不同降雨等级下杉木林土壤含水率和侧向流变化特征
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摘要
为了探究不同降雨等级对林下不同深度土壤含水率和侧向流变化的影响,探究南京城郊杉木林各层土壤含水率、侧向流变化对降雨事件的响应,分析土壤含水率变化量与累计降雨量和侧向流的关系,初步探讨杉木林的水源涵养机制。选取南京市铜山林场46年生杉木林,在大、中、小3种降雨等级下,采用ECH_2O土壤水分监测系统对土壤剖面0—5,5—15,15—30,30—60 cm的土壤水分含量进行了实时连续监测。结果表明:(1) 0—5,5—15 cm土层土壤含水率变化曲线和降雨量变化曲线具有同步性,15—30,30—60 cm土层含水率达到峰值时间滞后1～1.5 h;(2)小雨条件下,只有0—5,5—15 cm土层变化趋势较明显,侧向流主要发生在5—15 cm土层;(3)中雨条件下,雨强在8 mm/h和15.2 mm/h时,土层含水率出现2次明显的响应,侧向流主要发生在15—30 cm土层;(4)大雨条件下,累计降雨量22.8 mm时,5—15,15—30,30—60 cm土层出现峰值,侧向流主要发生在30—60 cm土层;(5)小雨、中雨、大雨过程中产生的最大侧向流分别为1.55,13.88,94.77 mm,随着降雨量的增加,侧向流有增加的趋势。土壤水分入渗为非饱和入渗,随着土层深度的增加,含水率峰值逐渐增大,侧向流增加较明显。土壤含水率变化和降雨量有较好的线性关系且相关性较强,随着降雨量的增加,土壤含水率和降雨量的相关性越来越差。土壤含水率变化量与累计降雨量和侧向流三者间互有显著相关性,最大侧向流与累计降雨量呈指数关系,y=0.7614e~(0.2238x)。
This study examined the impact of different rainfall levels on soil moisture content and Lateral flow in different soil depths of the forest to explore the response of the soil moisture content and the change of lateral flow in each soil layer in fir forest in Nanjing suburb, analyzed the relationship within the variation of soil moisture content, cumulative rainfall and the lateral flow, and preliminary discuss the water conservation mechanism of Chinese fir forest. The 46-year-old fir forest of Nanjing Tongshan Forestry Centre was selected as the study site. The soil moisture content of soil profiles 0—5 cm,5—15 cm,15—30 cm and 30—60 cm were monitored continuously by using the technology of system ECH_2O under the 3 types of rainfall levels(8 mm, 17.6 mm, 28.2 mm). The results indicated that:(1) the variation curves of soil water contents in 0—5 cm soil layer and 5—15 cm soil layer and the curves of rainfall variation were synchronous; the time when the water contents of 15—30 cm soil layer and 30—60 cm soil layer reached peak had lagged for 1.0～1.5 h;(2) under the condition of drizzle, the water contents only in 0—5 cm and 5—15 cm soil layer changed obviously, the lateral flow mainly occurred in 5—15 cm soil layer;(3) under the moderate rain condition, the soil moisture content occurred obvious responses twice when the rainfall intensities were 8.0 mm/h and 15.2 mm/h, the lateral flow mainly occurred in 15—30 cm soil layer;(4) under the heavy rain, the cumulative rainfall was 22.8 mm/h, and the peak occurred in 5—5 cm,15—30 cm and 30—60 cm soil layers, the lateral flow mainly occurred in 30—60 cm soil layer;(5) the maximum lateral flow in the course of drizzle, moderate rain and heavy rain was 1.55 mm,13.88 mm and 94.77 mm, respectively; the lateral flow trended to increase with the increase of rainfall. The water infiltration was the unsaturated infiltration, the peak value of water content increased gradually and the lateral flow increased significantly with the increase of soil depth. The relationship between the change of soil water content and rainfall and the correlation was strong. The correlation between soil moisture content and rainfall is getting worse with the increase of rainfall. There was a remarkable correlation between the change of soil water content and cumulative rainfall and lateral flow. The maximum lateral flow had the exponential relationship with the cumulative rainfall: y=0.7614 e~(0.2238x).
This study examined the impact of different rainfall levels on soil moisture content and Lateral flow in different soil depths of the forest to explore the response of the soil moisture content and the change of lateral flow in each soil layer in fir forest in Nanjing suburb, analyzed the relationship within the variation of soil moisture content, cumulative rainfall and the lateral flow, and preliminary discuss the water conservation mechanism of Chinese fir forest. The 46-year-old fir forest of Nanjing Tongshan Forestry Centre was selected as the study site. The soil moisture content of soil profiles 0—5 cm,5—15 cm,15—30 cm and 30—60 cm were monitored continuously by using the technology of system ECH_2O under the 3 types of rainfall levels(8 mm, 17.6 mm, 28.2 mm). The results indicated that:(1) the variation curves of soil water contents in 0—5 cm soil layer and 5—15 cm soil layer and the curves of rainfall variation were synchronous; the time when the water contents of 15—30 cm soil layer and 30—60 cm soil layer reached peak had lagged for 1.0～1.5 h;(2) under the condition of drizzle, the water contents only in 0—5 cm and 5—15 cm soil layer changed obviously, the lateral flow mainly occurred in 5—15 cm soil layer;(3) under the moderate rain condition, the soil moisture content occurred obvious responses twice when the rainfall intensities were 8.0 mm/h and 15.2 mm/h, the lateral flow mainly occurred in 15—30 cm soil layer;(4) under the heavy rain, the cumulative rainfall was 22.8 mm/h, and the peak occurred in 5—5 cm,15—30 cm and 30—60 cm soil layers, the lateral flow mainly occurred in 30—60 cm soil layer;(5) the maximum lateral flow in the course of drizzle, moderate rain and heavy rain was 1.55 mm,13.88 mm and 94.77 mm, respectively; the lateral flow trended to increase with the increase of rainfall. The water infiltration was the unsaturated infiltration, the peak value of water content increased gradually and the lateral flow increased significantly with the increase of soil depth. The relationship between the change of soil water content and rainfall and the correlation was strong. The correlation between soil moisture content and rainfall is getting worse with the increase of rainfall. There was a remarkable correlation between the change of soil water content and cumulative rainfall and lateral flow. The maximum lateral flow had the exponential relationship with the cumulative rainfall: y=0.7614 e~(0.2238x).
引文
[1]冯伟.毛乌素沙地东北缘土壤水分动态及深层渗漏特征[D].北京:中国林业科学研究院,2015.
[2]Yu Z, Carlson T N, Barron E J, et al. On evaluating the spatial-temporal variation of soil moisture in the Susquehanna River Basin[J]. Water Resources Research, 2001,37(5):1313-1326.
[3]李海防,史梅容,王金叶,等.广西猫儿山毛竹林不同层次土壤含水量的降雨响应[J].水土保持研究,2016,23(5):120-123.
[4]王正安,邸利,王彦辉,等.六盘山半干旱区华北落叶松林土壤水分对降雨的响应[J].干旱区资源与环境,2018,32(4):144-151.
[5]倪晨.花岗岩崩岗集水坡面土壤水分状况研究[D].武汉:华中农业大学,2016.
[6]刘昊,周宏飞,刘翔.强降雨条件下沙丘土壤水分运移特征分析[J].水土保持学报,2015,29(2):157-162.
[7]高红贝,邵明安.干旱区降雨过程对土壤水分与温度变化影响研究[J].灌溉排水学报,2011,30(1):40-45.
[8]刘宏伟,余钟波,崔广柏.湿润地区土壤水分对降雨的响应模式研究[J].水利学报,2009(7):822-829.
[9]吕刚,吴祥云.土壤入渗特性影响因素研究综述[J].中国农学通报,2008,24(7):494-499.
[10]吴胡强,邵永昌,庄义琳,等.南京城郊麻栎林坡面土壤体积含水率与侧向流对降雨响应[J].浙江农林大学学报,2014,31(5):683-689.
[11]王鹰翔,张金池,刘鑫,等.苏南丘陵区毛竹林坡面土壤水分对降雨的响应[J].水土保持通报,2016,36(1):22-26.
[12]Colman E A, Bodman G B. Moisture and energy conditions during downward entry of water into soils[J]. Soil Science Society of America Proceedings, 1944,9(C):3-11.
[13]杨帆,刘志军,马忠秋,等.太行山低山丘陵区坡地人工刺槐林降雨入渗及造林技术研究[J].中国生态农业学报,2005,13(3):172-174.
[14]黄志霖,李建新.太行山侧柏人工林林冠降雨截留及地表径流的研究[J].河南林业科技,2000,20(2):1-5.
[2]Yu Z, Carlson T N, Barron E J, et al. On evaluating the spatial-temporal variation of soil moisture in the Susquehanna River Basin[J]. Water Resources Research, 2001,37(5):1313-1326.
[3]李海防,史梅容,王金叶,等.广西猫儿山毛竹林不同层次土壤含水量的降雨响应[J].水土保持研究,2016,23(5):120-123.
[4]王正安,邸利,王彦辉,等.六盘山半干旱区华北落叶松林土壤水分对降雨的响应[J].干旱区资源与环境,2018,32(4):144-151.
[5]倪晨.花岗岩崩岗集水坡面土壤水分状况研究[D].武汉:华中农业大学,2016.
[6]刘昊,周宏飞,刘翔.强降雨条件下沙丘土壤水分运移特征分析[J].水土保持学报,2015,29(2):157-162.
[7]高红贝,邵明安.干旱区降雨过程对土壤水分与温度变化影响研究[J].灌溉排水学报,2011,30(1):40-45.
[8]刘宏伟,余钟波,崔广柏.湿润地区土壤水分对降雨的响应模式研究[J].水利学报,2009(7):822-829.
[9]吕刚,吴祥云.土壤入渗特性影响因素研究综述[J].中国农学通报,2008,24(7):494-499.
[10]吴胡强,邵永昌,庄义琳,等.南京城郊麻栎林坡面土壤体积含水率与侧向流对降雨响应[J].浙江农林大学学报,2014,31(5):683-689.
[11]王鹰翔,张金池,刘鑫,等.苏南丘陵区毛竹林坡面土壤水分对降雨的响应[J].水土保持通报,2016,36(1):22-26.
[12]Colman E A, Bodman G B. Moisture and energy conditions during downward entry of water into soils[J]. Soil Science Society of America Proceedings, 1944,9(C):3-11.
[13]杨帆,刘志军,马忠秋,等.太行山低山丘陵区坡地人工刺槐林降雨入渗及造林技术研究[J].中国生态农业学报,2005,13(3):172-174.
[14]黄志霖,李建新.太行山侧柏人工林林冠降雨截留及地表径流的研究[J].河南林业科技,2000,20(2):1-5.