College of Chemistry and Life Sciences，Weinan Nornal University，Key Laboratory for Eco-environment of Multi-River Wetlands in Shaanxi Province，Weinan，Shaanxi 714000
Taking the 1982 national soil survey data as a backdrop，the variation tendency of soil nutrients in farmland in Guanzhong irrigation district was analyzed.The results showed the contents of organic matter，total nitrogen，alkali-hydroly zable nitrogen and available phosphorus in Guanzhong irrigation soil greatly increased compared with the date of 1982，available potassium presented the whole decline.The improvement of agricultural land soil nutrient were relative with fertilizer input and straw returned modern agricultural cultivation way.