施用羊粪条件下人工草地土壤硝态氮淋失量研究

采用SRC（Soil-Resin-Core）装置，研究了三峡库区草畜配套体系中羊粪还田量与硝态氮淋失量的关系。研究结果表明，有机肥本身即可产生硝态氮在土壤中的累积，羊粪施肥量越高，土壤硝态氮累积量和全氮含量就越高。随着施肥次数的增加，全氮含量整体呈上升趋势，硝态氮含量因降雨、气温和牧草生长等因素的影响，存在明显的季节性。元月份土壤中的硝态氮含量显著高于其它季节。相关分析表明：土壤全氮和硝态氮含量影响20cm土层中硝态氮的淋失量，三者之间呈显著正相关关系；施肥提高了人工草地的产草量，但施肥量过高，草地产量下降，增加了氮素损失的可能性。在一定的产草量下，人工草地可容纳的羊粪量高于单位土地面积承载羊只所产生的羊粪量。说明在三峡库区发展集约化的种草养羊业，羊粪直接还田，从资源环境的角度分析是可行的。     

桓台县高产农田土壤硝态氮淋失动态研究

试验研究高产农田生态系统条件下N肥施用量和秸秆还田对土体硝态氮（NO3^--N）的时空分布动态结果表明，NO3^- -N含量在空间上随土壤深度而降低，这一相关关系可用Y=aX^b函数表达。小麦-玉米2季秸秆还田同单季小麦秸秆还田对NO3^- -N的动态影响较小，但相同施N量下未进行玉米秸秆还田0-40cm土层土壤中NO3^- -N含量偏高，土体NO3^- -N有淋失较强的趋势。土体NO3^- -N含量年度内波动大小与施N量密切相关，0-40cm土层土壤内NO3^- -N含量起伏最大，60cm土层以下相对稳定。各土层内NO3^- -N含量与施N量相关密切，这一相关关系影响到2m土层深度。土体中NO3^- -N含量周年内出现2次峰值和1次低谷，峰值出现在玉米和小麦收获后，低谷发生在小麦苗期-开花期土体养分大量吸收时期。9月下旬2m土层土壤NO3^- -N含量可高达10mg/kg，而且有淋失出2m土体的趋势。     

不同水氮用量对日光温室黄瓜季硝态氮淋失的影响

于2010年3～7月,在河北省辛集市马庄农场研究了不同水氮用量对黄瓜季硝态氮淋失的影响,结果表明,通过调节不同生育阶段灌水量使黄瓜全生育期土壤含水量保持在18.7%～22.1%,不仅可以满足黄瓜生长发育对土壤水分的要求,而且可以减少用水量30%。不同处理中以节水灌溉、习惯施氮处理（W2N1）土壤硝态氮含量最高,习惯灌水、减量施氮处理（W1N2）最低。全生育期内,土体95cm深度硝态氮淋失量与土壤含水量、土壤硝态氮含量均呈正相关,其中以初瓜期和盛瓜期相关性系数最高。与农民习惯水氮处理（W1N1）相比,节水减氮处理（W2N2）在节水30%减施氮25%的情况下,可以显著降低黄瓜季土壤硝态氮淋失量,整个生育期降低淋失量35.0%。3年连续试验结果表明,节水减氮处理（W2N2）与习惯水氮处理（W1N1）间黄瓜产量结果差异不显著,说明河北省温室大棚蔬菜生产,目前农民习惯施氮和灌水量有很大的节水节肥空间,根据蔬菜不同生育期需肥量和土壤含水量来合理分配水、氮可取得明显的节水节氮效果。     

不同温度及灌水量对土壤硝态氮淋失动态研究

应用＾１５Ｎ－尿素，采用土柱模拟试验，研究了不同温度及灌水量条件下土壤中硝态氮淋失动态，结果表明，土壤中硝态氮很容易随灌水而下渗，灌水量越多，下层土壤中硝态氮的浓度就越高；在施氮量相同的情况下，当温度上升时，土壤中硝态氮的浓度也高，更容易淋失。     

长期施肥条件下华北平原农田硝态氮淋失风险的研究

利用河北辛集潮土(21年)和北京昌平褐潮土(9年)两个长期定位施肥试验研究了华北平原冬小麦夏玉米轮作体系下农田氮素平衡和硝态氮淋失风险。结果表明,单施氮肥的增产效果有限,昌平试验点甚至出现减产现象;而适量有机肥与氮磷或氮磷钾配施可显著提高作物产量,降低氮素盈余。单施氮肥时,辛集和昌平土壤硝态氮峰值分别达20.7和30.0.mg/kg,出现在160200.cm和90120.cm土层;硝态氮累积量高且大部分集中在根区外土壤,硝态氮淋失风险大。氮磷或氮磷钾肥配施时,硝态氮峰值出现深度上移3040cm,根区和根区外土壤硝态氮累积量均大幅降低,淋失风险明显减弱;在氮磷或氮磷钾肥基础上适量施用有机肥时,硝态氮峰值出现深度进一步上移至根区土壤,深层土壤硝态氮累积量显著下降,淋失风险低。过量施用有机肥或过量施用氮肥时,深层土壤硝态氮累积量大幅增加,甚至超过单施氮肥处理,淋失风险大大增强。研究结果表明,氮磷钾肥与有机肥配合施用是提高作物产量、控制农田硝态氮淋失的重要途径。     

高产农田土壤硝态氮淋失与地下水污染动态研究

对桓台县区域农田监测研究表明,水肥管理不同的2个监测区域郭家区、李家区高产农田土体内NO_3~--N淋失迁移动态有差异,地下水污染亦不同。春天始土体内NO_3~--N含量趋于持续降低,浅层地下水NO_3~--N含量则持续升高,雨季后地下水中NO_3~--N含量尤剧烈升高,并达年内最高值,表现出农田N肥对地下水的直接污染,这可能与李家区灌溉次数多、土壤质地较轻和地下水位较浅有关。     

不同施磷量对蔬菜地土壤硝态氮淋失的影响

【目的】在两种蔬菜地土壤上研究不同磷肥施用量对土壤硝态氮淋失的影响,为武汉城郊蔬菜合理施用磷肥和安全生产提供理论依据。【方法】利用大型原状土柱渗漏装置,2种实验土壤(粉质粘土和粉质粘壤土)均为武汉城郊典型蔬菜土壤,分别采自华中农业大学校内蔬菜基地和湖北新洲。试验期间共种植了四种蔬菜(小白菜、 辣椒、 苋菜及萝卜)。试验设置了4个P2O5水平处理(0、 125、 250、 375 kg/hm2),氮肥施用量均为N 750 kg/hm2,钾肥施用量均为K2O 500 kg/hm2。试验期间年降雨量为1043.0 mm,各土柱总灌溉量为120.1 L。秋冬季每15天、 春夏季每10天收集一次淋洗液,另外根据天气和降雨情况适当调节,每次收集淋洗液时记录淋洗液体积并测定淋洗液硝态氮浓度。在每季蔬菜生长成熟后将蔬菜收获称重,烘干后测定蔬菜中氮素含量。【结果】1)与不施磷肥相比,施用磷肥显著增加了两种土壤上小白菜、 苋菜、 萝卜产量以及四季蔬菜总产量,其产量随磷肥施用量增加而增加或显著增加,在磷肥施用量最大时产量达到最大值。粉质粘土上的产量显著低于粉质粘壤土上的产量,粉质粘壤土总产量约是粉质粘土总产量的1.63~2.36倍。2)施用磷肥显著增加了小白菜、 苋菜氮素吸收累积量以及四季蔬菜总吸收累积量,且两种土壤上总氮素吸收累积量均在磷肥施用量最大时达到最大值。粉质粘壤土上氮素总吸收累计量显著高于粉质粘土上氮素总吸收累积量。3)磷肥水平对土壤总渗漏液体积并无显著影响(粉质粘壤土P2O5 125 kg/hm2处理除外),粉质粘土渗漏水量显著大于粉质粘壤土。4)施用磷肥降低或显著降低土壤淋失液硝态氮浓度(粉质粘土苋菜季除外),随着磷肥施用量的增加硝态氮淋失浓度不断降低,4季蔬菜平均淋失浓度最大降低了38.6%(粉质粘土)和28.8%(粉质粘壤土)。5)磷肥施用显著降低了两种土壤上硝态氮淋失量(苋菜季除外),且在粉质粘土上随着磷肥施用量的增加硝态氮淋失量不断降低,而在粉质粘壤土上硝态氮淋失量先降低后上升。粉质粘土硝态氮淋失量显著大于粉质粘壤土,磷肥施用降低硝态氮淋失量分别达到达26.4%~33.7%和23.5%~39.9%。【结论】磷肥施用增加了蔬菜产量和作物氮素吸收累积量,从而显著降低了两种土壤上硝态氮的淋失; 土壤质地对硝态氮淋失有较大影响,质地较轻的粉质粘壤土硝态氮淋失显著小于质地较重的粉质粘土; 粉质粘壤土上施用P2O5量为250 kg/hm2时能提高产量同时减少硝态氮淋失,而粉质粘土上施用P2O5量为375 kg/hm2时能获得较大产量和较少硝态氮淋失量。     

重庆市主要土壤类型硝态氮淋失及其影响因素

采用SRC(Soil-Resin-Core)装置,研究了重庆市主要土壤类型硝态氮淋失的差异以及硝态氮淋失与硝态氮含量、有效氮含量、降雨和气温等4个方面的关系。结果表明:酸性紫色土的硝态氮淋失量最大,而黄壤与碱性紫色土的硝态氮淋失量较小。酸性紫色土硝态氮含量、有效氮含量与硝态氮淋失量之间显著相关,而黄壤和碱性紫色土的硝态氮含量、有效氮含量与硝态氮淋失量之间没有显著的相关性。降雨量、气温也是引起硝态氮淋失的原因。农田施肥对地下水的污染受施肥量、施肥次数、降雨量和气温等综合作用的影响,可采取控制氮肥用量,减少施用人粪尿,避免在降雨量大的时期追肥的措施。     

红壤旱地施用有机肥的氮素淋失过程

随着我国畜禽养殖业的发展,畜禽排泄物产量不断增加,从1980年的6·9亿t增加至2002年的41亿t,2002年的畜禽粪便产生量是工业有机污染物的4·1倍,成为农业氮磷面源污染的主要来源[1,2]。农田土壤硝酸盐的淋失是我国地下水硝酸盐污染的一个重要原因[3]。国内外在化肥氮素淋失方面开展了大量的研究。在施用有机肥的氮素淋失方面,国外主要利用试验和模型研究不同管理措施对养殖场、牧场和农田的氮素迁移的影响[4~8],提出有机肥的区域管理措施和对策[9~10]。而国内主要利用室内培养试验或短期试验观测农田土壤氮素迁移,利用长期试验对有机肥氮素迁移的研究主要针对秸秆[11~14]。由于有机氮在土壤中     

漓江水陆交错带硝态氮淋失规律的模拟研究

以广西桂林市潜经村漓江水陆交错带为研究区域,按照不同淹没程度将水陆交错带分为重度淹没带(T_1)、中度淹没带(T_2)、轻度淹没带(T_3),运用室内土柱模拟试验,研究不同淹没带、不同尿素施肥量、不同价态阳离子对硝态氮(NO_3~--N)淋失的影响。结果表明:(1)在正常施肥条件下,重度淹没带NO_3~--N淋失量最大(117.5kg/hm~2),显著高于中度淹没带(108.0kg/hm~2)和轻度淹没带(102.7kg/hm~2)淋失量。(2)随着施肥量增加NO_3~--N淋失量显著增加,当施肥量分别是140kg/hm~2,180kg/hm~2,220kg/hm~2时,NO_3~--N淋失比值为1∶1.35∶1.94。(3)土壤中阳离子Na~+、Ca~(2+)的存在可显著减少11.38%~18.31%的NO_3~--N淋失量,但不同价态阳离子之间对NO_3~--N淋失量的影响差异不显著。(4)随着淹没程度减小土壤容重逐渐降低,土壤粘粒含量逐渐增加,有机质则呈先减小后增加的趋势。在低、正常施肥处理下,NO_3~--N淋失量与土壤容重呈显著正相关,与土壤粘粒含量呈显著负相关;在高施肥处理下,NO_3~--N淋失量与土壤有机质含量呈显著负相关。     

上海郊区蔬菜田氮素流失的研

Nitrogen （N） leaching in vegetable fields from December 2002 to May 2003 with equal dressings of total N for a sequential rotation of Chinese flat cabbage （Brassica chinensis L. var. rosularis） and lettuce （Lactuca sativa L.） in a suburban major vegetable production base of Shanghai were examined using the lysimeter method to provide a scientific basis for rational utilization of nitrogen fertilizers so as to prevent nitrogen pollution of water resources. Results showed that leached N consisted mainly of nitrate N, which accounted for up to more than 90% of the total N loss and could contribute to groundwater pollution. Data also showed that by partly substituting chemical N （30%） in a basal dressing with equivalent N of refined organic fertilizer in the Chinese flat cabbage field, 64.5% of the leached nitrate N was reduced, while in the lettuce （Lactuca sativa L.） field, substituting 1/2 of the chemical N in a basal dressing and 1/3 of the chemical N in a top dressing with equivalent N of refined organic fertilizers reduced 46.6% of the leached nitrate N. In the twoyear sequential rotation system of Chinese flat cabbage and lettuce, nitrate-N leaching in the treatment with the highest amount of chemical fertilizer was up to 46.55 kg ha^-1, while treatment plots with the highest amount of organic fertilizer had only 17.58 kg ha^-1. Thus, partly substituting refined organic fertilizer for chemical nitrogen in the first two seasons has a great advantage of reducing nitrate-N leaching.     

Nitrate leaching as affected by long-term N fertilization on a coarse sand

Abstract. A field experiment on a coarse sand (1987–92) was conducted with spring barley ( Hordeum vulgare L.), in order to evaluate the effects of increasing N fertilization on nitrate leaching under temperate coastal climate conditions. The N fertilizer levels were 60 and 120 kg N/ha. The experiment was conducted on a 19-year old permanent field trial with continuous spring barley, initiated in 1968, and included treatments with ploughing in autumn or spring, with or without perennial ryegrass ( Lolium perenne L.) as a catch crop undersown in spring. Prior to 1987, the low and high levels of N fertilizer were 70 and 150 kg N/ha, respectively. To calculate nitrate leaching, soil water samples were taken from a depth of 0.8 m using ceramic cups. The average annual nitrate leaching from plots with 60 and 120 kg N/ha was 38 and 52 kg N/ha/y, respectively. The increased leaching associated with increasing fertilizer application was not caused by inorganic N in the soil at harvest, but rather by greater mineralization, mainly in autumn. Growing of a catch crop was relatively more efficient for reducing nitrate leaching than a long-term low fertilizer application. A 50% reduction in N application decreased average yield by 26%, while nitrate leaching decreased by 27%.     

水稻油菜轮作稻田甲烷排放及其总量估算

利用静态箱/气相色谱法对川中丘陵区水稻油菜轮作稻田进行水稻全生长季CH4排放观测。结果表明,稻田CH4排放有明显的季节变化,呈“前低后高”的变化趋势,CH4排放峰出现在水稻抽穗扬花期;测定期内稻田CH4平均排放通量为6.20mg/m2.h。对影响稻田CH4排放的因素分析发现,淹水条件下水稻移栽到抽穗初期,水稻植株生长是影响稻田CH4排放的关键因素;水稻抽穗期到成熟期,温度是影响稻田CH4排放的关键因素。水稻油菜轮作稻田在水稻生长季中CH排放总量为173.96kg/hm2。     

中国北方农田氮磷淋溶损失污染与防控机制

突破厚包气带农田根层氮磷淋溶与地下水污染复杂定量关系和阻控机理是国际研究难点。本文系统梳理了重点研发专项"农田氮磷淋溶损失污染与防控机制"项目取得的主要进展,项目包括以下4方面研究内容:1)北方主要农区农田根层氮磷淋溶时空规律;2)根层—深层包气带氮磷淋溶机制和主控因子;3)黑土、潮土和褐土氮磷淋溶阻控机制及其效果; 4)典型农区氮磷淋溶风险与区域消减途径。主要科学发现包括:1)受土地利用类型、地下水埋深、包气带岩性、水文地质条件等综合因素的影响,黑土区、潮土区和褐土区根层氮磷淋溶规律与地下水硝酸盐超标率体现出空间不一致和较大差异性。黑土区虽然根层淋溶较小,然而受地形地貌影响,地下水水质对淋溶响应更强烈,应该进一步研究黑土区地下水水质对淋溶的响应机制。华北潮土区和褐土区厚包气带具有明显氮阻控能力,应该进一步加强厚包气带对氮磷淋溶减排机理与途径研究。2)基于长期施肥定位试验和12 m深观测井对包气带农田土壤氮盈余累积特征和淋失规律的研究发现,华北平原区的环境安全施氮量约为200kg(N)·hm~(-2)·a~(-1),超过环境安全阈值的多投入氮肥中有51%淋失到1m根层以下,不合理灌溉、强降水、大孔隙和裂隙是造成土壤硝酸盐淋溶的主要因素,对包气带累积硝态氮的淋失作用可影响至6m以下土层。3)利用深层取样和生物学方法结合,对厚包气带0～10.5m原位土壤微生物的反硝化活性和微生物区系组成的研究结果表明,表层土壤是微生物进行反硝化的主要场所,深层土壤中反硝化作用显著减弱,"碳饥饿"是限制底层土壤反硝化微生物丰度与活性的关键因素;室内培养试验证实添加碳源可有效激活土壤微生物的反硝化活性,为"根层截氮包气带脱氮"的淋溶阻控机理找到了突破口。4)利用黑土、潮土和褐土区氮磷淋溶阻控试验、全国农业面源污染国控监测网、北方农区地下水硝酸盐监测网和NUFER (NUtrient flows in Food chains, Environment and Resourcesuse)模型,提出了养分损失脆弱区区划和区域氮磷污染削减草案,可为农业绿色发展和面源污染阻控提供科学依据。     

雨养烟叶种植田无机氮淋溶特征

为了解烤烟种植下土壤氮淋溶与大田作物差异,评价烟田常规养分管理,探寻烟田无机氮淋溶的阻控策略。以贵州龙岗长期定位试验为平台,于2015—2017年开展常规管理下烟田氮素淋失及其影响因素研究。试验设5个处理:不施肥(CK)、化肥(NPK)、化肥+厩肥(NPK+M)、化肥+连作(NPK+L)、化肥+生物有机肥(NPK+BM)。结果表明,烟田全年无机氮淋溶量为3.62～6.08 kg/hm2,氮肥净淋溶率为0.09%～3.29%。无机氮的淋溶损失主要发生在烤烟生长季,尤其是5—6月,其占总淋溶量的40.33%～65.86%。烟田淋溶液中氮素形态主要是有机态,无机氮的比例平均仅为29.83%,缓苗期和旺长期(5—6月)淋溶液中无机氮比例高于烤烟成熟期(7—8月),前者无机氮比例平均33.00%,后者其平均为26.67%。降雨是影响烟田淋溶损失的主要因素,无机氮淋溶量与月降雨量呈非线性相关。施用化肥导致无机氮淋溶显著升高,有机肥配施化肥降低了土壤溶液淋溶,降低了氮肥淋溶损失。与烤烟玉米轮作处理相比,烤烟连作处理显著降低了土壤水淋溶,使氮肥净淋溶率降低59.57%。综上,目前烤烟常规管理下,雨养农...     

Nitrate leaching from a small catchment in central England

Abstract. Flow and nitrate concentrations were measured weekly for four years at twelve stream-water monitoring sites in a catchment in the English Midlands designated as a Nitrate Advisory Area. Farm surveys and satellite images have provided soil and land use information. Measurements show the nitrate load to be dominated by discharge, with large variability due to differing weather conditions from year to year. Within-year variability in nitrate concentrations is also related to weather conditions, with high concentrations when field capacity is reached if this occurs late in the year. There is also clear evidence of dilution of nitrate during intense storms. The effect of changing weather conditions makes it impossible to identify catchment-scale changes in leaching due to changes in agricultural practice over a period as short as four years. Measurements from a major spring in the catchment show an increasing trend in nitrate concentrations through the period. There is some evidence that the greatest N leaching to streams in the catchment is associated with intensive grassland on soils which are naturally poorly drained.     

长江中下游地区水稻田溶解态氮流失量的估算—以江苏省靖江市柏木乡为例

监测研究了长江中下游地区靖江市柏木乡典型水稻田施用N肥对地表水体的污染状况 ,并结合模型推求出该区降雨径流深度 ,由此估算水稻田溶解态N污染负荷量 ,稻田径流中N排放量为 36 .0 4kg/hm2 ,占N肥施用量的 17.3%。     

Contribution of dissolved organic nitrogen to N leaching from four German agricultural soils

Dissolved organic nitrogen (DON) substantially contributes to N leaching from forest ecosystems. However, little is known about the role of DON for N leaching from agricultural soils. Therefore, the aim of our study was to quantify the contribution of DON to total N leaching from four agricultural soils. Concentrations and fluxes of DON and mineral N were monitored at two cropped sites (Plaggic Anthrosols) and two fallow plots (Plaggic Anthrosol and Gleyic Podzol) from November 1999 till May 2001 by means of glass suction plates. The experimental sites were located near the city of Münster, NW Germany. Median DON concentrations in 90 cm depth were 2.3 mg l^—1 and 2.0 mg l^—1 at the cropped sites and 1.6 mg l^—1 and 1.3 mg l^—1 at the fallow sites. There was only a slight (Anthrosols) or no (Gleyic Podzol) decrease in median DON concentrations with increasing depth. Total N seepage was between 19 kg N ha^—1 yr^—1 and 46 kg N ha^—1 yr^—1 at the fallow sites and 16—159 kg N ha^—1 yr^—1 at the cropped sites. For the fallow plots, DON seepage contributed 10—21 % to the total N flux (4—5 kg DON ha^—1 yr^—1), at the cropped sites DON seepage was 6—21 % of the total N flux (6—10 kg DON ha^—1 yr^—1). Thus, even in highly fertilized agricultural soils, DON is a considerable N carrier in seepage that should be considered in detailed soil N budgets.     

An empirical model for estimating nitrate leaching as affected by crop type and the long-term N fertilizer rate

Abstract. An empirical model was developed for prediction of annual average nitrate leaching as affected by the long-term rate of N fertilization and crop type. The effect of N fertilization was estimated from annual values of nitrate leaching obtained from two Danish investigations of drainage from pipe drains with four rates of N fertilization on a loamy sand and sandy clay loam from 1973-89. The effect of crop at normal N fertilization was estimated from 147 observations of annual nitrate leaching obtained from field measurements. The nitrate leaching model consists of a relative N fertilization submodel and an absolute submodel for specific combinations of crop, soil and drainage at the normal rate of N fertilization. The relative submodel is Y/Y _lN= exp[0.7l(N/ N₁– I)], where Y is the nitrate leaching (kg N/ha per year) at fertilization rate N , and Y _IN and N₁ are the corresponding values at the normal rate of N fertilization. The relative submodel is valid for cereals, root crops and grass leys fertilized with mineral fertilizer at N/N ₁ < 1.5, and on the prerequisite that the fertilization rate N has been constant for some years. To illustrate the use of the relative leaching submodel, estimated values of Y _IN corrected to mean annual drainage for 1970 to 1990 in Denmark for spring cereals and grass on sandy and loamy soils are given as input to the relative leaching submodel. The model can be used for sandy to loamy soils to estimate the mean nitrate leaching over a number of years.