Decomposition and Nitrogen Release of Prunings from Hedgerow Species Assessed for Alley Cropping in Haiti
- Lionel Isaac,
- C. Wesley Wood * and
- Dennis A. Shannon
Decomposition and N release patterns from prunings of eight tree species were studied under field conditions. Leaves and stems (<1 cm diam) from 4-yr-old hedgerows were sealed in separate litter bags and placed on soil surface at low and high elevation (1150 m) sites in Haiti. Leaves decomposed faster than stems and leaf decomposition was described by a two-pool exponential model. At the low elevation, leaf C loss was highest (82%) in gliricidia [Gliricidia sepium (Jacq.) Kunth ex Walp.] and lowest (42%) in flamboyant [Delonix regia (Bojer ex Hook) Raf.] after 48 wk. At the high elevation, leaf C loss after 48 wk was 48% in leucaena [Leucaena leucocephala (Lam.) De Wit] and 29% in Acacia angustissima (Mill.) Kuntze. Initial N concentrations correlated with leaf C loss (Phase I) at low elevation while C:N and lignin:N correlated with leaf C loss (Phase II) at low and high elevations, respectively. Nitrogen release resembled carbon loss. At the low elevation, gliricidia, Leucaena shannonii Donn. Sm., and leucaena released >50 kg N ha−1 during the first 4 to 6 wk, whereas at high elevation A. angustissima contributed <40 kg N ha−1 during the period. Leaf N release correlated negatively with (lignin + polyphenol):N at low elevation. At the low elevation, gliricidia, L. shannonii, and leucaena provided adequate N for maize production in alley cropping. At the high elevation, A. angustissima contained adequate N, but N release rate may not meet peak N demands of an associated crop.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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