An experiment was conducted over two seasons to evaluate the effects of 5 t ha
-1 of different organic inputs (manure,
Brachystegia spiciformis
(miombo) leaf litter,
Leucaena leucocephala senesced leaves) and Compound D (8N-14P-7K) fertilizer (300 kg ha
-1), and their combinations on maize growth and yield on a sandy soil at Makoholi Experimental Station, Zimbabwe. Prior to planting, vegetation from a 12 year fallow (primarily annual grasses) was ploughed under in November 1990. Maize (
Zea mays
) hybrid (R201) was planted in both seasons. Yields were extremely high in the first season. Addition of
L.leucocephala leaf litter and manure to the soil, depressed plant growth up to tasselling and silking of maize, respectively.
Leuceana leucocephala
leaf litter resulted in a decrease in both shoot dry matter and grain yields. Total above ground dry matter was highest from the fertilizer only and the fertilizer plus miombo litter treatments, though both treatments were not significantly different from the control. Application of both manure and miomba litter resulted in suppression of growth compared to the control. Application of both manure and miombo litter resulted in suppression of growth compared to the control. Suppression of growth was overcome by the application of Compound D fertilizer. In the absence of fertilizer, there was no difference between manure and miombo litter, but miombo litter preformed better than manure in the presence of fertilizer. It is hypothesized that the application of
Leucaena, manure and miombo litter resulted in immobilization of nutrients.
Leucaena, which is rich in N but low in P, probably resulted in P immobilization.
