松嫩平原西部土地整理对盐渍化土壤的改良效果

Effects of land consolidation on improvement of salinity soil in Western Songnen Plain

为了研究松嫩平原西部土地整理对盐渍化土壤的改良效果，以吉林省白城市镇赉县土地整理项目区为研究区域，采用野外采样与室内分析相结合的方法，分析了原耕地、盐碱地和新增耕地土壤电导率、阳离子总量、阴离子总量、碱化度、pH值、有机质以及阳离子交换量等指标的差异。结果表明：在0～20和﹥20～40cm土层上，新增耕地土壤电导率显著低于盐碱地44.9%和37.0%（P＜0.05），显著高于原耕地35.7%和58.6%（P＜0.05）；新增耕地阳离子总量和阴离子总量均显著低于盐碱地（P＜0.05）；盐碱地土壤碱化度在37.0%～38.2%之间，pH值接近10.0，为重度碱化土壤，新增耕地土壤碱化度在18.0%～21.6%之间，pH值低于9.0，为中度碱化土壤，其土壤碱化程度与原耕地接近；新增耕地土壤有机质显著高于盐碱地33.4%和61.3%（P＜0.05），在0～20cm土层上显著低于原耕地21.5%（P＜0.05）；新增耕地阳离子交换量比盐碱地提高16.7%和25.1%（不显著，P＞0.05），同时显著高于原耕地4.8%和11.0%（P＜0.05）。典范对应分析表明，土壤盐渍化、肥力指标和土壤离子组成与样地类型分布存在着空间上的有序关系，样地类型由盐碱地向新增耕地的变化，在土壤理化性质层面是盐渍化指标降低、肥力指标升高的过程；在土壤离子组成层面是HCO3-、CO32-和Na＋等离子含量降低的过程。总体来看，松嫩平原西部土地整理能有效改良盐渍化土壤，但新增耕地土壤质量仍低于原耕地，建议在土地整理中通过完善灌溉与排水系统、将土地平整工程与深耕深松和增施有机肥相结合及采用生物措施等提升盐渍化土壤的改良效果。

Songnen plain is the main grain strategy reserve area of China, and it is also one of the three largest soda saline-alkali soil regions in the world. Soil salinization severely restricts the sustainable development of agriculture and the improvement of people’s living standards. The land consolidation major projects officially launched in the west of Jilin Province in 2007 provides an effective way for comprehensive controlling salinity land. In the process of land consolidation, one of the most important problems need to be addressed was how to combine land consolidation with soil improvement to realize the purpose of increasing cultivated land areas and improving salinity soil. In order to study the Western Songnen Plain land consolidation effect on improving salinity soil, this paper took the land consolidation project in Zhenlai county of Jilin Province as study area, selected the original cultivated land, saline-alkali land and newly-added cultivated land as plots, adopted the methods of classical statistical analysis and canonical correspondence analysis to comparative study the differences of soil physical and chemical properties and soil ionic composition of different plots. And then we put forward related suggestions for land consolidation and improving salinity soil. The results showed that, in 0-20 and〉20-40 cm soil layer, soil electrical conductivity of newly-added cultivated land was significantly decreased by 44.9% and 37.0% than saline-alkali land （P〈0.05）, but significantly higher than original cultivated land by 35.7% and 58.6%. The total actions and total anions of newly-added cultivated land were significantly lower than saline-alkali land （P〈0.05）. The exchange sodium percentage of saline-alkali land was around 38% and pH value was close to 10.0, that was classified to severe salinity soil. While the newly-added cultivated land soil exchange sodium percentage was 18.0% and 21.6%, and soil pH value was less than 9.0, that was classified to moderate salinity soil and close to the original cultivated land. Newly-added cultivated soil organic matter was higher than saline-alkali land by 33.4% and 61.3% significantly （P〈0.05）, but it was significantly lower than original cultivated 21.5% in 0-20 cm soil layer. Newly-added cultivated soil cation exchange capacity was increased by 16.7% and 25.1% than saline-alkali land （P〉0.05）, and it＇s slightly higher than original cultivated land. Canonical correspondence analysis results showed that soil physical and chemical properties and ionic composition had significant correlation with plot type distribution. Plot type changed from saline-alkali land to newly-added cultivated land was the process of soil salinization indices decreasing and fertility indices rising in the level of soil physical and chemical properties, and also the process of bicarbonate ion, carbonate ion and sodium ion content reduction in the level of soil ionic composition. Overall, the land consolidation project in Western Songnen Plain could improve salinity soil effectively, but the soil quality of newly-added cultivated land is still lower than the original cultivated land. Therefore, we suggest to improve salinity soil better through improvement of irrigation and drainage system, reasonable land leveling measure and scientific farming.