| Nitrification and denitrification,which leads to the waste and pollution of nitrogen fertilizer.Nitrification inhibitor can delay nitrification reaction in soil,regulate nitrogen conversion,improve nitrogen utilization and reduce nitrogen loss.In this work,the effects of nitrogen fertilizer ammonium sulfate combined with nitrification inhibitor nitrapyrin on nitrogen utilization,yield,quality and inorganic nitrogen morphological transformation in topsoil of facility tomato were studied by the field experiment and the suitable scheme for facilities of tomato production was screening,which provides theoretical and technical support for tomato to reduce nitrogen dosage,increase nitrogen efficiency and ensure the fruit safety in greenhouse.The results show that:1.The application of ammonium sulfate with nitrapyrin has a regulatory effect on the conversion of nitrogen in the soil.the nitrification of nitrogen in the soil inhibited by nitrapyrin.Compared with the single ammonium sulfate application treatment,the NH4+-N content in the initial fruit stage,the mature fruit stage and the final fruit stage of tomato increased by 7.28% ~ 64.12% and 1.87%~47.64%,respectively,in the treatment of nitrogen reduction by 10% and 15% of nitrapyrin.For the treatment of nitrogen reduction by20%,the NH4+-N content in the initial fruit and the fruiting stage did not increase significantly,and the NH4+-N content was significantly increased by 30.18% in the final fruit stage.In the first,last and last fruit stages of tomato growth,the NO3--N content in nitrogen-reducing combined with nitrapyrin treatments significantly decreased by 7.87% ~ 65.11% compared with the single ammonium sulfate application treatment in the tilth soil,and the NO3--N content in different nitrogen treatments was significantly different at the same growth stage.2.Ammonium sulfate combined with nitrapyrin has a positive effect on the absorption and utilization of nitrogen in facilities,which can effectively promote the nitrogen absorption of plants and improve the utilization rate of nitrogen fertilizer.In the 10% ~ 20% nitrogen reduction combined with nitrapyrin treatment,compared with the single ammonium sulfate application treatment,the nitrogen absorption amount and nitrogen fertilizer utilization rate were significantly improved,and the nitrogen absorption amount increased by 7.18%~8.23%.The nitrogen fertilizer utilization rate of 20% nitrogen reduction treatment increased the most,increasing to 38.3%.There was no significant difference in nitrogen uptake and nitrogen fertilizer utilization rate between nitrogen reduction combined with nitrapyrin treatments.3.The effect of ammonium sulfate combined with nitrapyrin on the tomato yield in the facility was obvious.Compared with the single ammonium sulfate application treatment,the yield of nitrogen reduction combined with nitrapyrin treatment increased by 2.75-3.75%.The maximum yield was 84995kg·hm-2 when nitrogen was reduced by 10%.There was no significant difference between nitrogen reduction of 15%,nitrogen reduction of 10% and nitrogen reduction of 20% in the total output.4.Ammonium sulfate combined with nitrapyrin can improve the nutritional quality of fruits.Compared with the single ammonium sulfate application treatment,nitrogen fertilizer combined with nitrapyrin significantly reduced the content of nitrate in tomato fruits by 25.83%~26.14%.Compared with the single ammonium sulfate application treatment,the Vc,soluble protein,reducing sugar and organic acid contents of the nitrogen reduction combined with nitrapyrin treatment increased in different degrees.The contents of Vc,soluble protein,reducing sugar and organic acid were the highest when nitrogen was reduced by 10%.5.The combined application plan of A and ammonium sulfate suitable for facility tomato production:on the basis of the Soil testing and fertilizer recommendation,the nitrogen of 261.375kg·hm-2 was combined with 0.30%(nitrogen dosage)nitrapyrin,which not only ensures the yield and quality of tomato but also reduce the loss of nitrogen. |
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