| Productivity of arable land resource provide the fundamental guarantee for food security.To achieve a high economic production,excessive fertilizer was used in vegetable soil,which led to nutrient imbalance,low efficiency,and probably increased environmental pollution,to those more attention had been paid.In order to increase the efficiency,save energy and reduce draining,it is important to reduce the amount of chemical fertilizers and increase the application of organic fertilizers,which might be of great importance in ensuring national food security,quality and safety of agricultural production and agricultural ecological security.A soil culture experiment,a pot experiment and a field experiment were conducted to study the effect of biological organic fertilizer on the change of soil nutrient,the uptake and utilization of nutrient,the growth of Bok choy and the leaching loss of nutrient.The main result are as follows:1)Total nitrogen,organic matter,alkali-hydro nitrogen,available phosphorus and available potassium availability were improved by biological organic fertilizer.Soil nutrient preserving capability was also improved.In the soil culture experiment,the nutrient of chemical fertilizer released faster in the early stage,and then became gradually smooth.Compared to the control treatment(with no fertilizer),the content of total nitrogen,organic matter,alkali-hydro nitrogen,available phosphorus and available potassium in soils increased by 34.68%-36.45%,3.28%-9.98%,36.36%-208.51%,75.37%-323.01% and 46.34%-66.67% respectively;the nutrient of formula fertilizer(chemical fertilizer + biological organic fertilizer)released steadily.Compared to the control treatment(with no fertilizer),the content of total nitrogen,organic matter,alkali-hydro nitrogen,available phosphorus and available potassium in soils increased by 26.19%-45.23%,13.4%-14.74%,50.90%-176.59%,92.83%-341.91% and 43.90%-61.90% respectively.2)Biological organic fertilizer promoted the absorption of N、P、K by Bok choy,and increased the utilization rate of fertilizer.In the pot experiment,compared to the chemical fertilizer treatment,the absorption of N、P and K of formula fertilizer treatment increased by 20.9%-25% under the same conditions of chemical fertilizer.Even if the chemical fertilizer is used reduced 15%-25% under the condition of no influence Bok choy on the absorption of nutrients.The soil nutrient content of different treatments in the pot experiment also confirmed the results of this experiment.3)The result of field experiment showed that nitrate nitrogen is the main form of leached N,accounted for 69%-99% of total leached N.The application of biological organic fertilizer can clearly reduce the leaching loss of total nitrogen,nitrate nitrogen,ammonium nitrogen,total phosphorus and water soluble phosphorus in soils,decreased by 5.5%-31.8%,17.94%-48.67%,3.57%-44.44%,5.49%-58.5% and 9.47%-58.5% respectively,compared to the chemical fertilizer treatment.The treatment of biological organic fertilizer/chemical fertilizer reduced 25% clearly reduced the leaching loss of Total nitrogen,nitrate nitrogen,ammonium nitrogen,total phosphorus and water soluble phosphorus in soils,decreased by 28%-330%,11%-304%,1.3%-32.88%,17%-153% and 8.23%-148% respectively.4)Biological organic fertilizer can promote the growth of crops.The biomass of Bok choy was not affected by reducing 15%-25% of the chemical fertilizer.There is a significant difference in biomass between the treatment of biological organic fertilizer/chemical fertilizer reduced 35% and the control treatment.The biomass among other treatment have no significant difference.In the field experiment,the yield of chemical fertilizer treatment,biological organic fertilizer/ chemical fertilizer treatment and biological organic fertilizer/ chemical fertilizer reduced 25% are 21538.2 kg/hm~2,22032.8 kg/hm~2 and 21390.7 kg/hm~2.There is no significant difference among all the treatments. |
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