生物质炭及硝化/脲酶抑制剂对滨海盐渍土土壤盐分及作物氮素吸收利用的影响

为研究生物质炭及硝化/脲酶抑制剂对滨海盐渍土土壤盐碱、氮素有效性、作物氮素吸收利用以及土壤氮平衡的影响,通过盆栽试验,共设9个处理:不施氮肥、常规化肥、生物质炭+常规化肥、常规化肥+硝化抑制剂DCD、常规化肥+脲酶抑制剂NBPT、常规化肥+DCD+NBPT、生物质炭+常规化肥+DCD、生物质炭+常规化肥+NBPT、生物...     

Dicyandiamide as a nitrification inhibitor in crop production in the Southeastern USA

Abstract

The yield response to N with and without the use of the nitrification inhibitor, dicyandiamide (DCD), was determined on the field crops, sweet corn, cotton, wheat, and grain sorghum; and on the vegetable crops, bell peppers, potato, and tomato, on a large number of different soils in Alabama, Florida, Kentucky, Mississippi, and Virginia. In general, DCD inhibited nitrification for several weeks but inhibiting nitrate formation was not often reflected in crop yield response to N. Increase in yield resulting from DCD use were found for sweet corn in Florida, grain sorghum in Alabama, and potato in one of two years in Florida. Results with cotton were erratic, sometimes resulting in increased, sometimes in decreased, yields. Use of DCD for wheat production in the Southeast did not prove to be advantageous. Generally when DCD use benefitted yields, this occurred at the lower N rates, indicating that preventing loss of N at the lower end of the response curve resulted in a measurable positive effect. The studies reported indicate that consistent benefit from DCD use in the southeastern United States is unlikely.     

烤烟钾素库源关系生理调控措施研究

在大田生产条件下 ,采用单株挂牌设置处理的研究方法 ,研究涂抹生长素与其它不同生长调节剂和烟株顶端调控等措施对烤烟钾吸收及其在库源中再分配的影响。结果表明 ,现蕾后不打顶或打顶结合生长素处理茎断面均有利于不同部位叶片含钾量的提高 ,以打顶结合涂抹生长素效果更好 ;内源生长素和外源生长素都有利于烟株体内的钾素向叶片中分配 ,其中外源生长素的活性更强 ,能更有效地提高烟株叶片的含钾量 ,且涂抹 2次比涂抹 1次的效果好 ,但涂抹次数间差异不显著。     

Dicyandiamide effects on nitrification and total inorganic soil nitrogen in sandy soils

Abstract

Inhibition of nitrification in soil results in a decreased ratio of nitrate‐nitrogen (NO₃‐N) to ammonium‐nitrogen (NH₄‐N). If the conditions for NO₃‐N loss by leaching or denitrification exist, nitrification inhibitors should increase concentrations of total inorganic soil nitrogen (N) (TISN) (NH₄‐N + NO₃‐N). This can then result in plants taking up more N and developing more crop yield or biomass. This study examined whether inhibition of nitrification by dicyandiamide (DCD) would result in increased concentrations of TISN under field conditions. The effects of DCD on soil N were evaluated in hyperthermic sandy soils planted to potato (Solanum tuberosum L., cv. Atlantic). Treatments were factorial combinations of N as ammonium nitrate (NH₄NO₃) at 67, 134, and 202 kg N ha^‐1 and DCD at 0, 5.6, and 11.2 kg DCD ha^‐1. Soil NH₄‐N, NO₃‐N, and TISN concentrations were determined for up to five potato growth stages at two locations for two years for a total of 16 determinations (cases), i.e., four were not determined. The N form ratio [NO₃‐N/(NH₄‐N + NO₃‐N] x 100 was decreased in 10 of 16 cases, indicating that nitrification was inhibited by DCD. With two of these 10 cases, TISN concentration increased, but with four others, TISN concentration decreased with at least one N rate. With four of these 10 cases, inhibition of nitrification had no effect on TISN concentration. Under the conditions of these field studies, DCD inhibited nitrification more often than not. Inhibition of nitrification was, however, more likely to reduce TISN concentration than to increase it. This may have been due to DCD effects on immobization of applied NH₄‐N.     

Research on dicyandiamide as a nitrification inhibitor and future outlook

Abstract

The action and decomposition of dicyandiamide (DCD), a nitrification inhibitor, is discussed.

DCD is especially efficient when used with animal manure slurries or potato starch waste water. As a consequence, nitrate leaching can be reduced, yields and N uptake increased. DCD‐amended mineral N fertilizers applied once can substitute for split N applications, thus reducing labor costs without any loss in crop yield and quality. With wheat and sugar beets, use of a DCD‐containing product ("Alzon 22") reduced the requirement of N for maximum yield. New formulations, such as DCD plus a reducing substance, ammonium thiosulfate (ATS), or new inhibitors, such as guanylthiourea (GTU), will receive more attention in the future.     

Dicyandiamide (DCD) as a nitrification inhibitor for rice culture in the United States

Abstract

Efficient nitrogen (N) fertilizer management for paddy rice production is difficult because of potentially high N losses from denitrification, NH₃ volatilization, and leaching. The use of a nitrification inhibitor, by slowing the rate of nitrification of NH₄ ⁺‐N sources prior to flooding, offers the potential to reduce denitrification losses that occur after flooding. Dicyandiamide (DCD) is one such nitrification inhibitor. The objective of this series of studies was to evaluate DCD for its effectiveness as a nitrification inhibitor in paddy rice production across an array of soils, management systems, and climate conditions.

Studies were conducted on fine‐ and medium‐textured soils in Arkansas, California, Louisiana, Mississippi, and Texas. Dicyandiamide was coated onto or formulated with urea (7 or 10% of total N as DCD‐N) and applied either broadcast pre‐plant incorporated or broadcast as a topdress application prior to flooding at the 4‐ to 5‐leaf development stage of the rice plant. These treatments were compared with urea applied either pre‐plant incorporated or in multiple applications timed to the peak N demand periods of rice. An array of N rates were used to model the yield response to levels of N. Similar studies utilizing ¹⁵N‐enriched urea were also conducted.

The studies indicated that use of DCD delayed nitrification and tended to result in rice grain yield increases as compared with urea applied pre‐plant without DCD in drill‐seeded rice; however, proper application of urea in split applications gave more consistent results. In water‐seeded continuously flooded rice culture, use of DCD was advantageous only if the flood was delayed for more than 14 days after urea application. The ¹⁵N‐enriched studies indicated that highest N fertilizer recovery was associated with split topdress urea applications; however, addition of DCD resulted in increased immobilization of fertilizer N and release of soil N.     

Inorganic nitrogen movement in tropical soils

A field experiment was conducted to follow the transformation of ammonium fertilizer applied in rainfed-upland fields. The study was done during the rainy season on a heavy-textured, poorly rained soil. Ammonium fertilizer was applied in rows, and soil samples from different depths were analyzed to check the vertical distribution of inorganic nitrogen. In order to learn the relation between nitrogen loss and nitrification, the effect of nitrification inhibitor was also checked. Ice variety IR5 was used to check nitrogen uptake.

The ammonium content decreased by about 40 per cent up to I month after fertilizing and about 90% up to 2 months after fertilizing in the unplanted plots. Up to 5 months it decreased to a level equal to or lower than that before fertilizer application. The accumulation of nitrate was observed in the lower soil layers-after 3 months, but the accumulated amount was too low to account for the loss of ammonia from the surface. The overall loss of mineral nitrogen within 60 cm of the surface was observed after 5 months in unplanted plots. The addition of nitrification inhibitor retarded the decrease of ammonium nitrogen up to 2 months. After 3 months, the nitrifying activity began to recover.

Only 23 to 27 per cent of the fertilizer nitrogen was taken up by the rice plants, indicating low efficiency.     

Nitrogen effect on yield and kernel protein content of sweet corn grown on sandy soils

Abstract

Early spring application of N to Iowa sandy, leachable soils results in reduced sweet corn yields and kernel protein content. Normally, split N applications are used to coincide with crop N demand. Our objectives were to determine if nitrapyrin, a nitrification inhibitor, applied with urea would provide high yields and kernel protein levels when applied at planting.

Nitrogen rate increased yield, ear leaf N concentration, and kernel protein content in 1976 and 1978, with the optimum rate dependent on the year and soil N residual. Urea, with or without nitrapyrin, significantly enhanced yield 13%, early leaf N concentration 17%, and kernel protein content 9% as compared with Ca(NO₃)₂ for both years. High leaching loss of NO₃‐N occurred with the Ca(NO₃)₂ source as compared with urea alone. Kernel protein concentration correlated well with ear leaf N concentration (r = .74) and yield (r = .61). Ear leaf K content was not affected by N rate or source, but Ca(NO₃)₂ enhanced uptake of Ca and Mg as compared with the urea sources. Urea, with nitrapyrin, decreased leaf Mg content in 1978, but not in 1976, as compared with urea alone.     

Interaction of Different Wheat Genotypes and Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate Using 15N Isotope Tracing Techniques

To investigate the effect of applying ¹⁵N-labeled ammonium sulfate with or without a nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on fertilizer use efficiency and crop productivity of different wheat genotypes, a field trial was conducted at the Nuclear Agricultural Department’s farm of Iran in 2013–2014. The treatments included five wheat genotypes with different 13 C isotope discrimination and three fertilizer treatments, an unfertilized control, ¹⁵N-labeled ammonium sulfate, and ¹⁵N-labeled ammonium sulfate with DMPP in three replications. Soil samples were taken after 2, 4, and 6 weeks after sowing and also at harvest time. Results from ¹⁵N experiment showed that DMPP delayed nitrification of ammonium for 42 days. Genotypes with lower discrimination index had greater uptake of ammonium ions which led to increase crop yield and nitrogen fertilizer use efficiency. The results also suggested that the use of DMPP may not be beneficial in some fast growing wheat genotypes.     

西吡对抑制硝化过程和其它微生物活性的影响

作物对氮肥的利用率很低^[3,4],水稻对氮肥的利用率又低于旱作.稻田中氮素平衡的资料指出,水稻对氮肥的利用率在20-60%之间,平均35%,土壤中残留3-21%,平均12%,损失31-61%,平均50%.     

氮肥减施下添加硝化抑制剂对夏玉米灌浆期叶片生理特性的影响

为明确氮肥减施条件下添加硝化抑制剂对夏玉米灌浆期叶片生理特性的影响,本研究设置氮肥正常施用量、氮肥不同减施量及其添加硝化抑制剂处理,研究玉米灌浆期叶片SPAD值、荧光特性、氮素代谢关键酶活、籽粒产量及氮效率的变化。结果表明,氮肥减施20%时添加硝化抑制剂处理能够显著增加果穗粒数,籽粒产量为11.59 t·hm^-2,达到正常施氮量水平。与正常施氮处理相比,氮肥减施30%和20%时添加或不添加硝化抑制剂,氮效率均显著提高,其中氮吸收效率和氮利用效率在各处理间表现不一致,氮吸收效率以氮肥减施30%处理最高,为0.72 kg·kg^-1,氮利用效率以氮肥减施30%添加硝化抑制剂最高,为72.23 kg·kg^-1。玉米灌浆期,氮肥减施20%并添加硝化抑制剂处理下穗位叶SPAD值优势明显,最大荧光和PSⅡ综合性能指数等荧光指标明显提高,氮素代谢关键酶硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性显著增强。综上,在本试验条件下,氮肥减施20%并添加硝化抑制剂能增强玉米灌浆期氮素代谢能力,协调碳氮代谢之间的关系,提高氮效率,增加玉米籽粒产量,达到玉米节本增效的目的。本研究结果为在夏玉米生产上推广施用硝化抑制剂提供了理论依据。     

Nitrapyrin affects the abundance of ammonia oxidizers rather than community structure in a yellow clay paddy soil

Purpose

Yellow clay paddy soil (Oxisols) is a low-yield soil with low nitrogen use efficiency (NUE) in southern China. The nitrification inhibitor nitrapyrin (2-chloro-6- (tricholoromethyl)-pyridine, CP) has been applied to improve NUE and reduce environmental pollution in paddy soil. However, the effects of nitrapyrin combined with nitrogen fertilizers on ammonia oxidizers in yellow clay paddy soil have not been examined.

Materials and methods

A randomized complete block design was set with three treatments: (1) without nitrogen fertilizer (CK), (2) common prilled urea (PU), and (3) prilled urea with nitrapyrin (NPU). Soil samples were collected from three treatments where CK, PU, and NPU had been repeatedly applied over 5 years. Soil samples were analyzed by quantitative PCR and 454 high-throughput pyrosequencing of the amoA gene to investigate the influence of nitrapyrin combined with nitrogen on the abundance and community structure of ammonia oxidizers in yellow clay paddy soil.

Results and discussion

The potential nitrification rate (PNR) of the soil was significantly correlated with the abundances of both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Application of urea significantly stimulated AOA and AOB growth, whereas nitrapyrin exhibited inhibitory effects on AOA. Phylogenetic analysis showed that the most dominant operational taxonomic units (OTUs) of AOA and AOB were affiliated with the Nitrosotalea cluster and Nitrosospira cluster 12, respectively. AOA and AOB community structures were not altered by urea and nitrapyrin application.

Conclusions

Nitrogen fertilization stimulated nitrification and increased the population sizes of AOA and AOB. Nitrapyrin affected the abundance, but not community structure of ammonia oxidizers in yellow clay soil. Our results suggested that nitrapyrin improving NUE and inhibiting PNR was attributable to the inhibition of AOA growth.

     

Can Nitrogen Source and Nitrification Inhibitors Affect In-Season Nitrogen Supply?

ABSTRACT

This study sought to identify whether piggery effluent-derived nitrogen sources can be formulated with urea and nitrification inhibitors to better synchronize nitrogen (N) supply with crop demand than conventional urea fertilizer alone. A 288 pot pasture growth and leaching growth accelerator trial (5 pasture cuts) was completed with a factorial treatment structure of three N sources (2.63 g N [kg soil]^?1 applied as 100% urea-N, 8% struvite-N + 92% urea-N, and 8% piggery pond sludge-N + 92% urea-N), five rates of three nitrification inhibitors (including 3,4-Dimethylpyrazole phosphate, DMPP; limonene+ethanol; and dicyandiamide, DCD), and matrix encapsulated forms of these inhibitors. Applying a combination of piggery sludge with urea increased N uptake during the first 4 weeks of plant growth (by 65%), though total N uptake throughout the trial (22 weeks) did not differ across the N-sources. The microbial community of the soil to which the sludge was added was significantly different from the un-amended soil at the conclusion of the trial. All inhibitor formulations significantly decreased leaching losses of mineral-N relative to the control (by 14 to 61%). The use of DMPP decreased initial nutrient uptake, deferring uptake until later in the experiment. Inhibitor addition resulted in microbial community effects that persisted throughout the trial. The study demonstrated that a piggery-derived N-source and a nitrification inhibitor can be used to manipulate plant N uptake to occur later or earlier in a growing period with equal cumulative uptake, achieving an 11% increase in residual N store, and decreased N leaching losses.     

Crop yield and soil nitrogen dynamics in an intermittently flooded rice field affected by nitrification inhibitors

A field experiment was conducted to study yield and soil N dynamics in an irrigated, intermittently submerged rice field at New Delhi, India, where chemically synthesized as well as neem derived urea coating nitrification inhibitors with prilled urea were applied. Rice (var. IR-32) was grown on a Typic Ustochrept alluvial soil. No nitrogen (control), prilled urea alone, prilled urea mixed with dicyandiamide (DCD), neem (powdered Azadirachta indica Juss. seeds) coated urea and Nimin (commercial derivative of neem) coated urea were tested for their efficacy in regulating yield and conservation of N. None of the inhibitors could increase biomass or grain yield over urea. But all the inhibitors were able to conserve soil ammonium and DCD was the most efficient nitrification inhibitor followed by Nimin coated urea. N-uptake, recovery, physiological and agronomic efficiencies were highest in urea treated plots. The performances of all the inhibitors were against the popular trend where crop yield and N-uptake were enhanced by their application. But, more studies are required on the performance of these inhibitors in rice fields to come to a stronger conclusion.     

Nitrogen transformations in particle size fractions from a second rotation pine forest soil

Abstract

A second rotation forest sand (Mt Burr sand) was separated by a combination of dry sieving and winnowing into different particle sizes rich in either soil or organic matter. These fractions were analysed for % loss on ignition, % organic carbon, total organic nitrogen and mineral nitrogen. Mineralization of soil organic nitrogen and nitrification of ammonium sulphate added to these fractions were studied. Amongst the heavier fractions obtained by sieving, the <125 μm fraction (the finest) contained the highest concentration of organic and exchangeable nitrogen and was the most active in nitrogen transformations. Amongst the lighter fractions obtained by winnowing, the 125 to 500 μm fraction had the highest organic nitrogen content but mineralization of nitrogen was greatest in the 500 to 2000 μm. Nitrification of native and applied ammonium nitrogen was similar in both the 125 to 500 μm and 500 go 2000 μm organic matter fractions.     

Plant availability of magnesium and phosphorus from struvite with concurrent nitrification inhibitor application

Struvite (MgNH₄PO₄.6H₂O) and nitrification inhibitors are applied to soils to, respectively, provide nutrients and reduce nitrogen (N) loss. Given its low N composition (5.7%) relative to that of phosphorus (P, 12.6%) and magnesium (Mg, 9.9%), struvite could be added to soil concurrently with N fertilizers as a source of P and Mg. Nutrient release from struvite could be impacted if nitrification of its ammonium component is reduced by a nitrification inhibitor. Accordingly, a pot trial gauged whether struvite‐fertilized ryegrass had comparable Mg or P uptake and shoot yields with treatments receiving conventional Mg and P fertilizers. Struvite precipitated from milk industry wastewater, or conventional fertilizers, were added to a soil–sand mixture of low fertility. The inhibitor dicyandiamide (DCD) was added to assess its effect on P uptake by ryegrass. Relative to Epsom salt, struvite led to increased Mg uptake without significantly affecting shoot biomass, indicating luxury consumption. Regarding shoot yield and P uptake, struvite was as effective as triple super phosphate. DCD significantly reduced P uptake in the first harvest; the inhibited nitrification of the ammonium is surmised to have diminished struvite dissolution. In later harvests, DCD led to a trend (albeit not statistically significant) of increased biomass; this N‐rich (66% N) compound was probably biodegraded and utilized as an N source. The impact of DCD on P uptake in this experiment was short‐lived. Nevertheless, DCD degradation occurs less rapidly in field conditions, potentially affecting early P supply which is vital for optimum yield.     

小麦苗期施入氮肥在土壤不同氮库的分配和去向

应用盆栽试验和15N标记技术研究了小麦苗期施入N肥后土壤不同N库的动态。结果表明 ,施肥后 28d ,作物所吸收的土壤N占总吸N量的 58.1% ,吸收的肥料N占 41.9%。作物对肥料N的利用率达到 55.3% ,N肥在土壤中的残留率为 24.3% ,损失率为 20.4%。施肥后短期以NH4+-4 N存在的肥料N占施N量的 50.5% ,随着硝化作用的进行和作物的吸收 ,土壤中的NH4+-N显著下降。NO3--N在第 7d达到高峰 ,表现为先升高后降低的趋势 ,说明施肥后在 7d以前有强烈的硝化作用发生。施肥后 2d ,以固定态铵存在的肥料N占 33.7% ,至 28d ,仅占施入N量的 2.4% ,说明前期固定的铵在作物生长后期又重新释放出来供作物吸收。在施肥后第 7d ,肥料N以微生物N存在的量占施肥量的 15.2% ;至 28d来自肥料N的微生物N也几乎被耗竭 ,仅占施N量的 2.4%。随作物生长 ,肥料N在各个土壤N库中的数量均显著下降。在其它N库几乎被耗竭的情况下 ,至施肥后 28d主要以有机N的形式残留。在不种作物的条件下 ,土壤N素的矿化量很低 ,作物的吸收作用导致土壤有机N库不断矿化 ,施入N肥后 ,土壤N素的矿化量增加 ,表现为明显的正激发效应     

Yield-scaled nitrous oxide emissions from nitrogen-fertilized croplands in China: A meta-analysis of contrasting mitigation scenarios

Nitrogen(N) losses in cropland resulting from the application of synthetic fertilizers decrease crop productivity and exacerbate environmental pollution.Mitigation measures, such as reduction in N fertilizer application rates, can have unintentional adverse effects on crop yield. We conducted a meta-analysis of soil N₂O emissions from agricultural fields across China under contrasting mitigation scenarios as a novel approach to identify the most effective strategy for the mitigation of emissions of N₂O derived from N fertilizer use in China. Current standard agricultural practice was used as a baseline scenario(BS), and 12 potential mitigation scenarios(S1–S12) were derived from the available literature and comprised single and combinations of management scenarios that accounted for crop yield. Mitigation scenarios S6(nitrification inhibitor 3,4-dimethylpyrazole phosphate) and S11(20% reduction in N application rate plus nitrification inhibitor dicyandiamide) in maize, rice, and wheat crops led to an average 56.0% reduction in N₂O emissions at the national level, whereas scenario S4(nitrification inhibitor dicyandiamide) led to yield optimization, with a 14.0% increase for maize and 8.0% increase for rice as compared to the BS. Implementation of these most effective mitigation scenarios(S4, S6, and S11) might help China, as a signatory to the 2015 United Nations Framework Convention on Climate Change(Paris Agreement), to achieve a 30% reduction in N₂O emissions by 2030.     

Assessing Nitrogen Fertilization Strategies in Winter Wheat and Cotton Crops in Northern Greece

The management of fertilizer application is crucial for agricultural production and environmental safety.The objective of this study was to assess the effciency of different fertilization strategies,applying fertilizers with and without nitrification inhibitors(NIs) in split application,in Greece.The assessment criteria used were based on crop yield,soil nitrogen(N)concentrations and economic effciency.For this purpose two crops(winter wheat and cotton)were seffected in order to explore the optimum fertilization strategy for each crop.Three treatments combining fertilizers with NIs were tested compared with conventional fertilization(CF).Slight differences in the quantity and the combination of fertilizers with NIs applied resulted in variable effects on crop yield,soil N and economic return.Split N application of 102 kg ha^-1,with half of the total amount applied at seeding,resulted in higher grain yield of winter wheat,lower NO₃^--N in soil and higher economic return.This result reveals the importance of N application at seeding in wheat crop.Fertilization strategy with 109.5 kg N ha^-1 and split P application resulted in higher cotton yield and higher economic profit.Split P application seemed to increase yield,even though it is not a common practise in the area.     

几种硝化抑制剂和包硫尿素(SCU)对土壤N素形态和小麦产量的影响

采用土壤盆栽法,研究了双氰胺(DCD)、硫脲(THU)和硫脲甲醛树脂(TFR)以及包硫尿素(SCU)对土壤氮素形态和小麦产量的影响。试验共设不施氮(CK)、单施尿素、包硫尿素(SCU)、以及尿素分别与DCD、THA、TUF的3个浓度梯度(分别按尿素用量的0.5%、1%、2%)配合施用共12个处理。结果表明:随添加浓度的增加,硝化抑制作用逐渐增强,高剂量硝化抑制剂显著降低土壤NO-3-N含量,在2%添加浓度下,DCD、THU、TFR的土壤NO-3-N浓度分别比单施尿素降低29%、22%和14%,对土壤表观硝化率的抑制强度也是2%DCD2%THU2%TFR;SCU处理与2%DCD作用强度接近,且在施用早期就体现抑制效果,并在追肥后第74 d土壤表观硝化率显著低于使用硝化抑制剂的处理(P0.05);硝化抑制剂和SCU都可以使土壤NH+4-N含量稳定在较高的水平,抑制剂用量越多,土壤NH+4-N含量越高;与单施尿素相比,尿素+DCD模式,均可提高小麦产量,且在0.5%、1%、2%添加浓度,都达到显著水平(P0.05);THU在1.0%和2.0%添加浓度,小麦产量显著高于单施尿素,但增产效果次于DCD。总体上,包硫尿素(SCU)比硝化抑制剂在控释氮素方面效果更持久,而3种硝化抑制剂中,在控制土壤NH+4-N转化、土壤硝化抑制方面,DCD和THU优于TFR;作为外源添加物的抑制剂长期应用可能对土壤环境造成潜在的危害,不同硝化抑制在土壤中的形态归趋和长期作用还有待进一步研究。