Effects Of Chemical Nitrogen Fertilizer And Organic Fertilizer On Nitrogen Fate In Paddy Field

Nitrogen is an essential nutrient for rice growth,and nitrogen fertilizer plays an important role in increasing rice yield.The single-season application rate in China's rice fields is far higher than the international safe fertilization standards.The high nitrogen fertilizer input and low utilization rate not only waste plant nutrient resources,but also generate certain ecological and environmental risks.Organic fertilizer replaces some chemical nitrogen fertilizer is an effective way to reduce the amount of chemical fertilizer application and improve nitrogen utilization efficiency.Carrying out research on the effect of chemical nitrogen fertilizer combined with organic fertilizer on nitrogen fate of paddy field has practical significance for achieving the goal of "one control,two reductions and three basics" and promoting clean production of rice.To this end,this paper adopts a combination of field dynamic monitoring and indoor chemical analysis to study the use of fresh pig manure?PM?under isonitrogen conditions?120 kg · hm-2 in early rice season and 135 kg · hm-2 in late rice season?.,Biogas slurry?BF?,pig manure compost?PC?,azureum green fertilizer?GM?or straw?GF?replace 20% nitrogen fertilizer and single fertilizer treatment?CF?on volatile nitrogen and runoff nitrogen in paddy field Of nitrogen loss,N₂O and other nitrogen losses,rice yield,above-ground nitrogen uptake,and nitrogen use efficiency.With a view to providing reference for cleaner production of rice.The main results and conclusions reached are as follows:1.Combined application of chemical fertilizer and organic fertilizer can reduce nitrogen loss in rice fields.Compared with CF,the combined application of organic fertilizers has relatively reduced the concentration of soluble inorganic nitrogen in the surface water,reduced ammonia volatilization emissions and runoff nitrogen losses,reduced N₂O emissions and their heating potential and gas emission intensity;morning and evening rice season The total reduction of nitrogen loss in each treatment ranged from 2.9% to 20.3% and 10.2% to 33.4%,and PM treatment was the best,followed by BF treatment.2.The combined application of chemical fertilizers and organic fertilizers can ensure rice yield and improve soil nitrogen accumulation in the case of reduced application of inorganic nitrogen fertilizers.The yield of each early rice treatment was: PM> GM> BF> CF> PC> NF,and the yield of each late rice treatment was: PM> CF> BF> GM> PC> NF,but the differences between treatments were not significant.In general,the inorganic nitrogen concentration of 0⁴0cm treated soil increased first and then decreased,and CF treatment residual inorganic nitrogen is higher than PM,BF,GM / GF treatment.3.Fertilizer combined with organic fertilizer can improve nitrogen efficiency.Compared with CF treatment,the nitrogen harvest index?NHI?of early rice season organic fertilizer treatment increased by 7.3% 19.4%,the nitrogen recovery efficiency?NRE?increased by 2.6% 36.2%,and the nitrogen harvest index?NHI?of late rice season organic fertilizer treatment Increased by 4.7% 7.3%,nitrogen physiological utilization rate?NPE?increased by 3.9% 17.5%,partial fertilizer productivity?PFPN?increased by 1% 8% for PM,BF,and GM in the early and late rice seasons.The PM treatment recovery efficiency?NRE?is the highest.In summary,PM and BF treatments are the best fertilization models.In this study,PM and BF can both achieve higher economic benefits and reduce environmental impact.Therefore,it is feasible to replace 20% chemical fertilizer with organic fertilizer such as fresh pig manure and biogas slurry.