Phytodesalination of a Salt-Affected Soil with Four Halophytes in China
摘要
In arid and semiarid regions of China, the decrease in agricultural production due to excessive salts is a very serious problem. Salt-affected soil distributes mainly at north, west, around Bohai Sea, and the mid-stream of the Yellow River. We could have ameliorated salt-affected soil such as alkali soil, saline-alkali soil by using flue gas desulfurization gypsums. Consequently, the effectiveness of these desulfurization by-products as soil amendments could be confirmed. However, soil containing much salt such as sodium chloride spreads widely in Tianjin city around Bohai Sea. In order to ameliorate this soil, it is necessary to remove much salt in soil at first. Phytodesalination refers to the use of halophytes to remove sodium from the soil. This plant-based method is of great importance especially for several developing countries. In this research, treatments by four halophytes, Artemisia argyi L., Limonium bicolor K., Melilotus suaveolens L., and Salsola collina P. were tested in pot experiment by using three salt-affected soils (Dagang district, Xiqing district and Jixiang county) in Tianjin. Soil properties were evaluated by pH, EC, ESP (exchangeable sodium percentage) and ions concentration (Na, Ca, Mg, Cl, HCO3, CO3 and SO4) before and after plant growing. Consequently, Na and Cl concentrations and EC at all test pot decreased after the growth of halophytes, and Na concentration in two halophytes increased. Moreover, we could propose the new soil amelioration method to add desulfurization gypsum to soil after phytodesalinization because of both high pH and high ESP after treatment.