Effects Of Nitrogen Regulator And Ammonium Sulfate On Soil Nitrogen Transformation And Maize Growth

Nitrogen fertilizer synergist plays an important role in regulating soil nitrogen transformation and crop growth and development.In order to utilize industrial by-product ammonium sulfate with high efficiency and environmental protection,we studied the effects of nitrogen fertilizer synergist and ammonium sulfate combined application on soil nitrogen transformation and growth and development of maize through culture and pot experiment,and defined the fertilizer formula and fertilization technology.The main research results are as follows:（1）A strong nitrification reaction occurred in the first 15 days after ammonium sulfate was applied to the soil.The addition of three kinds of nitrification inhibitors could significantly inhibit soil nitrification and slow down the conversion rate of inorganic nitrogen.The optimal dose of DMPP was 0.75%,the nitrification inhibition rate was 94.92%-95.30%,and the duration of action was more than 30 days.The optimal dosage of Nitrapyrin was 0.3%,the nitrification inhibition rate was 34.5%-53.4%,and the duration of action was about 15 days.The optimal dose of DMPG was 3%,the nitrification inhibition rate was 87.07%-91.01%,and the duration of action was about 30 days.（2）Application of ammonium sulfate combined with nitrification inhibitor can significantly reduce the N₂O and CO2 emission flux caused by its application（P<0.05）.The effect of 0.75%DMPP was better than that of 3%DMPG and 0.3%Nitrapyrin in reducing soil N₂O emission.Correlation analysis showed that soil pH was negatively correlated with NO₃^–-N.NO₃^–-N was positively correlated with N₂O flux（P<0.05）.There was a significant positive correlation between NH4+-N and N₂O flux（P<0.05）.There was a significant positive correlation between CO2 production rate and N₂O flux（P<0.05）.（3）The duration of 0.75%DMPP was about two months.The optimal application concentrations of humic acid and γ-PGA were 127 mg·kg-1 and 13.46 mg·kg-1,respectively.Humic acid and γ-PGA have synergistic effect.The application of humic acid and γ-PGA could increase the contents of NO₃^–-N,available P and available K in soil.The combined application of humic acid and γ-PGA could increase the plant height,stem diameter and biomass of maize.Humic acid can reduce soil pH value,while γ-PGA can increase soil pH value.Industrial ammonium sulfate is more suitable in maize jointing stage.（4）Correlation analysis showed that NO₃^–-N was significantly negatively correlated with biomass BM,stem diameter ST and plant height HI（P<0.05）.AP available P and AK available K were significantly negatively correlated with plant height HI and biomass BM（P<0.05）.There was a significant positive correlation between available K and NO₃^–-N（P<0.05）.There was a significant positive correlation between available P and available K（P<0.05）.There was a significant negative correlation between pH and NO₃^–-N（P<0.05）,and a significant positive correlation between pH and stem diameter（P<0.05）.In conclusion,the dose of DMPP should be less than 0.75%,and the application concentrations of humic acid and γ-PGA can be more than 127 mg·kg-1 and 13.46 mg·kg-1.And the compound effect is better.The effect of topdressing was better in maize jointing stage.Whether ammonium sulfate,DMPP,humic acid or γ-PGA can regulate soil pH value.