Application effect of the acidification storage of animal slurry returning to field

In recently years, China's livestock and poultry breeding industry has gradually developed in the direction of large-scale and centralization. With the continuous expansion of the scale of breeding, the problem of rapid increase of animal slurry emissions is becoming more and more seriously. Animal slurry were applicated reasonably can not only solve the problem of pollution, but also improving soil nutrients. There is a large amount of ammonium nitrogen in animal slurry. Unreasonable application will lead to the emission of a large amount of ammonia gas from animal slurry into the soil. In generally, the animal slurry should be stored for a period of time and then returned to the field. During the storage period, methane (CH4) emission was reduced, and the fertilizer efficiency of stored manure may improve. Acidification is a way to improve storage quality. At present, there are more studies abroad on the effect of treating animal slurry return to the field. However, the effect of the acidification storage of animal slurry on soil nutrients has been rarely reported in China. In order to explore the application effect about fresh (MS), acidification (HMS), storage (SMS), and acidification storage (SHSM) of animal slurry to field. The pot experiments were conducted to study the effect of animal slurry on soil nutrients and crop yield by using concentrated sulfuric acid and long-term storage of animal slurry. Two control groups were set up for the experiment: Animal slurry before and after storage, and animal slurry before and after acidification of H2SO4. Four different levels (5%, 25%, 50% and 100%) were set for each treatment. The results indicated that the concentration of animal slurry to the field should be strictly controlled (the level at 25%-50%). Animal slurry stored was benefit to the total nitrogen (TN) and total phosphorus (TP) of soil nutrients. After storage, the total nutrients (TN, TP, and total potassium (TK)) increased by 11.32%-73.16%, and the crop yield of SMS(100%) increased by 21.22%. However, after the acidification with H2SO4, the effect of animal slurry on the total soil nutrients changed significantly. Compared with MS, the TP content of HMS increased by 20.21%, 3.45%, 14.10% and 12.82%, and the content of available phosphorus increased by 64.59%, 0.48%, 2.66% and 19.69% at the level of 5%-100%, respectively. The crop yield of HMS(25%) increased by 27.94%. On the basis of the H2SO4 acidized and stored, the TN content of soil increased very significantly (P<0.05), the TN content increased by 20.65%, 25.14%, 46.99% and 82.98% at four different level. Acidification and storage processing to reduce the loss of TN have promoting effect to the increase of soil available nutrients, especially for the effect of available nitrogen significantly (P<0.05), and the crop yield of SHMS(25%) increased by 13.63%. Reasonable application of stored manure slurry and low concentration of animal slurry acidified by H2SO4 can increase crop yield. In generally, the application of stored animal slurry can promote the total nutrients content of soil, promoting the accumulation of phosphorus, and increasing the crop production. However, it is not suitable to apply too high concentration of animal slurry, which will inhibit the yield of crops. The application amount should be controlled within the range of 25% as far as possible.