ISHS Acta Horticulturae 645: VII International Mango Symposium
DECOMPOSITION AND NUTRIENT RELEASE PATTERNS OF THE GREEN MANURE PHYTOMASS IN IRRIGATED MANGO ORCHARD |
| Authors: | T.C. de A. Gomes, J.A.M. e Silva, E.M.B. Soares, M.S.L. da Silva |
| Keywords: | mulch, pearl millet, Sudan sorghum, Crotalaria juncea, semi-arid, Brazil |
| Abstract:
Decomposition rate and N, P, K, Ca and Mg release patterns of biomass of Crotalaria juncea, pearl millet (Pennisetum typhoides) and sudan sorghum in a mango orchard irrigated by micro-sprinkler was studied in the Northeast of Brazil. The litterbag method was used and 20 g of dry weight of plant upper part or fresh leaves of the three species were collected in nylon screen bags. The litterbags were distributed in the soil surface under the mango trees. Three bags of each material were collected after 1, 2, 4, 6, 8, and 12 weeks after distribution. All three species presented a fast decomposition phase from the fourth to the sixth week, followed by a slower decomposing phase. Yearly decomposition constants of leaves and upper part biomass (k) were, respectively, 4.59 and 3.88 for sudan sorghum, 6.34 and 3.71 for pearl millet and 7.01 and 5.30 for C. juncea. Potassium was the fastest releasing element. About 90% of potassium contained in the leaves of all three species and in C. juncea upper part were released during the first two weeks of decomposition. It was observed a strong immobilization of magnesium and calcium during the decomposition of the grasses biomass upper part. | |
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