蔬菜地土壤磷提取及模拟径流中磷素潜在流失的影响

蔬菜地磷素流失是一种典型农业非点源污染类型。通过观测地表径流中溶解态反应磷(DRP)、生物可利用磷(BAP)可以监测土壤磷素流失程度。受到各种客观条件的限制,这两个指标比较难于获取,而土壤中的总磷(TP)、Olsen(OP)、Mehlich-1(M-1P)和水溶性磷(Pw)可以通过常规分析手段获取。本文选取27个典型蔬菜样地,分析测定各样地土壤中的总磷(TP)、Olsen(OP)、Mehlich-1(M-1P)和水溶性磷(Pw)四个磷提取变量,采用了经典方法计算土壤磷流失潜能指标——磷吸持饱和度(DPS)。同时采用模拟径流实验得出典型蔬菜样地地表径流样中溶解态反应磷(DRP)、生物可利用磷(BAP)。结果表明:M-1P、Pw与DPS呈极显著正相关,相关系数分别达到了0.85和0.74(p<0.01);而M-1P、Pw与DRP浓度相关系数(r2=0.843和0.786,p<0.01)大于TP、OP与DRP浓度的相关系数(r2=0.554和0.722,p<0.01)。结论认为,通过测定M-1P、Pw和计算DPS能比较准确、便捷地预测土壤径流磷素流失风险程度。     

九龙江流域典型汇水区地表径流氮磷流失特征分析

选取九龙江流域5个典型汇水区，通过流域主要雨季天然降雨径流过程监测，对所获得的氮磷营养盐的监测数据进行归纳与分析，着重探讨了暴雨事件下径流氮磷流失及其形态的变化规律。结果表明：暴雨事件下农业汇水区地表径流氮输出以水溶态为主，磷以泥沙结合态为主，天然林地为主的汇水区则相反，前者以泥沙结合态为主，后者以水溶态为主；5个汇水区暴雨事件中总氮最高浓度值为日常采样浓度值的2．9～11．3倍，暴雨事件中总磷最高浓度值为日常采样浓度值的2．9～20．5倍；氮磷输出量均值的差异反映氮磷输出量大小受土壤质地、施肥量、土壤氮磷含量、土壤保水保肥性能等因素的综合影响。整个径流过程中水量和氮磷浓度随时间变化幅度较大，且2者变化呈大体相同的趋势。氮磷及其各形态的浓度多数在相同时间内达到峰值。泥沙结合态氮、水溶态磷变化幅度较小，水溶态氮和泥沙结合态磷浓度变化幅度较大。统计各汇水区雨量不同的降雨事件下氮磷流失负荷表明，特大暴雨对汇水区氮磷负荷的贡献非常显著。     

氮肥运筹和少免耕对麦田氮素径流流失的影响

采用田间小区定位试验研究了自然降雨条件下氮肥运筹和少免耕措施对稻麦两熟农田麦季氮素径流流失特征的影响。结果表明:自然降雨后麦田耕层土壤平均水分质量分数26.34%为径流事件发生的临界土壤水分质量分数。常规施肥(T0)条件下,麦季径流水量达2185.05 m3·hm-2,径流侵蚀泥沙量达716.08 kg.hm-2,少免耕(T2)处理增加麦田径流水量达29.67%,减少径流侵蚀泥沙量达13.96%,而肥料运筹(T1)与T0处理差异不显著;就整个麦季而言,T0处理条件下,径流水全氮(TN)平均质量浓度和径流侵蚀泥沙TN平均质量分数分别为10.51 mg·L-1和1.19 g·kg-1,T1处理显著降低径流水TN质量浓度和侵蚀泥沙TN质量分数分别达11.63%和5.93%,T2处理显著降低径流侵蚀泥沙TN质量分数达7.95%;麦季氮素径流流失主要集中在小麦生育前期,包括径流水氮素流失量和径流侵蚀过程中由泥沙流失的氮素量。T0处理条件下,氮素流失总量达31.76 kg·hm-2,其中,径流水氮素流失量占麦季氮素总流失量95%以上,T1处理减少麦季氮素总流失量达9.25%,而T2处理则增加麦季氮素总流失量达16.75%...     

氮肥运筹和少免耕对麦田氮素径流流失的影响

采用田间小区定位试验研究了自然降雨条件下氮肥运筹和少免耕措施对稻麦两熟农田麦季氮素径流流失特征的影响。结果表明：自然降雨后麦田耕层土壤平均水分质量分数26.34%为径流事件发生的临界土壤水分质量分数。常规施肥（T0）条件下,麦季径流水量达2185.05 m3·hm-2,径流侵蚀泥沙量达716.08 kg.hm-2,少免耕（T2）处理增加麦田径流水量达29.67%,减少径流侵蚀泥沙量达13.96%,而肥料运筹（T1）与T0处理差异不显著;就整个麦季而言,T0处理条件下,径流水全氮（TN）平均质量浓度和径流侵蚀泥沙TN平均质量分数分别为10.51 mg·L-1和1.19 g·kg-1,T1处理显著降低径流水TN质量浓度和侵蚀泥沙TN质量分数分别达11.63%和5.93%,T2处理显著降低径流侵蚀泥沙TN质量分数达7.95%;麦季氮素径流流失主要集中在小麦生育前期,包括径流水氮素流失量和径流侵蚀过程中由泥沙流失的氮素量。T0处理条件下,氮素流失总量达31.76 kg·hm-2,其中,径流水氮素流失量占麦季氮素总流失量95%以上,T1处理减少麦季氮素总流失量达9.25%,而T2处理则增加麦季氮素总流失量达16.75%。     

猪场污水还田与化肥配施对农田水土环境和作物产量的影响

畜禽粪污还田利用作为一种具有良好经济性和可操作性的资源化处理方式,近年来逐步成为规模化畜禽养殖场污染减排的方向,但其在还田过程中对水、土壤环境以及作物产量的潜在影响也不容忽视。以规模化养猪场为例,以常规化肥施用农田为对照,研究猪场厌氧污水还田与化肥配施对水环境(地表径流污染物流失负荷、地下水污染物浓度)、土壤环境(养分含量)和作物产量的影响。结果表明,与常规对照农田相比,污水还田农田地表径流化学需氧量(COD)、总磷(TP)和可溶性磷(DP)年流失负荷分别显著增加32.18%、15.46%和28.13%,但氨氮(以NH_4~+-N计)年流失负荷显著减少31.81%;地下水COD、硝态氮(NO_3~--N)、TP和DP等污染物浓度分别显著提高24.69%、17.04%、11.76%和21.05%;与初始土壤相比,污水还田农田不同土层中TN含量显著降低,常规对照农田TP含量显著降低;污水还田农田作物产量与常规对照农田无显著差异。     

不同施肥水平下菜地径流氮磷流失特征

研究施肥对菜地径流氮、磷流失的影响,对控制水体富营养化有重要意义。采用田间小区监测的方法,研究常规施肥、减量施肥1和减量施肥2等三种施肥水平对菜地径流氮磷流失的影响。结果表明,（1）不同施肥水平的径流氮、磷流失浓度均较高,径流TN、NH4＋-N、NO3--N的平均流失质量浓度分别在20.5~34、2.2~2.4、6.3~9.5 mg L-1之间,径流TP、DP的平均流失质量浓度分别在7.7~11.1、2.1~2.4 mg L-1之间,菜地土壤径流氮、磷流失风险较大。（2）减量施肥可明显降低径流TN和NO3--N的流失浓度,与当地常规施肥相比,减施肥料20%和30%可分别降低径流TN流失浓度的40%、32%和NO3--N流失浓度的23%、35%,而减量施肥对径流TP、DP的流失浓度影响不大。（3）不同施肥水平的径流TN、NO3--N流失负荷分别在5.8~7.6、1.6~2.3 kg hm-2之间,与常规施肥相比,减施肥料20%和30%可分别减少TN、NO3--N流失负荷的24%、19%和11%、29%。不同施肥水平的径流TP、DP流失负荷分别在1.7~2.9、2.5~2.7 kg hm-2之间,减量施肥并不能减少径流TP、DP的流失负荷。     

紫色土小流域土壤及氮磷流失特征研究

紫色土区土壤及其养分流失对长江水环境产生严重威胁。然而,有关该地区自然降雨侵蚀下土壤及氮磷流失规律的研究却较为少见。以紫色土农田利用为主小流域为研究对象,监测自然降雨侵蚀下土壤及其氮磷的流失过程,以期服务于流域尺度土壤及养分流失的模拟与控制。结果表明,次降雨径流含沙量与流量的变化基本同步,峰值含沙量往往出现在峰值流量处或略有提前,此后,含沙量迅速降低。硝态氮流失浓度与流量的变化成反比,峰值流量处流失浓度一般达到最低,此后,随着流量的降低,其流失浓度存在较为明显的升高过程。铵态氮与水溶性磷的流失表现为剧烈波动的变化特征。氮素流失的主要形态是硝态氮,其占到次降雨无机氮流失总量的88%～97%。     

崇明东滩旱作农田土壤磷素流失及其影响因素

对采用不同施肥和地表管理方式的梨园和菜地磷素的流失进行监测,研究了崇明东滩旱作农田土壤磷素的流失负荷、流失途径及其变化规律和影响因素,并分析了不同施肥和地表管理方式对农田土壤磷素流失的影响.结果表明,旱作农田土壤磷素径流流失、渗漏流失和泥沙流失浓度均超过水体富营养化总磷浓度临界值;土壤磷素流失以泥沙流失为主,泥沙总磷流失负荷占总磷流失总负荷的70.7%～82.2%;磷素流失主要发生在6、8和10月,这3个月总磷流失负荷占全年总磷流失总负荷的71.6%～73.0%.对磷素流失影响因素的相关分析表明,旱作农田土壤磷素流失与降雨量、降雨侵蚀力、径流量、径流水中总磷浓度等因素相关显著.与常规对照方式相比较,保持表土植被、覆盖地膜和精确滴灌,可减少旱作农田径流和泥沙产生量,降低总磷流失浓度,梨园和菜地总磷流失负荷消减率分别可达20.6%和12.6%.     

不同利用方式下黄壤旱坡地磷素状况及环境影响分析

通过对贵州黄壤进行采样以及采用无界径流小区法收集地表径流,探索不同利用方式下黄壤旱坡地磷素水平及其地表径流磷浓度的差异。结果表明,不同利用方式下黄壤旱坡地中全磷和有效磷(Olsen-P)含量的大小顺序为连作烟地>烤烟-玉米轮作地>连作玉米地>林地;CaCl_2浸提磷(土壤易解吸磷)和Na0H浸提磷(藻类可利用的土壤总磷)与土壤全磷和有效磷有显著的相关性;土壤富磷化的同时,其磷素的流失风险明显地提高。连作烟地地表径流总磷(TP)和磷酸根态磷(Ortho-P)浓度明显大于连作玉米地.而林地地表径流TP浓度明显小于旱地;黄壤旱坡地地表径流中TP和Ortho-P与土壤有效磷之间存在极显著的相关性(r为0.957、0.875),因而连作烟地磷素的环境影响潜能明显高于其它旱地以及林地。     

九龙江流域典型汇水区地表径流氮磷流失特征分析

选取九龙江流域5个典型汇水区,通过流域主要雨季天然降雨径流过程监测,对所获得的氮磷营养盐的监测数据进行归纳与分析,着重探讨了暴雨事件下径流氮磷流失及其形态的变化规律。结果表明:暴雨事件下农业汇水区地表径流氮输出以水溶态为主,磷以泥沙结合态为主,天然林地为主的汇水区则相反,前者以泥沙结合态为主,后者以水溶态为主;5个汇水区暴雨事件中总氮最高浓度值为日常采样浓度值的2.9～11.3倍,暴雨事件中总磷最高浓度值为日常采样浓度值的2.9～20.5倍;氮磷输出量均值的差异反映氮磷输出量大小受土壤质地、施肥量、土壤氮磷含量、土壤保水保肥性能等因素的综合影响。整个径流过程中水量和氮磷浓度随时间变化幅度较大,且2者变化呈大体相同的趋势。氮磷及其各形态的浓度多数在相同时间内达到峰值。泥沙结合态氮、水溶态磷变化幅度较小,水溶态氮和泥沙结合态磷浓度变化幅度较大。统计各汇水区雨量不同的降雨事件下氮磷流失负荷表明,特大暴雨对汇水区氮磷负荷的贡献非常显著。     

稻麦两熟农田稻季养分径流流失特征

采用田间小区定位试验研究了自然降雨条件下江苏稻麦两熟农田稻季养分径流流失规律。结果表明：稻季径流水量可达5705.55m3·hm-2;常规施肥（T0）条件下,稻田径流流失全N（TN）、全P（TP）和速效K（AK）的总量分别为11.29、0.19和13.22kg·hm^-2,流失率分别为3.8%、0.21%和9.8%;径流水中全N和速效K质量浓度随距施肥时间的延长而呈逐渐下降趋势;较常规施肥处理而言,秸秆还田（T1）和还田减肥（T2）处理不仅能够有效降低径流水中TN、TP和AK质量浓度,而且能够减少稻季养分径流流失总量,分别减少13.48%、17.55%,25.00%、31.25%和22.69%、53.48%,并降低养分流失率,分别达13.16%、-2.63%,23.81%、14.29%和22.45%、41.84%。     

密云县密云水库流域坡耕地养分流失特征

于2005年和2006年连续2 a对密云水库流域坡耕地进行水土流失小区试验,并完全按照当地农民习惯进行农事管理.试验结果表明:(1)降雨后坡耕地产生的地表径流量、泥沙量随坡度增大而增加,并与坡度正弦值呈一定的线性关系;(2)坡度对雨后地表径流和泥沙中养分含量影响不明显,但对泥沙养分流失量有明显影响;(3)养分流失以泥沙携带为主要途径,且通过泥沙携带途径流失的养分量占流失养分总量的比例随坡度增加而增加;(4)水库周边区域内坡耕地流失养分的主要来源为施用于坡耕地的化学肥料.(5)调整水库流域内坡耕地的种植结构、对坡耕地实施改造以截留或减少泥沙流失和控制化学肥料投入等措施对于治理流域内农业非点源污染、保护水源地水质显得尤为迫切.     

Phosphorus losses to water from lowland rice fields under rice-wheat double cropping system in the Tai Lake region

To assess P losses to surface water by runoff during the rice season and by drainage flow during the winter wheat season, serial field trials were conducted in different types of paddy soils in the Tai Lake Region (TLR) during 2000 and 2001. Four P application rates were set as 0 (CK), 30, 150, and 300 kg P/hm2 for flooded rice trials and 0 (CK), 20, 80, 160 kg P/hm2 for winter wheat trials respectively. Field experiments were done in two locations with a plot size of 30 m2 and four replications in a randomized complete block design. A simplified lysimeter was installed for each plot to collect all the runoff or drainage flow from each event. Total P (TP) losses to surface water during rice season by runoff flow from four treatments were 150 (CK), 220 (T30), 395 (T150), 670 (T300) g P/ hm2 in year 2000, and 298, 440, 1828, 3744 g P/hm2 in year 2001 respectively in Wuxi station, here the soil is permeable paddy soil derived from loam clay deposit. While the losses were 102, 140, 210, 270 in year 2000, and 128, 165, 359, 589 g P/hm2 in year 2001 respectively in Changshu station, here the soil is waterlogged paddy soil derived from silt loam deposit. During the winter wheat season, total P lost from the fields by drainage flow in the four treatments were 253 (CK), 382 (T20), 580 (T89), 818 (T160) g P/hm2 in year 2000--2001, and 573.3, 709.4, 1123.2, 1552.4 g P/hm2 in year 2001--2002 at the Wuxi station. While these were 395.6, 539.1, 1356.8, 1972.1 g P/hm2 in year 2000--2001, and 811.5, 1184.6, 3001.2, 5333.1 g P/hm2 in year 2001--2002 at the Changshu station. Results revealed that P fertilizer application rates significantly affected the TP concentrations and TP loads in runoff during the rice season, and by drainage flow during the winter wheat season. Both TP loads were significantly increased as the P application rate increases. The data indicate that TP losses to surface water were much higher during the winter wheat season than during the rice season in two tested sites. The data also reveal that the annual precipitation and evaporation rate affected the soil P losses to surface water significantly. Year 2000 was relatively dried with higher evaporation thus P losses to water by both runoff and drainage flow were less than in year 2001 which was a relatively wet year with lower evaporation. Results indicate that texture, structure of the soil profile, and field construction (with or without ridge and deep drains) affected soil P losses to surface water dramatically. Annual possible TP lost to water at the application rate of 50 kg P/hm2 year tested in TLR were estimated from 97 to 185 tones P from permeable paddy soils and 109-218 tones P from waterlogged paddy soils. There was no significant difference of TP lost between the CK and the T50 treatments in both stations, which indicate that there is no more TP lost in field of normal P fertilizer application rate than in control field of no P fertilized. Much higher TP lost in runoff or drainage flow from those other P application rates treatments than from the T50 treatment, which suggest that P losses to surface water would be greatly increasing in the time when higher available P accumulation in plough layer soil in this region.     

模拟降雨条件下农田径流中氮的流失过程

在室内降雨模拟试验条件下，研究暴雨径流中农田氮素养分流失及施肥处理的影响。结果表明，农田暴雨径流氮养分的流失量与累积径流量成正相关；施用NH     

Phosphorus Losses to Water from Lowland Rice Fields under Rice–Wheat Double Cropping System in the Tai Lake Region

To assess P losses to surface water by runoff during the rice season and by drainage flow during the winter wheat season, serial field trials were conducted in different types of paddy soils in the Tai Lake Region (TLR) during 2000 and 2001. Four P application rates were set as 0 (CK), 30, 150, and 300 kg P/hm² for flooded rice trials and 0 (CK), 20, 80, 160 kg P/hm² for winter wheat trials respectively. Field experiments were done in two locations with a plot size of 30 m² and four replications in a randomized complete block design. A simplified lysimeter was installed for each plot to collect all the runoff or drainage flow from each event. Total P (TP) losses to surface water during rice season by runoff flow from four treatments were 150 (CK), 220 (T30), 395 (T150), 670 (T300) g P/hm² in year 2000, and 298, 440, 1828, 3744 g P/hm² in year 2001 respectively in Wuxi station, here the soil is permeable paddy soil derived from loam clay deposit. While the losses were 102, 140, 210, 270 in year 2000, and 128, 165, 359, 589 g P/hm² in year 2001 respectively in Changshu station, here the soil is waterlogged paddy soil derived from silt loam deposit. During the winter wheat season, total P lost from the fields by drainage flow in the four treatments were 253 (CK), 382 (T20), 580 (T89), 818 (T160) g P/hm² in year 2000–2001, and 573.3, 709.4, 1123.2, 1552.4 g P/hm² in year 2001–2002 at the Wuxi station. While these were 395.6, 539.1, 1356.8, 1972.1 g P/hm² in year 2000–2001, and 811.5, 1184.6, 3001.2, 5333.1 g P/hm² in year 2001–2002 at the Changshu station. Results revealed that P fertilizer application rates significantly affected the TP concentrations and TP loads in runoff during the rice season, and by drainage flow during the winter wheat season. Both TP loads were significantly increased as the P application rate increases. The data indicate that TP losses to surface water were much higher during the winter wheat season than during the rice season in two tested sites. The data also reveal that the annual precipitation and evaporation rate affected the soil P losses to surface water significantly. Year 2000 was relatively dried with higher evaporation thus P losses to water by both runoff and drainage flow were less than in year 2001 which was a relatively wet year with lower evaporation. Results indicate that texture, structure of the soil profile, and field construction (with or without ridge and deep drains) affected soil P losses to surface water dramatically. Annual possible TP lost to water at the application rate of 50 kg P/hm² year tested in TLR were estimated from 97 to 185 tones P from permeable paddy soils and 109–218 tones P from waterlogged paddy soils. There was no significant difference of TP lost between the CK and the T50 treatments in both stations, which indicate that there is no more TP lost in field of normal P fertilizer application rate than in control field of no P fertilized. Much higher TP lost in runoff or drainage flow from those other P application rates treatments than from the T50 treatment, which suggest that P losses to surface water would be greatly increasing in the time when higher available P accumulation in plough layer soil in this region.     

Modeling agricultural non-point source pollution in a high-precipitation coastal area of China

Non-point source （NPS） pollution simulation in the high-precipitation coastal areas of China is difficult because varying annual typhoon incidence leads to highly contrasting rainfall patterns in dry years and wet years. An IMPULSE （Integrated Model of Non-point Sources Pollution Processes） based NPS model of the Changtan Reservoir watershed, which is a typical high-precipitation coastal area in China, was established based on the analysis of point and NPS pollution data, a digital elevation model, and data on land-use, soil, meteorology, economy, and agricultural management practice. Pre-processed pre-rain- fall soil moisture levels were introduced during the simulation to model the effects of typhoons on hydrology. Rainfall events were simulated sequentially through the year and the model was calibrated and verified using hydrological and water quality data. Accuracy of the simulated rainfall runoff and water quality in the Changtan watershed was found to be acceptable. The study showed that the NPS modeling system could be applied to the simulation and prediction ofNPS loadings in the Changtan Reservoir watershed.     

皖南丘陵地区小流域氮素径流输出的动态变化

以亚热带北部皖南丘陵地区小流域定位实地观测为基础 ,研究了农林共存小流域氮素径流输出规律。发现小流域氮素径流输出季节性变化明显。降雨和施肥是影响这一变化的重要因子 ,模拟分析表明 ,它们与氮素输出之间具有很好的线性相关关系     

Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast China

This paper presents the study carried out for controlling agricultural non-point source pollution (NSP) in a medium-sized watershed covering 1.47 × 10⁴ km² in Southeast China using quantitative analysis coupled with geographic information system (GIS), universal soil loss equation (USLE), soil conservation service-curve number (SCS-CN), nutrient loss equations, and annualized agricultural nonpoint source model (AnnAGNPS). Based on the quantitative results derived from GIS and environmental models, five control division units were generated for NSP control in Jiulong River watershed, namely, controlling unit for soil losses, controlling unit for livestock breeding and soil losses, controlling unit for excessive fertilizer use and livestock breeding, controlling unit for soil losses and fertilizer use, and controlling unit for excessive fertilizer use and soil losses. This study proved that integrating GIS with environmental models can be adopted to efficiently evaluate major sources and contributors of NSP, and identify the critical source areas of NSP, which enables adjusting measures to local conditions by further control division units developed through such study for control and management of water quality degradation induced by NSP in the Jiulong River watershed.