## 5 Conclusions  
The combination of USLE model with GIS and remote sensing is a suitable approach for soil erosion estimation, especially in the area where ground-based observation is difficult. The spatial distribution of different erosion prone areas can be easily identified based on the selection functions of GIS. Moreover, the USLE with five factors and GIS tools will help land users to determine the main causes of soil erosion on their land and from that they will have the most effective response measures.  
IK farming systems are effective in the prevention of soil erosion rates through the improvement of land surface cover. The AMs used in IK-based farming systems include the cultivation of biodiversity, the consideration planting density, and the ongoing modification of the annual planting. All of these factors have a significant impact on the vegetation index. The resulting C factor of IK farming systems is significantly higher than the NIK farming system.  
From the above insights, this study brings to light some aspects that should be included in future agricultural policies for this region. These future policies should not only focus on technical aspects, but also on the social dimensions of the area. A vital part of this is to include the perceptions and experience of smallholder farmers in the design and implementation of future agricultural projects. This also infers the participation of local people in managing soil erosion. There are some historic barriers to overcome, but conscientious collaboration is essential in order to achieve good stewardship of the agricultural land that is specific to each individual area. Our study found that while most farmers have previous knowledge and experience that is relevant in the prevention of serious soil erosion, other members of the community have very little awareness of this. There are socio-economic factors and resource constraints in applying AMs, but also there are psychological factors within the local culture that need to be further considered in regard to how they might enhance or impede the adaptation process. We support the views that there should be a combination of local knowledge and the introduction of new scientific technologies in order to deal with these concerns in the most effective way. In order to achieve this, attention should be given to improving the co-operative communication between scientists, public officials, and the local indigenous people.  
Conceptualization, C.V.H., T.G.P., T.Q.N., L.H.K.N., P.T.T., Q.N.P.L., and M.T.H.N.; methodology, C.V.H., T.G.P., and T.Q.N.; software, T.G.P., L.H.K.N., and P.T.T.; validation, C.V.H. and T.G.P.; investigation, C.V.H., T.G.P., T.Q.N., L.H.K.N., P.T.T., Q.N.P.L., and M.T.H.N.; resources, L.H.K.N., P.T.T., Q.N.P.L., and M.T.H.N.; data curation, C.V.H., T.G.P., and T.Q.N.; writing--original draft preparation, C.V.H., T.G.P., and T.Q.N.; writing--review and editing, C.V.H., T.G.P., T.Q.N., and L.H.K.N.; visualization, T.G.P.; supervision, C.V.H.; project administration, C.V.H. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Ministry of Education and Training of Vietnam; grant number B2019-DHH-02.  
The authors thank the Ministry of Education and Training of Vietnam for their financial support. We also thank the anonymous reviewers for their valuable comments, which greatly improved our paper.  
The authors declare no conflict of interest.  
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