宁夏龟裂碱土水盐运移及时空分布特征.

Takyric solonetz land, a typical subclass of alkali soil, is widely distributed in the North of Yinchuan Plain of Ningxia province, West Hetao Plain and north Xinjiang desert steppe in China. Due to the hard soil texture, poor permeability and difficult improvement, it has become the main factor severely affecting the development of local agriculture, and is expected to bring threat to the regional food security in the future. More and more improvement techniques have been developed to achieve a sustainable utilization of saline-alkali waste land, but the salt-water spatial and temporal distribution characteristics in newly reclaimed takyric solonetz land remains unknown. We conducted 3a field comparative experiments to analyze the water-salt spatial and temporal distribution under natural conditions in newly reclaimed takyric solonetz land at the farmland of Xidatan, Ningxia, China, which located in 106°24¢209²E, 38°50¢289²N. The results showed that: the soil moisture content was minimality in 0-20 cm soil, and its coefficient variation was maximum. Moisture content in 80-100 cm soil was larger, and its coefficient variation was smaller. Soil total salt and alkalinity variability were great, and which the spatial distribution were uneven. The variation coefficients of soil total salt and alkalinity in 20-40 cm soil were respectively 51.2% and 60.4%, and the variation coefficients of soil total salt and alkalinity in 40-100 cm soil was less. The soil total salt and alkalinity of 0-20 cm soil were the largest, and the soil total salt and alkalinity of 20-100 cm soil were reduced layer by layer. The moisture content of 0-40 cm soil varied greatly with the season, the change range of 40-100 cm soil was relatively stable, and the soil moisture content decreased year by year. Total salt and alkalinity of 0-20 cm was significantly higher than other soil layers. Soil desalination and salt accumulation in the soil layer 0-40 cm were alternating, salt change was active, and the soil total salt and alkalinity were increasing year by year. Soil mainly contains Na+, Cl-, SO4 2- and HCO3 - at 0-100 cm depth. Alkalinity and salt content at the 0-60 cm depth varied greatly among seasons.Soil moisture content gradually increased from the top soil layer (0 cm) to the deep soil layer (100 cm). These results will also provide a technical support for salt-water management of the newly reclaimed takyric solonetz farmlands, and a guide for the sustainable development and utilization of wasteland takyric solonetz land. [ABSTRACT FROM AUTHOR]