Effect of Age of Leaves of Samanea Saman (Jacquin) Merill on Utility as Green Manure

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(1 Dept. of Life Sciences, 2 Dept. of Botany, Ramnarain Ruia College, Matunga, Mumbai-400 019)


To fully exploit the concept that trees improve soil, a very common and abundant legume Samanea saman (Jacquin) Merrill was selected for study to establish the stage of growth at the time of litter collection as an important crop factor influencing its relative nutritive value with respect to residue mineral content and the chemical factors affecting rate of degradation and nutrient mineralization. Measurements of Moisture, N, C, Fibre, Lignin, Cellulose and Polyphenols were made to obtain suitability of the leaves for composting whereas the C: N, Lignin: N, Polyphenols: N, Lignin+Polyphenols: N, Cellulose+Lignin: N was determined to correlate with rate of degradation and nutrient mineralization. The Young leaves decomposed at a faster rate registering a higher content of N and P, whereas the old leaves exhibited a higher Ca content and greater N mineralization potential.

The tree investigated would thus be an excellent prospect for agroforestry programmes providing a viable solution to soil fertility problems with benefits derived from both pruning of Young leaves and natural shedding of Old leaves. The high percentage of low quality organic material in the leaf litters would also lead to enhanced accumulation of soil organic matter (humus) increasing soil fertility and reducing soil degradation.
Key words: Samanea Saman (Jacquin) Merill, Green Manure, agroforestry.