Effects of long-term located fertilization on wheat growth in shajiang black soil

Effects of different applications of fertilizer on the growth and grain yield were studied systematically according to the results of a 20-year located experiment．The results show that the effect of the fertilizers on wheat yield is IV >Ⅲ > 1I> I> CK．It is indicated that the application of a single chemical fertilizer has a little contribution to the increase of crop yield owing to its insufficient improvement of the soil fertility；even though it can promote strong seedlings and big tillers per plant，increase ears and grains per spike，etc．Single application of organic manure contributes greatly to the improved soil fertility，but it is not efficient for plant to absorb nutrients and take part in material syntheses and accumulation at the early growth stage．So it is difficult to realize final high yield due to its slow-relea sing character．On the contrary，it is clea r that the yield level with combined application of organic manure and chemical fertilizers is relatively coordinative，and the accumulated dry matter is also effective and econom ica1．Then it is suggested that the application of chemical fertilizers combined with organic manure will be an efficient way in sustainably improving wheat yield and soil fertility in shajiang black sol1；but we must attach serious importance to the application of potassium at the same time．