Sustainability strategies and soil fertility in the dryland Bình Thuận, Vietnam

Land degradation caused by both human impact and climatic factors leads to desertification and results in a reduction of the vegetation cover, erosion and a loss of soil fertility followed by socioeconomic problems. In particular, non-adjusted land use practices are the main driving forces for desertification. The present study examines how sustainability strategies under dragon fruit and peanut cultivation in Binh Thuận, Vietnam, influence soil fertility in a region that is characterised by Arenosols and a semi-arid climate. The coastal area is prone to desertification which complicates agricultural production. For that purpose, soil analyses for various soil parameters were combined with a socio-scientific survey based on the evaluation of quantitative interviews and a SWOT analysis. The results indicate that no significant effects of sustainability strategies on soil fertility could be measured. Furthermore, no evidence was found that intercropping enhances soil fertility, since soil parameters were not higher under dragon fruit intercropped with peanut than under monoculture. A higher nutrient concentration directly next to the dragon fruit shows that dragon fruit cultivation contributes more to soil fertility than peanut cultivation. This is especially because of the application of mulch around the plant which increases the humus content in soil and keeps the nutrients from leaching. However, the non-cultivated area in between the dragon fruit is more exposed to soil erosion. Differences in values next to and in between the plants are higher under dragon fruit. Therefore, it can be assumed that under peanut, nutrient concentrations are more balanced over the whole field. Due to a rising demand for food and pressure on land not yet used for agriculture, further research on Arenosols and the implementation of agricultural practices adapted to environmental conditions should be accelerated in order to achieve the SDGs (Sustainable Development Goals).