洋河流域缓坡地土壤磷素径流输出特征

坡面径流和侵蚀泥沙是磷素进入洋河水库的主要非点污染源。根据洋河流域多年的降雨特点,通过对天然降雨资料分析和人工模拟降雨,对该流域缓坡地表径流中磷素输出进行了初步的研究,结果表明:洋河流域缓坡地土壤磷素流失以颗粒态磷为主,不同土地利用方式下洋河流域缓坡地地表径流中磷含量的大小顺序为:小麦-玉米连作地>高产玉米地>低产玉米地>次生灌木林地;随着降雨强度的增加径流中颗粒态磷的含量逐渐增加,但O rtho-P的含量却下降;不同植被覆盖度下坡面地表径流中颗粒态磷和TP的含量随着植被覆盖度增大而减少,但径流中O rtho-P的含量则随着覆盖度的增加而增加。     

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；CaCl2浸提磷（土壤易解吸磷）和NaOH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。     

缓坡耕地土壤磷素释放的动态规律研究

研究坡耕地土壤磷素的释放规律有助于非点源污染的控制。在秦皇岛洋河流域缓坡耕地进行的试验表明:随着磷肥施用量的增加,坡耕地释放磷素的数量也相应的提高,在施磷量超过P2O5450 kg hm-2时,径流中正磷酸态P(Ortho-P)的含量会对水体产生明显影响;同时坡耕地土壤释磷的规律与玉米生长发育规律有显著关系,表现为:随着玉米由苗期→营养生长盛期→抽穗期→结实期,地表径流中Ortho-P的含量变化依次为:高→低→高→低。     

丹江口水库农业径流小区土壤氮磷流失特征

通过对丹江口水库小流域雨季(2013年8月)观测的降雨—径流农业小区试验数据,分析不同种植作物下农田地表产流规律,研究土壤氮磷流失特征,为库区农业面源污染控制提供依据。结果表明,农业小区径流总磷(TP)含量在0.13~0.82mg/L之间,颗粒态磷(PP)占TP比例超过60%,径流中TSS与PP也呈现极显著相关(p0.01),表明磷素流失主要以颗粒态流失为主。径流总氮(TN)含量范围为0.7~4.7mg/L之间,TN流失量与硝态氮极显著相关(p0.01),径流中硝态氮占TN比例也超过了50%,表明硝态氮是地表径流无机氮流失的主要成分。25°玉米、15°荒地径流小区的氮流失率超过了1.5%、磷流失率超过了0.12%,高于其它类型的小区,可能与这2种小区高坡度、低植被覆盖度有关。土壤氮的流失风险要高于磷,是面源污染的主要控制目标。利用梯田种植作物,同时在坡地上形成相对较高的植被覆盖密度是减少这一地区土壤养分流失有效手段。     

自然和人工模拟降雨条件下紫色土坡地的磷素迁移

采用人工降雨和自然降雨的方法对紫色土坡地磷素迁移进行比较研究。研究结果表明：紫色土坡地产生地表径流和壤中流两种径流模式，壤中流其径流动态过程受降雨强度和表层作物覆盖度的影响；持续性变化的大雨强更容易引起土壤磷非点源输出，导致水体富营养化；在中到暴雨条件下，壤中流累积迁移流量低于地表径流，差幅决定于土壤表层界面（植被覆盖）特征，地表径流中的磷迁移量是壤中流迁移的3～4倍。     

不同类型黄壤旱地的磷素流失及其影响因素分析

在贵州中部黄壤旱地上 ,通过模拟降雨试验方法 ,对不同类型黄壤旱地磷素流失及其影响的主要因素进行研究。结果表明 ,黄壤旱地磷素流失以颗粒态形式流失为主 ,其占地表径流总磷含量的 86 .4%～ 99.9% ;不同类型黄壤旱地随地表径流流失的颗粒态磷 (泥沙结合态磷 )量和磷酸根态磷 (水溶态磷 )量存在较大差异 ,高肥力旱地磷的流失量明显高于低肥力旱地。影响黄壤旱地颗粒态磷和磷酸根态磷流失量的首要土壤因子都是有效磷含量 ;在土壤磷素水平一致下 ,黄壤旱地颗粒态磷流失量与 <0 .0 0 1mm粘粒含量呈显著正相关 ,而磷酸根态磷流失量与土壤交换性钾含量呈显著负相关。此外 ,降雨强度对旱地磷素流失产生明显影响 ,高降雨强度将加速颗粒态磷的流失 ,从而明显地提高旱地磷素流失量 ;而低降雨强度促进磷酸根态磷的流失     

黄壤旱坡地梯化对土壤磷素流失的影响

在贵州中部黄壤旱坡地上 ,通过无界径流小区法以及野外坡面径流小区试验 ,对梯化和未梯化的黄壤旱坡地地表径流中磷酸根态磷、颗粒态磷以及生物有效磷的浓度变化 ,以及旱地梯化种植与传统顺坡种植下土壤磷流失量的差异进行了研究。结果表明 ,梯化与未梯化黄壤旱坡地地表径流中颗粒态磷和生物有效磷含量出现显著性的差异 ,旱坡地梯化后地表径流中颗粒态磷的含量减少 17.0 9%～ 5 7.94 % ,生物有效磷含量减少 16.0 1%～3 6.83 %。黄壤旱地土埂梯化种植能明显减少地表径流中颗粒态磷的流失量 ,其年均颗粒态磷的流失量比传统顺坡种植减少 71.64% ,但旱地梯化种植未能明显减少水溶态磷的流失量。土壤磷素水平的提高能明显增加旱坡地磷素的流失潜能 ,黄壤旱地梯化种植结合平衡施肥是减少土壤磷素流失以及保护水体质量的有效途径。     

昆明迤者小流域坡面地表径流磷素流失研究

基于松华坝水源区2008年自然降雨监测数据,采用径流小区法对坡面地表径流中磷素流失进行分析;结果表明:不同土地利用类型下,坡面地表径流磷索流失量与径流量、产沙量基本一致;人工次生林地(云南松纯林)在控制地表磷素流失上有显著效果;当地传统农业模式下的烤烟、玉米栽植,地表径流磷素流失显著.施肥后的1～3次降雨是磷素流失的主要时期.转变当地农业结构,扩大经济林地面积,减少人为活动对地表的影响是解决坡面地表磷素流失的关键.     

沈阳地区棕壤旱田氮磷流失特征研究

在野外布设正常施肥、不施肥的3组共6个径流小区,监测玉米生长期内的径流量和氮磷流失浓度,以分析氮磷流失特征。试验结果表明:7、8月份降雨集中,是氮磷流失的主要时期,应尽量减少扰动土层的农事活动;植被覆盖度是影响地表径流中氮磷流失浓度的重要因子,随着植物的生长和覆盖度的增加,氮磷流失浓度呈下降趋势;颗粒态是氮磷流失的主要形态;施肥后短时间内的降雨对氮磷流失浓度影响明显,因此避免在降雨多发期施肥是减少面源污染的有效途径。     

柴河流域种植方式与沟渠类型对农田径流氮、磷含量的影响

为了解高原湖泊流域内农田种植方式及沟渠类型对雨季径流中固体悬浮物及氮磷浓度变化的影响,在柴河流域不同农田种植方式(蔬菜地、玉米地、大棚种植区)的区域内选择典型自然沟渠及土质沟渠进行自然降雨过程中径流氮、磷含量分析。结果表明:(1)该区域农田径流水体总氮(TN)、总磷(TP)平均值为27.16,17.18mg/L,相对地表V类水质限值而言超标严重,溶解态氮(DN)与颗粒态磷是氮、磷的主要存在形态,符合面源污染特征;(2)降雨是影响径流污染物含量最重要的因素之一。除此之外,种植方式对总氮、溶解态氮及溶解态磷(DP)具有显著影响(P0.05),而沟渠类型对污染物含量的影响不显著(P0.05);(3)在同一降雨量(18.05 mm)条件下,蔬菜地及大棚区的农田径流氮含量(TN:32.26 mg/L和29.02mg/L,DN:21.33mg/L和17.46mg/L)显著高于玉米地(TN:18.33mg/L,DN:6.23mg/L),大棚区径流的磷素含量(TP:17.46mg/L,DP:2.16mg/L)则显著高于蔬菜地(TP:6.89mg/L,DP:1.38mg/L)及玉米地(TP:7.92mg/L,DP:0.64mg/L);自然沟渠相对于土质沟渠可以显著降低径流中的总磷、DN及DP含量(P0.05)。研究结果表明在同一降雨量条件下,土地种植方式仍是影响柴河流域面源污染的主要因素,沟渠虽然可以有效降低面源污染含量,但其影响却小于土地种植方式。因此建议在流域面源污染控制及水土保持过程中,首先需要对流域原有种植结构进行优化,然后在此基础上实现对现有沟渠生态化水平的改造与提升,以增加对面源污染物的控制效能。     

Dynamic changes of nitrogen and phosphorus losses in ephemeral runoff processes by typical storm events in Sichuan Basin, Southwest China

This study was carried out in the Xujiawan watershed in Sichuan Province, China. The area is characterized by easy weathering of bedrock (sedimentary sandstone and shale) and vulnerability to erosion due to coarse soil texture and weak soil structure. The objective of this study was to understand the dynamics of nitrogen (N) and phosphorus (P) losses during typical storm events. The results showed that runoff generation was sudden and ephemeral, giving rise to flash floods with sharp, narrow hydrographs and short time lags in this type of agricultural ecosystems. The time lag effect of runoff formation depended on soil conditions before storm events. Suspended solids (SS) concentration peaks occurred at the beginning of the storm flow and decreased as rainfall progressed. Meanwhile, SS losses increased at the beginning of runoff flow, then decreased due to flow volume change. Concentrations of NO₃⁻-N were four times higher than NH₄⁺-N in runoff. NO₃⁻-N concentrations first decreased as runoff volume increased until reaching relatively low concentrations, then increased again as runoff volume decreased. Both NH₄⁺-N and dissolved phosphorus (DP) in runoff remained at low concentrations with a small magnitude of variation. Suspended particulate nitrogen (SN) was the dominant N form. Losses of NO₃⁻-N were higher than NH₄⁺-N in the dissolved nitrogen (DN). Suspended particulate nitrogen losses were several times higher than DN in the early period of runoff formation, but the ratio of SN/DN decreased gradually as rainfall progressed, and by the end of the storm event the rate was lower than 1, indicating DN took the main form after the early physical flush. In the early period of storm events, suspended particulate phosphorus (SP)/DP was above 70 and decreased as rainfall progressed, but remained higher than 1, which showed that SP was the main form of P loss. The transport of N, and particularly P, was intimately linked to sediment in the runoff, indicating an obvious soil erosion-associated nutrient transport, especially in relation to P loss.     

三峡库区不同坡度石灰土坡耕地磷素流失特征

[目的]研究石灰土坡耕地在不同坡度下的磷素流失规律,以期为三峡库区农业面源污染的防治和水资源保护提供基础数据。[方法]在三峡库区香溪河流域坡耕地修建径流小区进行原位人工降雨试验,在雨强1.5mm/min时,分析10°,15°和20°这3种坡度下坡耕地的径流量、泥沙浓度,以及地表径流中总磷、颗粒态磷,泥沙中总磷、速效磷浓度的变化趋势,并对径流泥沙进行无机磷分级试验。[结果]坡度越大,地表径流量、径流总量、泥沙流失量越大,初始产流时间越短,但坡度对径流中泥沙流失浓度的影响不显著;不同坡度下径流中总磷(TP)、颗粒态磷(PP)浓度都随着产流时间逐渐变小最后趋于平衡,其中径流中TP主要以PP形式流失,达到80%以上;泥沙中磷素流失主要以无机态磷为主,无机磷分级试验表明被植物高效利用的有效态磷和缓效态磷占无机磷总量的54.1%~57.8%。[结论]坡度主要通过影响地表径流总量和径流携带的泥沙总量而影响磷素流失总量,石灰土坡耕地磷素流失主要以径流泥沙携带为主。     

Phosphorus Loss Mitigation in Leachate and Surface Runoff from Clay Loam Soil Using Four Lime-Based Materials

The increased eutrophication phenomenon in Quebec lakes calls for an urgent phosphorus-reducing strategy to meet the Quebec water quality standard of 0.03 mg L^?1 for phosphorus (P). The objective of this research was to evaluate the application of four lime-based products in reducing P losses through subsurface leachate and surface runoff and to determine their optimum application. Two sets of experiments were conducted: laboratory leaching study and runoff study with a rainfall simulator, using a clay loam soil collected from the Pike river watershed. The former followed a flow method with a full factorial design in three replicates. Soil columns were amended with different application dosages of lime ranging from 0 to 2% by soil weight. The results showed that all four lime-based products could be promising amendments in reducing P losses in the leachate. According to statistical analysis of ANOVA, high calcium hydrated lime and lime kiln dust #2 were found to be the most effective with an optimum application dosage of 1% while reducing total dissolved phosphorus concentrations in leachate from 0.057 to 0.009 and 0.023 mg L^?1, respectively. For the runoff study, a rainfall simulator with a maximum rainfall intensity of 2 cm h^?1 was built. High calcium hydrated lime and lime kiln dust #2 were able to reduce total dissolved phosphorus to 0.034 and 0.037 mg L^?1, respectively. However, particulate phosphorus was significantly increased at the studied application rate. The results from this study can offer a promising measure in reducing total dissolved phosphorus in groundwater while providing a solution to the existing environment issue of eutrophication.     

洪泽湖地区麦稻两熟农田及杨树林地降雨径流对地下水水质的影响

农业氮磷养分流失已经成为地下水污染的重要原因之一,为了探究和比较麦稻两熟农田和杨树林地氮磷流失对地下水的影响,本文在洪泽湖河湖交汇区设置农田和杨树林监测小区和监测井,进行了为期1年的地表养分流失和地下水水质监测。结果表明：1）林地雨前雨后表层土壤含水量均小于麦田,麦田土壤含水量较雨前平均提高8.95%,林地提高4.05%。2）麦田和杨树林地表层土壤硝态氮、铵态氮及有效磷流失总量分别为63.53 mg·kg^-1、5.61 mg·kg^-1及57.43 mg·kg^-1和16.78 mg·kg^-1、2.45 mg·kg^-1及0.73 mg·kg^-1,稻季田面水硝态氮、铵态氮、可溶性磷和颗粒态磷流失总量为8.32 mg·L^-1、27.44 mg·L^-1、2.39 mg·L^-1和2.99 mg·L^-1,监测期内杨树林氮磷流失总量明显低于农田。3）农田表层养分流失量与降雨量存在密切关系,基本随降雨量增大呈对数增长,而杨树林几乎不受降雨影响。4）农田产生径流的理论最小降雨量（麦田：3.3 mm;稻田：4.2 mm）远小于杨树林地（22.8 mm）,麦田铵态氮、正磷酸盐浓度,稻田和杨树林地总氮、硝态氮、铵态氮、总磷、可溶性磷、正磷酸盐浓度与降雨量存在显著相关性。5）农田径流中养分浓度与地下水氮磷含量存在显著相关性（P<0.05）,而杨树林地地下水氮磷含量保持在相对稳定水平,与径流中养分浓度无明显相关性。与农田相比,林地能够更好地控制径流养分流失,缓解地下水污染,有利于农业面源污染的控制。     

潮土磷素累积流失风险及环境阈值

潮土是中国分布比较广、施肥强度大的典型耕作土壤，潮土中磷素累积与流失对区域水环境的污染风险不容忽视。该研究在潮土面积最大的河南省采集磷素水平不同的典型潮土作为供试土壤，采用人工模拟降雨及土柱模拟试验方法，通过测定土壤中Olsen-P和溶解态活性磷CaCl2-P含量以及径流或淋滤液中各形态磷浓度，研究了潮土中磷素随地表径流和下渗流失特征，并通过分段线性模型对潮土的磷素环境阈值进行拟合。结果表明：1）不同形态磷在潮土土壤剖面中均有一定程度的累积，土壤Olsen-P和CaCl2-P含量表现为高磷最大，中磷次之，低磷最小，而磷吸持指数值表现为低磷最大，中磷次之，高磷最小。从磷素的剖面分布来看，低磷和中磷水平潮土Olsen-P和CaCl2-P含量随着土壤深度的增加而降低，而高磷水平的潮土Olsen-P和CaCl2-P含量在20～40 cm土层含量最高。2）不同磷水平潮土径流中总磷（TP）、可溶性总磷（TDP）和颗粒磷（PP）浓度和流失量大小表现为高磷最高，中磷和低磷水平土壤次之，潮土径流流失以PP为主。3）低磷和中磷水平潮土淋滤液中的各形态磷浓度和流失量随着土层深度的增加而降低，而在高磷水平的潮土淋滤液中，20～40 cm土层淋滤液中磷浓度和流失量要显著高于其他土层，在整个土壤剖面磷素浓度随着土层深度的增加呈现先上升后下降的趋势，潮土淋滤流失以TDP为主，其中，高磷和低磷水平潮土以可溶性有机磷占主导，而中磷水平潮土以钼酸盐反应磷（MRP）占主导。4）通过分段回归模型将不同含磷水平潮土的水溶性磷与土壤中Olsen-P含量进行拟合，得出潮土土壤磷素环境阈值为24.65 mg/kg，研究还表明径流和渗漏液中TP浓度与土壤CaCl2-P含量呈显著正相关，因此可通过测定CaCl2-P来预测并判断土壤磷素流失风险。     

Rainfall effects on erosion of earthworm casts and phosphorus transfers by water runoff

 We investigated whether, under a temperate climate and in a maize crop, earthworm casts could contribute to soil erosion and further favour the exportation of phosphorus by runoff waters. Recording of casts was made in compacted (wheel-tracks) and non-compacted inter-rows, for a 2-month period in spring. To assess the rainfall impact on cast evolution, half of the observation sites were protected against rain splash by a nylon mesh placed above the soil surface. The water runoff was collected and analysed for sediment contents and phosphorus concentration. The mean annual production of surface casts was calculated to be 34 kg (dry weight) year^–1 kg^–1 earthworm (fresh weight). Synchronization between cast erosion and rainfall events was shown under natural conditions (unprotected sites). The erosion rate was 4 times greater over rainy periods than dry ones, reaching 80% of cast numbers. It appeared that not the runoff effect but the splash effect, due to the kinetics of the drops, disrupted casts. Newly formed casts disappeared first, with the erosion rate decreasing twofold for casts more than 10 days old. Cast erosion and runoff, as well as worm casting activity, were greater under compacted sites than under non-compacted sites, indicating an influence of earthworms on soil erosion from compacted soils. The total phosphorus content was similar in casts and uningested soil (0.80 mg phosphorus g^–1). Potential phosphorus losses from cast erosion was calculated to reach 25–49 mg phosphorus m^–2 per rainfall event depending on soil compaction. The amounts of particulate phosphorus recovered in water runoff after each rainfall event varied from 1 mg to 11 mg phosphorus. These results are compared and discussed. Received: 20 October 1998     

不同放牧制度对呼伦贝尔草原径流中磷流失模拟研究

为了探究不同放牧制度对干旱半干旱地区草原土壤磷元素流失的影响,以呼伦贝尔砂质草原为研究对象,通过设置不同降雨强度,选择自由放牧、轮牧、休牧草场进行人工模拟降雨试验,利用混合深度模型模拟磷流失过程。结果表明:在4种雨强下,自由放牧草场总磷流失量最大,是休牧草场的1.31~1.50倍,是轮牧草场的1.59~1.74倍。颗粒态磷为草场土壤磷素的主要流失形式,其含量为溶解态磷的2.2~3.7倍。混合深度模型模拟结果显示,不完全混合模型的优于完全混合模型,并且在雨强较高情况下的模拟效果较好。在雨强小于1.5mm/min降雨事件中,放牧制度对磷元素流失影响显著(p0.05),轮牧草场磷流失最少。因此,适当的将呼伦贝尔草原自由放牧草场向休牧和轮牧草场转变,将有利于减少草场磷元素流失及草原生态可持续发展。     

植被覆盖条件下纳米碳对黄土坡面养分流失调控的试验研究

将纳米材料应用于坡面养分流失调控对减少黄土坡面养分流失等有着重要意义。基于神木六道沟流域上的坡面人工模拟降雨试验,分析了不同纳米碳含量(质量百分比分别为0%,0.1%,0.5%,0.7%,1.0%)对黄土坡面养分迁移过程的影响。结果表明:(1)同一作物的小区添加不同纳米碳含量对养分流失影响不明显;5种下垫面条件下,养分流失量均呈随纳米碳含量增加而降低的趋势,其中纳米碳含量为0.5%及0.7%对降低径流养分流失量的效果最好。不同纳米碳含量条件下,径流中的养分流失量从小到大为:空地玉米柠条绿豆苜蓿。(2)人工模拟降雨条件下,土壤表层养分在0—5cm内均有明显减少。而大于5cm深度的土壤中的养分值在降雨后有所增加,但随着深度增大养分增加量减少,而且添加不同浓度纳米碳导致养分值减少的速率不同。(3)不同纳米碳含量下与不同植被覆盖下径流中各离子的养分流失调控效果评价是径流中不同离子的平均浓度与平均流失率均随纳米碳含量的增加而减小,规律性较为明显。