CORN RESPONSE TO DIFERENT LEVELS OF NITROGEN IN ROTATION WITH MUCUNA UNDER TWO TYPES OF TILLAGE. RIO HATO, PANAMA. 1993-1994.

Abstract

During two years (1993-1994) was carried out an experiment with the objective of evaluate the response of corn to N application (0, 75 and 150 kg N-urea/ha) in rotation with Mucuna deeringiana. The legume was planted at the beginning of raining season (May) while the corn was planted in September. In the experiment two types of tillage were evaluated. One method consisted in incorporate the weeds and legumes before planting (conventional tillage) and the other consisted in leave it on the top of soil (zero tillage). There were evaluated four system: a) Plot consisted in cut the legume and leave the stubble on the soil (MucR+F); b) Plot where grew the legume, cut the foliage and remove it (MucR); c) Plot without legume, but the stubble of the previous plot was move it to this (MucF); d) Plot without legume (SLeg). The experimental design was a Completely Randomized Block design in a split-split-plot with three replications. The principal plots were the systems, the sub-plots were the tillage types and the sub-sub-plots were the nitrogen levels. A highly significant response was found in the residual effect in legume systems. The MucR and MucF were the best system with yields of 4.97 and 4.42 t/ha, respectively. The system MucR+F follows to these systems (4.12 t/ha) and the last was SLeg system with 2.50 t/ha. The N application response was highly significant, with mean yield of 4.81, 4.46 and 2.70 t/ha for the levels 0, 75 and 150 kg N/ha, respectively. The N level x System interaction was highly significant. The best yield was obtained in the MucR system.