天津市水体硝酸盐污染调查与空间分布研究

通过现场采样及室内分析,对天津地区的201个水样进行了硝酸盐污染现状调查研究。结果表明,各类型水体之间硝酸盐浓度存在明显差异。其中,主要水库、河流未发生硝酸盐污染。少部分排污河与农田排灌沟渠水体有硝酸盐污染倾向。地下水硝酸盐浓度较高,平均值达到15.56mg·L^-1,随着地下水深度的加深,地下水硝酸盐浓度呈明显的下降趋势。0～100m的浅层地下水硝酸盐污染状况比较严重,而大于100m的地下水尚未发生硝酸盐的污染。浅层地下水硝酸盐污染程度又与农区种植类型密切相关,大部分蔬菜种植区浅层地下水硝酸盐污染状况十分严重。运用Kriging法绘制了地下水硝酸盐浓度的空间分布图,表明天津市地下水硝酸盐污染存在明显的地区差异性。地下水硝酸盐浓度较高的区域主要分布在武清、西青、静海及宝坻等地区的蔬菜种植区。     

Vulnerability Assessments of Colorado Ground Water to Nitrate Contamination

Nitrate (NO₃-N) contamination of ground water aquifers is an important problem in the United States and throughout the world, particularly as ground water resources become increasingly relied upon to support human needs. Cost effective methodologies are needed to facilitate decision-making for ground water protection. To aid ground water protection organizations, we designed two tools to assess aquifer vulnerability to NO₃-N contamination in Colorado. The first tool is a statewide aquifer vulnerability map (VM) that identifies regions vulnerable to ground water contamination. The VM uses five factors that influence aquifer vulnerability on a regional scale: aquifer locations, depth to water, soil drainage class, land use, and recharge availability. We validated the VM using 576 discrete ground water sample points from throughout the state and found that the VM was able to delineate areas of increased aquifer vulnerability to NO₃-N contamination (r ²= 0.78). The second aquifer assessment tool is a vulnerability matrix (VMX) developed to help practitioners determine relative aquifer vulnerability to NO₃-N contamination on a field scale. The VMX consists of a series of factors that are rated and combined for a particular field. This rating is used to give landowners an index of general aquifer vulnerability to NO₃-N contamination for a specific field, and inform them of changes in management practices to reduce the vulnerability. The VMX can be used in conjunction with the VM to determine NO₃-N contamination potential from intensive agriculture.     

Sources of Nitrate in Snowmelt Discharge: Evidence From Water Chemistry and Stable Isotopes of Nitrate

To determine whether NO₃ ^? concentration pulses in surface water in early spring snowmelt discharge are due to atmospheric NO₃ ^?, we analyzed stream δ¹⁵N-NO₃ ^? and δ¹⁸O-NO₃ ^? values between February and June of 2001 and 2002 and compared them to those of throughfall, bulk precipitation, snow, and groundwater. Stream total Al, DOC and Si concentrations were used to indicate preferential water flow through the forest floor, mineral soil, and ground water. The study was conducted in a 135-ha subcatchment of the Arbutus Watershed in the Huntington Wildlife Forest in the Adirondack Region of New York State, U.S.A. Stream discharge in 2001 increased from 0.6 before to 32.4 mm day^?1 during snowmelt, and element concentrations increased from 33 to 71 μmol L^?1 for NO₃ ^?, 3 to 9 μmol L^?1 for total Al, and 330 to 570 μmol L^?1 for DOC. Discharge in 2002 was variable, with a maximum of 30 mm day^?1 during snowmelt. The highest NO₃ ^?, Al, and DOC concentrations were 52, 10, and 630 μmol L^?1, respectively, and dissolved Si decreased from 148 μmol L^?1 before to 96 μmol L^?1 during snowmelt. Values of δ¹⁵N and δ¹⁸O of NO₃ ^? in stream water were similar in both years. Stream water, atmospherically-derived solutions, and groundwaters had overlapping δ¹⁵N-NO₃ ^? values. In stream and ground water, δ¹⁸O-NO₃ ^? values ranged from +5.9 to +12.9‰ and were significantly lower than the +58.3 to +78.7‰ values in atmospheric solutions. Values of δ¹⁸O-NO₃ ^? indicating nitrification, increase in Al and DOC, and decrease in dissolved Si concentrations indicating water flow through the soil suggested a dilution of groundwater NO₃ ^? by increasing contributions of forest floor and mineral soil NO₃ ^? during snowmelt.     

Sewage Treatment Plants Efficiencies in Removal of Sterols and Sterol Ratios as Indicators of Fecal Contamination Sources

This study assessed the efficiency of sewage treatment plants (STPs) in removing sterols based on chemical analyses of both influents and effluents. Samples from 3s and three tertiary plants were collected and analyzed by gas chromatography mass spectrometry for 23 individual sterols including mestranol, norethindrone, equol, estrone, equilin, norgestrel, 17α-ethinylestradiol, 17α-estradiol, 17β-estradiol, estriol, dihydrocholesterol (cholestanol), coprostanol, epicoprostanol, cholesterol, desmosterol, campesterol, stigmasterol, β-sitosterol, coprostanone, cholestanone, epicholestanol, stigmastanol, and 24-ethylcoprostanol. The percentage of sterols remaining in effluent samples (compared to influent samples) ranged from 0% to 80% and varied among sterol compounds and with STP location and treatment type. Differences in the efficiency of sterol removal for secondary and tertiary STPs were statistically significant. Although the concentration of sterol compounds differed between influents and effluents, sterol abundances remained the same. The most abundant sterol detected was cholesterol, followed by the fecal sterol coprostanol, and the plant sterols 24-ethylcoprostanol and β-sitosterol. For three STPs, the hormone estrone was detected in effluents at concentrations of 0.03–0.05 μg L⁻¹. Ten sterol ratios specific for human fecal contamination and eight sterol ratios for differentiating among multiple sources of fecal contamination were calculated and showed that 12 ratios for influent and nine ratios for effluent were successful for human fecal source tracking. Based on sterol ratio values in this study, new criteria for identification of human fecal contamination were suggested.     

样品前处理对斑头雁组织稳定同位素碳、氮比值的影响

为了更好地确定不同处理方法对样品稳定同位素分析的影响,以斑头雁(Anser indicus)为研究对象,对比了不同酸化条件、干燥方法和粉碎形式对组织材料稳定同位素碳、氮比值的影响。结果表明,不同温度和盐酸浓度对卵壳δ1 3C值有影响,80℃较40℃、60℃条件下得到的卵壳δ1 3C值富集,3 mol·L-1HCl较1、5 mol·L-1HCl浓度条件下得到的卵壳δ1 3C值贫化;冷冻干燥和烘干2种干燥方法对肌肉稳定同位素δ1 3C、δ15N的影响均未达到显著水平,液氮研磨和直接剪碎2种粉碎形式下测得的羽毛δ1 3C、δ15N值差异不显著。本研究为使用稳定同位素技术开展鸟类学相关研究提供了参考依据。     

基于同位素分析研究山东禹城夏玉米水分来源

以2016年山东省禹城市夏玉米为研究对象,通过测定分析不同生长期内降水、土壤水、植物水、地下水、地表水的稳定氢氧同位素值,并利用直接对比法和多元线性混合模型,分析不同水源对夏玉米不同生长期贡献率,进而研究其水分来源。结果表明:禹城市大气降水线方程为δD=7.80δ18 O+8.61,其斜率和截距均小于全球大气降水线方程,表明降水在降落过程存在蒸发富集过程。夏玉米不同生长期水分来源存在差异,出苗期由于土壤含水量较低,植物主要利用浅层地下水且利用率为89.6%;拔节期降雨量丰富,夏玉米主要利用0—10cm表层土壤水,利用率为85.8%;抽穗期夏玉米主要利用10—60cm土壤水,利用率达62.9%;生长到灌浆期,根系分布在较深土层且20—100cm土壤含水量稳定,夏玉米主要利用20—100cm土壤水,利用率为69.7%;成熟期植物主要利用大于60cm的深层土壤水,利用率达96.1%,此时期土壤含水量较低且根系分布可达深层土壤。     

Use of Stable Isotope Ratios for Evaluating Sulfur Sources and Losses at the Hubbard Brook Experimental Forest

Water, Air, &; Soil Pollution - Anthropogenic S emissions have been declining in eastern North America since the early 1970s. Declines in atmospheric S deposition have resulted in decreases in...     

炭化苹果枝皮和木材对水中硝态氮和铵态氮的差异吸附

将苹果枝条的皮层和木材部分开后在450℃下低氧加热制得炭化枝皮和炭化木材,分析其超微结构及对铵态氮和硝态氮的吸附。结果表明,苹果枝皮比其木材部分的纤维素含量高,有更多的微观孔洞和沟壑,炭化后纵向沟壑和孔隙更发达。炭化枝皮对NH4+—N和NO3-—N的饱和吸附量分别为24.11,12.93mg/g,炭化木材的相应参数分别为22.24,11.99mg/g,炭化枝皮对NH4+—N和NO3-—N的吸附能力均比炭化木材的更强。两者对NH4+—N的吸附量比对NO3-—N的更大,吸附过程均能采用Freundlich和Langmuir等温吸附模型、准二级动力学模型和Elovich模型拟合。炭化枝皮的吸附能力比炭化木材更强,与其原料纤维素含量高及微观沟壑发达有关。     

Dissolved Organic Nitrogen Concentrations and Ratios of Dissolved Organic Carbon to Dissolved Organic Nitrogen in Throughfall and Soil Waters in Norway Spruce and Scots Pine Forest Stands Throughout Norway

Dissolved organic nitrogen (DON) plays an important ecological role in forest ecosystems, and its concentration is related to that of dissolved organic carbon (DOC). We investigated DON concentrations and ratios of DOC to DON in throughfall and soil waters in 16 Norway spruce and two Scots pine forest stands sampled at weekly intervals between 1996 and 2006. The stands are all included in the ICP Forests Level II monitoring program and are located throughout Norway. DON concentrations were significantly and positively related to DOC concentrations in throughfall (r ²?=?0.72, p?<?0.0001) and soil water at 5, 15, and 40 cm (r ²?=?0.86, 0.32, and 0.84 and p?<?0.0001, 0.04, and <0.0001, respectively). At most sites, the annual median DOC/DON ratio in throughfall ranged from 20.3 to 55.5, which is lower than values in soil water, which ranged from 24.5 to 81.3, gradually decreasing with soil depth. DON concentrations varied seasonally in throughfall at many plots and in soil water at 5-cm depth at one plot only, with higher values in the growing season, but there was no noticeable seasonality at greater depth. The ratios of DOC/DON in soil water were significantly positively related to the C/N ratio in soil at the same depth. Above-ground litter input was the main factor having a significant, negative relationship to DOC/DON in soil water at all depths studied. This might reflect the effect of site conditions on both DOC/DON ratios and litter quantity.     

不同施肥处理土壤及不同C/N比有机物料中有机N的矿化进程

采用室内恒温控湿好气培养试验研究长期不同施肥制度培育的土壤有机N库的供氮能力及不同C/N比有机物料掺混土壤后有机N的矿化特征与进程。结果表明:长期不同施肥制度培育的土壤有机N库的供氮能力各不相同,与不施肥处理相比,长期施用化肥或有机肥均能提高土壤的供氮能力,二者相结合可明显提高土壤供氮力;不同C/N比有机物料掺混土壤后有机N的矿化特征与物料的C/N比密切相关,有机N的矿化进程可区分为前期的快速分解和后期的缓慢分解。     

样本预处理方式对罗氏沼虾碳和氮稳定同位素比值检测的影响

为研究样本预处理方式对罗氏沼虾碳和氮稳定同位素比值检测的影响,分别选用3种保存温度(常温23℃/15 d、冷藏2℃/90 d、冷冻-18℃/360 d)、2种取样方式(虾仁取样、整虾取样),以新鲜沼虾样本为对照组,对比不同样本预处理方式对罗氏沼虾碳稳定同位素比值(δ¹³C)、氮稳定同位素比值(δ¹⁵N)、碳氮比(C/N)的影响。结果表明,不同保存温度和不同取样方式对罗氏沼虾δ¹³C、δ¹⁵N、C/N的影响明显。与对照组相比,常温保存条件下的δ¹⁵N偏移量最大(1.31‰~13.16‰,平均值为6.02‰),冷冻保存条件下的δ¹³C偏移量最大(2.34‰~2.84‰,平均值为2.57‰),室温保存条件下的C/N显著增加(P<0.05),冷藏和冷冻保存条件下的C/N显著减少(P<0.05)。不同取样方式对罗氏沼虾δ¹⁵N、δ¹³C的影响还取决于保存温度,在冷冻保存条件下,整虾取样的δ¹⁵N、δ¹³C显著高于虾仁取样,而在常温保存条件下,整虾取样的δ¹⁵N偏移量显著低于虾仁取样。因此,常温(23℃)和冷藏(2℃)条件不适合保存罗氏沼虾、冷冻(-18℃)保存罗氏沼虾的时间不宜超过60 d,建议新鲜沼虾采集后应立即干燥并开展碳和氮稳定同位素检测。本研究结果为水产品碳和氮稳定同位素比值检测的样本预处理方式提供了参考。     

Evaluation of the 15Nitrogen Isotope Dilution Technique for Estimating Crop Nitrogen Uptake from Organic Residues

Abstract

A field experiment was conducted to test the new approach for estimating crop nitrogen (N) uptake from organic inputs. The soil was prelabeled with ¹⁵N by applying ¹⁵N fertilizer to sunflower crop (Helianthus annuus L. var. Viki). The ¹⁴N plots, which received unlabelled fertilizer, were also set up. At harvest, ¹⁵N labeled residues were added to the unlabeled soils at a rate of 73 kg N ha^?1 (direct technique) and unlabeled residues were added to the ¹⁵N‐labeled soils at the same rate (indirect technique). Control plots without residues were also established. All plots were sown with the wheat (Triticum aestivum L. var merchouch)–fababean (Vicia faba L.)–wheat (Triticum aestivum L. var merchouch) cropping sequence.

In the cropping sequence, the first, second and third crop derived respectively 12.01, 2.4, and 1.93 kg N ha^?1 from crop residues estimated by the direct method and 14.77, 3.3, and 1.85 kg N ha^?1 estimated by the indirect method. The results showed no significant difference between the two techniques, which suggests that the new soil prelabeling technique compares well with the direct technique.     

Stable Isotope and Chloride, Boron Study for Tracing Sources of Boron Contamination in Groundwater: Boron Contents in Fresh and Thermal Water in Different Areas in Greece

Boron is biologically an essential element but is toxic at high concentrations to plants (above approximately 1 mg/L in irrigation water) and probably to humans: The EU Drinking Water Directive fixes a threshold of 1 mg/L and the World Health Organisation (WHO) set a recommended limit at 0.3 mg/L now increased to 0.5 mg/L. Because of this potential toxicity and the need of implementation of EU regulation on national level, the study of the boron levels in both ground- and surface water is of great significance for water management. In Greece, a significant number of thermal, mineral and superficial water springs are found especially in Northern Greece, that present high boron values rendering such water unacceptable according to the European standards. Nevertheless, such ground waters or borehole water with high temperature and high boron content are used for irrigation and drinking purposes, and could therefore have an antagonistic effect on crop yield and health. In order to study the boron contamination and to elucidate the origin of B, we collected a number of hot and fresh water all over Greece. In all the water sampled, the boron concentration exceeds the limit of 0.3 mg/L, which is the former recommended WHO limit. Moreover, in the irrigation water examined, the boron concentration exceeds the value of 0.75 mg/L, which is the limit for sensitive plants (for plants of moderate and plants of high tolerance, these values vary between 0.75–3 and > 3 mg/L respectively). In all cases, elevated boron could be attributed to natural sources, geothermal activity and/or seawater intrusion into the aquifers. This finding has important implications for water management: In a setting of high natural geochemical background values, source control of the pollution is not possible and water managers have to cope with a local to regional geochemical anomaly that implies boron specific water treatment or mixing with unpolluted resources to bring concentrations down.     

水位波动条件下土层中硝态氮迁移转化数值模拟

将溶质运移方程、一维饱和-非饱和土壤水分运动控制方程和Kool-Parker滞后模型联立耦合,建立了地下水位波动条件下土层中硝态氮迁移转化模型。采用有限元数值分析方法,模拟了在地下水位波动条件下硝态氮的迁移过程且与室内土柱实验结果进行对比。结果表明,所建模型的模拟结果与室内土柱实验结果吻合,地下水位波动对硝态氮迁移转化影响显著,其浓度随水位的下降而上升,随浓度的上升而下降。水位波动幅度越大,其浓度波动范围越大。所建数学模型能较好反应硝态氮随水位波动的迁移转化规律。     

水氮调控对设施土壤有机氮组分、全氮和矿质氮的影响

为探讨水氮调控对设施土壤有机氮组分、全氮和矿质氮的影响,通过膜下滴灌设施番茄田间定位试验,采用灌水下限(W_1、W_2、W_3)和施氮量(N_1、N_2、N_3)的两因素三水平随机区组设计,研究水氮调控对休耕期0—30cm土层土壤有机氮组分、全氮和矿质氮的影响。结果表明,不同水氮调控下,设施土壤有机氮主要是以酸解态氮为主,总体表现酸解态氮大于非酸解态氮含量。土壤有机氮组分在酸解态氮和非酸解态氮中分配比例差异明显。土壤有机氮各组分含量及占全氮比例的大小顺序为氨基酸氮/氨态氮未知氮氨基糖氮。除氨基糖氮,其余酸解态氮各组分和酸解总氮含量及其占全氮比例均随着土层深度的增加而降低,不同土层含量差异显著(P0.05)。土壤全氮、矿质氮和总有机氮含量随土层深度的增加也呈降低趋势,且含量差异达到极显著水平(P0.01)。除氨基糖氮,全氮与其他有机氮各组分、酸解总氮间均达到极显著正相关(P0.01);矿质氮仅与酸解氨态氮及酸解总氮的影响达到极显著(P0.01)和显著正相关(P0.05)。灌水下限、施氮量及水氮交互对设施土壤全氮、矿质氮和总有机氮及有机氮组分影响均达到极显著水平(P0.01)。因此,设施土壤氮素含量的变化与水氮管理模式紧密相关。氨态氮和氨基酸氮是设施土壤中最主要的有机氮形态,是土壤活性氮中的主要组分,亦是土壤供氮潜力的表征。考虑土壤供氮潜力,灌水下限35kPa、施氮量300kg/hm~2为该设施生产下最优的水氮管理措施。     

Effects of Nitrogen Levels and Nitrate/Ammonium Ratios on Oxalate Concentrations of Different Forms in Edible Parts of Spinach

Two hydroponic experiments were carried out to investigate the effects of nitrogen (N) levels and forms on the oxalate concentrations of different form in edible parts of spinach. Nitrogen was supplied at five levels (4, 8, 12, 16, 20 mM) in Experiment 1 and five ratios of nitrate (NO₃ ^?) to ammonium (NH₄ ⁺) (100/0, 75/25, 50/50, 25/75, 0/100) at a total N of 8 mM in Experiment 2. Biomass of spinach increased markedly from 4 mM to 8 mM N and reached the flat with further increase in N. The total oxalate and soluble oxalate in leaves and shoots (edible parts) increased significantly with increasing N levels from 4 to 12 mM, while the total oxalate and insoluble oxalate decreased markedly when N level was further increased from 12 to 20 mM. Oxalates of different forms in petioles increased first and then decreased and elevated again with increasing nitrogen levels. In the second experiment, decreasing NO₃ ^?/NH₄ ⁺ ratios markedly increased at first and then significantly decreased the biomass of spinach plants and the maximum biomass was recorded in the treatment of the NO₃ ^?/NH₄ ⁺ ratio of 50:50. The oxalate concentrations of different form in leaves and shoots were all decreased obviously as the ratio of NO₃ ^?/NH₄ ⁺ decreased from 100:0 to 0:100. Concentrations of total oxalate and soluble oxalate in petioles could be reduced by increasing ammonium proportion and were the lowest as the ratio of NO₃ ^?/NH₄ ⁺ was 50:50 and insoluble oxalate decreased as nitrate/ammonium ratio decreased. The concentrations of oxalate forms in leaves were all higher than those in petioles and soluble oxalate was predominant form of oxalates in both trials. It is evident that high biomass of spinach can be achieved and oxalate concentrations of different forms can be reduced by modulating N levels and NO₃ ^?/NH₄ ⁺ ratio, so this will benefit for human health especially for those people with a history of calcium oxalate kidney stones.     

有机肥与氮肥配施对日光温室黄瓜和土壤硝酸盐含量的影响

在保护地栽培条件下,采用裂区设计,研究不同有机肥用量和氮肥用量配施对黄瓜NO3--N含量、不同层次土壤NO3--N含量动态变化的影响。结果表明:增施氮肥显著提升黄瓜果实NO3--N含量,氮肥与有机肥配合能够降低黄瓜NO3--N含量,交互作用极显著。高有机肥用量与高氮肥用量施用及施用氮肥不配合有机肥,保护地黄瓜NO3--N含量达到二级污染程度。黄瓜NO3--N含量、土体NO3--N的供应水平和积累量与有机肥、氮肥的施用密切相关,高量施用有机肥上层土壤NO3--N易积累,高氮肥用量(N3)处理易使土体积累NO3--N,施用有机肥能够减弱土壤中NO3--N的淋失。生产中降低黄瓜NO3--N含量和土体NO3--N淋失、积累量的施肥措施是:施用有机肥量为45~90 thm-2,施用纯氮水平为450~750 kghm-2。     

Nitrate Reductase,Micronutrients and Upland Rice Development as Influenced by Soil pH and Nitrogen Sources

The average yield of upland rice under no-tillage system (NTS), a sustainable soil management, is lower than in conventional tillage (one plowing and two disking). One of the reasons given for this drop in crop grain yield would be the low-nitrate assimilation capacity of rice seedlings, due to the low activity of the nitrate reductase (NR) enzyme in the early development phase. A greenhouse experiment was conducted to evaluate the effects of the soil acidic and nitrogen source in the micronutrient concentrations, NR activity and grain yield of upland rice growing under NTS. The soil used in the experiment was an Oxisol. The experimental design was completely randomized in a factorial 3 × 4. Treatments consisted of three levels of soil acidity (high, medium, and low) combined with four nitrogen sources (nitrate, ammonium, ammonium + nitrification inhibitor, and control – without N fertilization). The reduction of soil acidity reduced the concentration of zinc and manganese in rice plants. Generally, the activity of the NR enzyme was higher in plants grown in soils with low acidity and fertilized with calcium nitrate. There was a greater response in growth and yield in rice plants grown in soils with high acidity. Under medium acidity, rice plants grown with ammonium sulfate were more productive (no differences were detected with the addition of the nitrification inhibitor).     

减氮配施有机肥对夏玉米——冬小麦土壤硝态氮及氮肥利用的影响

为实现华北平原夏玉米-冬小麦的高产及氮肥的高效利用,采用田间小区试验方法,研究了氮肥减量及其与有机肥配施对夏玉米-冬小麦轮作体系内土壤硝态氮分布及氮肥利用的影响。结果表明:与不施氮处理(CK)相比,施用氮肥增加了冬小麦和夏玉米的生物量和产量,而在农民习惯施氮基础上减量1/3不会显著影响到生物量和产量。其中减氮配施有机肥(ONM)处理的周年总产最高,相比习惯施氮(CN)和减氮处理(ON)分别提高了1.85%和3.78%。处理CN的0~180 cm土壤硝态氮累积量的周年变化均值达502.7 kg hm^-2,分别是处理CK、ONM、ON的2.95、2.17、1.56倍。与处理CN相比,处理ONM显著降低了剖面(0~180 cm)土壤中的硝态氮含量,其中在夏玉米季和冬小麦季的降低幅度分别为18.1%~66.7%和37.3%~87.2%。处理ON和ONM相比处理CN,植株周年总吸氮量无显著性差异,氮肥利用率却得到了显著提高。其中处理ONM的周年氮肥利用最高,比处理CN提高了36.9%。综合分析,减氮与有机肥配施不仅显著降低了0~180 cm土壤硝态氮含量,大幅度提高了氮肥利用率,且有助于增加冬小麦和夏玉米的生物量及产量。     

局部根区灌溉水氮耦合对设施黄瓜生长及土壤中硝态氮分布的影响

通过对设施黄瓜进行灌水量、灌溉方式、水氮根区位置的不同耦合,研究了局部根区灌溉下不同水氮耦合措施对设施黄瓜生长、土壤中硝态氮分布及累积的影响.结果表明,灌水量、灌溉方式、水氮根区供应位置对黄瓜地上部生物量及产量存在着不同的交互作用.亏缺灌溉量处理的地上部生物量及产量均低于相应灌溉方式下的正常水量处理.相同灌溉量处理条件下,交替根区灌溉的黄瓜生物量与产量显著高于两侧均水均氮处理,以正常交替水氮异区处理黄瓜地上部生物量及果实产量最大,分别达到1 143kg/hm2(干重)和1.75×105 kg/hm2(鲜重);而固定根区灌溉下,尤其在水氮异区条件下,生物量与产量则下降.在亏缺灌溉量下,交替根区灌溉处理的黄瓜生物量以及产量与常规充足灌溉处理没有显著差异.在正常灌溉量条件下,通过对局部根区灌溉下不同水氮耦合对土壤中硝态氮分布的分析表明,施氮是造成土壤中硝态氮积累的原因,土壤水分的垂向运动是影响硝态氮向下淋洗的一个主要因子.固定水氮同区、交替水氮同区处理硝态氮向下淋洗较强,水氮异区处理硝态氮向下淋洗相对较弱.交替水氮异区处理氮素主要累积在0-110 cm土层,深层累积量显著低于其他水氮耦合处理.综合黄瓜生长、土壤硝态氮淋洗等因素考虑,交替水氮异区处理是最佳的水氮耦合处理方式.