摘要
在次降雨条件下,秸秆覆盖可能影响径流对泥沙的分选作用从而改变侵蚀泥沙团粒分布。为明确秸秆覆盖对紫色土坡耕地侵蚀泥沙团粒分布的影响,设置不同秸秆覆盖量(0、0.2、0.4、0.6、0.8 kg/m^(2))和坡度(10°、15°、20°),在室内人工降雨条件下,探究侵蚀泥沙中各粒级团粒(<0.002、0.002~0.05、>0.05~2 mm)含量及其富集率(enrichment rate,ER)和中值粒径(D0.5)含量的变化特征。结果表明:1)<0.002、0.002~0.05和0.05~2 mm侵蚀泥沙团粒含量随降雨历时分别呈稳定、下降和上升的变化趋势。2)随秸秆覆盖量增加,<0.002 mm团粒含量整体呈先增加后减少的趋势,与裸坡相比,0.8 kg/m^(2)秸秆覆盖可显著减少30.97%~55.46%的<0.002 mm团粒含量,表明秸秆覆盖下紫色土坡耕地主要以<0.002 mm团粒流失。0.002~0.05 mm团粒含量整体呈增加的趋势,15°坡面0.2 kg/m^(2)秸秆覆盖下0.002~0.05 mm团粒含量比0、0.4、0.6和0.8 kg/m^(2)显著低22.54%、21.09%、36.01%和19.29%。3)同一坡度下中值粒径总体随秸秆覆盖量的增加呈先增加后降低趋势,20°坡面0.8 kg/m^(2)条件下中值粒径含量比0、0.4、和0.6 kg/m^(2)显著高26.28%、37.03%和34.48%。4)在各坡度和秸秆覆盖量条件下,ER0.002~0.05均大于1,而ER<0.002和ER0.05~2则均小于1。0.2 kg/m^(2)覆盖量的ER0.002~0.05均显著低于其他4个秸秆覆盖量,且随着秸秆覆盖量的增加呈现先减少后增大的趋势。5)<0.002 mm团粒含量及富集率与秸秆覆盖量间存在显著的二次函数关系,大部分在秸秆覆盖量为0.2 kg/m^(2)时最大。研究结果将为紫色土区坡耕地秸秆覆盖措施的优化提供科学依据。
Straw mulching can dominate the sorting effect of the runoff on the sediment under the secondary rainfall.Thus,there is the aggregate distribution of eroded sediment.This study aims to clarify the influence of straw mulching on the aggregate distribution of the eroded sediment in the purple slope cultivated land.Different amounts were adopted using straw mulching(0,0.2,0.4,0.6,and 0.8 kg/m^(2))and gradients(10°,15°,and 20°).A systematic investigation was implemented to determine the content of each particle size(<0.002,0.002-0.05,and 0.05-2 mm)and its enrichment rate(ER)and median particle size(D0.5)in the eroded sediment under the indoor artificial rainfall.The results show as follows:1)There was a stable variation trend of<0.002 mm eroded sediment aggregates with the rainfall duration.There was a gradual decrease and increase trend of 0.002-0.05 mm and 0.05-2 mm eroded sediment aggregates,respectively.2)The aggregate content of<0.002 mm increased first and then decreased,with the increase of the straw cover amount.While the aggregate content of 0.002-0.05 mm increased as a whole.Compared with the bare slope,0.8 kg/m^(2) straw mulching significantly reduced the<0.002 mm aggregate content by 44.87%-124.50%.It indicated that the purple slope under straw mulching mainly lost<0.002 mm aggregate content.The aggregate content of 0.2 kg/m^(2) on the 15°slope under straw mulching was significantly lower by 29.09%,26.73%,35.15%,and 23.89%than that of 0,0.4,0.6 and 0.8 kg/m^(2),respectively.At the 10°and 15°slope surfaces,the 0.05-2 mm eroded sediment content of 0.2 kg/m^(2) straw mulch was significantly higher than the rest straw mulch loads.3)The median particle size initially increased and then decreased under the same slope,with the increase of straw cover amount.The median particle size with the slope was also dominated by the straw cover amount.Specifically,the median particle size content of 0.8 kg/m^(2) on the 20°slope was significantly higher by 26.28%,37.03%,and 34.48%than that of 0,0.4,and 0.6 kg/m^(2),respectively.4)The ER0.002-0.05 was greater than 1 under the slope and straw cover,while ER0.002 and ER0.05-2 were less than 1.Furthermore,ER<0.002 shared no difference at 10°and 20°under the coverage of 0 and 0.4 kg/m^(2),respectively.While the rest of conditions shared the significant differences.The ER0.002-0.05 of 0.2 kg/m^(2) mulch was significantly lower than that of the rest stalks under the three gradients.There was a trend of first decreasing and then increasing with the increase of straw mulch.The ER0.05-2 of 0.2 kg/m^(2) coverage at each slope was significantly higher than that of the rest coverage(P<0.05).5)There was a significant quadratic function relationship between the aggregate content and enrichment rate of<0.002 mm and the straw mulch amount.The major maximum was reached when the straw mulch amount was 0.2 kg/m^(2).Once the amount of applied straw was greater than 0.4 kg/m^(2),the loss of clay particles was reduced effectively.The finding can provide the scientific basis for the distribution and optimization of straw mulching on the eroded sediment in the sloping farmland from the purple soil area.
作者
曾世昌
张海香
梁珂
李天阳
何丙辉
ZENG Shichang;ZHANG Haixiang;LIANG Ke;LI Tianyang;HE Binghui(College of Resources and Environment,Southwest University,Chongqing 400715,China)
出处
《农业工程学报》
北大核心
2025年第16期145-154,共10页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(42107347)
重庆市自然科学基金项目(CSTB2022NSCQ-MSX0385)
重庆市水利科技项目(CQSLK-2023023)。
关键词
秸秆覆盖
人工降雨
紫色土坡耕地
侵蚀泥沙团粒
富集率
straw mulching
artificial rainfall
purple slope cultivated land
erosion sediment aggregates
enrichment rate
