Study on evolution of soil salinity in Fengqiu County
封丘县土壤盐分的演变特征研究

Salinity perhaps is the most important problem affecting irrigation agriculture in the world, particularly in China. Soil salinization had ever been one of the four natural disasters which limited the agricultural productivity in Fengqiu county. Based on the data of 40 soil profiles newly observed together with the saline soil data obtained in 1981, a systematic study was carried out on the spatio-temporal characters of soil salinity. Results showed that the soil salinity have descended significantly during the past 27 years, saline soils, while regarded as genetic types, are present only in a few micro-landscapes. At present, the soils with relatively higher salt content are mainly distributed in the southeast of the study area and approximately in accordance with the trend of groundwater depth. The salinized soils with EC higher than 0.293 dS/m are only found in the limited strips in southeast corner of the study region. It is concluded that groundwater recession play an important role in the descending of the soil salinity. And accumulation of soil salt in the profiles at a depth 40 cm below the surface indicated that soil secondary salinization could occur whenever the matchable geohydrologic conditions come back again.