THE IMPACT OF MULCH BURNING AND TILLAGE METHODS ON SOIL CHEMICAL PROPERTIES, GROWTH AND YIELD OF MAIZE (Zea mays, L) ON A NIGERIA ALFISOL

Not much is known on the effects of mulch burning on no-tillage (NT) and conventional tillage (CT) soil chemical properties in the southern Guinea Savanna zone of Nigeria. A 6- year study was done to bridge this gap in knowledge. CT and NT were the main plots and dry maize plant and vegetation residue mulch at 7 tha-1 in the plots were the sub-plots which gave the following treatments; unburned residue mulch on CT (UCT) Burned residue mulch on CT (BCT), unburned residue mulch on NT(UNT) and burned residue mulch on NT (BNT) treatment effects on soil chemical properties maize growth and yield are as follows :UNT had the highest soil pH (6.53) and the lowest pH was in BCT(5.03) both in 2012. UNT increased pH was in BCT (5.03) both in 2012. UNT increased soil pH with increasing year of cultivation while burning reduced soil pH correspondingly. Similarly UNT had the highest organic carbon (17.56gkg-1) and BCT the lowest (2.02kg-1). They were significantly different (P<= 0.05). The trend of organic carbon for the 6 years was UNT>BNT>UCT>BCT. (P<=0.05). A similar trend was also obtained for NO3-N total N, available P, exchangeable K, Ca and Mg. The soil nutrients were negatively affected by mulch burning. Also observed were maize plant height, stem growth and leaf area. The result followed the trend of soil nutrient content as follows; UNT>BNT>UCT>BCT (P<0.05). Maize grain yield was poor, with the highest maize yield obtained in UNT (3.01 t ha-1) and the lowest grain yield was in BCT (0.57tha-1) in 2012 and the difference significantly at (P<=0.05) NT with unburned plant residue mulch is a key factor in improving soil chemical properties in the ecological zone.