發(fā)布時間：2018-06-05 09:00

  本文選題：植被類型 + 黃土坡地　； 參考：《環(huán)境科學(xué)學(xué)報》2017年06期

【摘要】：地形和植被會改變水分在土壤中的運移,進(jìn)而影響土壤中硝態(tài)氮(NO_3~--N)的分布,并可能導(dǎo)致對水體污染的差異.在黃土高塬溝壑區(qū)黑河流域選取3個樣點,采集刺槐林和草地在不同坡位(上、中和下坡位)的6 m深土樣,分析了坡位和植被對NO_3~--N遷移的影響,并初步評估了其對地表水及地下水污染的潛在風(fēng)險.不同坡位及植被條件下,土壤中硝態(tài)氮均沒有出現(xiàn)累積,在表層土壤達(dá)到最大值后逐漸減小.2種植被下NO_3~--N達(dá)到穩(wěn)定時的深度約為200 cm,穩(wěn)定濃度均為下坡位上坡位中坡位,但在同一坡位的穩(wěn)定濃度均有草地高于刺槐林的特點,說明坡位及植被覆蓋類型均會影響NO_3~--N在土壤中的分布.整個流域地表水NO-3含量枯水期及汛期分別為(6.90±2.10)mg·L~(-1)和(5.84±2.86)mg·L~(-1),而坡地表層土壤(0~20 cm)中可移動態(tài)NO_3~-為(29.55±6.59)mg·L~(-1),明顯大于地表水中的濃度,很有可能隨徑流流失造成地表水氮素污染.地下水枯水期和汛期的NO_3~-含量分別為(24.61±23.72)mg·L~(-1)和(15.70±10.78)mg·L~(-1),而坡地深層土壤(200 cm)中NO-3為(0.78±0.16)mg·L~(-1),由于濃度較低,對地下水造成污染的可能性較小.
[Abstract]:Topography and vegetation will change the movement of water in soil, and then affect the distribution of NO3- N in soil, which may lead to the difference of water pollution. In the Heihe River Basin of the Loess Plateau and gully region, the samples of 6 m deep soil from Robinia pseudoacacia forest and grassland in different slope positions (upper, middle and lower) were collected, and the effects of slope position and vegetation on no _ 3--N migration were analyzed. The potential risk of surface water and groundwater pollution was preliminarily evaluated. Under different slope positions and vegetation conditions, no accumulation of nitrate nitrogen in soil was observed. After the topsoil reached the maximum value, the depth of NO3- N under planting cover was about 200 cm, and the stable concentration was at the middle slope position in the upper slope position of the downhill position, and the concentration of nitrate nitrogen in the soil decreased gradually after the surface soil reached the maximum value, and the depth of NO3- N under the soil cover was about 200 cm. But the stable concentration in the same slope was higher than that in the Robinia pseudoacacia forest, indicating that both the slope position and the vegetation cover type would affect the distribution of NO3- -N in the soil. The contents of no-3 in the surface water of the whole basin were 6.90 鹵2.10)mg / L ~ (-1) and 5.84 鹵2.86)mg / L ~ (-1) respectively during the dry season and flood season respectively, while the movable no _ 3 ~ (3 +) was 29.55 鹵6.59)mg / L ~ (-1) in the topsoil soil of sloping land, which was obviously higher than that in the surface water, and it was very likely that the surface water could be polluted by nitrogen with runoff. The contents of NO3- in groundwater during dry season and flood season are 24.61 鹵23.72)mg / L ~ (-1) and 15.70 鹵10.78)mg / L ~ (-1), respectively, while in the deep soil of sloping land, the content of no ~ (- 3) is 0.78 鹵0.16)mg / L ~ (-1), so the possibility of groundwater pollution is low because of its low concentration.
【作者單位】： 西北農(nóng)林科技大學(xué)資源環(huán)境學(xué)院;西北農(nóng)林科技大學(xué)黃土高原土壤侵蝕與旱地農(nóng)業(yè)國家重點實驗室;
【基金】：國家自然科學(xué)基金(No.51179161) 中央高校基本科研業(yè)務(wù)費專項(No.2452015105)~~
【分類號】：S153.6;X52

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