Effects Of Compost Technology On Dissolved Organic Matter And Its Fertilizer Efficiency

Developing organic fertilizer industry not only solve a series of agricultural production problems caused by using excessive chemical fertilizers, such as soil hardening and soil ecological fertility declining, but also is the key industry to disposing organic solid waste and reducing environmental pollution. However, traditional organic fertilizer plays a role on slow fertilizer effect and the farmer need to use more than ten times chemical fertilizer dosage. Developing efficicent organic fertilizer to improve the farmer's motivation and promote fertilizer industry development is of great significance. So, it is important to research the key indicators to develop efficient organic fertilizer products. According to the 4 quality indexes(organic matter, total NPK nutrient, p H and water content) of the current national organic fertilizer agricultural industry standard, it couldn't assess compost quality efficiently. The application practice show that organic fertilizer effect depends not only on its NPK inorganic nutrient content, but also on its active organic ingredients such as dissolved organic matter(DOM). This study compared different compost technology how effected compost product features, especially the active organic components, and explored the effectiveness of dissolved organic matter, to improve the quality of organic fertilizer and provide theoretical basis for improving organic fertilizer evaluation index system. The main results were as follows:(1) The results of compost test with different oxygen status showed that organic matter and humic acid in aerobic and anaerobic composting had been a downward trend with compost continued. The content of both organic matter and humic acid in aerobic treatment were lower than that in the same period of anaerobic treatment. After 90 days composting, organic matter content dropped to around 50% and humic acid dropped to 75 g/kg. NPK Total nutrient content of aerobic composting exceeded that of anaerobic composting. GI in aerobic composting were higher than that in the same period of anaerobic treatment, and all final compost products' GI were more than 80%, which were harmless to crops.(2) Under the condition of temperature control in incubator, dissolved organic carbon both in SH and SY treatment went down slowly after rising first, and were basically stable at around 30 g/kg finally. Under the condition of fermentation tank compost, dissolved organic carbon both in BH and BY treatment had firstly declined and raised after 20 days. The test results under different conditions showed that dissolved organic carbon content in anaerobic composting was higher than that in aerobic composting. Anaerobic compost remained more DOM, of which was a kind of active ingredient of organic fertilizer. The infrared spectrum analysis of DOM from incubator showed that compared with SH treatment, active group, such as –COOH, alcohol and –OH of phenol increased markedly and fulvic acid substances with small molecular weight and low degree of aromatization was more in SY treatment.(3) The compost humus composition of preliminary analysis showed that as composting continuing, fulvic acid transformed to humic acid and HI had been on the rise, which indicated the compost humification degree was increasing. Aerobic compost humification degree was always higher than the anaerobic compost.(4) Compared with using equivalent chemical fertilizer, it could significantly improve the corn biomass to use compost extraction while the increasing rate was over 20%. The more DOC content was used, the biomass was bigger. The correlation analysis results showed that there was a significant positive correlation relationship between the application of DOC concentration and corn biomass. It also showed that it could promote maize to absorb NPK nutrient with DOM liquor while the more DOC content was used, the absorbing ability was sronger. Compared with control, the N, P and K content of maize plants respectively increased by 5.37% to 36.53%, 6.24% to 26.86% and 6.24% to 36.53%. By measuring p H of soil, it could improve soil's p H in different degree by adding compost DOM liquor. While the more was added, p H would increase more. And at the same time, dissolved organic carbon of soil would increase obviously while the more DOM liquor was added. Compared with control, the content of dissolved organic carbon increased by 19.83% to 169.24%. The results about soil available components showed that DOM had the ability to activate soil nutrients. It could increase soil alkali-hydrolysable nitrogen, available phosphorus and available potassium content in different degree with adding different DOM liquor. While the more was added, soil nutrients content would increase more. Compared with control, the content of soil alkali-hydrolysable nitrogen increased by 4.08% to 38.95%, while the content of soil available phosphorus increased by 0.33% to 28.44%. Besides, the content of soil available potassium increased by 0.87% to 37.73%.(5)The organic fertilizer containing different DOC content pot experiment showed that there was a significant positive correlation relationship between DOC concentration in organic fertilizer and its efficiency. The correlation relationship between biomass and DOC concentration was more closely than organic matter and NPK nutrient.The above results provided a theoretical basis for enhancing efficiency with improving compost technology and completing organic fertilizer evaluaton standard.