Gliricidia sepium Carbon Inputs and Soil Carbon Pools in a Costa Rican Alley Cropping System |
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| Authors: | Maren Oelbermann R Paul Voroney Donald CL Kass |
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| Institution: | 1. Department of Earth Sciences , University of Waterloo , Waterloo, ON, Canada;2. Department of Land Resource Science , University of Guelph , Guelph, ON, Canada;3. Area de Cuencas y Sistemas Agroforestales, CATIE , Turrialba, Costa Rica |
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| Abstract: | Alternative land management practices, including agroforestry, help to maintain levels of soil organic matter (SOM) and can facilitate soil carbon (C) sequestration for mitigating atmospheric CO2 emissions. This study quantified C inputs and determined the changes of the soil C pool in a 19-year-old Gliricidia sepium alley cropping system, studied at two fertiliser levels (tree prunings only ? N], and tree prunings plus chicken manure + N]), and was compared to a sole crop system. Carbon input from tree prunings ranged from 455 to 457 g C m? 2 y? 1, whereas C inputs from crop residues were similar between alley- and sole crops ranging from 121 to 159 g C m? 2y? 1. The soil organic C (SOC) pool in the alley crop was 16–23% higher than the sole crop. In the 19th year of alley farming, SOC was significantly higher (p < 0.05) in the alley crop (3.2%) compared to the sole crop (2.4%), and was also greater compared to that at the time of establishment of the agroforestry system (2.8%). Gross SOC turnover to a 20-cm depth ranged from 12 to 14 years in the + N and ?N alley crops compared to 49 and 50 years in the + N and ?N treatments for the sole crops. Residue stabilisation efficiency in the alley crops was 39% and 55% in + N and ?N treatments respectively. |
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| Keywords: | agroforestry systems carbon inputs gross soil organic carbon turnover mulch soil carbon residue stabilisation efficiency |
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