Modeling the soil nutrient balance of integrated agriculture-aquaculture systems in the Mekong Delta, Vietnam

Abstract

This study quantifies soil nutrient balances of Integrated Agriculture-Aquaculture Systems in the Mekong Delta of Vietnam. Eleven farms were monitored to collect data on farm activities and nutrient inputs and outputs to compute these balances of the rice-based and high input fish system in O Mon district (R-HF); the rice-based and medium input fish system in Tam Binh district (R-MF); and the orchardbased and low input fish system in Cai Be district (O-LF). For the estimation, the Nutmon model has been adapted to the specific conditions in these integrated systems in Asia (Nutmon-Asia). New regression models of leaching and gaseous losses of nitrogen were applied to fields used for upland crops and paddy rice. Reference values were used for the assessment of nitrogen fixation in paddy soils, wet atmospheric deposition, and irrigation water. The results showed that farms in all three systems have nitrogen, phosphorus and potassium surpluses (84 kg N, 73 kg P, and 69 kg K ha -1 year -1 ). The O-LF system had the smallest nitrogen surplus while the smallest surplus of phosphorus and potassium was seen in the R-HF system. High surpluses of phosphorus and potassium were found in vegetable fields, whereas a negative potassium balance was found in the rice fields of all three systems. The positive farm nutrient balances indicate that it is likely that soil fertility will be maintained although there is a risk for environmental contamination.

Factors affecting farmers’ adoption of integrated rice–fish farming systems in the Mekong delta, Vietnam

“…Dang et al. (2008b) and Phong et al. (2011b) confirmed the contribution of nutrients from, for example, pig waste to fish production.…”

“…As the cost of input was correlated to income and RF farmers had a higher net income ⁄ ha this might indicate a higher efficiency of input use in RF systems. Dang et al (2008b) and Phong et al (2011b) confirmed the contribution of nutrients from, for example, pig waste to fish production. Comparing high, medium and low input systems, Phong (2010) concluded that efficiency of IAA systems in the Mekong delta was higher for nutrient use in the medium input systems, however, the production efficiency was highest for high input systems, while the environmental impact per unit produced was highest in low input systems.…”

Maximizing Yields, Nutrient Uptake and Balance for Mustard-Mungbean-T. Aman Rice Cropping Systems through Nutrient Management Practices in Calcareous Soils

“…Quantification of the loss or add of nutrients under different cropping system has been less attended in calcareous soils of Bangladesh. Nutrient balance is an important tool for assessing the fate of removal, reserve and added nutrients in soils (Blaise et al, 2005;Phong et al, 2011). Nutrient balance has been helped of plant fertilization and yield maximization (Paul Fixen et al, 2014;Bindraban et al, 2000;Smaling et al, 1993).…”

Diversity and Distribution of Earthworms in Different Soil Habitats of Assam, North-East India, an Indo-Burma Biodiversity Hotspot

“…Besides, some earthworm species are also known for their nutritional importance. For instances, the west-African night crawler and the English red worm have been widely used in north America as food for bait, ornamental fish and other difficult-to-raise fish species since 1940 [8]. The fact that earthworms are essential for the entire ecosystem since they perform numerous functions like breakdown of soil organic matter and release of plant nutrients into adjacent soil.…”