脲酶活性的抑制剂调控技术是提高尿素利用率最有效的生物化学方法之一.采用分步合成法在室温下合成一种含有Schiff碱的Cooper(Ⅱ)配合物型脲酶抑制剂(C15H14N302SClCu,简称FTU1),利用熔点仪、红外光谱仪、同步热差分析仪进行表征,比较FTUI与市售常用的第2类脲酶抑制剂(乙酰氧肟酸,简称AHA)的抑制脲酶活性,探讨FTUI对脲酶活性和土壤微生物多样性的影响,揭示其微生物效应.结果表明:FTUI抑制脲酶的活性比AHA高,在FTUI为尿素用量的0.1％～1.0％范围内就可高效抑制土壤脲酶活性,且抑制作用随浓度增大而增强,1.0％时达到最高抑制率71.20％;FTUI对土壤细菌、放线菌和真菌的生长都具有一定的促进作用,最高增长率分别达到60.30％、71.70％和1 592.85％,对土壤真菌的影响更为敏感.FTUI对刀豆脲酶和土壤脲酶有良好的抑制作用,且能促进土壤微生物的生长,浓度为1.0％时效果最显著.

研究不同浓度第四类新型Schiff碱配合物型脲酶抑制剂对油菜生长及其对土壤氮素转化的影响,旨在为此类新型脲酶抑制剂在农业上的推广应用提供依据。采用室外盆栽方法,比较新型脲酶抑制剂（SU）和市售脲酶抑制剂乙酰氧肟酸（AHA）对油菜产量、品质、生长状况、氮素吸收利用和土壤表观硝化率等指标的影响。结果表明:SU和AHA均能提高油菜产量,提高油菜品质指标和养分指标,其中SU对油菜增产和养分增效的效果比AHA明显;SU平均提高油菜产量28.0%,显著降低油菜硝酸盐含量28.8%～50.8%,同时促进油菜对氮、磷的吸收,使氮肥利用率平均提高68.0%,在一定程度也能降低土壤表观硝化率,平均降低35.2%。不同浓度新型抑制剂处理的油菜指标和抑制尿素水解效果不同,表现为低中浓度的抑制剂对油菜增产和养分增效效果优于高浓度,其中抑制剂用量为纯氮施入量的1%时对尿素水解抑制的效果最好,因此施入纯氮量的1%为此类抑制剂的最佳用量。

The widespread presence of urease in agricultural settings places enormous pressure on the soil environment. Urease inhibitors have been used as promising biochemical methods in reducing urease efficiency to ensure food security and agricultural sustainability. Compared with metal salts, organic products and plant extracts, complex-type urease inhibitors are low toxic, highly inhibitory and stable.They have become a hot topic of research for domestic and foreign scholars. This article reviews the status of research into complex-type urease inhibitors, expounds their dynamic and thermodynamic mechanisms and summarizes the mechanistic research carried out to date. Some prospects for and disadvantages of using complex-type urease inhibitors have been proposed.

[目的]研究第四类脲酶抑制剂对土壤微生物的影响,揭示此类脲酶抑制剂的微生物学效应,为农业生产中施用含Schiff碱配合物型脲酶抑制剂缓控释尿素的安全性评价提供理论依据.[方法]采用室内恒温恒湿培养的方法,测定在不同浓度(按尿素施用量的0.1％,0.5％,1％)新型Schiff碱铜配合物型脲酶抑制剂作用下土壤脲酶活性以及土壤细菌、真菌和放线菌微生物量指标.[结果]①当抑制剂施用浓度为0.1％和0.5％时对土壤脲酶活性影响不显著,当施用浓度为1％时,对土壤脲酶活性抑制效果最好,最大抑制率达40.8％,起到了适度调控的目的;②土壤细菌、真菌和放线菌对尿素水解的敏感程度不同,其中放线菌和真菌比较敏感,尿素水解对其最大抑制率分别为46.4％和89.7％.与此相反,尿素的水解反而会促进细菌生长,最大促进率达83.6％;③第四类脲酶抑制能够促进土壤细菌、放线菌和真菌的生长,其对细菌、放线菌和真菌的最大促进率分别为86.2％,31.9％和83.6％.因此第四类脲酶抑制剂对土壤放线菌生长的促进作用较小,对土壤细菌和真菌生长的促进作用较大.[结论]第四类脲酶抑制剂对土壤脲酶活性有很好地抑制作用且能促进土壤细菌、真菌和放线菌的生长,施用抑制剂浓度为1％时效果最显著,即1％为其最佳用量.

Four kinds of Schiff base Cu(II) complexes (the fourth type of novel urease inhibition) were synthesized by the coordination of transition metal Cu(II) ions with aldehyde amine type Schiff base ligands, they were aqua-(5-methoxy-2-(((pyridin-2-yl)methyl)imino)methyl)phenolato-N,N',O)-(nitrato-O)-copper(II) (1), catena-[(mu 2-Isothiocyanato-N,S)-(4-chloro-2-(((Pyridin-2-yl)methylimino)methyl)phenolato-N,N',O)-copper(II)methanol solvate] (2), di-mu-bromobis[1-({[2-(piperidin-1-yl)ethyl]imin o}methyl)naphthalen-2-olato]-di-copper (II)(3) and tetrakis(m-bromo)-bis(m-4-chloro-2-((2-(piper idin-1-yl)ethyl)carbonoimidoyl)phenolato)-tri-copper(II) (4), respectively. The structural characterization of four complexes was performed by Infrared spectrum, Thermogravimetric analysis and X-ray diffraction. The inhibitory effect of complexes on Jack bean urease was studied by phenol red method, the kinetic mechanism of complexes inhibition of urease was investigated by Lineweaver-Burk plot of reciprocal, and the interaction mechanism between complex and urease was discussed by molecular docking. The results showed that IC50 values of four complexes inhibit Jack bean urease are 5.36 mu M, 8.01 mu M, 2.25 mu M and 1.00 mu M, respectively, which are much lower than that of the acetohydroxamic acid (27.7 mu M) coassayed as a standard urease inhibitor. It has a strong urease inhibitory activity and is a promising urease inhibitor. The inhibitory mechanism of complex 1 and complex 2 on the Jack bean urease belonged to mixed-type inhibition, and the complex 3 and complex 4 is anti-competitive inhibition. Molecular simulation docking calculations show that complexes 3, 4 can form a more stable urease inhibition binding model than complexes 1 and 2 through salt bridges with amino acids, which also theoretically explains the results of experiments on inhibition of urease activity in vitro.

To enhance the effectiveness of urea, a novel, binuclear, slow‐release urea fertilizer was developed with the application of drum‐coating technology, which used large granular urea as the core carrier, attapulgite (APT)–fly ash (FA) as the inner coating, and Eudragit as the outer coating. The nutrient‐release characteristics of the binuclear slow‐release fertilizer with 10% coating synthesized under optimized conditions were studied in soil and water, and the relationships between pH, electrical conductivity, and nitrogen release rate were determined through fitting function. The structure and properties of the samples were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results indicated that the optimum preparation conditions were as follows: the inner coating shall be 4% binder concentration, 10 g APT and FA in total, APT/FA = 7:3; coating film material of Eudragit E100, 75% ethanol concentration, with coating accounting for >9% and plasticizer accounting for 1%. The product showed excellent release performance, with 65.74% of the nutrients leaching in the soil column within 28 d. Therefore, this work has demonstrated the potential of this new double‐coated fertilizer system in agriculture for improving the effectiveness of fertilizers.Core Ideas A novel binuclear slow‐release urea fertilizer was developed with the application of drum‐coating technology under optimized conditions. Binuclear fertilizer exhibited an excellent release behavior of 65.74% nutrient leaching in the soil column within 28 days. The relationship between the nutrient release rate of binuclear fertilizer in water and soil column was exponential fitting. The method of predicting the rate of nutrient release using pH and EC was feasible and accurate.

Slow controlled release fertilizer (SRF) is the hot direction of new fertilizer development, but there is no unified, perfect, standardized classification basis. This paper documents a review of literature related to the classification of SRF, summarizes the history about development for the classification of SRF in three phases, proposes an improved classification of physical, chemical, and compound types. The aim of the current review is to provide evidence on which to base the selection and further development of innovative enhanced efficiency SRF. The study also further clarifies the attribution of various fertilizers and illustrates the use of representative fertilizers in each category. In addition, the compound type of SRF is given the positive perspectives.