Effects of Garden Waste Compost and Bentonite on Muddy Coastal Saline Soil

Abstract

In order to effectively utilize resources and improve the amelioration effect of coastal saline soil, we studied the effects of applying garden waste compost and bentonite on highly saline coastal soil. Four treatments were established: a nonamended control; application of 68 kg·m−3 of garden waste compost; application of 15 kg·m−3 of bentonite; and mixed application of 68 kg·m−3 of garden waste compost and 15 kg·m−3 of bentonite. The results showed that the soil salinity of the three treatments was significantly lower than that of the nonamended control. The desalination effect of the mixed application was the best, and the salinity in the 0–20 and 20–40 cm soil layers decreased to 3.95 g·kg−1 and 3.82 g·kg−1, respectively. Application of both the garden waste compost alone and the mixed application significantly improved the physical and chemical properties of the soil. However, the mixed application had the best effect because of its ability to increase the total porosity, saturated hydraulic conductivity, and soil nutrient levels. The growth of Robinia pseudoacacia cv. Idaho in the mixed application treatment was also better than other treatments. Principal component analysis and comprehensive scores indicated that the addition of 68 kg·m−3 of garden waste compost and 15 kg·m−3 of bentonite was the optimal application.