A Study On Rice Yield-increasing Models And Mechanism Of Mixed Application Of Organic And Inorganic Fertilizer

Agricultural organic waste such as, poultry and animal feces, straw, biogas fertilizer, are high quality organic fertilizer source. But it also the pollution source of agricultural ecological environment. At present, agricultural organic wastes are carelessly disposed. This not only caused the waste of organic resources, but also affected the life of pepole in country and town. Field plot experiment was used to study the effects of mixed application of organic and inorganic fertilizer on rice yield, photosynthetic characteristics, the key enzyme activities of carbon and nitrogen metabolism, the main metabolic intermediate products of carbon and nitrogen metabolism, fertilizer use efficiency and the concentrations of total nitrogen, total phosphorus, NH4+-N and NO3-N in the leaching fluid of the experiment field. It provided scientific fundamental for the fertilizer utilization of agricultural organic wastes.1. The rice yield of the treatment of pig manure bio-organic fertilizer instead of 20% chemical nitrogen fertilizer (treatment D) was the highest in early rice season, increased 8.5% as compare to chemical fertilizer treatment (treatment B). In the late rice season, the rice yield of the treatment of manure bio-organic fertilizer instead of 10% chemical nitrogen fertilizer (treatment C) was the highest, and treatment D took the second place, increased about 12.5% and 11.6 as compared to chemical fertilizer treatment (treatment B), respectively.2. The nitrate reductase (NR) activity in flag leaves with the treatment of biogas fertilizer instead of 20% chemical nitrogen fertilizer (treatment G) was the highest in booting stage of early and late rice season. In both milk tage and yellow ripening stage, the NR activity in rice flag leaves in the other treatement of organic and inorganic fertilizer were relatively increased, even more than the treatment G and treatment B. The sucrose phosphate synthase (SPS) activity in flag leaves with the treatment D was the highest in each period of early rice season, treatments C and treatmnet E (manure bio-organic fertilizer instead of 30% chemical nitrogen fertilizer) reached a very high level, and other organic and inorganic fertilizer treatments were relatively better than treatment B. The SPS activity with the treatment of straw instead of 10% chemical nitrogen fertilizer (treatment H) was the highest, but there are no significant difference between organic inorganic fertilizer treatments and chemical fertilizer treatment.3. The photosynthetic characteristics were improved by organic and inorganic fertilizer treatment. The net phptosynthetic rate and stomatal conductance in flag leaves were significantly increased, and the intercellular CO2 concentration and transpiration rate in flag leaves were decreased by organic and inorganic fertilizer treatment. This can effectively improve the photosynthesis of rice and further increase the rice yield.4. The N, P, K nutrient use efficiency of rice was increased with mixed application of pig manure bio-organic fertilizer and inorganic fertilizer. However, the nitrogen use efficiency was decreased as the increase of the proportion of the pig manure bio-organic fertilizer. The N, P, K nutrient efficiency of rice with treatment D was the best by comprehensive analysis5. Organic-inorganic fertilizing significantly improved the accumulation of soil organic matter, and the organic amount in soil with treatments H and F (pig manure instead of 20% chemical nitrogen fertilizer) were the highest. The alkali-hydro nitrogen amount in paddy soil with treatments D and F were the highest. The results also showed that the total phosphorus, available phosphorus and pH value was increased when treated with organic-inorganic fertilizer. But the total potassium and available potassium were decreased in full-year variation. Thus, Organic-inorganic fertilizer can improve paddy soil quality.6. The concentration of TN,TP,NO3--N and NH4+-N in percolating water with the treatments D, F and H were lower than other treatments. It indicated that reasonable mixed application of organic and inorganic fertilizer can decrease paddy soil nutrient leaching, decrease the pollution of fertilizer and ultimatly protect the ecological environment.