s:2043:"%T Interaksi antara pohon dan tanaman pangan pada sistem budidaya pagar 
%A Hairiah, D.K. 
%A Purnomosidhi P 
%A Guritno B 
%A van Noordwijk, M. 
%X Tree-soil- crop interactions in simultaneous agroforestry systems such as hedgerow inter cropping contain positive as well as negative aspects.Overall improvement may depend on controlling the negative ,competitive interactions, rather than improving the positive interactions through much supply. Along term hedgerow inter cropping experiment on an acid soil in lam pug was used to separate interaction terms. the experiment has shown consistent yield advantages (compared to a no-tree control) for regularly pruned hedgerows of a local tree peltophorum daysirachis, but not for more conventional tree species. positive and negative terms of interaction equation were measured by comparing crop (maize) yields with or without fresh much additions, with and without a root barrier between hedgerows and crops and after removing hedgerows to test residual effects on soil improvement. Results for the first growing season, with consistent rainfall surplus, showed a strongly positive residual effect on soil fertility when the hedgerow trees were removed after 8 years of alley cropping. For calliandrs and leucaena crop yields in these plots were higher than those obtained with the highest N fertilizer rate tested (135 kg ha-1). In the normal alley cropping system .however, only peltophorum out yielded the controls, as before. The difference is largely due to above ground interactions (shade),as the effects of fresh mulch application and belowground interaction (measured by the effects of root trenches ),were small.the relative success of the local tree, peltophorum dasyfrachis, is not due to pronounced positive effects (these are just average ), but to small negative effects. The tree is less competitive than the others, partly because of a deep root system (that is why it was first selected ),but especially because of a dense canopy shape, giving high milch/shape ratio. 
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