樟子松人工固沙林土壤水分动态密度效应研究  

Study on the density effect of soil moisture dynamics of Pinus sylvestris var.mongolica artificial sand-fixation forest

作　　者：韩辉 张学利 党宏忠[2] 白雪峰 郎明翰 宋鸽 刘春颖 HAN Hui;ZHANG Xueli;DANG Hongzhong;BAI Xuefeng;LANG Minghan;SONG Ge;LIU Chunying(Liaoning Zhanggutai Desert Ecosystem Research Station,Liaoning Institute of Sandy Land Control and Utilization,Fuxin 123000,China;Institute of Ecological Protection and Restoration,Chinese Academy of Forestry,Beijing,100091,China;Liaoning Academy of Agricultural Science,Shenyang 110161,China)

机构地区：[1]辽宁章古台科尔沁沙地生态系统国家定位观测研究站,辽宁省沙地治理与利用研究所,辽宁阜新123000 [2]中国林业科学研究院生态保护与修复研究所,北京100091 [3]辽宁省农业科学院,辽宁沈阳110161

出　　处：《辽宁林业科技》2024年第3期1-10,共10页Liaoning Forestry Science and Technology

基　　金：辽宁省科技重大专项(辽西北防沙治沙关键技术研究与示范);国家自然科学基金项目(32071836)。

摘　　要：研究樟子松人工固沙林土壤水分时空动态随林分密度的变化规律,采取有针对性的措施可以提高系统的稳定性和可持续性。该研究在科尔沁沙地南缘樟子松人工林中选取同龄、高密度(810株·hm^(-2))、低密度(404株·hm^(-2))林分设置样地,以无林地(草地)为对照,采用烘干法和TDR测定相结合的方法,2004-2022年监测0~3 m土层的土壤含水率,并同步监测林外降水量。结果表明:2004-2022年,0~1 m土层高、低两种密度林分的年均土壤含水率分别为11.1%、11.8%,两者无显著差异(t=0.935,P=0.3);土壤含水率的季节变化可划分为低值期(4-5月)、平缓期(5-6月)、上升期(6-8月)、高峰期(8-9月)和下降期(9-10月)。高(低)两种密度林分0~1m土层水分状况的统计表明,非旱、轻旱、中旱和重旱比例分别为59.7%(65.0%)、24.4%(15.3%)、13.8%(12.8%)和2.2%(6.9%)。林分在从中龄林向近/成熟林的演化过程中,高密度林分0~1 m土层土壤水分处于非旱状态的占比由58.3%增至60.3%,低密度林分则由44.8%增至73.7%,低密度林分增幅更显著。高、低密度林分0~1 m土层非旱状态占比最高的月份均为8月,重旱状态占比最高的月份均为6月。在科尔沁沙地南缘,樟子松不同密度林分土壤含水率均随土层深度的增加而减小。0~1 m土层不同密度林分土壤含水率年际尺度差异不显著,土壤含水率的季节、年际变化与同期降水量变化的格局相似,但不完全一致。不同密度林分的林地均存在不同程度的干旱,干旱所占比例约65%,生长季各月都发生过不同程度的干旱,6月份为重旱多发期。在中龄林向近/成熟林的演化过程中,土壤干旱改善情况低密度林分好于高密度林分,因此建议适时疏伐改善樟子松林地土壤水分状况。Studying the spatial and temporal dynamics of soil moisture in Pinus sylvestris var.mongolica plantations for sand fixation and its changes with stand density can help to take targeted measures to improve the stability and sustainability of the system.This study selected two P.sylvestris var.mongolica plantations of the same age but different densities(810 trees·hm^(-2) and 404 trees·hm^(-2),referred to as high-density and low-density stands respectively)on the southern edge of Horqin Sandy Land,and used grassland without trees as a control.The soil moisture content of the 0~3 m soil layer was monitored long-term(2004-2022)using a combination of oven drying and TDR methods,and precipitation outside the forest was monitored simultaneously.The results showed that from 2004 to 2022,the average annual soil moisture content of the 0~1 m soil layer in the high-density and low-density stands was 11.1%and 11.8%respectively,with no significant difference between them(t=0.935,P=0.3).The seasonal variation of soil moisture content can be divided into a low period(April-May),a flat period(May-June),a rising period(June-August),a peak period(August-September),and a declining period(September-October).The statistical analysis of the water status in the 0~1 m soil layer of the high(low)density stands showed that the proportions of non-drought,light drought,moderate drought,and severe drought were 59.7%(65.0%),24.4%(15.3%),13.8%(12.8%),and 2.2%(6.9%)respectively.During the evolution of the stands from middle-aged to near/mature forests,the proportion of non-drought conditions in the 0~1 m soil layer increased from 58.3%to 60.3%in the high-density stand and from 44.8%to 73.7%in the lowdensity stand,with a more significant increase in the low-density stand.The months with the highest proportion of nondrought conditions in the 0~1 m soil layer were August for both high and low-density stands,and the months with the highest proportion of severe drought were June.On the southern edge of Horqin Sandy Land,the soil moisture content o

关 键 词：樟子松 不同密度 土壤水分变化 土壤水分有效性 

分 类 号：S715[农业科学—林学]