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不同形态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最逐渐增加，但Ortho-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．随着植被覆盖虚增大而减少，但径流中Ortho-P的含量则随着覆盖度的增加而增加。     

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     

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。     

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。     

不同利用方式及施肥对黑土地表磷素养分流失的影响

本文针对黑土利用现状,在吉林农业大学教学试验场黑土区选择不同利用方式的玉米地、休闲地、果园、草地,并在玉米区进行了不同数量的施肥。通过野外试验,采集2002年度5~10月历次自然降雨(共7次)产流及泥沙样品,同时采集降雨前后的耕层土壤样品,研究了黑土区地表径流对磷素养分特征及肥力退化的影响。结果表明:径流TP流失比和DP流失比随覆盖度都表现为先增加后逐渐降低;不同利用方式表层土壤的TP和DP相差很大,就全磷富积表现为果园>草地>玉米地>休闲地,可溶性磷的富积却表现为:休闲地>玉米>果园>草地;随P肥用量的增加而径流磷素(TP、DP)浓度及径流磷素流失量也增加;流失泥沙TP浓度随着磷素施入的增加而增加;泥沙磷素浓度、泥沙磷素流失量均比CK大,但泥沙流失量均比CK小;增施氮磷虽能增加作物的产量,但N、P施用量必须适度,从试验期间径流、泥沙的TP、DP流失量观测,可以初步得出黑土氮磷配合施肥的宜于选配的方案是B5区N98P44N570。     

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.     

模拟降雨条件下潮土磷素流失特征及影响因素研究

潮土是我国重要的耕作土壤,磷素的流失不仅影响土壤肥力和作物产量,而且会增加地表水环境的污染负荷.本研究采用人工模拟降雨试验方法,研究了不同降雨强度和坡度条件下,潮土径流中磷素的动态变化和径流中磷素流失特征,以期为控制潮土区径流面源污染提供理论依据.结果表明:(1)整个降雨过程中,径流中总磷(TP)和颗粒态磷(PP)变化...     

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。     

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。     

秸秆覆盖对东北黑土区坡耕地产流产沙及氮磷流失的阻控

为揭示秸秆覆盖对东北黑土区坡耕地产流产沙及氮磷流失的阻控,通过田间试验,探讨秸秆覆盖模式下,玉米生育期对不同坡度试验小区径流、泥沙和氮磷流失的阻控效果。结果表明:随着耕地坡度的增加,地表径流量、土壤及氮磷流失量逐渐增加。玉米种植条件下,地表径流量与降雨量呈正相关,土壤流失量与降雨量不相关。秸秆覆盖模式对土壤流失的阻控效果均为随坡度的降低,阻控率增加,秸秆覆盖对地表径流和土壤流失阻控率均超过90%。土壤中氮素流失以溶解态氮为主,溶解态氮占总氮的60%以上;磷素流失以颗粒态磷为主,颗粒态磷占总磷的80%以上。秸秆覆盖对土壤中总氮、总磷阻控率均超过85%,对于控制水土流失和降低面源污染风险具有积极意义。     

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。     

Plant nutrient losses in runoff from conservation tillage corn

Conservation tillage in north Mississippi, U.S.A., reduced total (sum of solution and sediment) plant nutrient losses in runoff from corn, even though solution nitrogen (N) and phosphorus (P) concentrations in runoff were greater than from conventional-till and sediments were enriched severalfold in N and P. Plant nutrient losses were reduced by conservation tillage because of the significant reductions in soil loss. Soil losses from corn grown for grain were reduced more than 92% by reduced and no-till practices. Corresponding total losses of N and P were reduced about 70 and 80%, respectively.Conservation tillage reduced plant nutrient losses associated with sediments but increased solution P concentrations and losses in runoff. Solution P concentrations and losses, which were related to crop management, decreased in the following order: no-till corn (grain) ? no-till corn (silage) > reduced-till corn (grain) > conventional-till corn (grain) > conventional-till corn (silage). Solution P concentrations and losses in runoff increased with an increase in crop residues left on the soil surface after harvest and with a decrease in annual soil loss.     

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.     

三峡库区坡耕地免耕秸秆覆盖下氮磷流失特征

为有效防治三峡库区坡耕地氮磷流失,在三峡库区长坪小流域连续进行两年野外径流小区监测试验。在自然降雨条件下进行免耕秸秆覆盖(SM)和对照(CK)两个处理的田间试验,研究了免耕秸秆覆盖措施对地表径流和氮磷养分流失的影响。结果表明：(1)降雨量与径流量极显著正相关,径流主要由几次暴雨事件造成,需要重点防范玉米季暴雨造成的水土流失。免耕秸秆覆盖能减少地表产流产沙,相比对照处理,免耕秸秆覆盖减少19.1%的径流流失,减少63.6%的泥沙流失。(2)免耕秸秆覆盖分别降低了21.3%,25.8%的总氮和总磷流失量,径流量和氮磷流失量呈极显著正相关,免耕秸秆覆盖主要通过减少径流量来减少氮磷流失。(3)坡耕地油菜—玉米种植制的氮磷流失风险期为6—7月初,该时期CK处理41.3%的径流量贡献了81.4%,52.1%的总氮和总磷流失,SM处理38.4%的径流量贡献了75.2%,48.2%的总氮和总磷流失,在该时期通过免耕秸秆覆盖可分别减少17.5%,31.7%的总氮和总磷流失。研究表明,免耕秸秆覆盖是控制三峡库区坡耕地氮磷养分流失的良好水土保持措施。