| Soil fertility management is an important issue in agricultural production. Farmers in undeveloped countries must use cultural practices to improve soil fertility. One recommended technique is alley cropping of Leucaena leucocephala and food crops. The objectives of this study were (i) to determine the pattern of leucaena leaf mulch decomposition, P and K release and evaluate the potential of nutrient release by this plant over time, (ii) assess the impact of different rates of P, K, Zn inorganic fertilizers and leucaena leaves applied on corn yield components and selected soil chemical characteristics.; Mesh bags of leucaena were placed onto soils for 32 weeks, retrieved periodically for dry matter determination and analyzed for chemical compositions. Application of inorganic P-K fertilizers didn't affect leucaena leaf dry matter decomposition or P and K release. Consistently in the three environments, the best fit is obtained by the use of the asymptotic or three parameters model of decay for dry matter disappearance and P and K content. Phosphorus immobilization up to 16 weeks was observed. After 32 weeks of decay cumulative leucaena leaf P and K release in the three environments reached up to 4.5 kg ha-1 of P and 35.2 kg ha-1 of K. These results suggested that the decomposition time (32 weeks) was not optimal and special attention should be given to plant age in further studies.; The effects of P, K and Zn inorganic fertilizer with or without Leucaena prunings on corn yield and components were studied during three cropping seasons at four sites in Haiti selected for differences in parent material and soil chemical properties. At Pernier, application of Zn at the rate of 10 kg ha-1 together with 60 P and 40 K gave the highest corn yield. Pruning applications improved net income from an average of {dollar}26.20 to {dollar}74.30 ha-1 at Salagnac, from an average of {dollar}95.65 to {dollar}134.90 at Bergeau and from an average of {dollar}137.20 to {dollar}250.45 ha-1 at St. Georges for no pruning and pruning treatments, respectively. The third cropping season gave the highest yield and net income in the four environments. Leucaena pruning effects were greater when they are associated with application of P and K fertilizers. |
