ISWC OpenIR  > 水保所知识产出(1956---)
汉江中游小流域水土- 养分流失过程与调控研究
刘 泉
Subtype博士
Thesis Advisor李占斌
2013-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword农业非点源污染 侵蚀产沙过程 N、p 流失过程 调控 汉江中游
Abstract

本文根据 2011-2012 年汛期在陕南地区石泉后沟农业小流域的监测和实验,开展
了水土流失与非点源污染迁移机理与过程模拟研究,探讨了汉江中游小流域主要水土
保持措施拦截、削减农业非点源污染物的作用机理,为南水北调中线工程水源地农业
非点源污染的控制提供理论基础。通过研究,取得主要结论如下:
(1)阐明陕南后沟小流域的降雨产流特征及其产沙的时空分布。汛期径流小区
降雨量与径流量呈极显著关系,在 9°坡耕地降雨产流量与降雨量呈极显著的线性关
系,而在 14°-25°坡耕地降雨产流量与降雨量之间存在极显著的二次曲线函数关系。
不同坡度临界产流降雨量,表现出随着坡度增加产流临界降雨量呈下降的趋势。
坡地产流表现为蓄满产流,壤中流是坡地的优先流;作物前期和中后期生长阶段
的壤中流占总径流量比例是作物收获和土地空置阶段的 1.14-1.35 倍。
汛期初期降雨过程流域出口径流流速与流量呈现幂函数变化趋势,而后期降雨过
程径流流速与流量呈现线性变化趋势。径流动能与泥沙流失量在汛期初期和末期呈现
幂函数和线性关系,而汛期中期,两者呈现幂函数关系。
(2)不同土壤类型和地表覆被条件下,流域前期土壤水分状况对降雨产流过程
具有显著的影响,这个过程可以用 SCS 模型进行模拟。当初损参数设置为 0.3 时,实
测径流量和计算径流量相接近,CN 值为 58。
(3)阐明不同土地利用类型和海拔下土壤可蚀性的变化规律。后沟小流域典型
坡面土壤可蚀性研究表明,随着海拔升高林草地和玉米地土壤可蚀性逐渐降低,在
390m 处达到最大值,随后逐渐降低;在海拔 420-430m 的梯田处基本达到最小值,
并趋于稳定;通过修建梯田,能够增加土壤抗蚀性。
(4)阐明了不同下垫面对降雨侵蚀力和土壤侵蚀模数的影响,揭示了流域侵蚀
产沙与降雨径流的关系。后沟小流域多年降雨侵蚀力最大值出现在 7 月份,平均降雨
侵蚀力 R 值为 3403.66 MJ·mm/(hm 2 ·h·a)。该小流域年土壤侵蚀量为 15587.41t,年
均土壤侵蚀模数为 2013.877 t/km 2 ,属中度土壤侵蚀强度,小流域内坡耕地年均泥沙侵蚀量为 9853.47t,占小流域年侵蚀总量的 63.2%。小流域内土地利用类型的土壤侵
蚀量的顺序为:园地>坡耕地>退耕地>果园。四种不同土地利用类型的土壤流失量
最大值均发生在 7 月份,单场降雨过程土壤最大流失量分别占汛期坡耕地、退耕地、
园地、果园地监测土壤侵蚀量的 31.76%、32.78%、39.05%、11.44%。
在四种土地利用类型中,果园泥沙流失量与径流量的最佳回归方程为三次曲线方
程,坡耕地、退耕地、园地径流中泥沙含量与径流量关系显著,拟合方程采用 S 形曲
线方程较为合适。
(5)小流域氮、磷流失过程在汛期内表现出明显的阶段性。通过对小流域汛期
内氮、磷流失过程分阶段数值模拟结果表明,分段模拟结果可信度更高。虽然对于整
个汛期和分阶段模拟氮磷流失过程,流失量与径流量和产沙量的表达式均为:
T=aR b S c ,但是分阶段模拟氮磷流失量的预测值更接近实测值。
不同土地利用类型下年均氮、磷流失量有明显不同。果园和蔬菜园地的 TN、TP
流失浓度超过地表水Ⅱ水质标准分别为 15 倍和 1.25 倍。TN、TP 流失量排序为:蔬
菜园地>退耕地>坡耕地>果园地,年均 TN 流失量分别为:坡耕地 4.92kg/hm 2 、退
耕地 7.20kg/hm 2 、蔬菜园地 15.29kg/hm 2 、果园地 1.37 kg/hm 2 ;年均 TP 流失量分别为
坡耕地 0.09 kg/hm 2 ,退耕地 0.22kg/hm 2 ,蔬菜园地 0.25kg/hm 2 ,果园地 0.05kg/hm 2 。
(6)揭示了小流域出口径流、泥沙流失过程与 TN、TP 含量的关系。坡耕地、
退耕地,蔬菜园地和果园地径流中 TN 含量与径流量的函数关系均可以利用三次函数
进行拟合。坡耕地、退耕地和果园泥沙含量与 TP 含量可以用三次函数曲线进行拟合,
而果园可以用 S 形曲线方程、幂函数方程和对数方程进行模拟。
(7)为研究沟渠拦截氮磷的效果,在不同时间对沟渠不同断面水体进行了监测。
研究结果表明,在具有(没有)侧面外来水源干扰的沟渠断面,沟渠径流氮浓度增加
(降低)速度要超过磷含量的增加(降低)速度;沟渠径流 NH 4 + -N 浓度下降速度要
快于 TN,沟渠径流 NO 3 - -N 浓度的变化规律不明显,总体有波动稍增趋势;沟渠径
流 NH 4 + -N 含量的下降速度要快于 TN,降雨结束后,沟渠径流 NO 3 - -N 含量总体有波
动稍增趋势;不同断面径流中 TN、NH 4 + -N、NO 3 - -N 和 TP 浓度的变异系数为:下游
>上游>中游;TP 变异系数最大,在 48.32-113.66%之间;NO 3 - -N 变异系数最小,在
9.71-20.24%之间。
关键词:农业非点源污染;侵蚀产沙过程;N、P 流失过程;调控;汉江中游

Other Abstract

According to the monitoring and experiments in flood seasons during 2011-2012
in the Hougou agricultural watershed, we carried out the transport mechanisms and
modelling studies of water and sediment erosion and non-point source pollution,
discussing the interception of soil and water conservation measures and reduce
effectively of agricultural non-point source pollution for the South-North Water
Diversion Project. By the method of combining theoretical analysis and experiments
study, the main results were as follows:
(1) Clarify the characteristic of runoff and spatial and temporal distribution of
sediment yield. During the flood season, there is in highly significant correlation with
rainfall and runoff in runoff plot, among there was a highly significant linear correlation
in the 9° plot,there existed very significant curve function correlation in 14°-25° plots.
Moreover, the rainfall of critical runoff yield decline with slope degree increase.
Stored-full runoff was the main pattern of runoff yield in slope farmland in the
Hougou agricultural watershed, and the subsurface flow accounted for a larger
percentage of total runoff. Moreover, the subsurface flow ratio is 1.14-1.35 times at the
seedling stage and the vigorous stage.
Runoff rate is increase with volume of runoff increase; there is power function and
linear relation between runoff velocity and runoff volume in the early and the later of
flood season. There are power functions and linear relation between runoff kinetic
energy and sediment loss in the early and the later of flood season, however, power
function relation in the middle of flood season.
(2) The SCS model not only reflects the runoff yield conditions under different
soil types and vegetation covers in the Hougou agricultural watershed, but also fully
considered the soil moisture impacts runoff. When loss parameter is 0.3, and CN value  is 58, monitored runoff and calculated runoff is very closer in runoff plot in the Hougou
agricultural watershed.
(3) Clarify the change laws of soil erodibility under different land use and
elevations. The study of slope indicated that soil erodibility of woodland,abandoned
land and cornfield is drop off over increasing elevation, the maximum soil erodibility at
the point of 309 m, then declines gradually,the minimum soil erodibility of terraced
field at elevation between 420 m and 430 m, the value is tending towards stability.
(4) Clarify the effect of the rainfall erosivity and soil erosion modulus under
different land use, and reveal the relation between runoff and sediment yield. The
maximum rainfall erosivity in July, average R value is 3403.66 MJ·mm/ (hm 2 ·h·a), and
average soil erosion amount is 15587.41t/a, soil erosion modulus is 2013.877 t/(km 2 ·a) ,
which in the scope of middle soil erosion intensity in the Hougou agricultural
watershed. However, average soil erosion amount of slope land is 9853.47 t/a, which
takes up of more than 63.2% in total soil erosion amount.
The order of soil erosion amount in different land use is: garden field>slope land
>abandoned land>orchard field.The results showed that the maximum soil erosion
amount of slope land, abandoned land, garden field, orchard field in July, which takes
up of more than 31.76%, 32.78%, 39.05%, 11.44% in total soil erosion amount in a rain
event during flood season, respectively.
The best regression equation is cubic curve-fitting equation between soil loss
amounts and runoff of orchard field, however, the best regression equation is S curve
equation between soil loss amounts and runoff of slope land, abandoned land, garden
field.
(5) The N and P loss processes shows in stages obviously in flood sesons during
2011-2012. N and P loss predictions done stage-by-stage can have improved accuracy.
Although the fitted equations between the amount of N and P loss between runoff and
sediment yield were N=aR b S c assessed stage-by-stage, the method was supported by the
study for predicting the amount of N and P loss in the Hougou agricultural watershed.
The process of N and P loss in runoff and sediment is different obviously under
different land use. The N and P loss concentrations in orchard field and garden field
have exceeded surface water Class Ⅱ water standard more than 15 and 1.25 times. For  four land uses, the order of N and P loss is garden field>abandoned land>slope land
>orchard field. According to the monitored results, average TN amount loss of garden
field, abandoned land, slope land, orchard field are 15.29, 7.20, 4.92, 1.37kg/(hm 2 ·a),
however, average TP amount loss of garden field, abandoned land, slope land, orchard
field are 0.25, 0.22, 0.09, 0.05kg/(hm 2 ·a), respectively.
(6) Reveal the relation between runoff, sediment and TN, TP concentration. The
cubic function can express relation between the TN concentration in runoff and runoff
from slopeland, abandoned land, garden field, orchard fields, especially orchard field.
The cubic function can express relation between the TP concentration and sediment
from slopeland, abandoned land, garden field; however, S curve equation; power
function and logistic equation can express the relation in orchard fields.
(7) Ditch water of different sections was monitored at different times to study the
ecological effectiveness of ditch. The results showed that ditch and aquatic plant had
function of interception and purification water. N and P concentration of water
decreased when water flow through the ditch. Generally reduction range of TN and was
higher than that of TP. Moreover, reduction range of NH 4 + -N was higher than that of
TN. However, NO - 3 -N concentration had slight fluctuated incremental trend in ditch
after rains. The coefficient of variation of TN, NH 4 + -N, NO - 3 -N and TP in different
sections is downstream>upstream>midstream. The coefficient of variation of TP is
the highest; the range is 48.32-113.66%, and the coefficient of variation of NO - 3 -N is
the smallest; the range is 9.71-20.24%.
Key Words :Agricultural non-point source pollution, Sediment yield processes, N and
P loss processes, Controlling, the middle reaches of Han River

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8966
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
刘 泉. 汉江中游小流域水土- 养分流失过程与调控研究[D]. 北京. 中国科学院研究生院,2013.
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