E. Handayanto, A. Sholihah
Although organic matter is applied repeatedly over crop cycles, the relationship between quality of legume residues and N release has been generally determined over single crop cycles (8 to10 weeks). To evaluate the N recovery by maize (Zea mays L.) from legume residues over two planting cycles, freshly chopped (1 to 2 mm) and 15N labeled residues of Centrosema pubescens Benth. and Calopogonium mucunoides Desv. were applied at the rate of 100 mg N·kg-1 soil in a glasshouse study. After the harvest of the maize plants (8 weeks), soil in the pots was split into two halves, one of which recieved a further addition of unlabelled legume residues (100 mg N·kg-1 soil), while the other did not. Recovery of N from the residues ranged from 12 to 44%, most of which was from the first application. Repeated addition of unlabelled N rich and low pholyphenol Centrosema residues, led to a stimulation effect on the previously applied 15N labelled legume residues, whereas new addition of N poor, high polyphenol legume residues led to a retardation effect. There was no compensation for initial N release from N poor, high polyphenol legume residues at second application.
Department of Soil Science, Faculty of Agriculture, Brawijaya University, 651451, Jl. Veteran, Malang, Indonesia; Department of Agronomy, Faculty of Agriculture, Malang Islamic University, Malang 65141, Jl. M.T Haryono, Indonesia
