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西北干旱灌溉区种植春小麦和牧草对耕地盐渍化的影响
李昂1, 张鸣1, 张建1, 吴应珍2, 葛承暄3
1.兰州城市学院 化学与环境工程学院, 甘肃 兰州 730070;2.甘肃农业大学 人文学院, 甘肃 兰州 730070;3.甘肃省耕地质量建设管理总站, 甘肃 兰州 730000
摘要:
[目的]研究西北干旱灌溉区种植春小麦和牧草对耕地盐渍化的影响差异,为该区防治土壤次生盐渍化工作提供科学依据。[方法]以小麦(Triticum aestivum)和混播牧草披碱草/苜蓿(Elymus dahuricus/Medicago sativa)及其下部土壤为研究对象,通过测定植被的盖度、高度、地上生物量及其下部土壤的水、盐含量等指标,来分析和比较种植春小麦和牧草对耕地盐渍化的影响,以及不同植被特征指标与土壤水、电导率间的定量关系。[结果]小麦和牧草的盖度、高度、地上生物量均随生长时间的延长呈显著升高趋势。小麦收获后,小麦地裸露类似于裸地,而牧草继续生长并保持覆盖耕地。当耕地被植被覆盖时,其地表的日照强度、表层土壤(0-5 cm)的温度和盐含量均显著低于裸地,而地表的湿度和表层土壤的含水率正好相反,均显著高于裸地。相关分析显示,植被地上生物量与土壤含水率、植被盖度与土壤盐含量间相关性最强,土壤含水率与盐含量间呈显著负相关关系。进一步回归分析显示,植被地上生物量每提高1 kg/m2,可使植被覆盖区的表层土壤含水率升高6%,盖度每提高1%,可使表层土壤的电导率降低2.2 μS/cm。[结论]西北干旱灌溉区种植春小麦因生育期较短易引发土壤的次生盐渍化,而牧草覆盖耕地时间较长可预防耕地发生盐渍化危害。
关键词:  秦王川灌区  次生盐渍化  植被覆盖  农田生态保育
DOI:10.13961/j.cnki.stbctb.2018.03.006
分类号:
基金项目:国家自然科学基金项目“豆禾牧草混播防治兰州新区周边耕地土壤退化机理研究”(31560185)
Effects of Growing Spring Wheat and Forage Grass on Salinization of Cultivated Land in Irrigated Region of Northwest China
LI Ang1, ZHANG Ming1, ZHANG Jian1, WU Yingzhen2, GE Chengxuan3
1.School of Chemistry and Environmental Engineering, Lanzhou City University, Lanzhou, Gansu 730070, China;2.College of Humanities, Gansu Agricultural University, Lanzhou, Gansu 730070, China;3.Construction Management Station of Gansu Province Cultivated Land Quality, Lanzhou, Gansu 730000, China
Abstract:
[Objective] The effects of planting spring wheat and forage grass on salinization of cultivated land were analyzed in order to provide scientific basis for the prevention and control of soil secondary salinization in irrigated region of Northwest China.[Methods] Triticum aestivum, mixed grass (Elymus dahuricus/Medicago sativa) and soil under them were taken as the study objects. The coverage, height, above-ground biomass of vegetation and soil moisture and electrical conductivity were measured to investigate the impacts of spring wheat and forage grass on land salinization.[Results] During the whole growth stage, the coverage, height and biomass of T. aestivum and grass increased significantly. After wheat harvest, wheat field was bare as naked land, while grass still covered the land surface. Compared with the bare land, surface sunlight intensity, temperature and salt content of surface soil (0-5 cm) under vegetation coverage were much lower, while ground humidity and soil moisture content were much higher. Correlation analysis indicated that the strongest correlation occurred between biomass and soil moisture and between coverage and soil salt, and there was a negative relation between soil moisture and salt. Regression analysis demonstrated that soil moisture content increased by 6% as biomass increased by 1 kg/m2, and soil electrical conductivity decreased by 2.2 μS/cm as vegetation cover increased by 1%.[Conclusion] Planting spring wheat in irrigated regions of Northwest China will cause soil secondary salinization, while planting forage grass may weaken hazard of soil secondary salinization.
Key words:  Qinwangchuan irrigated region  soil secondary salinization  vegetation coverage  ecological conservation and improvement for farmlands