滇池流域富磷区磷流失特征及控磷植物群落恢复研究
发布时间：2018-09-17 11:44
【摘要】：在富营养化水体中,磷被普遍认为是浮游植物季节性增长形成蓝藻水华的限制因子。富磷区磷素雨季流失将对周边水系环境构成严重威胁。然而,在富磷区,针对磷分布特征、磷流失特征、植被分布特征以及有效控磷植被群落的研究方面,研究工作还较少。而这方面的研究是当前恢复富磷区植被、控制水土流失和磷流失的急需解决的重要问题。 为此,我们以滇池东南部上蒜镇柴河汇水区内的富磷区域作为研究对象,对磷及其它土壤养分元素空间分布特征,以及相应植被分布特征进行了分析,设置3个汇水断面监测雨季径流输出状况；并选择区域内典型地被,建设马桑群落、野古草群落、蔗茅群落、云南松群落、华山松群落、旱冬瓜群落、云南松-旱冬瓜针阔混交林群落、蓝桉群落和黑荆群落等9个径流小区,对径流小区植被覆盖率、物种多样性、土壤肥力、凋落物层覆盖率、单位面积草本植物分蘖数等进行调查分析,结合产流量、污染物输出状况等,确定控磷植物群落关键指标；依据富磷区植被分布特征,确定植被恢复的理论。通过调查研究,得出以下主要结果与结论： (1)富磷区土壤环境变化复杂,植被分布受限于土壤环境 滇池流域东南富磷区,土壤磷浓度以磷矿区为中心,向四周呈现递减式扩散。研究区内土壤全磷浓度范围在1.15～80.2g/kg,变化梯度较大。土壤N：P比变化幅度也大,范围为0.006～0.98。土壤pH值、土壤有机质、全氮、全磷以及碱解氮和速效磷,在空间上具有强烈的变动性。土壤各养分元素的比值中,土壤N：P比值基本低于1,最小值为0.006。富磷区土壤特殊的肥力特征,影响着区域内植被的分布。 (2)富磷区的高磷浓度的土壤地段,植物具有低氮需求下的高固碳能力特征 高磷浓度的土壤地段的植物组分中,戟叶酸模的C：N：P的比值为104：4.7：1,蔗茅的为132：4.3：1,紫茎泽兰的为106：6：1,刺芒野古草群落的为189：6.4：1,马桑群落的为118：6.2：1,白健杆的为193：6.5：1。相比Redfield比值系数,这些植物体现出氮的比值相对较低的特征。表明这些植物在仅需要少量N素的补给下,具有对C的高效固定能力,这也是这类先锋植物重要的适应性特征。 (3)依据富磷区土壤肥力与群落物种数分析,土壤全氮是群落植被覆盖率及物种丰富度指数的限制因子 各植物群落的各结构特征指数与土壤全磷、土壤最高磷浓度及土壤pH值均呈现显著负相关关系。植被覆盖率与这3个指标间相关系数分别为-0.793、-0.786和-0.714。植被覆盖率与土壤全氮、土壤有机质和土壤碱解氮呈现显著的正相关关系,相关系数分别为0.786、0.736和0.727。这些肥力指标与植被覆盖率的相关性均为显著相关。高浓度磷和低背景氮是影响植被覆盖率的主要土壤因素。 各植物群落的物种丰富度指数与土壤全氮、土壤有机质和土壤碱解氮呈现显著的正相关关系,相关系数分别为0.904、0.893和0.724。各植物群落的物种丰富度指数与土壤pH值、土壤全磷呈现负相关关系,相关系数分别为-0.805、-0.635。植物群落物种丰富度指数最大限度受限于土壤全氮,其次为土壤有机质,并与土壤pH值呈现显著的负相关关系。 主成分分析中,第一主成分贡献率达70.7%,主要包含土壤有效氮、土壤全氮,土壤有机质,土壤全磷和土壤pH值信息,它们具有的载荷分别为0.925,0.894,0.859,-0.870和-0.840。富磷区植被及群落特征分布的首要影响因素是土壤氮素水平。 (4)磷矿开采区及周边裸露区域是富磷区磷流失的关键区域 研究区水土流失强度最大的区域为戟叶酸模群落,水土流失强度为330t/ha2.a,其次为磷矿开采区区域,为149t/ha2.a。研究区农田面积相对最大,水土流失量也最大,土壤流失量为988t/a裸露地区域,土壤流失量为957t/a。根据表层土壤全磷含量测算,则土壤全磷年流失量最高的区域为磷矿区及周边裸露地区域,磷的年流失量达57.8t,占年总流失量65.3t的88.5%。农田土壤磷流失也相对较严重,年流失量为4.98t。戟叶酸模群落,面积仅为0.1ha,但磷年流失量达1.15t。 磷矿区及周边裸露区域面积为研究区的5.6%,但潜在磷流失量占了研究区年流失量的88.5%,本区域是富磷区磷流失的关键区域。 (5)雨季径流输出与植物群落覆盖率、凋落物覆盖率相关联 径流系数与植被覆盖率为显著负相关关系,相关系数为-0.837,显著度p0.005,；群落径流系数与凋落物覆盖率之间也呈现极其显著的负相关关系,相关系数为-0.810,显著度p0.008。群落径流系数与乔木层盖度、灌木层盖度、草本层盖度、物种丰富度指数、草本层分蘖数、单位面积凋落物质量等相关性不显著。径流系数(y)和植被覆盖率(x%)之间的回归方程为：y=4.29*10-7X3-0.011x+0.810。径流系数(y)和群落凋落物覆盖率(x%)之间的回归方程为：y=e(b0+b1)/x=e11.342/x。 (6)控磷植物群落恢复策略 在富磷区关键区域(磷矿区及周边裸露地区域)土壤因子中,与植被覆盖率相关系数最高的是土壤全氮,相关系数为0.990,p0.0005；其次,为土壤有机质,为极其显著正相关关系,相关系数均为0.959；在时间进程上,植被覆盖率(y%)的回归方程为回归方程为：y=-0.2304x2+9.3781x-7.5858, R2=0.9586。 利用径流系数(y)和植被覆盖率(x%)之间的回归方程计算,如果把磷矿开采区植被从0恢复到75%,则径流量理论上则削减了80%。植被覆盖率达75%时,土壤全氮含量限值为0.890g/kg,依据磷矿区土壤发育进程,当土壤全氮从0.361g/kg提高到0.871g/kg时,需要自然发育的年限是15.5年。 在富磷区雨季水土流失和污染物流失严重的关键区域,短期内迅速恢复植被覆盖率,是有效削减水土流失和径流的最有效途径。在富磷区的植被退化区域,影响植被恢复的首要限制因子为土壤氮素。此外,土壤机械组成、pH值、有机质含量等也对植被恢复具有重要的影响作用。建议在新开采的矿区,保存发育较为完好的表层土壤,阶段性利用储存的表土逐步恢复地段植被。其次,在已经遭受破坏的地段,氮素养分过低,可选择戟叶酸模、蔗茅、野古草等先锋植物,该类植物具有在低氮需求下,高固碳的能力,可逐步提高裸露地段的植被覆盖率,并逐年有效改善土壤环境。
[Abstract]:In eutrophic waters, phosphorus is generally regarded as a limiting factor for the seasonal growth of phytoplankton to form cyanobacterial bloom. Phosphorus loss in rainy season in phosphorus-rich areas will pose a serious threat to the surrounding water system environment. There are few studies on this subject, which is an important problem to be solved urgently for restoring the vegetation and controlling soil erosion and phosphorus loss in phosphorus-rich areas.
Therefore, the spatial distribution characteristics of phosphorus and other soil nutrients and their corresponding vegetation distribution were analyzed in the area rich in phosphorus in Chaihe catchment area of Shanglianzhen, southeastern Dianchi Lake, and three catchment sections were set up to monitor the runoff output in rainy season. The vegetation coverage, species diversity, soil fertility, litter layer coverage, and the number of herbaceous tillers per unit area in 9 runoff plots were investigated and analyzed. According to the characteristics of vegetation distribution in phosphorus-rich areas, the theory of vegetation restoration was determined. Through investigation and study, the following main results and conclusions were obtained:
(1) the soil environment in the phosphor rich area is complicated and the vegetation distribution is limited by the soil environment.
The total phosphorus concentration ranged from 1.15 g/kg to 80.2 g/kg, and the variation gradient was large. The soil N:P ratio also varied widely, ranging from 0.006 to 0.98. The ratio of soil N:P was lower than 1 and the minimum was 0.006. The special fertility characteristics of the soil in the phosphorus-rich region affected the distribution of vegetation in the region.
(2) in the high phosphorus concentration soil area of the phosphorus rich area, plants have the characteristics of high carbon sequestration under low nitrogen demand.
The ratio of C:N:P of Euphorbia officinalis was 104:4.7:1, that of Sugarcane Festuca was 132:4.3:1, that of Eupatorium adenophorum was 106:6:1, that of Eupatorium adenophorum was 189:6.4:1, that of Masao was 118:6.2:1, and that of White Robin was 193:6.5:1. The relatively low nitrogen yield indicates that these plants have the ability to fix C efficiently with only a small amount of N, which is also an important adaptive characteristic of these pioneer plants.
(3) According to the analysis of soil fertility and community species number in phosphorus-rich areas, soil total nitrogen is the limiting factor of community vegetation coverage and species richness index.
The correlation coefficients between vegetation coverage and soil total nitrogen, soil organic matter and soil alkali-hydrolyzable nitrogen were - 0.793, - 0.786 and - 0.714, respectively. The correlation coefficients were 0.786, 0.736 and 0.727, respectively. The correlation between these fertility indices and vegetation coverage was significant.
The species richness index of each plant community was positively correlated with soil total nitrogen, soil organic matter and soil alkali-hydrolyzable nitrogen, and the correlation coefficients were 0.904, 0.893 and 0.724, respectively. The species richness index was limited by soil total nitrogen, followed by soil organic matter, and was negatively correlated with soil pH.
The contribution rate of the first principal component was 70.7%, mainly including available nitrogen, total nitrogen, soil organic matter, total phosphorus and soil pH information. Their loads were 0.925, 0.894, 0.859, -0.870 and-0.840 respectively. The primary influencing factor of the distribution of vegetation and community characteristics in phosphorus-rich areas was soil nitrogen level.
(4) the bare area of the phosphate mining area and the surrounding area is the key area of phosphorus loss in the phosphorus rich area.
The area with the highest soil erosion intensity was Euphorbia officinalis community, the soil erosion intensity was 330 t/ha 2.a, followed by phosphate mining area, 149 t/ha 2.a. The area of farmland in the study area was the largest, the amount of soil erosion was also the largest, the amount of soil erosion was 988 t/a in the exposed area, and the amount of soil erosion was 957 t/a. The highest annual loss of total phosphorus was in the phosphorus mining area and the surrounding bare areas. The annual loss of phosphorus reached 57.8 t, accounting for 88.5% of the total annual loss of 65.3 t. The annual loss of phosphorus in farmland soil was relatively serious. The annual loss of phosphorus was 4.98 t. Euphorbia folica community, with an area of only 0.1 ha, but the annual loss of phosphorus reached 1.15 t.
The area of phosphorus mining area and its surrounding bare area is 5.6% of the study area, but the potential phosphorus loss accounts for 88.5% of the annual phosphorus loss in the study area.
(5) runoff output in rainy season is related to plant community coverage and litter coverage.
The correlation coefficient between runoff coefficient and vegetation coverage was - 0.837 and significance p0.005, and the correlation coefficient between runoff coefficient and litter coverage was - 0.810 and significance p0.008. The regression equation between runoff coefficient (y) and vegetation coverage (x%) was y = 4.29 * 10-7X3-0.011x + 0.810. The regression equation between runoff coefficient (y) and litter coverage (x%) was y = e (b0 + b1) / x = e11.342 / X.
(6) restoration strategy of plant communities controlled by phosphorus
Among the soil factors in the key areas of phosphorus-rich areas (phosphorus mining areas and surrounding bare areas), the highest correlation coefficient with vegetation coverage was soil total nitrogen, the correlation coefficient was 0.990, p0.0005; secondly, for soil organic matter, the correlation coefficient was extremely significant positive correlation, the correlation coefficient was 0.959; in the time course, the regression equation of vegetation coverage (y%). The regression equation is: y=-0.2304x2+9.3781x-7.5858, R2=0.9586.
The regression equation between runoff coefficient (y) and vegetation coverage (x%) was used to calculate the runoff. If the vegetation in the phosphorus mining area was restored from 0 to 75%, the runoff would be reduced by 80% theoretically. When the vegetation coverage reached 75%, the limit of soil total nitrogen content was 0.890 g/kg. According to the process of soil development in the phosphorus mining area, when the soil total nitrogen increased from 0.361 g/kg to 0.871 g/kg. The natural development period is 15.5 years.
Rapid restoration of vegetation coverage is the most effective way to effectively reduce soil erosion and runoff in the key areas with severe soil erosion and pollutant loss during rainy season in phosphorus-rich areas. It is suggested that in the newly mined mining area, the surface soil should be preserved and well developed, and the stored surface soil should be used to gradually restore the vegetation. Secondly, in the damaged area, the nitrogen nutrient is too low, and the pioneer plants such as Euphorbia officinalis, Sugarcane maw and Ancient Wild Grass can be selected. Under the condition of low nitrogen demand and high carbon sequestration capacity, the vegetation coverage of bare land can be gradually increased and the soil environment can be effectively improved year by year.
【学位授予单位】：云南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：Q948
本文编号：2245798
[Abstract]:In eutrophic waters, phosphorus is generally regarded as a limiting factor for the seasonal growth of phytoplankton to form cyanobacterial bloom. Phosphorus loss in rainy season in phosphorus-rich areas will pose a serious threat to the surrounding water system environment. There are few studies on this subject, which is an important problem to be solved urgently for restoring the vegetation and controlling soil erosion and phosphorus loss in phosphorus-rich areas.
Therefore, the spatial distribution characteristics of phosphorus and other soil nutrients and their corresponding vegetation distribution were analyzed in the area rich in phosphorus in Chaihe catchment area of Shanglianzhen, southeastern Dianchi Lake, and three catchment sections were set up to monitor the runoff output in rainy season. The vegetation coverage, species diversity, soil fertility, litter layer coverage, and the number of herbaceous tillers per unit area in 9 runoff plots were investigated and analyzed. According to the characteristics of vegetation distribution in phosphorus-rich areas, the theory of vegetation restoration was determined. Through investigation and study, the following main results and conclusions were obtained:
(1) the soil environment in the phosphor rich area is complicated and the vegetation distribution is limited by the soil environment.
The total phosphorus concentration ranged from 1.15 g/kg to 80.2 g/kg, and the variation gradient was large. The soil N:P ratio also varied widely, ranging from 0.006 to 0.98. The ratio of soil N:P was lower than 1 and the minimum was 0.006. The special fertility characteristics of the soil in the phosphorus-rich region affected the distribution of vegetation in the region.
(2) in the high phosphorus concentration soil area of the phosphorus rich area, plants have the characteristics of high carbon sequestration under low nitrogen demand.
The ratio of C:N:P of Euphorbia officinalis was 104:4.7:1, that of Sugarcane Festuca was 132:4.3:1, that of Eupatorium adenophorum was 106:6:1, that of Eupatorium adenophorum was 189:6.4:1, that of Masao was 118:6.2:1, and that of White Robin was 193:6.5:1. The relatively low nitrogen yield indicates that these plants have the ability to fix C efficiently with only a small amount of N, which is also an important adaptive characteristic of these pioneer plants.
(3) According to the analysis of soil fertility and community species number in phosphorus-rich areas, soil total nitrogen is the limiting factor of community vegetation coverage and species richness index.
The correlation coefficients between vegetation coverage and soil total nitrogen, soil organic matter and soil alkali-hydrolyzable nitrogen were - 0.793, - 0.786 and - 0.714, respectively. The correlation coefficients were 0.786, 0.736 and 0.727, respectively. The correlation between these fertility indices and vegetation coverage was significant.
The species richness index of each plant community was positively correlated with soil total nitrogen, soil organic matter and soil alkali-hydrolyzable nitrogen, and the correlation coefficients were 0.904, 0.893 and 0.724, respectively. The species richness index was limited by soil total nitrogen, followed by soil organic matter, and was negatively correlated with soil pH.
The contribution rate of the first principal component was 70.7%, mainly including available nitrogen, total nitrogen, soil organic matter, total phosphorus and soil pH information. Their loads were 0.925, 0.894, 0.859, -0.870 and-0.840 respectively. The primary influencing factor of the distribution of vegetation and community characteristics in phosphorus-rich areas was soil nitrogen level.
(4) the bare area of the phosphate mining area and the surrounding area is the key area of phosphorus loss in the phosphorus rich area.
The area with the highest soil erosion intensity was Euphorbia officinalis community, the soil erosion intensity was 330 t/ha 2.a, followed by phosphate mining area, 149 t/ha 2.a. The area of farmland in the study area was the largest, the amount of soil erosion was also the largest, the amount of soil erosion was 988 t/a in the exposed area, and the amount of soil erosion was 957 t/a. The highest annual loss of total phosphorus was in the phosphorus mining area and the surrounding bare areas. The annual loss of phosphorus reached 57.8 t, accounting for 88.5% of the total annual loss of 65.3 t. The annual loss of phosphorus in farmland soil was relatively serious. The annual loss of phosphorus was 4.98 t. Euphorbia folica community, with an area of only 0.1 ha, but the annual loss of phosphorus reached 1.15 t.
The area of phosphorus mining area and its surrounding bare area is 5.6% of the study area, but the potential phosphorus loss accounts for 88.5% of the annual phosphorus loss in the study area.
(5) runoff output in rainy season is related to plant community coverage and litter coverage.
The correlation coefficient between runoff coefficient and vegetation coverage was - 0.837 and significance p0.005, and the correlation coefficient between runoff coefficient and litter coverage was - 0.810 and significance p0.008. The regression equation between runoff coefficient (y) and vegetation coverage (x%) was y = 4.29 * 10-7X3-0.011x + 0.810. The regression equation between runoff coefficient (y) and litter coverage (x%) was y = e (b0 + b1) / x = e11.342 / X.
(6) restoration strategy of plant communities controlled by phosphorus
Among the soil factors in the key areas of phosphorus-rich areas (phosphorus mining areas and surrounding bare areas), the highest correlation coefficient with vegetation coverage was soil total nitrogen, the correlation coefficient was 0.990, p0.0005; secondly, for soil organic matter, the correlation coefficient was extremely significant positive correlation, the correlation coefficient was 0.959; in the time course, the regression equation of vegetation coverage (y%). The regression equation is: y=-0.2304x2+9.3781x-7.5858, R2=0.9586.
The regression equation between runoff coefficient (y) and vegetation coverage (x%) was used to calculate the runoff. If the vegetation in the phosphorus mining area was restored from 0 to 75%, the runoff would be reduced by 80% theoretically. When the vegetation coverage reached 75%, the limit of soil total nitrogen content was 0.890 g/kg. According to the process of soil development in the phosphorus mining area, when the soil total nitrogen increased from 0.361 g/kg to 0.871 g/kg. The natural development period is 15.5 years.
Rapid restoration of vegetation coverage is the most effective way to effectively reduce soil erosion and runoff in the key areas with severe soil erosion and pollutant loss during rainy season in phosphorus-rich areas. It is suggested that in the newly mined mining area, the surface soil should be preserved and well developed, and the stored surface soil should be used to gradually restore the vegetation. Secondly, in the damaged area, the nitrogen nutrient is too low, and the pioneer plants such as Euphorbia officinalis, Sugarcane maw and Ancient Wild Grass can be selected. Under the condition of low nitrogen demand and high carbon sequestration capacity, the vegetation coverage of bare land can be gradually increased and the soil environment can be effectively improved year by year.
【学位授予单位】：云南大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：Q948
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