Reducing gaseous emissions in organic-amended soils while further enhancing yield potential is critical. Urease and nitrification inhibitors may offer a promising solution. However, the effectiveness of inhibitors in organic-amended soils remains unclear because organic amendments (OAs) differ markedly in nitrogen forms, carbon supply, and their effects on the soil environment. Therefore, we conducted a multilevel meta-analysis to evaluate the effects of inhibitors on cereal productivity and soil gaseous emissions under different OAs, and to identify how yield, NH3, and N2O responses varied with management practices, OA properties, climate, and soil characteristics. The results showed that inhibitor effectiveness depended strongly on amendment type. Under straw return and biochar application, inhibitors significantly increased yield by 4.2%-5.6%, biomass by 4.6%-4.9%, plant nitrogen uptake by 5.8%, and nitrogen use efficiency by 9.7%-15.7%, while reducing NH3 volatilization by 21.6%-23.1% and N2O emissions by 32.8%-43.9%. In contrast, under organic fertilizer amendment, inhibitors significantly reduced CH4 and N2O emissions by 27.8% and 31.2%, respectively, but provided limited yield benefits. Further analyses revealed trade-offs between the productivity and mitigation effects of inhibitors, with responses varying markedly across amendment types and response variables. Inhibitor type was an important predictor and should be given primary consideration in practical applications, while amendment properties also contributed substantially. As fertilizer input increased, the N2O mitigation benefit of inhibitors showed diminishing returns. Overall, co-application of inhibitors in organic-amended soils shows considerable potential, but tailored and practical management strategies are needed to maximize both agronomic and environmental benefits.

The addition of inhibitors and organic materials in corn fields is an important measure to ensure yield and improve soil fertility. Understanding the effects of the addition of inhibitors and organic material on soil microbial carbon use efficiency (CUE) and microbial mechanisms is crucial for promoting carbon (C) sequestration in agricultural systems. This study explored the effects of the addition of inhibitors (N-(nbutyl) thiophosphoric triamide (NBPT) and 3,4-dimethylpyrazole phosphate (DMPP)) and organic materials (corn stalks and pig manure (PM)) on soil microbial CUE through a field experiment with the continuous addition of inhibitors, corn stalks, and PM incorn fieldss for 7 years. Overall, the application of inhibitors reduced soil microbial CUE by 39.20% by reducing microbial immobilization C and promoting microbial respiration, but did not affect the microbial community structure. Under inhibitor application conditions, the addition of PM improved soil microbial CUE by 37.38%, which was mainly achieved by increasing microbial immobilization C, fungal, and bacterial copies. Long-term addition of organic materials and fertilizers was beneficial to the increase in soil microbial CUE, because the input of nutrients stimulates microbial growth. Although high soil microbial CUE was beneficial to soil C sequestration, it also required appropriate exogenous organic matter addition to ensure soil organic carbon (SOC) increase. In this study, when fertilizer-containing inhibitors were used, combined application with PM was beneficial to improve soil microbial CUE and promote SOC sequestration.

The development of efficient urease inhibitors represents a promising strategy for agricultural applications. This review examines the status of commercial urease inhibitors and the challenges encountered while systematically summarizing the urease inhibitory activities and structure-activity relationships (SARs) of 339 synthetic compounds belonging to 12 structural types reported from 2001 to 2025. It emphasizes phosphoramidate, thiourea, coumarin, azine, and amine derivatives that exhibit potent urease inhibitory activity. Furthermore, SAR analysis indicates that derivatives containing electron-withdrawing substituents, such as halogens and nitro groups, demonstrate significantly higher urease inhibitory potency compared with those with electron-donating substituents, such as methyl groups. The review also compares the binding modes and key active sites of representative inhibitors from each subtype with those of plant urease (4H9M) and soil microbial urease (4CEU) through molecular docking analysis. Finally, it outlines the challenges and future research priorities for soil urease inhibitors. This review enhances our understanding of urease inhibitors and guides the development of highly effective soil urease inhibitors to address critical global environmental sustainability challenges.

The denitrification process is the main process of the soil nitrogen (N) cycle in paddy fields, which leads to the production of large amounts of nitrous oxide (N2O) and increases N loss in paddy soil. Plant-derived bio denitrification inhibitor procyanidins are thought to inhibit soil denitrification, thereby reducing N2O emissions and soil N loss. However, the denitrification inhibition effect of procyanidins in paddy soils with high organic matter content remains unclear, and their high price is not conducive to practical application. Therefore, this study conducted a 21-day incubation experiment using low-cost proanthocyanidins (containing procyanidins) and paddy soil with high organic matter content in Northeast China to explore the effects of proanthocyanidins on N2O emissions and related microorganisms in paddy soil. The results of the incubation experiment showed that the application of proanthocyanidins in paddy soil in Northeast China could promote the production of N2O in the first three days but inhibited the production of N2O thereafter. Throughout the incubation period, proanthocyanidins inhibited the enzyme nitrate reductase (NaR) activity and the abundance of nirS and nirk denitrifying bacteria, with a significant dose-response relationship. Although the application of proanthocyanidins also reduced the soil nitrate nitrogen (NO3--N) content, the soil NO3--N content increased significantly with increasing incubation time. In addition, the application of proanthocyanidins increased soil microbial respiration, ammonia-oxidizing archaea (AOA) amoA gene abundance, and soil ammonium nitrogen (NH4+-N) content. Therefore, the application of proanthocyanidins to paddy soil in Northeast China can effectively regulate denitrification. However, in future studies, it is necessary to explore the impact of proanthocyanidins on the nitrification process and use them in combination with urease inhibitors and/or nitrification inhibitors to better regulate soil N transformation and reduce N2O emissions in paddy soil.

2-Cyclopenten-1-one (CCO), a bioinhibitor derived from Chamomila recutita L., is being evaluated as an alternative to synthetic nitrogen inhibitors. To facilitate its practical application, this study assessed the effects of CCO on nitrogen dynamics, greenhouse gas emissions, maize productivity, and farm economics in Alfisols of northern China, using a randomized block design with five treatments: chemical fertilizer alone (NPK) and NPK supplemented with CCO at 0.5 %, 1.0 %, 2.0 %, and 5.0 % of total nitrogen. The abundance of the ammonia oxidizer amoA gene was also monitored to clarify nitrogen loss mechanisms and fertilizer recovery. Results showed that the 1 % CCO treatment most effectively synchronized soil nitrogen supply with crop demand, reducing NH3 emissions by 32.5 % and N2O emissions by 21.9 % compared with NPK alone. This dosage also enhanced ammonium availability and increased CH4 oxidation approximately five-fold, leading to a 17 % yield increase, a 26.8 % improvement in apparent nitrogen recovery efficiency, and the highest net profit (214.3 USD ha-1). Microbial and enzymatic analyses revealed that the 1 % dosage effectively suppressed key ammonia oxidizers, thereby reducing nitrification. In contrast, suboptimal concentrations underperformed: the 2 % dosage increased N2O emissions by 72 % (2.08 vs. 1.21 kg ha-1), whereas the 0.5 % dosage raised NH3 losses by 40 % (1.89 vs. 1.35 kg ha-1) compared with the optimal 1 % dosage. Overall, the calibrated 1 % CCO treatment markedly reduced global warming potential and greenhouse gas intensity, demonstrating its potential as a sustainable strategy to enhance nitrogen use efficiency, mitigate environmental risks, and improve farm profitability.

Reducing greenhouse gas (GHG) emissions and ammonia (NH3) volatilization by improving fertilization methods to increase crop yield is beneficial for the green and sustainable development of agriculture. This study evaluated the effects of farmer practice fertilization (FP), nutrient expert optimized fertilization (NE—optimized fertilizer usage and time), the application of stable compound fertilizer (SF), and the application of controlled-release coated urea (CRU) on greenhouse gases, NH3 volatilization, and corn yield through field experiments set up in the corn planting area in western Liaoning Province. The results showed that compared with FP treatment, NE could significantly reduce NH3 volatilization by 28% and increase N2O release by 41%. Compared with FP treatment, SF could significantly reduce NH3 volatilization by 48.54%, N2O release by 38.54%, CO2 release by 13.96%, global warming potential (GWP) by 16.60%, and greenhouse gas emission intensity (GHGI) by 27.23%, and could significantly increase corn yield by 15.86%. Compared with FP treatment, CRU could significantly reduce NH3 volatilization by 63.46%, CO2 release by 11.98%, GWP by 10.73%, and GHGI by 13.77%, while increasing N2O release by 6.71%. Overall, NE, SF, and CRU treatments all showed better effects than FP treatment in increasing corn yield or reducing NH3 volatilization and GHG emissions. Among them, SF treatment demonstrated superior performance over NE and CRU treatments in terms of NH3 volatilization, corn yield, and GHGI. Therefore, the application of stable compound fertilizer is the optimal choice for corn planting in western Liaoning, with broad application prospects.

Ureolytic microorganisms are significant in the transformation of soil nitrogen as they secrete urease to hydrolyze urea. This study aimed to investigate the effects of different fertilization regimes on ureolytic microbial functional guilds (bacteria, fungi, and archaea) in various agricultural ecosystems. Soil samples were collected from a long-term agricultural field experiment involving paddy and dryland soils. The experiment consisted of four fertilization treatments: nitrogen fertilizer (N), nitrogen fertilizer combined with composite urease/nitrification inhibitor (NI), nitrogen fertilizer combined with straw (NS), and nitrogen fertilizer combined with manure (NO). A metagenomic sequencing technique was used to assess the composition of ureolytic microbial functional guilds using the target ureC gene, along with the evaluation of soil physicochemical properties, the abundance of ureC genes from different microbial guilds, and the urease activity. The results showed that the NI treatment significantly increased the abundance of ureC genes from different microbial guilds in the two agricultural ecosystems compared with other fertilization treatments. In dryland soil, the abundance of ureC genes was positively correlated with urease activity. The ureolytic bacterial functional guild exhibits greater dominance at all taxonomic levels compared to the ureolytic fungal and archaeal functional guilds. The alpha diversity of ureolytic microbial functional guilds was greater in dryland soil than in paddy soil. Principal coordinate analysis showed that the structure of the ureolytic microbial functional guilds could be separated into two groups based on agricultural ecosystems. Phosphorus is a key environmental factor affecting the ureolytic microbial functional guilds in two agricultural ecosystems, and the structure of the ureolytic bacteria functional guild is more susceptible to pH. The results suggest that the structure of ureolytic microbial functional guilds is primarily determined by agricultural ecosystems rather than by fertilization treatments. Additionally, fertilization treatments across different agricultural ecosystems significantly impacted the community composition of ureolytic bacteria, fungi, and archaea microorganism.

Commonly, agricultural practices utilize urea as a nitrogen (N) source, which can lead to N losses to the environment. Application of urease inhibitors (UIs) or nitrification inhibitors (NIs) can mitigate these losses to some extent but not completely. A preliminary study showed that 2-Cyclopenten-1-one (CCO), an organic compound derived from chamomile (Chamomila recutita L.) can inhibit soil urease activity and also nitrification and therefore has the potential to act as a dual-function inhibitor for decreasing fertilizer-induced N losses and increasing N use efficiency. In this study, a field experiment was conducted to evaluate the effect of CCO on N transformations and NH3, N2O and CH4 emissions from soil, and monitor changes in the ammonia oxidizer amoA gene abundance. Three replicates of five fertilized treatments were included: Urea (fertilizer only), thiophosphoric triamide (NBPT) (a urease inhibitor), dicyandiamide (DCD) (a widely used synthetic nitrification inhibitor), NBPT combined with DCD, and CCO, along with an unfertilized control.The results indicated that, the ability of CCO to reduce N losses and improve maize yield was potentially superior to DCD, NBPT, or the combination of DCD and NBPT. Compared with the urea treatment, the addition of CCO significantly reduced urease activity and nitrification, which subsequently increased the content of NH4+-N and decreased the content of NO3--N in the soil during the maize growth period. Moreover, the cumulative NH3 and N2O emissions, global warming potential (GWP) and greenhouse gas intensity (GHGI) of the maize field were lowest from the CCO applied plots during the growth season, decreasing by 32.5 %, 21.94 %, 7.69 % and 20.92 %, respectively, compared to urea treatment. Notably, CCO application significantly reduced the abundance of ammonia-oxidizing archaea and bacteria in soil. These results suggest that CCO is effective for suppressing urease activity and the nitrification rate in soil and has the potential to be a novel naturally sourced dual-purpose inhibitor.

以东北潮棕壤为供试土壤,通过室外水稻盆栽试验,研究不同水分管理模式下氮肥和秸秆配施对稻田CH4排放的影响.在长期淹水(CF)和干湿交替(AWD)两种水分管理模式的基础上,设置无氮肥对照(CK)、单施秸秆(S)、单施尿素(U)、尿素+秸秆(US)4个处理,对水稻整个生长季CH4排放进行监测,并测定不同生育期间土壤微生物量碳(MBC)含量以及收获后水稻产量.结果显示:AWD模式下CH4累积排放量低于CF模式;两种水分模式下CK与U处理CH4累积排放无显著差异,添加秸秆处理(S,US)CH4累积排放量显著增加.CF模式下US处理CH4累积排放量显著高于S处理,但在AWD模式下正好相反.AWD模式在降低CH4排放的同时并未显著降低水稻产量,尿素的施用显著增加了水稻产量,秸秆还田虽然对水稻产量无显著影响,但它显著提高了土壤微生物量碳含量,有助于培肥地力.与CF模式相比,AWD模式显著降低了CH4排放,同时,US处理施在降低CH4排放和保证水稻产量的同时,增加土壤MBC含量,有助于培肥地力.因此,AWD模式是东北潮棕壤发育的水田中较为优异的水分管理模式,U和US处理是较为优异的施肥措施.

Understanding the effects of different amounts of straw returning and nitrogen fertilizer application on soil CO2 emission from maize field can provide theoretical support for carbon sequestration and CO2 emission reduction and the implementation of black soil region conservation plan. Three rates of straw returning were set up in the semi-arid area of northwest Liaoning Province, China, i.e. 3000 (S1), 6000 (S2) and 9000 kg·hm-2(S3, full amount of straw returned to the field); crossed with three nitrogen fertilizer application rates in the sub-region, respectively, i.e. 105 (N1), 210 (N2, conventional nitrogen application rate) and 420 kg N·hm-2(N3). In addition, there was a control treatment (CK) without nitrogen fertilizer and straw returning. Soil samples were collected after 4 years field experiment with maize plantation. The influence of different treatments on maize field soil CO2 emission and the relationship between CO2 emission and soil dissolved organic carbon (DOC) and microbial biomass carbon (MBC) were investigated in an incubation experiment. The results showed that both of straw returning and nitrogen fertilizer application promoted soil CO2 emission in maize field, which were increased significantly with the increases of straw returning amount and nitrogen application amount. Nitrogen fertilizer application was the most important factor promoting soil CO2 emission in maize field. Straw returning combined with nitrogen fertilizer promoted soil CO2 emission by increasing microbial biomass and increasing DOC consumption. MBC and DOC stimulated soil CO2 emission significantly in maize field, and were mainly affected by their contents in the early stage of incubation. From the perspective of ensuring the fertilization of straw return to the field while reducing CO2 emissions, results from our experiment showed that 210 kg N·hm-2 conventional nitrogen application in combination with 6000 kg N·hm-2 straw returning (N2S2) was the most promising mode in the semi-arid area of northwest Liaoning Province.

Nitrification inhibitors (NIs) affect nitrogen (N) cycle and crop yield, but how the combinations of NIs influence N transformation and maize yield remains unclear. An outdoor pot experiment was performed to explore the effect of three NIs (nitrapyrin (CP), 3, 4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD)) and their combinations on mineral N transformation, yield and N use efficiency (NUE) of maize in a brown soil and a cinnamon soil from northeast China. Higher yield and NUE were obtained in the brown soil than that in the cinnamon soil. All treatments with NIs significantly increased NH4+-N content, grain yield and NUE in both soils, especially for NIs combination (DMPP + DCD in the brown soil and CP + DCD in the cinnamon soil). These two treatments significantly increased yield and apparent nitrogen recovery by 1.84 and 2.31 times, 10.24 and 6.39 times, respectively, compared with N fertilizer treatment. They also showed lower apparent nitrification rates (17.2% and 53.7%, respectively) compared with single NIs treatments. Considering both the inorganic N supply and agronomic effect of NIs, DMPP + DCD and CP + DCD are the best strategies for the application of NIs in the brown soil and cinnamon soil.

Heterocyclic nitrogen compounds containing two adjacent nitrogen atoms generally have a significant effect on soil nitrification inhibition, and 3,5-dimethylpyrazole (DMP) is a typical representative of this structure. However, the inhibitory effect and the regulatory mechanism of DMP on soil N transformation are unclear. In this study, a microcosm with different concentrations of DMP was carried out in brown soil to detect the dynamic changes of soil NH4+–N, NO3–N and related soil enzyme activities. Results showed that DMP inhibited soil nitrification effectively and decreased soil nitrate reductase activity, while increasing nitrite reductase and dehydrogenase activities. The inhibition effects were dose dependent, and DMP at the rate of 0.025 g kg−1 dry soil showed the strongest inhibitory effect on N transformation in brown soil. The soil dehydrogenase activity was increased with an increasing DMP application rate. The changes in the soil’s chemical and biological properties caused by DMP application provided a new idea for systematically explaining how DMP participated in the soil N transformation process. This study further implied that DMP would play positive roles in alleviating environmental pressure by delaying nitrate-N formation and decreasing the activity of nitrate reductase.

Application of nitrification inhibitors (NIs) with nitrogen (N) fertilizer is one of the most efficient ways to improve nitrogen use efficiency (NUE). To fully understand the efficiency of NIs with N fertilizer on soil nitrification, yield and NUE of maize (Zea mays L.), an outdoor pot experiment with different NIs in three soils with different pH was conducted. Five treatments were established: no fertilizer (Control); ammonium sulfate (AS); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate (DMPP) (AD); ammonium sulfate + nitrogen protectant (N-GD) (AN); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate + nitrogen protectant (ADN). The results showed that NIs treatments (AD, AN and ADN) significantly reduced soil nitrification in the brown and red soil, especially in AD and ADN, which decreased apparent nitrification rate by 28% - 44% (P < 0.05). All NIs treatments significantly increased yield and NUE of maize in three soils, especially ADN in the cinnamon soil and AD in the red soil were more efficiency, which significantly increased maize yield and apparent nitrogen recovery by 5.07 and 6.81 times, 4.39 and 8.16 times, respectively. No significant difference on maize yield was found in the brown soil, but AN significantly increased apparent nitrogen recovery by 70%. Given that the effect of NIs on both soil nitrification and NUE of maize, DMPP+N-GD was more efficient in the cinnamon soil, while N-GD and DMPP was the most efficiency in the brown and red soil, respectively. In addition, soil pH and soil organic matter play important role in the efficiency of NIs.

The application of nitrification inhibitors (NIs) based on ammonium (NH4+) is considered to be an efficient way to reduce nitrogen (N) loss by delaying the nitrification process through influencing ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). However, the inhibition mechanisms of NIs on AOA and AOB in different soils remain unclear. Hence, we explored the two commonly used NIs (3, 4-dimethylepyrazole phosphate (DMPP) and dicyandiamide (DCD) and their combination (DMPP + DCD) on the soil nitrification and abundance of ammonia oxidizers (AOA and AOB) in three black soils (HLJ, NA, and DA) with different physicochemical properties using a 120-day incubation experiment. The results demonstrated that NIs significantly increased NH4+-N concentrations and decreased NO3−-N concentrations in all three tested soils. There was no significant difference in inhibiting nitrification in HLJ among all NI treatments, while DCD was more efficient in NA, DMPP + DCD had better efficiency in DA. The potential nitrification rate (PNR) was greatly decreased by NIs addition, and PNR was significantly positively correlated with AOB (p < 0.05). AOA was dominant in the acid soil. All NI treatments significantly inhibited soil nitrification through inhibiting the growth of AOB in the two soils with higher pH. The abundance of AOA and AOB was significantly correlated with different soil types (positively correlated with soil pH, and negatively correlated with organic matter). Moreover, soil pH and soil organic matter were considered to be the most important factors influencing the inhibition efficiency of NIs and the abundance of AOA and AOB. The application of the NIs combination (DMPP + DCD) was considered to be the most cost-effective way to inhibit soil nitrification in soil with higher pH and lower SOM, which provides a theoretical basis for a field experiment.

为揭示有机无机配施条件下15N尿素在稻田土壤中的残效状况,在我国北方棕壤性水稻土上进行盆栽试验,结合土壤氮素供应及水稻对肥料氮的吸收利用,探寻最佳的施肥方式.设置空白(CK)、尿素(N)、秸秆+尿素(NS)、猪粪+尿素(NM)、稳定性尿素(NI)、秸秆+稳定性尿素(NIS)、猪粪+稳定性尿素(NIM)7个处理.结果 表明,稳定性尿素、秸秆、猪粪的添加均能影响15N标记的尿素在土壤中的残留、转化及水稻吸收利用.相比于N,NI显著延缓了尿素水解(P＜0.05),增加水稻返青期和分蘖期铵态氮的供应,增加各生育期生物量及产量,提高了水稻的收获指数和氮素回收利用率.秸秆和猪粪的添加均显著提高了土壤微生物量碳氮,增强了氮素供应能力.NS或NIS增加了水稻穗及地上部分对肥料氮的吸收利用,其具有最高的收获指数(0.39 ～ 0.47).相比于N,NIM提高水稻产量约137％,增加水稻分蘖期和成熟期生物量分别约1.98％和53％,提高了氮素回收利用率,约是N的1.82倍.秸秆配施氮肥的微生物量碳氮具有较好的耦合性,猪粪添加的增产效果更为明显.总之,在我国北方稻田土壤中,从产量及生物量的角度,NI、NIM为推荐施用模式,从肥料氮固持及培肥土壤的角度,NS、NIS是值得长期探索的施用方式.

We studied the effects of urease/nitrification inhibitor combinations on urea hydrolysis and nitrification, aiming to screen out the effective inhibitor combinations for black soil and cinnamon soil in Northeast China. Urease inhibitor, N-butyl thiophosphate-triamine (NBPT), and its combination with nitrification inhibitor dicyandiamide (DCD), 3, 4-dimethylpyrazole phosphate (DMPP), 2-chloro-6 (trichloromethyl)-pyridine (CP), 2-amino-4-chloro-6-methylpyrimidine (AM) and 3-methylpyrazole (MP) were added to urea separately. Samples were collected 15 times in each of all the treatments during 125 days. We examined the changes of urea nitrogen, ammo-nium, nitrate, and nitrification inhibition rate in the two soils. Our results showed the hydrolysis of urea in black soil and cinnamon soil was about 7 d, and the addition of NBPT with or without diffe-rent nitrification inhibitors slowed down the hydrolysis to 21 d at least. Compared with the treatment with common urea, inhibitor addition significantly increased soil NH4+-N, decreased soil NO3--N, and maintained the high NH4+-N content in soil for a longer time. In black soil, application with nitrification inhibitor inhibited soil nitrification significantly and lasted for more than 125 d. DMPP and CP combined with NBPT increased the NH4+-N content in black soil by 1.6-1.8 times, while the nitrification inhibition rate was 47.9% and 24.1% at 125 d, respectively. In the cinnamon soil, the application of nitrification inhibitor could prolong the duration of ammonium oxidation from 80 d to 110 d. DCD and DMPP combined with NBPT increased the NH4+-N content in cinnamon soil by 2.1-3.4 times, while the nitrification inhibition rates at 125 d were 25.3% and 23.2%, respectively. Therefore, NBPT+DMPP combination with urea was recommended for utilization in black soil, followed by NBPT+CP. In cinnamon soil, NBPT+DCD combination with urea was recommended, followed by NBPT+DMPP.

We examined the effects of nitrification inhibitors (NIs) on soil nitrification, maize yield and nitrogen use efficiency (NUE), aiming to screen out high efficiency stabilized ammonium chloride fertilizer in red soil. Nitrification inhibitors 2-chloro-6-trimethyl-pyridine (CP), 3, 4-dimethyl-pyrazolate phosphate (DMPP), and dicyandiamide (DCD) and their combinations were added into ammonium chloride (NH4Cl) to make six stabilized nitrogen fertilizers. With blank (CK) and NH4Cl (N) as the controls, we conducted a maize pot experiment with the same amount of nitrogen addition. The results showed that compared with the treatment of N, soil ammonium content in CP+DMPP and DMPP+DCD increased by 56%-62%, which was significantly higher than that in CP, DMPP, and DCD, while the apparent nitrification rate of red soil was significantly reduced by 33%-34%. All the six treatments with nitrification inhibitors and their combinations significantly improved biomass and nitrogen absorption efficiency of maize. Compared with the N treatment, the application of adding NIs alone was significantly higher than that of the treatments of NIs combinations, with an average of 1.3 times increase. DCD was the most efficient one in improving maize yield, nitrogen uptake, and nitrogen adsorption efficiency, which increased by 4.1, 6.3 and 4.4 times, respectively. Comprehensively, DCD performed the best in reducing cost and improving yield and nitrogen use efficiency in red soil.

We carried out pot experiment to investigate nitrogen transformation characteristics, yield increasing effect, and apparent utilization rate of nitrogen fertilizer in loess soils by combining chemi-cal inhibitor and biostimulant humic acid to investigate the application effect and provide a theoretical basis for new type highly efficient and stable urea in loess soil. In this study, blank (CK) and urea (N) were set as controls, and humic acid alone (F), N-butyl thiophosphate-triamine (NBPT), 3,4-dimethyl-pyrazolate phosphate (DMPP), 2-chloro-6-trimethyl-pyridine (CP) and humic acid were respectively combined with three biochemical inhibitors to urea. The results showed that compared with N treatment, F, NBPT+F, DMPP+F, CP+F treatments significantly increased maize yield, chlorophyll content, leaf area index and nitrogen uptake, and had obvious effects on soil available nitrogen contents. The addition of humic acid increased chlorophyll content of maize leaves in all cases compared to the application of biochemical inhibitors alone. Compared with CP treatment, CP+F treatment could significantly increase nitrogen uptake, chlorophyll content, and nitrogen adsorption efficiency of maize. Addition of humic acid with NBPT increased nitrification inhibition rate by 10.7% compared with NBPT alone, but decreased yield, leaf area index, nitrogen uptake, nitrogen use efficiency. Compared with DMPP treatment, DMPP+F treatment significantly reduced maize yield, leaf area index, nitrogen uptake, nitrogen use efficiency and nitrification inhibition rate. Considering maize yield, plant N uptake, N fertilizer uptake rate and soil ammonium N and nitrate N contents, the addition of humic acid and CP is recommended for urea application in loess areas to enhance urea performance, yield, and fertilizer utilization.

[目的]研究添加脲酶/硝化抑制剂的高效稳定性尿素在黑土和褐土中的作用效果,为科学合理选择抑制剂提供科学依据.[方法]以春玉米为试材,采用东北典型的黑土和褐土进行盆栽试验.供试抑制剂包括N-丁基硫代磷酰三胺(NBPT)、3,4-二甲基吡唑磷酸盐(DMPP)、2-氯-6(三氯甲基)-吡啶(CP).试验设不施氮肥(U0)、施普通尿素(U),和在尿素中添加NBPT、DMPP、CP、NBPT+DMPP、NBPT+CP、DMPP+CP,共8个处理.在玉米苗期、大喇叭口期、灌浆期、成熟期取样,测定土壤尿素态氮、NH4+-N和NO3–-N含量,计算硝化抑制率,玉米抽雄吐丝后测定棒三叶叶面积和叶绿素含量,收获后测定玉米生物量、氮素含量等指标.[结果]1)与普通尿素(U)相比,黑土上添加NBPT+DMPP、NBPT+CP处理玉米苗期土壤中NH4+-N含量分别提高1.32、0.96倍,NO3–-N含量分别降低1.35、1.04倍,玉米叶面积增加,叶片叶绿素含量增高.褐土中,添加DMPP+CP处理在玉米苗期土壤NH4+-N含量提高3.09倍,NO3–-N含量降低1.49倍,玉米叶绿素含量提高1.61倍,显著高于对照和单一抑制剂处理.2)在黑土中,与普通尿素相比,添加NBPT+DMPP、NBPT+CP处理的玉米籽粒产量分别增加1.64和2.18倍;氮素表观利用率分别提高3.02和3.34倍,高于其他处理.褐土添加DMPP+CP处理的籽粒产量增加1.41倍,氮素表观利用率提高4.98倍,高于其他处理.[结论]在黑土中,尿素配施NBPT+DMPP、NBPT+CP可以有效抑制NH4+-N向NO3–-N的转化,增加玉米氮素吸收量,提高氮肥利用率,从而获得较高的产量,是黑土栽培玉米施用氮肥的最佳选择.褐土中,DMPP+CP的硝化抑制率显著高于添加单一抑制剂,有效抑制铵态氮的硝化作用,减少氮素损失,增加玉米氮素吸收量,从而使玉米高产,因此,添加DMPP+CP是制备褐土玉米专用高效稳定性尿素的最好选择.

[目的]对单个区域或者单种作物开展的抑制剂或者稳定性肥料效果研究受土壤类型和气候区域限制,无法为稳定性肥料在不同地理区域的生产和施用提供科学的数据支持.为此,我们在全国范围进行了稳定性肥料施用效果试验,为稳定性肥料的科学施用提供依据.[方法]稳定性肥料产业技术战略联盟于2009-2018年在全国7大地理区域进行了大田试验,比较了等养分条件下,施用稳定性肥料和常规施肥的增产效果,统计分析了2014-2018年的研究结果.[结果]在华南、西南、华中、华东、华北、西北、东北地区,等常规施肥养分稳定性肥料(SF)相对常规施肥(CK)的作物平均增产率分别为5.00％、13.40％、6.96％、8.68％、16.30％、8.72％和5.80％,氮肥农学利用率(NAE)增幅分别为36.11％、29.84％、27.25％、51.02％、54.73％和21.00％(无华北NAE数据);80％常规施肥养分稳定性肥料(80％SF)处理相比CK的增产率分别为1.62％、10.38％、1.78％、6.34％、8.35％、1.44％和0.09％,NAE 增幅分别为78.24％、81.41％、49.22％、20.10％、38.96％和62.10％;80％SF 处理相对SF 处理的作物产量平均减少3.92％、1.22％、1.25％、3.49％、0.07％、1.08％和0.05％,NAE 增幅分别为30.95％、40.11％、17.27％、-20.48％、-10.19％和33.97％,与SF 处理的作物产量相比,减施20％常规施肥养分稳定性肥料在各个区域均带来小幅减产,80％SF处理相对SF处理的减产幅度在华中、华北、西北和东北地区差异显著(P＜0.05),在华南、西南和华东地区差异不显著,80％SF处理相对SF处理的NAE差异多不显著;从全国范围来看,等常规施肥养分稳定性肥料处理平均能提高作物产量8.54％和提高NAE 21.77％,80％常规施肥养分稳定性肥料处理能使产量和NAE分别提高3.13％和26.39％.主成分分析结果发现,稳定性肥料增产率主要受到两种有效公因子的影响,即养分因子和pH因子;稳定性肥料增产率与土壤养分主要呈负相关关系,土壤养分越低,稳定性肥料的增产效果越强,稳定性肥料在贫瘠土壤上产生的经济效益越大(西北极端干旱地区土壤除外);稳定性肥料增产率与土壤pH呈正相关关系,土壤pH越高,稳定性肥料肥效和增产效果越强.[结论]施用稳定性肥料在全国主要种植区域均取得了明显的增产节肥效应,完全可以替代常规施肥模式.综合对比等常规施肥养分稳定性肥料施肥模式和80％常规施肥养分稳定性肥料施肥模式对增产和提高NAE的效果,华东、华中、华北、西北、东北以等常规施肥养分施用稳定性肥料的效果较好,华南、西南稳定性肥料的施用量则以80％的常规施肥养分量为宜.影响稳定性肥料肥效和增产效果最重要的土壤因素是土壤养分,其次是土壤pH.