摘要
以典型荒漠区原生盐碱荒地及开垦农田为研究对象,通过对比研究,以阐明原生盐碱荒地开垦后不同管理措施下土壤可溶盐总量的变化规律,开垦后土壤剖面中可溶盐总量的垂直分布和季节变化规律。结果表明:开垦显著降低了0～50 cm土壤的可溶性盐含量,开垦达100 a以上老耕地的可溶性盐含量(2.31 g/kg)仅为原生盐碱荒地(26.62 g/kg)的11%;长期的耕作改变了土壤可溶性盐分在土层中的分布,原生荒漠土壤盐分具有鲜明的表聚特征,0～30 cm土层的盐分含量占整个土壤剖面的79%,开垦50 a后,土壤中的盐分分布趋于均匀,各离子浓度的垂直分布不再明显;开垦使土壤中的盐分离子组成也发生了变化,Cl-、K+、Na+离子浓度降低,而SO42-、Mg2+、Ca2+离子浓度增加,耕作层土壤由SO4-2-Cl-1盐土转变为Cl-1-SO4-2盐土;盐碱荒地土壤可溶盐浓度伴随着降水变化具有显著的季节变化特征,而季节对开垦耕地没有显著影响。总体而言,盐碱荒地经过多年开垦利用后,土壤可溶性盐分和pH值均显著降低。
The primary saline land in Xinjiang is mainly used for agriculture. Soil saline content pattern is an impor tant factor affecting plant productivity after cultivation, it is also critical for the stability and sustainability of oasis ecosystem. In this study, the pattern was investigated of total soil soluble saline under different planting patterns in Sangong River basin. Then, the vertical distribution pattern was studied of total soil soluble saline in both primary saline land and cultivated saline land; At last, the seasonal pattern was studied of total soil soluble saline. Results showed that cultivation significantly decreased soil total dissolvable salt concentration at 0 - 50 cm layers, the longer the cultivation, the lower the contents of the soil soluble salt in soil. The total soil dissolvable salt concentration was 2.31 g/kg in cultivated land and 26.62 g/kg in primary soil salinizealkalization, the former accounted to 11% of the later soil. Long term cultivation changed the vertical distribution of soil dissolvable salt along soil profile. In the pri mary saline desert land, the total dissolvable salt concentration showed an obvious trait of surface assemblage. The total dissolvable salt concentration at 0 30 cm soil layers took 79% to the whole soil profile, in contrast, after a cul tivation history of 50 years, the salt distributed equally along the whole soil profile. In addition, the practices of culti vation also changed the composition of base ions, with a decreasing pattern of CI, K, Na concentrations and in creasing pattern of SO42, Mg2＋, Ca2＋ concentrations along the whole soil profile. As a consequence, the type of saline soil changed from SO42C1 dominated soil to C11 SO,2 dominated soil. The soil dissolvable salt concentration in the natural salinizationalkalization soil showed a significant seasonal pattern which was accompanying the precipi tation variation, while no difference was observed in the cultivated land among different seasons. This study indicat ed that keeping the soil water flow down the soil profile persistently is critical for the sustainable use of the natural salinizationalkalization soil.
出处
《干旱区地理》
CSCD
北大核心
2013年第2期285-291,共7页
Arid Land Geography
基金
国家重点基础研究发展计划资助(2009CB825102)
中科院知识创新工程重要方向项目(KZCX2-EW-QN-316)
西部博士项目“光降解在温带干旱区凋落物分解中的作用”(XBBS201007)
关键词
新疆
开垦
盐分聚积
盐分分布
Xinjiang
cultivation
salinity accumulation
salinity distribution
