Fertilizer use in Malawi is limited due to the relatively high fertilizer price, improvement of fertilizer efficiency is therefore necessary to enhance both maize yield and soil fertility. 2-years compost application was conducted to evaluate its effectiveness in improving soil fertility and enhancing maize yields. Compost application was shown to be effective even at the early stage of application in improving soil fertility and consequently enhancing maize yields. Before compost application, soil fertility was quite poor reflected in a low maize yield (0 to 1.5 t/ha), however compost application made 2 to 4 times larger maize yields. Despite the sufficient amount of N (92 kgN/ha), single application of chemical fertilizer adversely affected maize yield coupled with the poor initial growths. Soil moisture content became 4 times larger with compost application with a shift from 5 to 20%. Moreover, CEC was improved from 10.2 meq/100mg to 13.7 meq/100mg by compost application, resulting in an increase of nutrient retention capacity. Soil C % decreased in 2.5 years if no compost was applied, but soil C % increased by compost application. As such compost application can be effective to maintain soil C % for enhancement of soil fertility. Nitrogen use efficiency (NUE) was greatly improved 2 to 5 times larger when chemical fertilizer (46 kgN) was applied mixed with compost while a single chemical fertilizer application (92 kgN) represented lower NUE than mixed application.
Keywords: compost, maize yield, soil fertility, CEC, soil C, nitrogen use efficiency