Effects of natural zeolite on physical and chemical properties and water retention capacity of chernozem in Songnen Plain of northeastern China

ObjectiveTo study the effects of natural zeolite on modifying the water retention capacity of chernozem and provide theoretical reference for the improvement of soil water retention, the effects of natural zeolite on the physical and chemical properties of chernozem in Songnen Plain of northeastern China and soil water characteristic curve were studied.

MethodChernozem was modified by natural zeolite, cultured in a pot for 60 days. The soil bulk density was measured by cutting ring method. Soil total porosity, capillary porosity and aeration porosity were calculated by formula method. Determination of soil water characteristic curve was measured by centrifuge test.

ResultThe results showed that there was a positive correlation between soil bulk density and the amount of natural zeolite, soil bulk density increased with the increasing amount of nature zeolite. Soil bulk density increased significantly at the 10% mixing amount of natural zeolite. However, there was a negative correlation between the capillary porosity and total porosity and the amount of natural zeolite, the capillary porosity and total porosity decreased with the increasing amount of natural zeolite. The maximum ventilation porosity was obtained at the 10%mixing amount of natural zeolite. The result of the water retention capacity of different mixing amount of natural zeolite was: 20% natural zeolite (NZ)>15%NZ≈10%NZ>5%NZ>CK. The soil water characteristic curve of each group can be fitted well by Gardner model. The coefficients a and b of water characteristic curve equation were negatively correlated with water holding capacity, and positively correlated with saturated water content. The saturated water content and the fitting coefficient a were fitted too. The results showed that R² is 0.941 8.

ConclusionIt is feasible and economical to improve water retention capacity of chernozem by 10% mixing amount of natural zeolite. The saturated water content is high, the initial level of water characteristic curve is not necessarily high yet. The results show that the water retention properties of chernozem can be effectively improved by mixing natural zeolite. This study provides a theoretical and experimental reference for soil improvement in chernozem.