anambra Irrigation Project (LAIP) in eastern Nigeria showed that heavy use of machinery led to increases in bulk density and decreases in field water infiltration rate, The relative proportion of clay in the irrigated fields increased as a result of irrigation, suggesting that mobilized clay from uncemented main and distribution canals is carried and deposited in the rice fields. Both irrigation and the use of machinery have had substantial negative effects on soil nutrient levels, and there is a danger of this process continuing. Soil management for sustainable production in the area should centre on applying organic matter in combination with inorganic fertilizers, monitoring the soil properties on yearly basis before the cropping season for fertilizer and lime recommendations, and varying the depth of tillage to increase or maintain the effective soil depth.