中国农业科学 ›› 2016, Vol. 49 ›› Issue (16): 3162-3173.doi: 10.3864/j.issn.0578-1752.2016.16.010

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

不同降雨条件下紫色土横垄坡面地表微地形变化特征

 键1,尹 忠2,郑子成1,何淑勤3,李廷轩1

 
  

  1. 1四川农业大学资源学院,成都 611130
    2四川省林业调查规划院,成都 610081
    3四川农业大学林学院,成都 611130
  • 收稿日期:2016-03-03 出版日期:2016-08-16 发布日期:2016-08-16
  • 通讯作者: 郑子成,E-mail:zichengzheng@aliyun.com
  • 作者简介:罗键,E-mail:luojian_sicau@163.com
  • 基金资助:
    国家自然科学基金(41271307,40901138)、四川省教育厅项目(15ZB0009)、四川农业大学学科建设双支计划团队项目(2015)

Variation Characteristics of Microtopography of Ridge Tillage of Purple Soil Under Different Rainfall Patterns

LUO Jian1, YIN Zhong2, ZHENG Zi-cheng1, HE Shu-qin3, LI Ting-xuan1   

  1. 1College of Resources, Sichuan Agricultural University, Chengdu 611130
    2Sichuan Forestry Inventory and Planning Institute, Chengdu 610081
    3 College of Forestry, Sichuan Agricultural University, Chengdu 611130
  • Received:2016-03-03 Online:2016-08-16 Published:2016-08-16

摘要: 【目的】地表微地形是影响坡面侵蚀过程的重要因素之一。它影响着地表填洼量、渗透速率、地表径流等过程,同时这些过程也会对微地形变化产生影响。论文探讨了不同降雨条件下地表微地形动态变化特征,为深入理解坡面水蚀机理,以及坡耕地水土流失的有效防治与耕作措施的合理布设提供科学依据。【方法】以川中丘陵区横坡垄作坡面为研究对象,以直线坡面为对照,通过室内人工模拟降雨方法,结合GIS技术,从地表糙度的角度,分析递增和递减降雨条件下,紫色土坡面地表微地形的变化特征。【结果】不同降雨条件下横垄坡面高程值变化范围最高可达-180—80 mm,主要集中在-20—20 mm,地表高程减小区域所占比例相对较大。直线坡面高程变化量在-10—10 mm,主要集中-5—5 mm。不同措施在递增降雨系列下的土壤侵蚀面积均大于递减降雨系列;不同降雨条件下横垄坡面地表糙度值介于57.47—65.32 mm,且不同坡位地表糙度值均呈现出上坡>下坡>中坡。直线坡面地表糙度值在5.71—6.28 mm内变动,不同坡位受随机糙度的影响具有明显的空间变异性;横垄坡面不同降雨条件下微坡度栅格数随坡度的增加呈现出先减小后增加再减小的变化趋势,坡度主要集中于0°—5°和30°—35°。对于直线坡面,栅格统计数随坡度的增加呈现出逐渐减小的变化趋势,微坡度主要集中在0°—10°。不同降雨条件下横垄坡面微坡向栅格数主要分布在北坡和南坡,且其余坡向分布较为均匀。直线坡面在不同降雨条件下微坡向分布差异较大。【结论】水蚀过程中,地表高程值变化、地表糙度体现了微地形垂直方向上的变化,地形因子体现了微地形的空间分布,将其结合起来可较好的反映横垄坡面微地形变化特征。递增型降雨雨型与紫色土区夏季主要侵蚀雨型特点相似,更易造成的土壤侵蚀的发生,是研究区坡耕地土壤侵蚀防控的主要雨型。该研究结果可以为地表微地形量化、揭示坡耕地土壤侵蚀效应本质提供新思路。

关键词: 紫色土, 微地形, 微坡度, 微坡向, 横坡垄作

Abstract: 【Objective】Soil surface microtopography is one of the important factors that affects processes such as surface depression storage, penetration rate and surface runoff. Conversely, some of these processes also alter microtopography due to erosion and deposition. The objective of this paper was to investigate the dynamic variation characteristics of microtopography under different rainfall patterns, which to further understand water erosion mechanism on sloping farmland, and to provide a scientific basis for optimizing the configuration of tillage measures and the prediction of soil erosion.【Method】This paper took sloping of ridge tillage in Hilly Area of Central Sichuan basin as the research object and the linear slope was used as control. From the perspective of soil roughness, methods involving artificial rainfall and GIS were adopted to analyze the variation characteristics of microtopography of purple soil.【Result】The range of relative elevation was from -180 mm to 80 mm on the sloping of ridge tillage under different rainfall patterns, which mainly focused on -20 mm-20 mm, the proportion of soil surface elevation reduction was relatively higher. However, the range of relative elevation was from -10 mm to 10 mm on the linear slope, which mainly focused on -5 mm-5 mm. The soil erosion area of increased rainfall series was higher than that of decreased rainfall series for different tillage measures. The value of soil roughness was from 57.47 mm to 65.32 mm on the sloping of ridge tillage under different rainfall patterns, and the value of soil roughness showed that upslope>downslope>midslope under different slope positions. The value of soil roughness was from 5.71 mm to 6.28 mm on the linear slope under different rainfall patterns, but soil roughness of different slope positions had obvious variability affected by the random roughness. Grid number of micro-slope of the sloping of ridge tillage showed a decreasing-increasing-decreasing with the increase of slope under different rainfall patterns, and the slopes were mainly concentrated at 0°-5°and 30°-35°. Grid number of micro-slope of the linear slope decreased gradually with the increase of slope, and the slope was mainly concentrated at 0°-10°. Grid number of micro-aspect of the sloping of ridge tillage mainly focused on the northern slope and the southern slope, and distributions of the other micro-aspect were relatively even, but there was an obvious difference in the linear slope under different rainfall patterns. 【Conclusion】The variation of elevation values and soil roughness reflected the vertical variability of microtopography, while the terrain factors could reflect the spatial distribution of microtopography in the process of water erosion. The combination of them reflected variation characteristics of microtopography of the sloping of ridge tillage well. The increased rainfall pattern was similar to the major erosion rainfall pattern in purple soil region in summer which resulted in relatively severe soil erosion on sloping farmland, and it was the main rainfall pattern of soil erosion prevention and control in the study area. This study could provide a new ideas for quantification of microtopography and reveal the essence of soil erosion on sloping farmland.

Key words: purple soil, microtopography, microslope, microaspect, ridge tillage