Dipterocarpus alatus is predominantly known for its beneficial effects to agricultural crops grown in association with it. It plays a major role in the sustainability of agro ecosystem as a whole through soil fertility enhancement, moisture conservation and erosion control. In Thailand, D. alatus is a versatile wood that is beneficial to almost every part.
The above-ground biomass (AGB) plays a pivotal role in controlling soil erosion, determining nutrient cycling, and improving the ecological environment. Microorganisms decomposed the above-ground biomass that eventuates in the accumulation of soil organic matter and nutrients through a process called humification. Leaf litter fall is a mechanism whereby recycle of ecosystem nutrients occurs and it magnifies soil fertility.
Sungthonganwises and Taweeki (2021) designed a research that has been published in Asian Journal of Plant Sciences. The central theme of this study was to examine the rate of D. alatus leaf fall per unit area; percent degradation; nitrogen, phosphorus and potassium content and the amount of nitrogen, phosphorus, and potassium released.
The experiment was conducted in the Khon Kaen, Roi Et, Yasothon and Mukdahan provinces of Northeast Thailand from 2018-2020. Total rainfall of 72.8 mm occurred in winter season, 211.1 mm occurred in summer season and 1,111.9 mm occurred in rainy season during the period of crop growth. The maximum and minimum temperatures were recorded.
Mesh fabric was installed around the D. alatus tree canopy in Khon Kaen, Roi Et, Yasothon and Mukdahan provinces. Fallen leaves of D. alatus were collected in the hot, rainy and winter seasons. To study the rate of degradation and potential for nutrient release, leaves of D. alatus were packed in a litter bag and placed on the soil surface in various experimental areas.
The results of this study depicted that the highest biomass of D. alatus leaves fell in summer at Khon Kaen (483.33 g m–2), followed by winter in Yasothon (286.67 g m–2). A higher percentage of D. alatus leaf degradation occurred at the end of the rainy season than at the beginning of the rainy season, causing the maximum release of potassium, 2.89-7.5 kg ha–1 and the amount of nitrogen released was 0.72-4.93 kg ha–1 after 4 months.
To put it in a nutshell, organic fertilizer of D. alatus plays a fundamental role in improving soil fertility by transforming it into organic matter and inorganic substances in soil. Crops which are present around the D. alatus tree can employed circulating nutrients especially nitrogen and potassium because the leaves of D. alatus contain high amount of nitrogen content and rubber balls have high amount of potassium.
Finally yet importantly, the percentage degradation of D. alatus leaves at the end of the rainy season was greater than in the beginning, causing the maximum release of potassium, nitrogen and phosphorus, in addition to protect wind and chemical spray around rice fields or field crops. This study will be a guideline for researchers to uncover the ecological benefits of D. alatus in terms of the rate of decomposition and the amount of macronutrients released that were not able to explore.
Dipterocarpus alatus, Soil Moisture, Above-ground biomass (AGB), Litter Decomposition, Nutrient Release, agro ecosystem