Effects Of Swine Manure-straw Compost On Soil Nutrients, Enzyme Activities, Wheat Nitrogen And Phosphorus Uptake In Wheat Growing Season

In the context of high production costs, shortage of agricultural resources and serious environment pollution, waste recycling is of great significance for improving the resource utilization, alleviating the cost pressure, mitigating the environmental pollution and achieving sustainable development. Based on Rice-wheat Rotation Area in Chengdu Plain, a field experiment with 5 different fertilizing treatments (no fertilizer, pure fertilizer, total straw returning+pure fertilizer, total straw returning+ the lower application of swine manure, total straw returning+the higher application of swine manure) was conducted. By usage of mathematical statistics method, the paper analyzed the influence of applying straw and swine manure on soil nutrients, enzyme activities, nitrogen and phosphorus uptake by plant in wheat growing season. Further exploration of their correlations were studied, aims at revealing the influence of applying straw and swine manure on soil biochemical properties and nutrients uptake by plant, with a view to provide a scientific basis for the comprehensive utilization of agriculture wastes in Chengdu Plain. The main results of two growing seasons are as follows:With the continuous advance of growth stage, the readily potassium permanganate oxidizable organic carbon in rhizosphere and non-rhizosphere soils varied in different trends, decreased and increased, respectively. Readily potassium permanganate oxidizable organic carbon of soil applied with swine manure outperform that of soil without swine manure. The contents of ammonium nitrogen and nitrate nitrogen in rhizosphere and non-rhizosphere soils were high at the prophase of wheat and lowest at anaphase. Compared with soil applied chemical fertilizers only, applying straw had no significant effect on soil ammonium nitrogen and nitrate nitrogen. Swine manure partly replacing chemical fertilizers increased the content of nitrate nitrogen in rhizosphere and non-rhizosphere soils, the increase ranges were 16.05 to 27.06 percent and 5.02 to 28.59 percent, respectively. It is worth noting the potential environmental risks that caused by the application of lower swine manure. Affected by different fertilization treatments, soil available phosphorus was obviously different during the whole growth period. Compared with other fertilization treatments, the higher application of swine manure had significantly. improved the contents of available phosphorus in rhizosphere and non-rhizosphere soils (P<0.05), the increase ranges were 9.63 to 34.79 percent and 16.81 to 44.65 percent, respectively.During the growing season of wheat, the catalase activities of rhizosphere and non-rhizosphere soils showed decreasing trend, higher swine manure replacing chemical fertilizers had significantly improved the activity of soil catalase (P<0.05). The activities of sucrase, urease and neutral phosphatase responded quite sensitively to the changes of fertilization treatment. The activity of sucrase fluctuated widely during the whole growing period of wheat, while the activities of urease and neutral phosphatase changed with "U"-shaped, were higher at seeding stage and maturing stage. The sucrase and urease activities of rhizosphere soil enhanced with the increase of waste applying amount, and swine manure partly replacing chemical fertilizers had significantly improved the activity of soil urease, the increase ranges was 20.39 to 26.33 percent (P<0.05). Compared with soil applied chemical fertilizers only, applying swine manure had significantly improved the activity of neutral phosphatase in rhizosphere soil, the increase range was 13.32 to 24.34 percent (P<0.05). The response sensitivity of three hydrolase in non-rhizosphere soils to the changes of fertilization treatment was lower than that of rhizosphere soil. The activity of soil sucrase changed with the single peak, was higher at jointing stage. During the growing period of wheat, the activities of urease and neutral phosphatase had some fluctuation, but still remained stable overall. Applying chemical fertilizers only and swine manure partly replacing chemical fertilizers had no significant effect on three hydrolase in non-rhizosphere soils (P>0.05). Compared with soil applied chemical fertilizers only, applying total straw had significantly improved the activity of soil sucrase (P<0.05).Fertilizing had significantly enhanced the grain yield of wheat, the increasing effect of applying straw and lower swine manure were better than that of pure fertilizer. Compared with applying chemical fertilizers only, applying straw was not effective to promote the amounts of accumulated nitrogen, phosphorus and the removal rate of nitrogen, phosphorus by Wheat aboveground (P>0.05). Applying lower swine manure had significantly improved the amounts of accumulated nitrogen, the production efficiency of nitrogen, the removal rate of phosphorus and the production efficiency of phosphorus (P<0.05). the increase ranges were 13.11 to 34.43 percent.9.76 to 21.21 percent.20.25 to 21.78 percent and 12.90 to 22.69 percent, respectively. Applying higher swine manure could significantly improve the amounts of accumulated phosphorus (P<0.05). but decreased the removal rate of nitrogen and phosphorus, the production efficiency of nitrogen and phosphorus in different degree.Single correlation analysis indicated that the readily potassium permanganate oxidizable organic carbon of rhizosphere and non-rhizosphere soils were significantly positively correlated with sucrose activity, the range of correlation coefficient were 0.621 to 0.733. The readily potassium permanganate oxidizable organic carbon of non-rhizosphere soils were significantly positively correlated with urease (P<0.05). Canonical correlation analysis further indicated that nitrate nitrogen content of rhizosphere soil have the larger correlation with the activities of urease and neutral phosphatase. The readily potassium permanganate oxidizable organic carbon contents of rhizosphere and non-rhizosphere soils have the larger correlation with the activity of neutral phosphatase. At the same time, the application of waste was helpful to enhance the contents of available nutrients and enzymatic activity, the promotion effect of applying swine manure was better but had no significant effects on that of non-rhizosphere soils. Multiple stepwise regression analysis indicated that the ammonium nitrogen contents of rhizosphere soils and nitrate nitrogen contents of non-rhizosphere soils were the primary factors affecting nitrogen absorption of wheat, and the main factors that affecting phosphorus absorption in rhizosphere and non-rhizosphere soils were available phosphorus contents.Considering soil nutrients, enzyme activities, grain yield, nitrogen and phosphorus uptake by applying agricultural residue in Chengdu Plain, we suggest that the carrying capacity per 667m2 should be excretion quantity of 3 swines half year under total rice straw returning modes in wheat growing season.