Pruning management effects on soil carbon and nitrogen in contour-hedgerow cropping with Leucaena leucocephala | (Lam.) De Wit on sloping land in Haiti
Application of hedgerow prunings to the soil in alley cropping ispracticed to sustain crop yield but information is lacking on effects ofhedgerow management on soil C and N dynamics under continuous cropping.Cumulative effects of 3.5 years of leucaena [ Leucaenaleucocephala(Lam.) De Wit] hedgerow ma...
|Published in:||Nutrient Cycling in Agroecosystems, Vol. 65, No. 3 (2003), p. 253-263|
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- Application of hedgerow prunings to the soil in alley cropping ispracticed to sustain crop yield but information is lacking on effects ofhedgerow management on soil C and N dynamics under continuous cropping.Cumulative effects of 3.5 years of leucaena [ Leucaenaleucocephala(Lam.) De Wit] hedgerow management on soil organic CandN and potential C and N mineralization were determined in an alley croppingexperiment in Haiti. Treatments were combinations of pruning uses and pruningregimes in a 3 × 3 factorial with a no-tree control (rock walls) in arandomized complete block design with 3 replicates. A hedgerow + fertilizertreatment in an adjacent trial was included for comparison. Soil samplescollected at 0–5, 5–10 and 10–20 cm depths weresealed in mason jars and incubated at 25 °C for 30 days.Organic C and N and inorganic N were measured before the incubation. InorganicNand respired CO2-C were measured after the incubation. After 3.5years, surface soil samples with prunings applied as mulch or incorporated atplanting had, respectively, 20 and 16% higher organic C, 34 and 18% higherorganic N concentrations, higher potential C and N mineralization and higherrelative N mineralization than with prunings removed. Soil C and N dynamicsweresimilar between pruning application methods. The two-cut regime with a longerregrowth period after cutting (0–40 DAP) had highest organic C in the0–20 cm soil layer whereas two-cut with a shorter regrowthperiod (0–30 DAP) had highest C turnover. Within soil layers, pruningapplication had higher organic C and N and potential C and N mineralizationthanthe no-tree control and alley plots with prunings removed in the 0–5cm layer whereas the latter treatments had similar C and Ndynamicsat all depths. Addition of N-P-K fertilizer in presence of fresh prunings didnot increase soil organic C and N but enhanced N dynamics in the surface soil.