Author : Tutanes, Gil A.

Summary : A field experiment was conducted at the experimental station of the Catanduanes Agricultural and Industrial College in Panganiban, Catanduanes in August 1990 - March 1991 to determine the shortest turnaround time from green manure species incorporation to rice planting and to identify the green manure that would give the highest grain yield. Three green manures (Indigofera tinctoria, Crotolaria juncea, and Sesbania rostrata) and four timings of planting after green manure incorporation (7 days, 14 days, 21, days and 28 days after green manure incorporation) was used in this study. Two months before the main rice cropping season, all legume manure sources were planted. After 60 days, the plants were simultaneously incorporated into the soil and rice was planted. Results revealed that of the three legumes species, Sesbania rostrata proved effective as a green manure. Sesbania rostrata has unique growth and adaptive characteristics that permitted it to grow vigorously in pre-rice system with a remarkable biological and agronomic affeciency. Its substantial dry matter and essential nutrients to rice with resulted to high rice grain yield. Crotalaria juncea and Indogofera were also effective as green manure but their effect were not as great as that of Sesbania rostrata. Planting rice 14 days after green manure incorporation was the best planting timing, regardless of green manure source, because it produced the highest biomass and grain yield. Therefore, plantng rice 14 days after green manure incorporation is enough time for green manure to decompose and give better response to rice.