Best Management Practices for mitigating agricultural nutrient pollution in the Mun River Basin, Thailand

Highlight: Rice paddies and staple crop fields are predominant in Mun River Basin. The cropping increase nutrient loading and soil loss to the river. Proper soil conservation practices can improve surface water quality. In this study, interconnections between soil and water quality were analyzed and the results suggest best management practice for the agricultural lands.

Researcher Name: Asst. Prof. Dr. Arika Bridhikitti

Years of execution: 2019-2021

Funder Name: National Research Council of Thailand co-funded by the National Natural Science Foundation of China

Objectives:

To understand the spatial patterns of the associations between the land-soil properties and the hydro-water quality characteristics
To propose suitable soil-water conservation measures for improving the water quality

Abstract: The Mun River in NE Thailand is one of the significant tributaries of the Lower Mekong River. Its poor river quality has been reported and agricultural activities were claimed to be major causes. This study aims to assess best management measures appropriately responsive to nutrient pollution in the Mun River Basin’s agricultural ecosystems. The data used for the analysis was acquired from field measurement during the 2018 wet season via satellite retrieval and secondary data collection. Linkages between land-soil datasets and hydro-water quality datasets were assessed through canonical correlation analysis. The results suggest possible conservation measures with crop yield improvement and fertilizer cost reduction in the western basin. For the southern basin which exhibits high sediment loading, integrated conservation measures for soil loss reduction with in-stream flow deceleration should be chosen. In the eastern basin, woody buffer strips and check dams should be prioritized. Both nutrient and sediment pollution were experienced in the middle part of the Mun River Basin and applications of low-P manure with mineral NK were recommended. Nonetheless, other soil-water conservation measures can be optionally applied to enhance effectiveness in watershed management.

Region*	Conservation measures
Region*	Vegetative measures	App. of fertilizers	Mechanical measures
West	Intercropping, Relay cropping, Strip cropping	Low-P manure with mineral N and K	Optional
West	Filter/buffer strip	Low-P manure with mineral N and K	Optional
South	Mulching, Filter/buffer strip, Strip cropping	Optional	Contour cultivation, Minimum tillage, No tillage or Sub soiling, Check dams
Middle	Optional	Low-P manure with mineral N and K	Optional
Lower	Buffer strip (woody forest is preferable)	Optional	Check dams

Reference: Bridhikitti, A., Prabamroong, T., Gaohuan, L., & Guo-An, Y. (2021). Best management practices for mitigating agricultural nutrient pollution in the Mun River Basin, Thailand. Soil and Water Research, 16(2), 121-128.