Modeling the water and nutrient movement under biochar presence, slow-release fertilizer application and different water management, for two soil types during a rice column experiment in Cambodia

Abstract

Experimenting and developing accessible sustainable agricultural practices have become an economic and ecological major point in Cambodia. This study combines a modelling component with a soil column experiment testing biochar presence, slow-release fertilizer application, and alternate wetting and drying practices on two agronomically predominant soil types (Prateah Lang and Prey Khmer). Two thirds of water balance models were performed with high statistical indicators (NSE = 0,90; 0,98). The data input of the remaining third needs to be reviewed. For nutrient transport and transformation, it was possible to develop models with appropriate statistical indicators despite actual calibrated parameter values, by ignoring the dynamics of irrigation and multiple soil horizons. These models remain to be developed by the integration of concentration and leached amount of nutrient measurements still being processed. Parallel to this, the study highlighted several practices effects. Slow-release fertilizer positively impacts root length and plant height. Biochar improves root length, nutrient adsorption and Prateah Lang's hydraulic response, but seems to lead to the deterioration of Prey Khmer's texture. Alternate wetting and drying water practice system allows to increase root length without impacting plant height and seems to be diminishing water flow nutrient concentration. However, the sustainability of these approaches must be established. Indeed, it is important to take into account the economic and social aspects by considering yield and the workforce's accessibility to these technologies.