Response of maize to trash burning and nitrogen fertilizer in a newly opened secondary forest

The growth and yield of maize grown on an unploughed newly opened secondary forest in Nigeria in 1985-87 was studied. In each year, trash was either removed or burnt in situ and each of these treatments was given N fertilizer or none. In the first year, only N fertilizer increased yields. In the second and third years, yields were increased by N fertilizer and by trash burning. Trash burning consistently increased the amount of P in the soil