Abstract: 【Objective】This experiment was carried out to study the effect of urea-formaldehyde fertilizer with different components on summer maize and to provide a theoretical basis for one time fertilization in summer maize, thus simplifying fertilization steps, saving fertilization cost, increasing fertilizer efficiency, reducing loss of nutrients and achieving environmental protection.【Method】Maize variety "zhengdan958" was used as materials in a field experiment. Under field conditions in two consecutive years, three urea-formaldehyde fertilizer treatments (UF1, UF2 and UF3), conventional fertilization (CF) and no fertilization (CK) were designed. Research mainly focused on the influence of different urea-formaldehyde treatments on yield of summer maize, nitrogen use efficiency, accumulation amount of above-ground portion nitrogen and content of inorganic nitrogen in soil.【Result】Results of the experiment showed that urea-formaldehyde of different components had different fertilizer efficiency. All slow release fertilizers of UF1, UF2 and UF3 could increase yield of summer maize and nitrogen use efficiency, among which UF2 was the best. Compared with conventional fertilization, UF2 had increased yield of summer maize by 7.63% and nitrogen use efficiency by 16.43 percentage points. UF3 increased yield by 4.98% and nitrogen use efficiency by 0.82 percentage points. In terms of effect, UF1 was only next to it. By using it, the average yield increase of summer maize was 6.53% and nitrogen use efficiency was improved by 12.30 percentage points. In addition, urea-formaldehyde with different components showed different releasing rates. Compared with conventional fertilization, use of urea-formaldehyde fertilizer could keep relatively high content of inorganic nitrogen in 0-20cm soil layer. And for UF2, the content was the highest, which was up to 80.09 mg·kg^-1. UF1 took the second place which was up to 66.47 mg·kg^-1 and UF3 had the lowest content of 51.18 mg·kg^-1. The inorganic nitrogen content of conventional fertilization increased because of topdressing urea at bell-mouthing stage, which was up to 27.46 mg·kg^-1 in filling period. In 20-40 cm soil layer, the inorganic nitrogen contents of UF1 and UF2 were stable between bell-mouthing stage and filling stage and decreased after filling stage. The inorganic nitrogen content of UF1 was as low as 13.40 mg·kg^-1and lower than conventional fertilization by 1.05 mg·kg^-1 in harvesting period. The inorganic nitrogen content of UF2 was 14.13 mg·kg^-1, which was lower than conventional fertilization by 0.32 mg·kg^-1 in harvesting period. But the inorganic nitrogen content of UF3 was slightly higher than other treatments and higher than conventional fertilization by 1.51 mg·kg^-1 during the harvest period. Therefore the one-time urea-formaldehyde fertilization met the demand for nutrients during the whole maize growth period.【Conclusion】Relatively higher output and nitrogen use efficiency were obtained from UF2 treatment among different urea-formaldehyde fertilizers. It was conclude that this fertilizer application method can be served as the special slow release fertilizer in the north of North China Plain where low and medium productive soil dominates the land.

Key words: urea-formaldehyde fertilizer, summer maize, yield, nitrogen use efficiency, soil inorganic nitrogen content