水基聚合物包膜尿素实现山东夏玉米氮肥减施和一次性基施

Applying waterborne polymer coated urea to realize input reduction and one-time basal application of nitrogen fertilizer in summer maize production in Shandong Province

【目的】相比于普遍的树脂包膜材料,新型水基聚合物包膜材料具有环境友好、成本低等特点。我们研究了水基聚合物包膜尿素在氮肥减量和一次性基施条件下,满足山东省夏玉米全生育期氮素营养供给和实现夏玉米稳产高效的可行性。【方法】采用田间释放率测定方法,研究供试水基聚合物包膜氮肥(WF)和树脂包膜氮肥(PF)的控释性能,计算理论最佳掺混比例。于2018—2020年在山东青州和桓台开展3年田间试验,设置常规用量(N 225 kg/hm^(2))和减施30%氮量(N 157.5 kg/hm^(2))两个氮素水平,分别采用普通尿素(BF)、水基聚合物包膜尿素(WF)、树脂包膜尿素(PF)、WF和PF按1∶0.52质量比例掺混(MF) 4种氮肥,以不施氮肥为对照(CK),共9个处理。普通尿素采用基施加追施方法,包膜尿素均为一次性基施。测定了土壤氮含量、土壤有机质含量、氮素利用率、氮素累积吸收量和夏玉米产量。【结果】WF、PF两种包膜尿素在青州和桓台2个试验点的总释放率分别超过了90%和80%,WF的田间释放率高于PF且其释放特征更符合夏玉米生育前期对氮素的需求。同一氮肥用量下,青州、桓台两地WF、PF和MF处理间3季夏玉米平均产量均无显著差异,与BF1普通尿素(常规用量)处理也均无显著差异,但BF减氮30%处理的产量显著低于BF常规用量处理,且只有WF减氮30%处理的产量显著高于BF减氮30%处理。与BF常规用量处理相比,在青州和桓台试验点3季夏玉米的6个包膜肥处理均显著增加了氮肥利用率;在青州试验点WF减氮30%和PF减氮30%处理的氮肥农学效率分别增加了49.0%和32.5%,在桓台试验点只有WF减氮30%处理显著增加了40.9%。在青州,抽雄期和成熟期WF和PF处理的NH_(4)^(+)-N含量均显著高于BF常规用量处理,WF常规用量和PF常规用量处理的NO_(3)^(-)-N含量显著高于BF常规用量处理;在桓台,抽雄期和成熟期各处理土壤NH_(4)^(+)-N含量均无显著差异,PF和WF处理的土壤NO_(3)^(-)-N含量均显著高于BF常规用量处理。【结论】新型水基聚合物包膜尿素的氮素释放总量高,且前期释放特征更符合夏玉米拔节期至抽雄期的氮素需求。氮肥减施并一次性基施条件下,两种包膜尿素均可提高夏玉米抽雄期和成熟期的土壤无机氮水平,维持稳定的夏玉米产量,提高氮肥利用率和农学效率。新型水基聚合物包膜尿素提升产量和氮肥农学效率的效果优于树脂包膜尿素,也优于二者掺混。

【Objectives】We studied the effects of N nutrition on summer maize across the growth period under one-time basal application and 30%reduction of N input of the two slow-release urea products.【Methods】The release properties of urea coated with waterborne polymers(WF)and polyethylene terephthalate(PF)were studied by field release method,and the theoretical optimal blended ratio of the two coating urea products was calculated.Field experiments were carried out from 2018 to 2020 in Qingzhou and Huantai,Shandong Province.Conventional N rate(N225 kg/hm^(2),level 1)and 30%reduction(N157.5 kg/hm^(2),level 2)were setup,and ordinary urea(BF),WF,PF,and WF to PF in 1∶0.52(MF)were used as N resource treatments under each N level,with no N fertilizer as control(CK).Common urea BF1 and BF2 treatment were applied twice(basal and topdressing),while the coated urea products were all basal-applied once.Soil N contents in the key growing stages of maize were determined.The yields,N uptake and urea use efficiency of summer maize were investigated at harvest.【Results】The total N release rates of WF(>90%)was higher than that of PF(80%)during the whole maize growing period in the two sites,and the release characteristics of WF was more consistent with the nitrogen demand of summer maize at the early growth stage.In Qingzhou and Huantai,the average maize yields of three seasons among the fertilizer treatments,except BF2,were not significantly different.The maize yield in BF2 was significantly lower than that in BF1,and only WF2 produced higher(P<0.05)yield than BF2.Compared with BF1,all the six coated urea treatments increased the average apparent nitrogen utilization of three seasons in the two experimental sites.WF2 and PF2 in Qingzhou increased the average agronomic efficiency by 49.0%and 32.5%,while only WF2 in Huantai increased that by 40.9%.At tasseling and maturing stages of maize in Qingzhou,the soil NH_(4)^(+)-N contents in WF1,WF2,PF1 and PF2 treatments were significantly higher than that in BF1;the soil NO_(3)^(-)-N contents in WF1 and PF1 were higher than BF1,and those in WF2 and PF2 were similar with BF1.In Huantai,the soil NH_(4)^(+)-N contents were similar among all the treatments at tasseling and maturing,while the soil NO_(3)^(-)-N contents in the PF and WF treatments were significantly higher than in BF1.【Conclusions】Compared with resin coated urea,the new waterborne-polymer coated urea has higher N release rate,and more consistent release characteristics with the N requirements of summer maize.Under the condition of reducing 30%conventional N input and once basal application,both kinds of the coated urea can provide higher N supply at the tasseling and maturing stage of maize,thereby maintaining a stable yield and N uptake of summer maize,and improving the nitrogen use efficiency and agronomic efficiency.The new waterborne-polymer coated urea showed more stable effect on yield and agronomic efficiency than polyethylene terephthalate resin coated urea.