The Study On Difference Of Water And Fertilizer Effect Of Dry-land Farming In Loess Plateau

Compared with 22 years long-term experiment of applying fertilizers on continuous wheat, This experiment studied the difference between the effect of field comparison experiment and long-term experiment on soil nutrient fertility and Nitrate accumulation, the effects of different fertilizing on yield,water use efficiency,fertilizer use efficiency and nutrient absorption were analyzed, to keep agriculture sustainable developing.The result showed that long term application of manure could increase soil nutrient, combination applying of NP and manure was significant, combination fertilizer application was better than single applying N or P. The soil nutrient content of field comparison experiment increased obviously, organic matter,total N and total P increased respectively by 27.1%,84.2% and 34.8%,available N,P and K increased respectively by 46.9%,540.0% and 10.2%,the soil fertility level was close to NP treatment. Combination applying of N and P or manure can reduce nitrate accumulation, the nitrate accumulation was highest with single applying N, and the nitrate accumulation in field comparison experiment was fewer than of which long term application of N in long term experiment. The pondage reduced obviously with Long term application of manure, but there was no clear difference when pondage in field comparison experiment compared with Control in long term experiment. On current, field fertilizing not only could increase soil nutrient, but also reduce nitrate accumulation, and the pondage was higher, so ecosystem is still at good situation.In field comparison experiment, wheat'sear numbers increased with Combination applying of manure and chemical fertilizer, and the weight of thousand-grain improved with single applying P, single applying P.or combination applying M could increase grain and weight of thousand-grain in long term experiment. The yield increased by 21.5% and 111.7% with Combination applying of N and P in two experiments, and the interaction of N and P was good; Comparing with long term experiment, the yield in field comparison experiment increased by 2103.4 kg/hm2 to 3316.5kg/hm2, especially in P treatment, the yield increased by 334.6%. Combination applying of N and P could not only improve the contribution ratio of fertilizer to yield but also improve efficiency of N,P, the contribution ratio of fertilizer to yield in comparison experiment was better than which in long term experiment.The WUE increased respectively by 24.1% and 95.2% in NP treatment in two experiment; Comparing with long term experiment, the WUE in field comparison experiment increased by 46.5% to 290.0%. The FUE increased with single applying N and combination applying of P, but the FUE was generally lower in field comparison experiment.The change of N,P accumulation in plants was similar to each other ,N,P in each organs transferred from stems and leaves to ears or grains, the K accumulation was higher in stems and leaves, and there was obviously decreased in maturation stage. The N,P accumulation was higher in application of manure treatment, was lower in long term experiment in P and Control.Wheat's dry matter accumulation increased with stage's change in two experiments, and there was a high accumulation at elongation and booting. Combination applying of manure and chemical fertilizer could increase dry matter accumulation sharply, and dry matter accumulation improved by 27.2% in NP treatment at Maturation in long term experiment, comparing with long term experiment, dry matter accumulation in field comparison experiment was higher, the difference of N, P and Control was great.The P harvest index was higher than N harvest index, K harvest index was lowest with applying fertilizer in dry land. In comparison experiment, combination applying of N and P could improved nutrient harvest index, K harvest index was highest in NPM treatment; In long term experiment, single applying of manure and N was benefit to improve N, P harvest index, K harvest index was highest in NP treatment. At certain extent, nutrient harvest index in comparison experiment was higher than which in long term experiment, the difference of NPM was great.