渭干河-库车河三角洲绿洲农田表层土壤盐分特征分析

Salinity Characteristics of Farmland Surface Soil in Weigan-Kuqa River Delta Oasis

采用野外采样和室内试验相结合的方法,对渭干河-库车河三角洲绿洲不同作物类型农田表层土壤盐分离子含量进行分析,为干旱区绿洲农田土壤盐渍化的治理、合理利用及因地制宜的精准改良提供一定的理论依据。结果表明:土壤总盐含量为3.43 g/kg,属于轻度盐渍化,其中棉田最高为5.28 g/kg,谷物地最低为1.60 g/kg;土壤呈微碱性。各盐分离子中SO2-4比重最大,表层土壤以硫酸盐类盐渍土为主。在阴离子中,SO2-4比重最高,其中在果林地最高,在棉田最低;在阳离子中,K++Na+比重最高,其中在混合作物地最高,在棉田最低。农田表层土壤总盐分含量与Ca2+含量呈极显著正相关;Mg2+含量与p H值呈显著正相关,与Cl-含量呈极显著正相关,与HCO-3含量呈显著负相关。棉田表层土壤总盐分含量与Ca2+含量呈极显著正相关,Mg2+含量与Cl-含量呈极显著正相关。谷物地、混合作物地和果林地表层土壤总盐分含量与K++Na+、SO2-4含量呈极显著正相关,与Cl-含量呈极显著负相关,与p H值呈显著正相关;Ca2+含量与Mg2+含量呈极显著正相关;SO2-4含量与p H值呈显著正相关,与K++Na+含量呈极显著正相关,与Cl-含量呈极显著负相关;Cl-含量与K++Na+含量、p H值均呈极显著负相关。表层土壤总盐分在空间上从绿洲内部向外围及扇缘逐渐增多,非盐渍化与轻度盐渍化土壤主要分布于绿洲内部及东北部,中度盐渍化土壤主要分布于绿洲的南缘,重度盐渍化土壤主要分布于绿洲的西岸、外围与扇缘地带。

Combining field sampling with laboratory experiments,farmland surface soil salt content from different land use types were analyzed in Weigan-Kuqa river delta oasis. The results showed that total soil salt content was 3. 43 g/kg,belonging to mild salinization,the cotton field had the highest value of 5. 28 g/kg,the grain field had the lowest value of 1. 60 g/kg;the soil was slightly alkaline. SO2-4 had the largest portion among all salt ions,surface soil consisted mainly of sulfates saline soil. Among anions,SO2-4 had the largest portion,the fruit trees field had the highest value,and the cotton field had the lowest value;among cations,the portion of K＋ ＋Na＋were the largest,the mixed crop field had the highest value,and the cotton field had the lowest value. There was a extremely significant positive correlation between nbsp;farmland total salt content and Ca2＋content,significant positive correlation between Mg2＋content and pH value,extremely significant positive correlation between Mg2＋ content and Cl- content, and significant negative correlation between Mg2＋content and HCO3-content. There was a extremely significant positive correlation between surface soil total salt content and Ca2＋ content, extremely significant positive correlation between Mg2＋content and Cl-content in cotton field. The total surface soil salt content were extremely significant positively correlated with K＋ ＋ Na＋ content, SO2-4 content, extremely significant negatively correlated with Cl-content, and significantly positively correlated with pH value;there was a extremely significant positive correlation between Ca2＋ content and Mg2＋ content, significant positive correlation between SO2-4 content and pH value, extremely significant positive correlation between SO2-4 content and K＋ ＋Na＋content, and significant negative correlation between SO2-4 content and Cl-content;Cl-content was extremely significant negatively correlated with K＋ ＋Na＋content and pH value in cereal field,mixed crops field and fruit field. The total salt content in surface soil gradually increased spatially from the interior oasis to the periphery and its fan edges. The soil with no salinization and mild salinization were mainly distributed in the central and northeast part of oasis, the soil with moderate salinization mainly distributed in the northern region of the oasis,and the soil with severe salinization was mainly distributed in the western,periphery and the fan edges of the delta oasis.