2019 ASHS Annual Conference

Cambodia’s population has increased by 1.5% per year and remains among the fastest-growing regions in Asia. Continuing population growth, suggesting that there will increase competition for land, water, and nutrients to meet the simultaneously rising demand for food. Soil Organic Carbon (SOC) plays a crucial role in enhancing crop productivity through carbon sequestration and soil microbial biomass. The decline of SOC causes poor aggregation, accelerates soil erosion and reduces soil biological and enzymatic activities. SOC can be enhanced by addition of biomass-C inputs such as crop residue on the soil surface, root biomass of living mulch, and the absence of soil disruption. Meanwhile, crop productivity could also be enhanced by proper nutrient management practices. Our research study aims to investigate the effects of different soil mulching and soil nutrient management on SOC and its fraction and soil enzyme activities. This research is conducted at two locations (Battambang and Siem Reap province) with different soil texture for three cropping cycles. Our hypothesis is that the inputs of different soil mulching (i.e. Arachis pintoi, Morning Glory, and Rice straw) and soil nutrient management (cattle manure, UREA fertilizer, manure + UREA fertilizer) in a short-term management practices could increase the soil labile carbon and enzymatic activities compared to non-mulching in chili pepper production. The experimental plots are laid out in spit plot with two factors. Soil mulching treatments serve as main plots and soil nutrient management treatments serve as sub-plots. The Composite soil samples will be collected following three cycles cropping system at four depths: 0-5, 5-10, 10-20, and 20-40 cm depths. Soil samples will be air dried, sieved and analyzed for Hot-water extractable C – HWEOC, permanganate oxidizable C – POXC, chemically stabilized organic C-CSOC, Dehydrogenase, β-glucosidase, β-glucosaminidase, and Phosphatase. We expect that using of soil mulching (legume living mulch, non-legume living mulch, and crop residue) and nutrient management (manure and/or inorganic fertilizer) which are under conservation tillage will improve SOC and its fraction and soil enzyme activities, while treatment of non-legume without fertilizer will reveal in the lowest results of SOC and its fraction.

Keywords: β-glucosidase, Living mulch, Hot-water extractable C, permanganate oxidizable C, inorganic fertilizer, manure, Dehydrogenase