Studies on saline soils in Khon Kaen Region, Northeast Thailand

Abstract

The effects of several amelioration treatments on the physical and chemical properties of the saline soils (Paleustult) in the Khon Kaen Region, Northeast Thailand, were studied. The application of CaS04, CaCOa, converter slag, or compost into the plow layer, the placement of crude oil or rice husks below the plow layer and rice straw mulching were compared.The plots with these treatments were constructed in the field and the moisture content, pH, EC, permeability, clay dispersion, NH4-N and NO~-N contents were determined. The evaluation of each amelioration treatment was as follows. Compost application was the most effective, followed by mulching. The addition of adequate, but not excessive amounts of calcium materials was necessary to increase the soil buffering capacity. The crude oil and rice husk plots showed very wide seasonal pH fluctuations as in the case of the control plot.To simulate rainfall infiltration, a leaching experiment was conducted using soils collected periodically from the above plots. The turbidity level (clay dispersion) of the leachate of CaS04 and CaCOa plot soils was much lower than that of the other plot soils. Compost application also had a suppressive effect on clay dispersion. Clay was dispersed easily in soils from the rice husk and crude oil plots and a high turbidity level of the leachate was observed for the rainy season samples of these plots. By mulching, dispersion was strongly suppressed, which may be due to the stability of the soil aggregates.Leaching speed was negatively correlated with the clay dispersion and it remained high throughout the experimental period (2 years) in the CaS04, CaC03, converter slag, and compost plots.Therefore, the combination of compost and calcium application to the soil with mulching was considered to be a suitable procedure for the amelioration of this kind of soil.

The potential of NAA and ICP-MS for determining soil dispersibility in relation to landslide incidents

“…While it is commonly believed that the occurrence of dispersive soil is limited to region with arid or semi-arid climates, other countries globally have encountered challenges associated with this phenomenon [2,3]. Dispersive soil has been reported in various tropical nations, including Thailand, Vietnam, Indonesia, and Malaysia [4,5,6,7]. Several regions of Malaysia, prior studies have documented the presence of this particular type of soil in Batu Gajah, Wangsa Maju, Shah Alam and East Sabah.…”