Evaluation of calibrated passive sampling for quantifying ammonia emissions in multi-plot field trials with slurry application

Background

There is a great need for simple and inexpensive methods to quantify ammonia emissions in multi-plot field trials. However, methods that meet these criteria have to be thoroughly validated. In the calibrated passive sampling approach, acid traps placed in the center of quadratic plots absorb ammonia, enabling relative comparisons between plots. To quantify ammonia emissions, these acid trap samplings are scaled by means of a transfer coefficient (TC) obtained from simultaneous measurements with the dynamic tube method (DTM). However, dynamic tube measurements are also comparatively costly and time-consuming.

Aims

Our objective was to assess the best practice for using calibrated passive sampling in multi-plot field trials. One particular challenge in such experiments is to evaluate the influence of ammonia drift between plots.

Methods

In a series of eight multi-plot field trials, acid traps and DTM were used simultaneously on all plots to measure ammonia emissions caused by different slurry application techniques. Data obtained by both methods were correlated, and the influence of the ubiquitous ammonia background on both methods was evaluated by comparing net values, including the subtraction of the background with gross values (no background subtraction). Finally, we provide recommendations for calculating a TC for calibrating relative differences between plots, based on simultaneous acid trap and dynamic tube measurements on selected plots.

Results

Treatment mean values obtained by both methods correlated well. For most field trials, R² values between 0.6 and 0.8 were obtained. Ammonia background concentrations affected both methods. Drift between plots contributed to the background for the acid traps, whereas the contamination of the chamber system might have caused the background for the DTM. Treatments with low emissions were comparatively more affected by that background.

Conclusion

For a robust application of calibrated passive sampling, we recommend calculating the TC based on a treatment with high ammonia emissions, reducing the relative influence of the ubiquitous ammonia background.     

Crop nitrogen recovery and soil nitrogen dynamics in a 10‐year field experiment with biowaste compost

When fertilizing with compost, the fate of the nitrogen applied via compost (mineralization, plant uptake, leaching, soil accumulation) is relevant both from a plant‐production and an environmental point of view. In a 10‐year crop‐rotation field experiment with biowaste‐compost application rates of 9, 16, and 23 t ha^–1 y^–1 (f. m.), the N recovery by crops was 7%, 4%, and 3% of the total N applied via compost. Due to the high inherent fertility of the site, N recovery from mineral fertilizer was also low. In the minerally fertilized treatments, which received 25, 40, and 56 kg N ha^–1 y^–1 on average, N recovery from mineral fertilizer was 15%, 13%, and 11%, respectively. Although total N loads in the compost treatments were much higher than the N loads applied with mineral fertilizer (89–225 kg N_tot ha^–1 y^–1 vs. 25–56 kg N_tot ha^–1 y^–1; both on a 10‐year mean) and the N recovery was lower than in the treatments receiving mineral N fertilizer, soil NO ‐N contents measured three times a year (spring, post‐harvest, autumn) showed no higher increase through compost fertilization than through mineral fertilization at the rates applied in the experiment. Soil contents of N_org and C_org in the plowed layer (0–30 cm depth) increased significantly with compost fertilization, while with mineral fertilization, N_org contents were not significantly higher. Taking into account the decrease in soil N_org contents in the unfertilized control during the 10 years of the experiment, 16 t compost (f. m.) ha^–1 y^–1 just sufficed to keep the N_org content of the soil at the initial level.     

华北平原春玉米种植体系中土壤无机氮的时空变化与盈亏

在华北平原北部高肥力土壤条件下,研究了不同氮肥管理模式（包括不施氮、推荐施氮和经验施氮）对春玉米物质生产、土壤无机氮时空动态、氮素盈亏和平衡的影响。结果表明：1）推荐施氮和经验施氮未能显著提高春玉米产量,但显著提高了总吸氮量,而氮素收获指数与总吸氮量呈相反趋势。2）春玉米生长季内,土壤铵态氮含量始终处于较低水平,土壤中无机氮形态以硝态氮为主;全生育期内的土壤硝态氮含量,经验施氮均明显高于其它施氮措施,推荐施氮居中,不施氮最低。3）受土壤肥力和天气的影响,春玉米生长期间土壤硝态氮会发生大幅度的垂直运移,潜在淋洗量很大。4）不施氮处理中土壤矿化量占总吸氮量的75％,其中绝大部分矿化集中于春玉米生育后期,土壤Nmin残留量比播前起始值下降了21．4％;经验施氮中施氮量过大造成大量的损失,表观损失率高达42．6％,残留率为48．60k;而推荐施氮处理不仅能够保持产量和土壤供氮能力的稳定,更减少了氮素损失的可能。     

The dynamics of soil-soluble nitrogen and soil-retained nitrogen in greenhouse soil

Field experiments were conducted to determine the effects of nitrogen (N) fertilization and manure addition on the soil-soluble nitrogen (SSN) (soil mineral N (SMN); soil-soluble organic N (SSON)) and soil-retained N (SRN) (soil fixed ammonium; soil microbial biomass N). The combined application of manure and inorganic N (different N fertilizer rates: M3N0, M3N1, M3N2, and M3N3; different manure rates: M0N2, M1N2, M2N2, and M3N2) was used in a greenhouse fertilization experiment. SSN and SRN increased with increasing N rate up to M3N2. SSON decreased with increasing manure rate and was the highest in the M1N2, whereas SMN and SRN were the highest in the M3N2, and increased with increasing manure rate on all sampling dates. Both SSN and SRN declined significantly with increasing soil depth in the different application rates of manure (p < .05). Moreover, the SSN and SRN significantly varied with plant growth and followed a different pattern during the growing season. SSN and FA peaked in the first ear fruit period, but SMBN was at its highest level in the second ear fruit period. There was a significant positive relationship (p < .05) between SSN and SRN throughout the plant growing season, and the annual apparent loss of N in the M3N3 was the highest. The combined application of inorganic N fertilizer and manure at an appropriate rate may be an effective strategy for maintaining the long-term health of greenhouses.     

Soil mineral nitrogen dynamics in fallow periods in a rainfed semiarid Mediterranean agricultural systems

Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events.As an agronomic practice,fallow periods can be included even within the existing European Union common policy for crop diversification.This study aimed to quantify the effects of previous mineral fertilization on soil mineral nitrogen (Nmin) content and potential nitrate leaching during no-till fallow periods of crop rotation.The Leaching Estimation and Chemistry Model (LEAC...     

Impact of cattle slurry acidification on carbon and nitrogen dynamics during storage and after soil incorporation

Acidification of animal slurry is recommended in order to reduce NH₃ emissions, but relatively little is known about the effect of such treatment on C and N dynamics during acidification, storage, and after soil application. A laboratory study was performed, and the CO₂ emissions from a high–dry matter slurry (HDM), a low–dry matter slurry (LDM), and the same respective acidified slurries (AHDM and ALDM) were followed during a storage period and after soil incorporation. The N‐mineralization and nitrification processes, as well as microbial‐biomass activity were also estimated in soil receiving both the acidified and nonacidified materials. We observed a strong CO₂ emission during the acidification process, and acidification led to a small increase in CO₂ emissions (≈ 11%) during storage of AHDM relative to HDM. No effect of LDM acidification on CO₂ emissions during storage was observed. About 30% of C released during storage of AHDM was inorganic C, and for ALDM the C release was exclusively inorganic. Soil application of AHDM and ALDM led to a decrease in soil respiration, nitrification, and microbial‐biomass‐C values, relative to soil application of HDM and LDM, respectively. Furthermore, it was shown that this effect was more pronounced in ALDM‐ than AHDM‐treated soil. Considering both steps (storage and soil application), acidification led to a significant decrease of C losses and lower C losses were observed from LDM slurries than from HDM slurries.     

麦秆还田氮肥运筹对水稻产量及土壤氮素供应的影响

通过田间对比试验,研究了小麦秸秆全量还田后不同N肥运筹模式对水稻生长及土壤N素供应的影响。结果表明,小麦秸秆全量还田使水稻增产5.3%,且N肥运筹模式由传统模式A(基蘖肥:穗肥=5:5,基肥:分蘖肥=6:4)优化为B(基蘖肥:穗肥=6.5:3.5,基肥:分蘖肥=8:2)时,增产幅度更大,达9.3%。秸秆全量还田主要通过提高水稻结实率和成穗率,增加有效穗数,实现水稻增产。秸秆还田影响了水稻生长进程,表现为抑制水稻前期(孕穗期)生长和N素累积,而促进后期生物量增加和N素累积。同一时期,N肥模式B水稻生物量、N素累积量均高于模式A。秸秆全量还田后,土壤矿质N发生变化,水稻生育前期较不还田处理(CK)低,而后期较CK高,且N肥运筹模式B较A高。秸秆还田提高了N肥利用率,RNA、RNB分别比CK增加4.1和8.6个百分点,且土壤N素表观盈余量表现为:RNBRNACK。因而,小麦秸秆全量还田,并采用N肥运筹模式B,是实现水稻高产,维持土壤N素平衡的有效措施。     

长期施肥对土壤微生物生物量碳、氮及矿质态氮含量动态变化的影响

利用位于陕西杨凌的17年长期定位试验研究了长期不施肥(CK)、单施化肥(F)、化肥配施有机肥(F+M)和化肥加秸秆还田(F+S)处理对小麦-玉米轮作体系中作物不同生长时期土壤微生物生物量碳、氮(SMBC、SMBN)和矿质态氮含量的影响。结果表明,0—10 cm土层土壤SMBC、SMBN和矿质态氮含量的变化范围分别为264.8~752.2、37.51~14.8和3.83~8.5 mg/kg。不同处理相比,F+M处理中各采样时期(小麦苗期、拔节期、灌浆期及玉米播种期、大喇叭口期、灌浆期和收获后)土壤SMBC和SMBN含量均为最高,分别为不施肥对照的1.382~.65和1.892~.50倍;F+S处理矿质态氮含量最高,SMBC和SMBN也高于F和CK处理,大部分采样时期的差异达显著水平(P0.05);与CK相比,长期单施化肥也使各时期SMBC和SMBN含量提高。在小麦拔节期到灌浆期的旺盛生长阶段各施肥处理土壤SMBN含量均下降,而矿质态氮含量变化不大,处于较低水平;在玉米大喇叭口期到灌浆期的旺盛生长阶段,F+M、F+S和F处理土壤矿质态氮含量显著下降,而SMBN含量均有所升高。表明在土壤矿质态氮含量较高时,作物首先利用矿质态氮,而在土壤矿质态氮含量处于较低水平时,微生物固持的氮素可能会释放出来供作物吸收利用。     

Comparison of field techniques for sampling soil solution in an upland peatland

Abstract. Results from recent studies of peatland biogeochemistry suggest that appropriate soil water sampling techniques are required in order to advance our understanding of peatland soil systems. In a comparative field experiment, concentrations of inorganic solutes and dissolved organic carbon (DOC) were measured in soil water extracted at a depth of 10 cm beneath the surface of deep peat by three techniques: zero-tension (z-t) lysimeters, PTFE suction samplers, and polysulfone suction samplers. The majority of solute concentrations were broadly similar, but mean concentrations of silicon, DOC, iron and aluminium in water extracted by z-t lysimeters and PTFE samplers were in ratios of 1:5; 1:2; 1:5 and 1:3 respectively. Mean conductivity and concentrations of chloride and hydrogen ion were significantly larger in the z-t lysimeter samples, which had sodium, potassium and magnesium to chloride ratios that were very similar to local rainfall. The z-t lysimeters appeared to sample macropores preferentially, while the suction samplers collected micropore water.     

Simulating site-specific nitrogen mineralization dynamics in a Swedish arable field

Abstract

The objective of this work was to test whether a dynamic soil C and N model using site-specific information improved estimates of apparent net N mineralization compared with regressions only based on static soil properties. This comparison was made using data from a 34-point sampling grid within a Swedish arable field during two growing seasons, using a simple carbon balance and nitrogen mineralization model (ICBM/N) for the dynamic approach. Three free model parameters were simultaneously optimized using non-linear regression to obtain the best model fit to the data from all grid points and both years. Calculated annual mean net mineralization (Nm_sim) matched the measured Nm mean exactly, and was 44 and 71 kg N ha^?1 for the two growing seasons 1999 and 2000, respectively. However, the variability in calculated Nm_sim values among the 34 grid points was smaller than that measured, and only a small proportion of the variation within a single year was explained by the model. Despite this, the model explained 56% of the total variation in Nm during the two growing seasons, mainly due to the good fit to the seasonal overall difference. Significant factors influencing net mineralization included the soil environment controlling mineralization, total N in soil organic matter and N in crop residues. Uncertainties in estimation of θ _fc and θ _wp (soil water content at saturation and wilting point) and the possible influence of unknown horizontal and vertical water flows made high-precision calculations of soil water content difficult. The precision and general applicability of the actual measurements thus set limits for estimating critical parameters, and the limitations of both the experimental design and the model are discussed. It is concluded that improvements in precision in sampling and analysis of data from the grid points are needed for more critical hypothesis testing.     

新疆绿洲区连续五年施用沼液对农田土壤质量的影响

以施用化肥为对照,通过5年田间小区试验,研究沼液灌溉对绿洲设施蔬菜地土壤质量的影响。试验结果表明:连续施用沼液能够有效调节绿洲农田耕层土壤酸碱度,有利于改良碱性土壤;沼液灌溉能够显著提高设施蔬菜地土壤肥力,尤其是表层土壤中有机质和全氮、全磷、速效氮、有效磷、速效钾、钙、铁、锌和铜等植物必需营养元素含量;然而,连续施用沼液也会导致表层土壤电导率显著升高,土壤中重金属元素显著积累,虽然5年内设施蔬菜地土壤盐分和重金属等有害元素含量均在蔬菜种植允许范围内,但随着沼液灌溉年限的增加,土壤存在次生盐渍化现象和重金属超标风险,尤其以Cd、As和Ni的风险最大。     

沼液配施化肥对太湖地区水蜜桃品质及土壤氮素累积的影响

将沼液农田回用是有机废弃物资源化与循环利用的重要途径。以7年生蜜露桃树为供试材料,通过连续2年牛粪沼液和水葫芦沼液的果园田间施用试验,研究等氮量条件下不同比例沼液与化肥配施对水蜜桃果实大小、 单重、 产量和果实品质及土壤矿质氮积累状况的影响。结果表明, 1）水葫芦沼液、 牛粪沼液和化肥配施可提高水蜜桃的产量与品质,在水葫芦沼液25% 配施比例、 牛粪沼液50% 配施比例下产量及果实的可溶性固形物、 糖分含量分别为最高,水葫芦及牛粪沼液中的水分含量是影响桃树产量和品质的关键因子,其适宜用量为200 kg/(planta); 2）各施肥处理土壤NH+4含量随土壤深度增加呈递减趋势; 沼液比例过高（75%和100%）会导致土壤硝酸盐在表层和近地下水层的累积,比例低下则硝酸盐累积不明显; 习惯施肥（过量施肥）和低比例沼液（相应的高化肥比例）处理硝酸盐主要累积于犁底层之上; 3） 连续2年在沼液灌溉条件下,25%的水葫芦沼液、 50%的牛粪沼液配施比例处理其近地下水层土壤硝酸盐含量均低于15 mg/kg,处于安全可控范围,但在该地区（高地下水水位）进行长期沼液灌溉尚需进一步观测和评价。     

Injection of pig slurry and its effects on dynamics of nitrogen and carbon in a loamy soil unter laboratory conditions

Dynamics of nitrogen (N) and carbon (C) were investigated in a loamy soil amended or injected with pig slurry. Treatments were with or without acetylene C₂H₂ (which is assumed to inhibit reduction of nitrous oxide (N₂O) to dinitrogen (N₂), and soil cores were conditioned for 15 days at 25°C while pH, production of CO₂ and N₂O, ammonia (NH₃) emission and (nitrate) (NO₃ ^–) and (ammonium) (NH₄ ⁺) concentrations were monitored. There was no significant difference in CO₂ production between the injected and surface applied pig slurry treatments, and within 15 days ca. 5% of the C applied had been mineralized, if no priming effect was assumed. Neither the production of N₂O nor the total gaseous production of the denitrification process (N₂O plus N₂) were affected by the way the pig slurry was added to the soil. NH₃ volatilization, however, decreased by 90% when pig slurry was injected. The addition of C₂H₂ significantly increased the CO₂ production and the concentration of NH₄ ⁺, but significantly decreased the concentration of NO₃ ^–. It was concluded that the injection of pig slurry to a dry soil was an acceptable alternative to its application to the soil surface, as not only was NH₃ volatilization reduced, but the production of N₂O and N₂ through denitrification was not stimulated. It is also suggested that the composition of the organic C fraction in the pig slurry, most likely the concentration of fatty acids, had an important effect on the dynamics of N and C in the soil. Received: 12 May 1997     

沼液化肥配施对芦笋地土壤肥力及芦笋品质的影响

针对芦笋种植过程中大量化肥长期施用所造成的土壤肥力退化和芦笋品质下降的问题,以沼液有机替代化肥来研究相同氮磷钾养分施用的前提下,沼液不同用量替代化肥施用对芦笋地土壤肥力及芦笋品质的影响。试验设不施肥处理（CK）、常规施肥处理（NPK）、沼液全氮替代化肥施氮质量25%、50%、75%和100%的处理,共6个处理,分析了沼液替代化肥施用条件下,沼液不同用量对土壤理化性质、微生物量、酶活性、重金属含量及芦笋品质的影响。结果表明：与常规施肥（NPK）处理相比,沼液替代化肥用量≥50%的处理显著增加了土壤有机质的质量分数32.7%～41.5% （P<0.05）,但其对土壤全氮、全磷和全钾质量分数无显著影响（P>0.05）;同时,沼液替代量75%和100%的处理显著提高土壤pH值0.72和1.0,并显著提高土壤速效钾质量分数48.6%和48.8%（P<0.05）,而其对土壤碱解氮和有效磷质量分数没有显著影响（P>0.05）。与不施肥（CK）处理相比,常规施肥、沼液替代化肥施用各处理均能增加土壤蔗糖酶的活性,但沼液替代化肥用量≥50%的处理均显著降低了土壤酸性磷酸酶的活性（P<0.05）,而对土壤脲酶和过氧化氢酶活性影响均不显著。与NPK处理相比,沼液替代化肥施用显著提高了土壤微生物生物量碳和氮的含量20.2%～61.2%和28.8%～162.0%（P<0.05）,但沼液替代量≥50%处理的土壤微生物碳/氮比值与NPK处理相比都显著降低了31.4%～38.6% （P<0.05）。常规施肥、沼液替代化肥施用对芦笋地表层土壤重金属Cu、Cr、Cd、Ni、Pb和Zn的含量均无显著影响。与NPK处理相比,75%和100%沼液替代化肥处理芦笋嫩茎中显著增加了可溶性蛋白含量111.1%和155.6%,并显著提高微量元素Zn的含量27.8%和30.0%（P<0.05）。可见,沼液替代化肥施用能够显著提高芦笋地土壤有机质和速效养分的含量,促进芦笋地土壤肥力水平的提高,以及芦笋可溶性蛋白和Zn含量的提高,优化芦笋品质,其中以沼液替代量≥75%效果较好。可见,沼液化肥配施能够提升土壤肥力水平,促进芦笋品质的提高。     

施氮水平对黄土旱塬区小麦产量和土壤有机碳、氮的影响

施用氮肥是雨养农业区提高作物产量和土壤有机碳（SOC）、氮[TSN（Total soil N）]含量的重要养分管理措施。利用长期田间试验（1984～2007）,定量评价了常规耕作条件下5个施氮水平N 0（N0）、45（N45）、90（N90）、135（N135）和180（N180）kg/hm2处理下,小麦子粒产量、SOC、TSN和氮肥利用效率的变化。研究了施氮水平对黄土旱塬区旱地小麦产量、SOC和TSN积累的影响。结果表明,1984～2007年期间,N0、N45、N90、N135和N180处理小麦产量的平均值依次为1.2、2.4、2.9、3.2和3.4 t/hm2;N0处理的小麦产量随试验年限而降低,年降低幅度达67 kg/hm2（P0.001）;但增施氮肥后降低趋势得到显著控制,当施氮水平提高到N 90 kg/hm2时,产量随年限呈现出缓慢升高的趋势。随着施氮水平的提高,地上部氮肥利用率由40%（N45处理）降低到28%（N180）。不同施氮水平条件下,SOC含量随年限呈缓慢升高趋势。23年后（2007年）,N0、N45、N90、N135和N180处理下,0—20 cm土层SOC储量依次为16.9、18.2、18.7、19.0和19.1 t/hm2;TSN储量依次为2.03、2.16 、2.24 、2.34和2.37 t/hm2。施氮水平与产量呈显著的抛物线关系（R2＝0.993）。产量与SOC存在着极显著的线性相关关系（R2=0.997）。增施N 1 kg/hm2,小麦产量可提高29 kg/hm2,SOC提高1.2 kg/hm2,TSN提高0.13 kg/hm2。根茬还田量的增加是导致黄土旱塬区SOC和TSN提高的主要因素。     

猪场废水灌溉对潮土硝态氮含量变化的影响

该文应用猪场废水处理工艺中3个阶段的出水（原水—猪圈舍干清粪后冲洗直接流入积水池的水;厌氧水—原水经厌氧池处理后的出水;仿生态塘水—经曝气和植物吸收处理的厌氧水）与地下水1︰5（体积比）配比和厌氧水不同灌溉量进行冬小麦小区灌溉试验,通过监测土壤硝态氮含量动态变化和残留量筛选适宜的混合水类型和厌氧水灌溉量,为制定合理的猪场废水灌溉制度提供理论依据。试验结果表明：应用3种混合水灌溉0～100 cm土壤剖面硝态氮含量随深度增加呈现“S”形变化趋势,小麦收获后各层土壤硝态氮含量均比初始值有所增加;收获后3种混合水灌溉处理0～100 cm土层中的硝态氮累积量比拔节期均有很大增加,仿生态塘水︰地下水1︰5处理变化幅度最小,较适宜灌溉;厌氧水灌溉量与土壤中硝态氮淋溶量和残留量成正相关关系,中灌水量（500 m3/hm2）较适宜。灌浆期灌水大大增加了收获后土壤中的硝态氮含量,灌浆期宜使用地下水灌溉。     

稻田土壤养分空间变异与合理取样数研究

以嘉善县陶庄农场内一块0.52hm2的水稻田为研究区,采用地统计方法和常规统计方法进行土壤pH及养分(全氮、全碳、速效钾、速效磷、速效镁、速效锰、速效铜、速效锌)的空间变异及其合理取样数目研究。结果表明,各土壤养分在田间尺度均存在一定的空间变异,全氮、全碳、速效钾、速效磷等主要养分的空间格局呈南北向条带状,与农户经营田块的方向基本一致;不同农户耕种、管理下的4田块的土壤养分差异显著;反映土壤肥力的土壤全碳、全氮等养分的合理取样数目在95%的置信度和5%的相对误差条件下为45～个,基本上每个农户经营田块为1个,即可反映土壤养分的真实情况。因此,试验区以N素管理为主的精确田间管理的土壤采样可以采用以农户经营地块为单位的混合样采样方式,以减少土壤采样量和分析成本。