Effects Of Partial Mineral Nitrogen Substitution By Organic Fertilizer Nitrogen On Emissions Of Greenhouse Gases In The North China Plain

The exchange fluxes of greenhouse gases ?CO₂?N₂O and CH₄? under five treatments different treatments from a summer maize-winter wheat crop rotation field from 2013/6 to 2014/6 in the North China Plain were investigated by static chamber method.The study included five treatments:C₀N₀?no nitrogen fertilizer?, C₀N₁?farmer's practice?, C₀N₂ ?optimized fertilization?, C₁N₂?The total amount of nitrogen application refers to the nitrogen level of optimized fertilization, Organic fertilizer nitrogen accounted for 100%?, C₂N₂?The total amount of nitrogen application refers to the nitrogen level of optimized fertilization, Organic fertilizer nitrogen accounted for 50%?.To monitor the exchange fluxes of greenhouse gases ?N₂O, CH₄ and CO₂? annually, we can investigate the influence of fertilization on the exchange fluxes of N₂O,CH₄ and CO₂ and their total amounts, and evaluate the balance of greenhouse gas of soil-crop ecosystem under different management practices. The primary results showed as follows:1?Nitrogen application could significantly improve the summer maize and winter wheat yield, High nitrogen content did not mean high yield, From the aspects of crop production, organic fertilizer was better than inorganic fertilizer. The summer maize and winter wheat production of C₀N₁ accounted for about 86.6% of C0N₂'s, compared to C₀N₂, the yields of C₁N₂ and C₂N₂ respectively increased by 5%,3.5%.2?Soil respiration rate was higher in maize season than in wheat season.The relationship between soil temperature ?5 cm? and soil respiration rate ?0-10 cm? could be described by the indicial equation. Q10 ?Temperature sensitivity of soil respiration? ranged from 1.75 to 2.02.Execept C₀N₀, there was a significantly negative correlation ship between soil moisture?0-10 cm? and soil respiration rate in other treatments.3?Considering the uptake from plant and Soil respiration, winter wheat-summer maize rotation ecosystem was a sink for CO₂, which decreased global warming potential.4?There is a positive correlation between N₂O emissions and nitrogen fertilizer application during treatments of C₀N₀?C0N₂ and C₀N₁.. The order of annual Cumulative N₂O emissions was:C₁N₂ (1.656 kg N₂O-N ha^-1)< C₀N₂ (1.999 kg N₂O-N ha^-1)< C₂N₂ ?2.247 kg N₂O-N ha-1?5?The North China Plain upland soil was a small sink for CH₄ which was negligible to the total reenhouse effect.6?Nitrogen fertilizer reduces the total GWP of farmland ecosystem.The total GWP reached significant difference ?p< 0.05? between C₀N₀ and every other treatment.Organic nitrogen instead of nitrogen fertilizer was a better measure to the balance between food production and ecological environment for the North China Plain.