Potential of on-farm produced compost and organic amendments in soil fertility management for organic maize production in southwestern Nigeria

Abstract

Soil fertility is central to organic crop production in the low activity soils of southwestern Nigeria. Studies on the use of organic amendments in the management of soil fertility and productivity have indicated the potential of organic practices in this region. In an experiment to study the effects of 5, 10 and 15 t ha−1 of composted pig manure on soil organic matter (SOM) and nutrient dynamics, compost was applied in 2005 and 2006 while land was left fallow in 2007. Parameters observed include aggregate stability, SOM fractions and N mineralization (laboratory and field incubation). Macroaggregate stability indices increased with compost rates. Distribution of SOM fractions, which accounted more for aggregate stability than total organic carbon with time, was better in compost-treated cultivated land compared to adjacent grassland. Nitrogen mineralization was highest with 10 t ha−1 of compost in both years. Soil chemical properties and nutrient uptake of maize after fallowing also showed that 10 t ha−1 of compost was most effective. Observations from another study involving green manure, compost, organo-mineral and mineral fertilizers have also demonstrated significant effects of organic amendments on soil fauna and other properties compared to mineral fertilizer even in the short run without yield compromise.