引用本文:高儒学,戴全厚,甘艺贤,严友进,彭旭东.不同雨强下喀斯特坡耕地养分流失特征研究[J].土壤学报,2019,56(5):1072-1084.
GAO Ruxue,DAI Quanhou,GAN Yixian,YAN Youjin,PENG Xudong.Characteristics of Nutrient Loss from Sloping Farmland in Karst Region as A Function of Rainfall Intensity[J].Acta Pedologica Sinica,2019,56(5):1072-1084
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 195次   下载 329 本文二维码信息
码上扫一扫!
分享到: 微信 更多
不同雨强下喀斯特坡耕地养分流失特征研究
高儒学, 戴全厚, 甘艺贤, 严友进, 彭旭东
贵州大学林学院
摘要:
为揭示西南喀斯特坡耕地的养分流失特征,通过人工模拟降雨试验,研究不同雨强下喀斯特坡耕地养分流失的过程机制及特征。结果表明:(1)喀斯特坡耕地产流产沙从地下过渡到地表的临界雨强在30 mm•h-1~50 mm•h-1之间,产流量和产沙量均随降雨强度的增大而增大,且产流产沙主要以地表为主。(2)小雨强(15 mm•h-1和30 mm•h-1)下,喀斯特坡耕地TN、TP、TK主要通过地下径流进行流失,大雨强(≥50 mm•h-1)下,喀斯特坡耕地TN、TP、TK地表流失比例为地下漏失的3倍左右;TP径流流失量及流失浓度均随雨强的增大而增大,TN和TK径流流失量及流失浓度却随雨强的增大变化不明显。(3)喀斯特坡耕地泥沙养分流失也主要是以地表流失为主,地表流失量较地下高出约5.03倍,且泥沙中流失的养分浓度均大于径流中流失的养分浓度;地表泥沙养分富集率整体高于地下漏失部分;地表、地下泥沙养分流失总量与养分流失模数均随降雨强度的增大而增大。(4)喀斯特坡耕地径流总量与径流养分(TP、TK)、泥沙养分(TN、TP、TK)均呈极显著正相关关系( P<0.05),径流总量与径流TN呈现极显著正相关关系( P<0.01)。研究结果可为喀斯特区坡耕地养分流失防治及面源污染治理等提供理论参考依据。
关键词:  喀斯特坡耕地  降雨强度  径流  泥沙  养分流失  富集率
DOI:10.11766/trxb201808270236
分类号:
基金项目:国家重点研发计划课题项目(2016YFC0502604)、贵州省一流学科建设项目(GNYL[2017]007)、贵州省重大专项(黔科合重大专项字[2016]3022号)
Characteristics of Nutrient Loss from Sloping Farmland in Karst Region as A Function of Rainfall Intensity
GAO Ruxue, DAI Quanhou, GAN Yixian, YAN Youjin, PENG Xudong
College of Forestry,Guizhou University
Abstract:
【Objective】As the multi-media environment in the karst region is so peculiar, few case-specific research methods are available, making it hard to carry out researches in this region of how soil nutrients are lost from slope farmlands. Although some have been done, outcomes vary sharply and are far from complete, adequate or systematic to exposit rules of nutrient loss from slope farmlands in the karst region, let alone mechanisms of underground soil nutrient lost. Therefore, this study was unfolded to explore characteristics and mechanisms of soil nutrient loss from slope farmlands in the karst region as a function of rainfall intensity, in an attempt to provide certain theoretical reference for control of nutrient loss and non-point source pollution from slope farmlands in the karst region. 【Method】An in-lab experiment was carried out with soil packed in a steel trough to s imulate bare slope farmland in morphological structure, 20% in bedrock outcropping rate, 20° in slope gradient, and 3% in porosity. Besides, the experiment was designed to have five levels of rainfall intensity, i.e. 15 mm∙h-1, 30 mm∙h-1, 50 mm∙h-1, 70 mm∙h-1and 90 mm∙h-1, to scour the aritificial slope farmland. Before the experiment began, the soil was made saturated in moisture with a light rainfall event, and effluent was collected for 30 minutes after the slope began to yield runoff. 【Result】(1) The rainfall intensity critical for runoff and sediment yield to transit from underground to surface varied in the range of 30 mm∙h-1~50 mm∙h-1 and runoff and sediment yield increased with rising rainfall intensity, and occurred mainly on the surface. (2) Under light rainfalls, 15 mm∙h-1 or 30 mm∙h-1 in intensity, loss of TN, TP and TK occurred mainly with underground runoff, while under heavy rainfalls, ≥ 50 mm∙h-1 in intensity, the loss of nutrients with surface runoff gained in proportion to the total loss and reached three times as much as that with underground runoff. The runoff loss of TP increased in both volume and concentration with rising rainfall intensity, but the loss of TK and TN did not change so significantly. (3) The nutrient loss with sediment occurred mainly on the surface, reaching about 5.03 times higher than that underground, and nutrients in the sediment were higher in concentration than those in the runoff. Nutrient enrichment rate of the surface sediment was on the whole higher than that of underground leaching. The totals of nutrient losses with surface and underground sediments and their moduli all increased with rising rainfall intensity. And (4) Significantly positive relationships were found of the total volume of runoff with nutrients (TP & TK) in runoff and nutrients (TN, TP & TK) in sediment (P< 0. 05), and with TN in runoff, too (P < 0. 01). 【Conclusion】The losses of TN, TP and TK occur mainly with runoff in slope farmlands in the karst region, and partly with sediment. Under rainfalls light in intensity (15 mm∙h-1 ~ 30 mm∙h-1), attention should be paid mainly to control of nutrient loss with underground runoff. The impact of rainfall intensity is significant on TP loss with runoff in volume and concentration, as well as on totals of nutrients lost with surface and underground sediments and their nutrient loss moduli. The total volume of runoff is significantly related to the losses of nutrients with runoff and sediment.
Key words:  Sloping farmland in karst region  Rainfall intensity  Runoff  Sediment  Nutrient loss  Enrichment rate