Assessment of the contribution of agroforest legumes in the rehabilitation of degraded uplands
1987
Manguiat, I.J.
A long-term study is being conducted in a "Kaingin" [swidden agriculture] at Puting Lupa, Calamba, Laguna [Philippines] to assess the contribution of Agro-forest legumes in the rehabilitation of degraded uplands. The results obtained so far after three croppings indicated that the corn yields obtained in the control plots were always the lowest in each of the three croppings. However, green leaf manuring with ipil-ipil showed a very interesting trend whereby there was a near doubling of yield increment from the first to the second cropping and another near doubling from the second to the third cropping. This implies that green leaf manuring with ipil-ipil could contribute substantially to the rehabilitation of degraded uplands because it tends to have a cumulative effect on the grain yield of corn grown in a "kaingin". Presumably, not all of the organic N added in the form of ipil-ipil leaves are mineralized and subsequently utilized by the immediate crop; rather, a residual effect was observed on the succeeding crop. This is one of the major advantages that green manuring has over fertilization with inorganic nitrogenous fertilizer such as ammonium sulfate.
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