硝化抑制剂DCD、DMPP对褐土氮总矿化速率和硝化速率的影响

采用¹⁵N库稀释-原位培养法研究了硝化抑制剂DCD、DMPP对华北盐碱性褐土氮总矿化速率和硝化速率的影响.试验在山西省运城市种植玉米的盐碱性土壤上进行,设单施尿素、尿素+DCD、尿素+DMPP 3个处理.结果表明：施肥后2周,DCD、DMPP分别使氮总矿化速率和氮总硝化速率减少了25.5%、7.3%和60.3%、59.1%,DCD对氮总矿化速率的影响显著高于DMPP,两者对氮总硝化速率的影响无显著差异;而在施肥后7周,不同硝化抑制剂对氮总硝化速率的影响存在差异.施肥后2周,3个处理的土壤氮总矿化速率和硝化速率分别是施肥前的7.2～10.0倍和5.5～21.5倍;NH₄⁺和NO₃^-消耗速率分别是施肥前的9.1～12.2倍和5.1～8.4倍,这是由氮肥对土壤的激发效应所致.硝化抑制剂使氮肥更多地以NH₄⁺形式保持在土壤中,减少了NO₃^-的积累.土壤氮总矿化速率和总硝化速率受硝化抑制剂的抑制是N₂O减排的主要原因.     

硝化抑制剂DCD、 DMPP对褐土氮总矿化速率和硝化速率的影响

采用15N库稀释-原位培养法研究了硝化抑制剂DCD、DMPP对华北盐碱性褐土氮总矿化速率和硝化速率的影响.试验在山西省运城市种植玉米的盐碱性土壤上进行,设单施尿素、尿素+DCD、尿素+DMPP 3个处理.结果表明:施肥后2周,DCD、DMPP分别使氮总矿化速率和氮总硝化速率减少了25.5％、7.3％和60.3％、59.1％,DCD对氮总矿化速率的影响显著高于DMPP,两者对氮总硝化速率的影响无显著差异;而在施肥后7周,不同硝化抑制剂对氮总硝化速率的影响存在差异.施肥后2周,3个处理的土壤氮总矿化速率和硝化速率分别是施肥前的7.2 ～10.0倍和5.5 ～21.5倍;NH4+和NO3-消耗速率分别是施肥前的9.1 ～12.2倍和5.1 ～8.4倍,这是由氮肥对土壤的激发效应所致.硝化抑制剂使氮肥更多地以NH4+形式保持在土壤中,减少了NO3-的积累.土壤氮总矿化速率和总硝化速率受硝化抑制剂的抑制是N2O减排的主要原因.     

不同硝化抑制剂对红壤氮素硝化作用及玉米产量和氮素利用率的影响

本研究分析添加不同种硝化抑制剂及其组合的高效稳定性氯化铵氮肥对红壤硝化作用、玉米产量和氮肥利用率的影响,旨在筛选出适合酸性红壤的高效稳定性氯化铵态氮肥。在氯化铵中分别添加硝化抑制剂2-氯-6-三甲基吡啶(CP)、3,4-二甲基吡唑磷酸盐(DMPP)和双氰胺(DCD)及其组合,制成6种高效稳定性氯化铵态氮肥,以不施氮肥(CK)和施氯化铵(N)为对照,进行等氮量玉米盆栽试验。结果表明: 与N处理相比,CP+DMPP和DMPP+DCD处理红壤中铵态氮含量提高56%～62%,显著高于CP、DMPP和DCD处理;土壤表观硝化率显著降低33%～34%。添加硝化抑制剂及其组合的6个处理均显著提高了玉米生物量和氮肥吸收利用率。与N处理相比,单独添加硝化抑制剂处理生物量均显著高于硝化抑制剂组合处理,平均提高1.3倍;添加DCD处理效果最显著,玉米籽粒产量、吸氮量和氮肥吸收利用率分别显著提高4.1、6.3和4.4倍。为了达到既能低成本又能提高产量和氮肥利用率的效果,在红壤上添加硝化抑制剂DCD是最佳选择。     

氮肥调控剂对潮褐土中不同氮源氮素转化及油菜生长的影响

采用土壤培养和盆栽试验相结合的方法,研究了硝化抑制剂双氰胺(DCD)与纳米碳配合施用对尿素和碳酸氢铵在华北平原典型土壤潮褐土中转化的调控效果及其对油菜生长的影响.结果表明： 尿素和碳酸氢铵在施入土壤后的2周内,土壤无机氮的供应强度差别较大,2周以后则基本相似.2种氮源对油菜生长及氮素利用的影响在生育前期(播种后34 d)差异显著,但最终达到商品生物量收获时,氮源之间差异不大.DCD对尿素和碳酸氢铵在潮褐土中的转化表现出显著的硝化抑制作用,其抑制强度和有效抑制时间随DCD用量的增加而增强,且以对碳酸氢铵施入土壤后的硝化抑制效果更好.在本研究条件下,DCD用量以占肥料纯氮量的1.0%～1.5%相对较佳,可显著提高油菜产量,改善叶色,降低植株硝酸盐含量,提高氮肥利用率.纳米碳与DCD配合施用对土壤铵氧化有明显的协同抑制效果,且可以显著刺激油菜前期的生长发育和氮素利用,降低油菜硝酸盐含量.     

氮肥调控剂对潮褐土中不同氮源氮素转化及油菜生长的影响

采用土壤培养和盆栽试验相结合的方法,研究了硝化抑制剂双氰胺(DCD)与纳米碳配合施用对尿素和碳酸氢铵在华北平原典型土壤潮褐土中转化的调控效果及其对油菜生长的影响.结果表明:尿素和碳酸氢铵在施入土壤后的2周内,土壤无机氮的供应强度差别较大,2周以后则基本相似.2种氮源对油菜生长及氮素利用的影响在生育前期(播种后34 d)差异显著,但最终达到商品生物量收获时,氮源之间差异不大.DCD对尿素和碳酸氢铵在潮褐土中的转化表现出显著的硝化抑制作用,其抑制强度和有效抑制时间随DCD用量的增加而增强,且以对碳酸氢铵施入土壤后的硝化抑制效果更好.在本研究条件下,DCD用量以占肥料纯氮量的1.0％ ～1.5％相对较佳,可显著提高油菜产量,改善叶色,降低植株硝酸盐含量,提高氮肥利用率.纳米碳与DCD配合施用对土壤铵氧化有明显的协同抑制效果,且可以显著刺激油菜前期的生长发育和氮素利用,降低油菜硝酸盐含量.     

脲酶/硝化抑制剂在黑土和褐土中对尿素氮转化的调控效果

本试验研究脲酶/硝化抑制剂不同组合在黑土和褐土中对尿素水解和硝化作用的调控效果,旨在筛选出适合东北黑土、褐土的高效抑制剂组合。采用室内恒温、恒湿培养试验,以不施氮肥(CK)和施用普通尿素肥料(U)为对照,研究分别添加脲酶抑制剂N-丁基硫代磷酰三胺(NBPT)及其与硝化抑制剂双氰胺(DCD)、3,4-二甲基吡唑磷酸盐(DMPP)、2-氯-6(三氯甲基)-吡啶(CP)、2-氨基-4-氯-6-甲基嘧啶(AM)、3-甲基吡唑(MP)组合制成的6种高效稳定性尿素在黑土和褐土中的尿素水解和氨氧化特征。在培养125 d内分别取土壤样品15次,通过测定2种土壤中尿素态氮、铵态氮和硝态氮含量,及氨氧化作用强度,计算硝化抑制率,确定最适合2种土壤的抑制剂或组合。结果表明: 尿素在黑土和褐土中水解时间约7 d,添加NBPT以及其与不同硝化抑制剂组合均能将尿素水解时间延长21 d以上。与U处理相比,添加抑制剂可显著增加土壤NH₄⁺-N含量,降低NO₃^--N生成量,维持土壤中高NH₄⁺-N含量的时间更久。黑土中,添加硝化抑制剂的处理均能显著抑制土壤硝化作用,有效硝化抑制时间超过125 d;DMPP、CP与NBPT配施使黑土NH₄⁺-N含量提高1.6～1.8倍,培养125 d时其硝化抑制率分别为47.9%和24.1%。褐土中,U处理培养80 d左右基本完成硝化过程,而添加硝化抑制剂使硝化过程延长至少30 d;DCD、DMPP与NBPT配施使土壤NH₄⁺-N含量提高2.1～3.4倍,培养125 d时其硝化抑制率分别为25.3%和23.2%。因此,尿素与NBPT+DMPP和NBPT+DCD制成的高效稳定性尿素分别在黑土和褐土中施用效果最好,其次分别是NBPT+CP和NBPT+DMPP。     

高效稳定性硫酸铵氮肥在黑土中的施用效果

为筛选高效稳定性氮肥,采用盆栽试验,通过监测施用不同处理的稳定性硫酸铵对黑土铵态氮和硝态氮含量、表观硝化率、硝化抑制率、玉米生长指标、产量和氮素效率等指标的影响,研究添加不同生化抑制剂配方的稳定性硫酸铵态氮肥在吉林黑土玉米栽培中的施用效果。本试验以不施氮肥(CK)和施硫酸铵(N)为对照,在硫酸铵中分别添加硝化抑制剂3,4-二甲基吡唑磷酸盐(DMPP)、2-氯-6-三甲基吡啶(CP),氮保护剂(N-GD)和肥料增效剂(HFJ)及其组合,制成9种稳定性硫酸铵氮肥。结果表明: 与单施硫酸铵氮肥处理相比,在黑土中添加DMPP和DMPP组合显著影响土壤中铵态氮和硝态氮含量及土壤表观硝化率,铵态氮含量提高1.4～2.0倍,硝态氮含量降低13.6%～17.9%,土壤表观硝化率降低55.3%～59.8%;添加DMPP、DMPP+HFJ和DMPP+N-GD组合硝化抑制率最高,达到16.5%以上;添加DMPP+HFJ+N-GD和HFJ的硫酸铵处理玉米叶片叶绿素含量增加最显著,增加4.5～5.3倍;硫酸铵添加硝化抑制剂和肥料增效剂对株高无显著影响;添加HFJ的硫酸铵处理玉米生物量、籽粒产量、经济系数、收获指数、氮肥农学利用率、氮素吸收利用率、肥料贡献率和氮肥偏生产力增加最显著,分别增加1.2、2.5、0.7、0.6、2.7、2.1、1.3和2.5倍。添加HFJ和DMPP、DMPP+HFJ、DMPP+N-GD处理的硫酸铵处理在黑土中施用效果最好,但是DMPP成本较高,因此,兼顾成本和氮肥利用率,建议稳定性硫酸铵态氮肥生化抑制剂首选氮肥增效剂HFJ,其次选择DMPP+HFJ或者DMPP+N-GD。     

Effect of phenylphosphorodiamidate on urea hydrolysis,ammonia volatilization and rice growth in an alkali soil

Summary In order to improve nitrogen recovery by rice, the effect of a urease inhibitor phenylphosphorodiamidate (PPD) on the efficiency of fertilizer urea was studied in laboratory and greenhouse. Addition of PPD to urea (5% w/w) delayed urea hydrolysis by 3 to 4 days and reduced ammonia volatilization from 45% (without PPD) to 8.5% (with PPD). Ammonia volatilization obeyed first order kinetics. Urea hydrolysis was sufficiently strongly inhibited to match the nitrification potential of the soil. N application to rice by three different modes showed that a delayed mode (4 splits) was superior to two conventional modes (3 splits) in nitrogen recovery and fertilizer efficiency since it met nitrogen requirement of plants at reproductive stage. In 2 out of 3 modes of application, there was a 14% increase (relative) in grain yields and dry matter, and 6.8% increase in N uptake efficiency on application of PPD along with urea. The results indicate that urease inhibitors like PPD can be effectively used to block urea hydrolysis, reduce ammonia volatilization losses and improve N use efficiency by rice.     

The influence of mineral fertilizer combined with a nitrification inhibitor on microbial populations and activities in calcareous Uzbekistanian soil under cotton cultivation

Application of fertilizers combined with nitrification inhibitors affects soil microbial biomass and activity. The objective of this research was to determine the effects of fertilizer application combined with the nitrification inhibitor potassium oxalate (PO) on soil microbial population and activities in nitrogen-poor soil under cotton cultivation in Uzbekistan. Fertilizer treatments were N as urea, P as ammophos, and K as potassium chloride. The nitrification inhibitor PO was added to urea and ammophos at the rate of 2%. Three treatments--N200 P140 K60 (T1), N200 PO P140 K60 (T2), and N200 P140 PO K60 (T3) mg kg(-1) soil--were applied for this study. The control (C) was without fertilizer and PO. The populations of oligotrophic bacteria, ammonifying bacteria, nitrifying bacteria, denitrifying bacteria, mineral assimilating bacteria, oligonitrophilic bacteria, and bacteria group Azotobacter were determined by the most probable number method. The treatments T2 and T3 increased the number of oligonitrophilic bacteria and utilization mineral forms of nitrogen on the background of reducing number of ammonifying bacteria. T2 and T3 also decreased the number of nitrifying bacteria, denitrifying bacteria, and net nitrification. In conclusion, our experiments showed that PO combined with mineral fertilizer is one of the most promising compounds for inhibiting nitrification rate, which was reflected in the increased availability and efficiency of fertilizer nitrogen to the cotton plants. PO combined with mineral fertilizer has no negative effects on nitrogen-fixing bacteria Azotobacter and oligo-nitrophilic bacteria.     

稳定性铵态氮肥在黑土和褐土中的氮素转化特征

以稳定性氯化铵为氮源,采用室内培养的方法,研究0.20、0.50、1.00 g N·kg^-1干土3种浓度的稳定性铵态氮肥在黑土、褐土中的氮素转化特征.结果表明: 在褐土中,随着氯化铵添加量的增加,土壤中发生硝化作用的时间逐渐推迟,添加0.20、0.50 g N·kg^-1干土处理开始发生明显硝化反应的时间分别为第3、7天,在高浓度氮量(1.00 g N·kg^-1干土)添加下硝化作用受到明显抑制;在黑土中,各浓度氮量添加处理开始发生硝化反应的时间相同,均为第3天,且随着添加量的增加,硝化作用潜势逐渐减弱.只加铵态氮肥的处理中,添加0.20 g N·kg^-1干土的氯化铵氮肥在褐土和黑土中的硝化反应时间分别可维持3周和2周左右;添加0.50 g N·kg^-1干土的氯化铵氮肥在褐土和黑土中的硝化反应时间分别可维持4周和3周左右.与单施氯化铵相比,黑土和褐土在0.20、0.50 g N·kg^-1干土添加浓度下,按纯氮量的1.0%添加3,4-二甲基吡唑磷酸盐(DMPP)、4.0%添加二氰二胺(DCD)均能显著抑制硝化作用,降低硝态氮的含量,抑制硝化作用潜势.综上,在褐土中,随着氯化铵添加浓度增加,土壤硝化作用受到抑制效果大于黑土.在0.20、0.50 g N·kg^-1干土外源铵态氮时,添加抑制剂可以显著抑制铵态氮的硝化作用.因此室内硝化抑制剂培养试验时,建议铵态氮添加量不超过1.00 g N·kg^-1干土,以0.50 g N·kg^-1干土效果最好.     

Control of urea hydrolysis and nitrification in soil by chemicals—Prospects and problems

Summary A review is made of the recent work to assess the prospects of regulating urea hydrolysis and nitrification processes in soils by employing chemicals that can retard urea hydrolysis and nitrification. The possible benefits from control of nitrogen transformations in terms of conserving and enhancing fertilizer nitrogen efficiency for crop production and the problems associated with their use with regard to N metabolism of plants have also been discussed with examples. Prospects of using cheap and effective indigenous materials and chemicals for control of urea hydrolysis and nitrification under specific soil situations appear eminent in improving the fertilizer nitrogen efficiency. Urease inhibitors may be helpful in reducing problems associated with ammonia volatilization if this is not offset by leaching of urea. On the other hand retardation of nitrification appears useful in reducing losses that accompany nitrification due to leaching and denitrification, and with the plants that metabolize equally well with relatively higher amounts of NH₄–N may be more effective in improving the utilization of fertilizer N under these situations.     

添加生化抑制剂和腐植酸的稳定性增效尿素在黄土中的施用效果

采用田间盆栽试验,研究生化抑制剂与生物刺激素腐植酸结合制成的高效稳定性增效尿素肥料在黄土中的氮素转化特征、增产效果和氮素肥料表观利用率,以探明其施用效果,为开发适宜黄土施用的新型增效尿素肥料提供理论依据。本研究以不施氮肥(CK)和施尿素氮肥(N)为对照,在尿素中分别添加腐植酸(F)、N-丁基硫代磷酰三胺(NBPT)、3,4-二甲基吡唑磷酸盐(DMPP)和2-氯-6-三甲基吡啶(CP),以及腐植酸与3种生化抑制剂分别组合(NBPT+F、DMPP+F、CP+F)。结果表明: 与N处理相比,F、NBPT+F、DMPP+F和CP+F处理均能显著提高玉米的产量、叶片叶绿素含量、叶面积指数和植株吸氮量,对土壤铵态氮和硝态氮含量也有显著影响。与单独施用生化抑制剂相比,添加腐植酸可提高玉米叶片叶绿素含量。与CP相比,CP+F玉米的植株吸氮量、叶绿素含量、氮肥吸收利用率均显著提高;与NBPT相比,NBPT+F硝化抑制率提高10.7%,但玉米产量、叶面积指数、植株吸氮量和氮肥利用率等均有所降低;与DMPP相比,DMPP+F显著降低了玉米产量、叶面积指数、植株吸氮量、氮肥利用率和硝化抑制率等。综合玉米产量、植株吸氮量、氮肥吸收利用率以及土壤铵态氮、硝态氮含量等指标,在黄土地区施用尿素肥料时,建议添加腐植酸和CP以提升尿素性能,从而提高产量和肥料利用率。     

Nitrification and ammonia volatilisation losses from urea and dicyandiamide-treated urea in a sandy loam soil

Summary Nitrification and ammonia volatilisation losses from urea and dicyandiamide (DCD)-treated urea were studied in a sandy loam soil. Laboratory experiments indicated that 20 ppm (of soil) DCD effectively inhibited nitrification of urea over sixty days. If the urea was treated with DCD (20 ppm), ammonia emission from the soil was extended over 105 days; with urea alone, it was negligible after 15 days. A field study indicated that DCD treatment increased volatilisation losses of ammonia tremondously if urea was applied to the soil surface; these losses were minimised if the urea was placed at 5 cm depth. It would seem that nitrification inhibitors must be combined with a placement technique.     

生物炭配施硝化/脲酶抑制剂对亚热带水稻土活性氮气体排放的影响

探究施用生物炭和脲酶抑制剂/硝化抑制剂对亚热带水稻土氮素硝化过程的调控作用、氨挥发和N₂O排放的温室效应潜能的影响,确定生物炭与硝化和脲酶抑制剂的最佳组合,可为削减施用氮肥带来的活性氮气体排放对环境的负面风险提供理论依据。本研究采用室内好气培养试验方式,以单施尿素(N)为对照,设置7个试验处理[尿素+生物炭(NB),尿素+硝化抑制剂(N+NI),尿素+脲酶抑制剂(N+UI),尿素+硝化抑制剂+脲酶抑制剂(N+NIUI),尿素+硝化抑制剂+生物炭(NB+NI),尿素+脲酶抑制剂+生物炭(NB+UI),尿素+硝化抑制剂+脲酶抑制剂+生物炭(NB+NIUI)],观测生物炭与脲酶抑制剂(NBPT)/硝化抑制剂(DMPP)配施下土壤无机氮含量、N₂O排放及氨挥发的变化动态。结果表明: 1)培养期间,与N处理(5.11 mg N·kg^-1·d^-1)相比,NB处理的土壤硝化速率常数显著增加33.9%,N+NI处理显著降低22.9%;NB处理显著提高了氨氧化细菌(AOB)丰度,增幅达56.0%。2)与N处理相比,N+NI和NB+NI处理的NH₃累积排放量均显著增加约49%;N+UI处理降低了NH₃累积损失量,NB+UI处理抑制效果更明显。3)各处理的N₂O排放速率高峰均出现在施肥后前10 d;NB处理的N₂O排放高峰出现最早,N处理排放速率最高(5.87 μg·kg^-1·h^-1);硝化抑制剂与脲酶抑制剂配施减少土壤N₂O排放的效果最佳。综合计算各处理直接N₂O和间接N₂O(NH₃)排放产生的温室效应潜能(GWP)发现,N+NI和NB+NI处理较N处理分别增加了34.8%和40.9%,而NB和NB+UI处理的GWP显著降低了45.9%和60.5%。因此,生物炭与脲酶抑制剂配施对降低土壤活性氮气体排放所产生的温室效应潜能效果最佳。     

Interaction of salinity and enhanced ammonium and potassium nutrition in wheat

Wheat (Triticum aestivum L.) was grown to maturity in a pot experiment in a calcareous silty sand soil. N was applied at two levels as granulated N-P fertilizers, amended or not with nitrification inhibitors (1% and 5% DCD, 1% N-serve). Potassium as KCl was given at three levels of application. P was applied at a uniform rate. Two levels of salinity were obtained by using the soil as such (EC= 0.3 mmho/cm) and by adding NaCl to the same soil (EC=2.4 mmho/cm). 1% DCD and 1% N-serve treatments gave significantly higher wheat grain yields and N-uptake than the other ones. Nitrate content of leachates indicated a prevalent nitrate nutrition in the treatment without nitrification inhibitors. The 5% DCD treatment showed a yield depression. In the lower N level treatments, a significant yield increase, generated by 1% DCD and N-serve was found in the salinized soil as compared to the non-saline soil. Soil salinity reduced N-uptake when nitrification inhibitors were not present. In treatments having the inhibitors, N-uptake was equal or greater in the salinized than in the non saline soil. An enhanced ammonium nutrition increased the P uptake.     

脲酶／硝化抑制剂对土壤有效态氮、微生物量氮和小麦氮吸收的影响

研究了脲酶抑制剂(NBPT)、硝化抑制剂(DCD)及二者组合在草甸棕壤上施用对尿素态N转化及土壤总有效态N、微生物量N的影响．结果表明,尿素配施NBPT、DCD及抑制剂组合能够增加尿素水解后土壤NH4^+含量2％-53％。显著降低了氧化态N的浓度,抑制了土壤中铵态N的氧化,增加土壤总有效N34％-44％,小麦吸N量增加0．26％-6．79％。其中以脲酶抑制剂与硝化抑制剂组合的效果最明显．抑制剂施用增加了微生物在小麦生长初期对有效态N固持,有利于后期土壤有效态N的矿化．     

抑制剂和猪粪对尿素氮在稻田土壤中转化的影响

为了阐明稻田土壤中尿素在配施抑制剂和猪粪的情况下不同形态氮的响应特征,探究不同管理措施下稻田土壤氮素保持和供给能力。本研究采用¹⁵N标记尿素进行盆栽试验,设置不施肥(CK)、猪粪(M)、尿素(N)、猪粪+尿素(NM)、尿素+抑制剂(NI)和尿素+抑制剂+猪粪(NIM)6个处理。抑制剂选用脲酶抑制剂(PPD+NBPT)和硝化抑制剂(DMPP)组合,测定返青期、分蘖期和成熟期土壤氮库的分配、尿素氮在氮库中的保存及水稻吸氮状况。结果表明: 施用猪粪显著提高了土壤铵态氮、固定态铵含量和微生物生物量氮,提高了分蘖期尿素氮在各氮库中的贮存,显著增加了水稻产量。与N处理相比,添加抑制剂促进了NH₄⁺的矿物固定和微生物对尿素氮的固持;与NM处理相比,施用抑制剂增加了黏土矿物对¹⁵NH₄⁺的固定。通径分析表明,施用猪粪能促进水稻吸收肥料氮,增加水稻产量;添加抑制剂可通过铵的矿物固定将更多的肥料氮暂时储存;NIM能将更多的氮贮存在微生物生物量氮中,至作物生长后期,铵的释放和微生物周转矿化可为水稻提供更多的有效氮源。在我国北方稻田,NM和NIM处理是推荐的施肥方式。     

农田减氮调控施肥对华北潮土区小麦-玉米轮作体系氮素损失的影响

针对华北平原麦玉轮作区氮肥用量大、氮损失及土壤氮素累积严重的问题,探索不同减氮调控施肥措施对作物产量、氮损失及土壤无机氮累积的影响.通过(2016—2017年)设置两年大田试验,以农民施肥为对照,研究控释肥处理、微生物肥处理及配施硝化抑制剂处理减少氮用量后对小麦、玉米产量和地上部吸氮量、氮损失及土壤无机氮含量的影响.结果表明: 2016年微生物肥处理的小麦产量显著低于控释肥处理和硝化抑制剂处理,与农民施肥处理无显著性差异;且小麦和周年作物地上部吸氮量都显著降低.2017年各处理间作物产量和吸氮量无显著性差异.3种减氮调控施肥处理均能保持和改善耕层土壤肥力;且微生物肥处理随种植时间延长对土壤碱解氮、速效钾和有机质含量均有提升.随种植时间延长无机氮累积严重,微生物肥处理和添加硝化抑制剂处理均可降低40～100 cm土壤剖面的无机氮含量,而控释肥处理可提高0～40 cm土层无机氮含量.氮损失中氨挥发>淋溶量>N₂O排放>径流,径流损失可忽略不计,其中以农民施肥处理氮损失最大,微生物肥处理可显著降低氨挥发损失量,但淋溶量较大.综上所述,减量施氮条件下,控释肥处理和添加硝化抑制剂处理可保证作物产量及地上部吸氮量,微生物肥处理随种植年限的延长可保证作物产量和吸氮量.微生物肥和添加硝化抑制剂处理可降低40～100 cm土层无机氮含量,控释肥处理对削减无机氮量效果不明显;几种减氮调控措施均可降低氮损失,但微生物肥处理需调整措施来降低氮的淋溶量.     

Phytoextraction of Cadmium and Zinc By Sedum plumbizincicola Using Different Nitrogen Fertilizers,a Nitrification Inhibitor and a Urease Inhibitor

Cadmium (Cd) and zinc (Zn) phytoavailability and their phytoextraction by Sedum plumbizincicola using different nitrogen fertilizers, nitrification inhibitor (dicyandiamide, DCD) and urease inhibitor (N-(n-Butyl) thiophosphoric triamide, NBPT) were investigated in pot experiments where the soil was contaminated with 0.99 mg kg^?1 of Cd and 241 mg kg^?1 Zn. The soil solution pH varied between 7.30 and 8.25 during plant growth which was little affected by the type of N fertilizer. The (NH₄)₂SO₄+DCD treatment produced higher NH₄⁺?N concentrations in soil solution than the (NH₄)₂SO₄ and NaNO₃ treatment which indicated that DCD addition inhibited the nitrification process. Shoot Cd and Zn concentrations across all treatments showed ranges of 52.9–88.3 and 2691–4276 mg kg^?1, respectively. The (NH₄)₂SO₄+DCD treatment produced slightly higher but not significant Cd and Zn concentrations in the xylem sap than the NaNO₃ treatment. Plant shoots grown with NaNO₃ had higher Cd concentrations than (NH₄)₂SO₄+DCD treatment at 24.0 and 15.4 mg kg^?1, respectively. N fertilizer application had no significant effect on shoot dry biomass. Total Cd uptake in the urea+DCD treatment was higher than in the control, urea+NBPT, urea+NBPT+DCD, or urea treatments, by about 17.5, 23.3, 10.7, and 25.1%, respectively.     

氢醌和双氰胺对种稻土壤N2O和CH4排放的影响

通过盆栽试验,研究了脲酶抑制剂氢醌（ＨＱ）、硝化抑制剂双氰胺（ＤＣＤ）及二者的组合（ＨＱ＋ＤＣＤ）对种稻土壤Ｎ２Ｏ和ＣＨ４排放的影响．结果表明,在未施麦秸粉时,所有施抑制剂的处理均较单施尿素的能显著减少水稻生长期供试土壤Ｎ２Ｏ和ＣＨ４的排放．特别是ＨＱ＋ＤＣＤ处理,其Ｎ２Ｏ和ＣＨ４排放总量分别约为对照的１／３和１／２．而在施麦秸粉后,该处理的Ｎ２Ｏ排放总量为对照的１／２,但ＣＨ４排放总量却较少差别．不论是Ｎ２Ｏ还是ＣＨ４的排放总量,施麦秸粉的都比未施的高出１倍和更多．因此,单从土壤源温室气体排放的角度看,将未腐熟的有机物料与尿素共施,并不是一种适宜的施肥制度．供试土壤的Ｎ２Ｏ排放通量,与水稻植株的ＮＯ－３Ｎ含量和土表水层中的矿质Ｎ量分别呈显著的指数正相关和线性正相关;ＣＨ４的排放通量则与水稻植株的生长量和土表水层中的矿质Ｎ量呈显著的线性负相关．在Ｎ２Ｏ与ＣＨ４的排放间,未施麦秸粉时存在着定量的相互消长关系;施麦秸粉后,虽同样存在所述关系,但难以定量化．