EFFECT OF LONG TERM FERTILIZATION ON CROP YIELD AND SOIL FERTILITY IN SEMI ARID AREA

A 15 years long term experiment with four kinds of manure (crop residue, soybean cake, false indigo leaves, chemical fertilizers and check) under equal quantities of N、P nutrients were conducted at the Experimental Farm of Dryland Farming Institute of Hebei Academy of Agricultural and Forestry Sciences since 1979 The crop rotation was winter wheat and summer corn The effect of these fertilizers on winter wheat corn yields and soil fertility were studied The results showed: 1 There were no significant difference on crop yield among the fertilizer application treatments, the highest yield was annually 6508 5 kg/hm 2 with the chemical fertilizer application; 2 Total and available soil nutrients increased with all fertilizer application; 3 The manure with high carbon contain had better results in organic inorganic complexity and soil humus united pattern; 4 All soil active enzyme increased The sugarcane and urea enzyme increased more, and green manure had better effect; 5 Soil moisture and soil physical properties were improved