不同耕种模式下降雨等级对紫色土坡耕地产流产沙的影响

引用本文

任雨之, 郑江坤, 付滟, 王文武, 曾倩婷, 向明辉, 陈鑫. 不同耕种模式下降雨等级对紫色土坡耕地产流产沙的影响[J]. 中国水土保持科学, 2020, 18(3): 90-98. DOI: 10.16843/j.sswc.2020.03.011.

REN Yuzhi, ZHENG Jiangkun, FU Yan, WANG Wenwu, ZENG Qianting, XIANG Minghui, CHEN Xin. Effects of rainfall levels on runoff and sediment yield of slope farmland in purple soil under different tillage and crop patterns[J]. Science of Soil and Water Conservation, 2020, 18(3): 90-98. DOI: 10.16843/j.sswc.2020.03.011.

项目名称

国家自然科学基金"华北土石山区典型林分坡地径流形成机制研究"（41601028）；中国博士后科学基金面上项目"四川紫色土壤有机碳流失机理及对碳储量的影响"（2012M511938）；水利部公益性行业科研专项"水土保持生态效应监测与评价技术研究"（201501045）

第一作者简介

任雨之(1996-), 女, 本科生。主要研究方向:土壤侵蚀与水土保持。E-mail:373632768@qq.com

通信作者简介

郑江坤(1982-), 男, 博士, 副教授。主要研究方向:生态水文和水土保持。E-mail:jiangkunzheng@126.com

文章历史

收稿日期：2019-01-14
修回日期：2019-10-16

Contents Abstract Full text Figures/Tables PDF

不同耕种模式下降雨等级对紫色土坡耕地产流产沙的影响

任雨之 ¹, 郑江坤 ¹, 付滟 ¹, 王文武 ¹, 曾倩婷 ¹, 向明辉 ², 陈鑫 ²

1. 四川农业大学林学院水土保持与荒漠化防治四川省高校重点实验室, 611130, 成都;
2. 遂宁水土保持试验站, 629006, 四川遂宁

收稿日期：2019-01-14; 修回日期：2019-10-16

项目名称：国家自然科学基金"华北土石山区典型林分坡地径流形成机制研究"（41601028）；中国博士后科学基金面上项目"四川紫色土壤有机碳流失机理及对碳储量的影响"（2012M511938）；水利部公益性行业科研专项"水土保持生态效应监测与评价技术研究"（201501045）

第一作者简介：任雨之(1996-), 女, 本科生。主要研究方向:土壤侵蚀与水土保持。E-mail:373632768@qq.com

通信作者简介：郑江坤(1982-), 男, 博士, 副教授。主要研究方向:生态水文和水土保持。E-mail:jiangkunzheng@126.com

摘要：为了探讨紫色土坡耕地在不同降雨等级下的水土流失特征，为选择水土保持效应高的耕种模式提供依据，基于遂宁水土保持试验站1989-2016年降雨与径流输沙数据，划分4类耕种模式，就不同降雨等级下径流小区产流产沙规律进行分析。结果表明：1）小、中雨基本不造成侵蚀，侵蚀性降雨主要为大、暴雨，集中于6-8月。2）等高沟垄大雨下水土保持效应最好。相比顺坡垄作，横坡垄作大暴雨下可减流50%~56%，暴雨下减沙93%~95%，且差异显著（P < 0.05）。顺坡垄作种植黄花较玉米可减沙88%~98%，大、暴雨下差异显著。植物篱定植初期产流产沙反而大于对照区，且在大雨下差异显著；而定植3年后，植物篱减流减沙作用明显，且香根草优于新银合欢。3）沟垄小区产流产沙量在特大暴雨与大、暴雨间差异显著。顺垄黄花小区产流量大，暴雨是大雨下的6.4倍，且差异显著；横（顺）垄小区大暴雨与大、暴雨的产沙量差异显著。定植初期植物篱小区产流量在各降雨等级间差异不显著（P>0.05），而油桃小区产沙量在大暴雨与大雨间差异显著。定植3年后植物篱及其对照小区产流产沙量在大暴雨与大、暴雨下均差异显著，大暴雨下产流量和产沙量分别为大、暴雨的3.3~6.6倍和8.8~113.5倍。各类措施减沙均优于减流效应，减沙作用随降雨等级增大呈降低趋势，考虑农业管理和经济收益，应结合实际情况选择适宜的耕种模式。

关键词：降雨等级耕种模式紫色土径流深产沙量

Effects of rainfall levels on runoff and sediment yield of slope farmland in purple soil under different tillage and crop patterns

REN Yuzhi ¹, ZHENG Jiangkun ¹, FU Yan ¹, WANG Wenwu ¹, ZENG Qianting ¹, XIANG Minghui ², CHEN Xin ²

1. Key Laboratory of Soil and Water Conservation & Desertification Combating of Sichuan Provincial Colleges and Universities, College of Forestry, Sichuan Agricultural University, 611130, Chengdu, China;
2. Soil and Water Conservation Experiment Station of Suining, 629006, Suining, Sichuan, China

Abstract: [Background] In order to select better tillage and crop patterns for soil and water conservation of slope farmland in the purple soil, the characteristics of soil and water loss were investigated. [Methods] Based on the data of rainfall, runoff and sediment yield from 1989 to 2016 at Soil and Water Conservation Experimental Station in Suining city, four periods were divided according to different patterns that include ridge and furrow tillage, economic and fruit forest, cross ridge and planting hedgerows. Runoff and sediment yield of different plots under different patterns were analyzed according to rainfall levels. [Results] 1) Light rain and medium rain hardly caused soil erosion. The erosive rainfall was concentrated in June-August, which was mainly represented by rainstorm and heavy rain. 2) The effect of contour ridge and furrow treatment was the most obvious under heavy rain. Compared with downhill ridge in farmland, cross ridge reduced runoff yield by 50%-56% under large rainstorm and reduced sediment yield by 93%-95% under rainstorm significantly (P < 0.05). Compared with Zea mays, planting Hemerocallis citrina Baroni in downhill ridge significantly reduced sediment yield by 88%-98% under heavy rain and rainstorm. Runoff and sediment yield of planting hedgerows was bigger than that of the control plots in the initial stage of planting hedgerows, which was significantly different under heavy rain. However, after three years of planting, hedgerows had great effects of reducing runoff and sediment, and the effect of Vetiveria zizanioides was better than that of Leucaena leucocephala. 3) Runoff and sediment yield of ridge and furrow plots during extraordinary rainstorm was significantly different from that during rainstorm and heavy rain. During large rainstorm, runoff yield of planting Hemerocallis citrina Baroni with downhill ridge was 6.4 times of that during heavy rain, and the difference was significant. The sediment yield during large rainstorm was significantly different from that during rainstorm and heavy rain in cross ridge and downhill ridge plots. At the initial stage of planting hedgerow, runoff yield of hedgerow plots was no significantly different from that of no-hedgerow plots during different rainfall levels (P>0.05). While sediment yield of Amygdalus persica hedgerow plots was significantly different from that of no-hedgerow plots during large rainstorm and heavy rain. Three years after planting hedgerow, runoff and sediment yield during large rainstorm was significantly different from that during rainstorm and heavy rain. The runoff yield during large rainstorm was 3.3-6.6 times of that during rainstorm and heavy rain, meanwhile, sediment yield during large rainstorm was 8.8-113.5 times of that during rainstorm and heavy rain. [Conclusions] Overall, sediment reduction effect of various tillage and crop patterns is better than runoff reduction effect. With the increase of rainfall level, the sediment reduction rate was decreasing. Therefore, considering the agricultural management and economic benefits, the appropriate patterns should be selected according to the actual situation of sloping farmland.

Keywords: rainfall level tillage and crop patterns purple soil runoff depth sediment yield

川中丘陵区紫色土分布集中，坡耕地比例大，降雨时空分布不均，土壤侵蚀十分严重。降雨是侵蚀发生的动力，降雨量、降雨强度、历时等降雨特征显著影响坡面土壤侵蚀^[1-2]。有学者通过划分天然降雨为不同降雨类型，深入探讨降雨类型与土壤侵蚀的关系^[3]。侵蚀性降雨是坡面土壤侵蚀的主要原因, 通过合理布置耕作、工程和生物措施，能减轻水土流失。沟垄耕作可改变小地形，分散拦蓄地表径流，减少冲刷，其中横坡垄作在小雨强下具有较强防治侵蚀效应^[4]。植被在减弱降雨动能、固土和阻缓径流等方面作用明显，与植被类型、盖度等密切相关^[5]。小雨强下草本对泥沙的拦截率高于灌木，而中、大雨强下规律不明显^[6]。依据降雨侵蚀规律布设植物篱可控制细沟发育，减少土壤侵蚀量，是治理紫色土坡耕地水土流失良好的生态措施^[7]。目前对川中丘陵区不同降雨等级下水土流失规律的定量研究较少，探索水土保持效果较优的耕种模式，可为川中丘陵区紫色土水土流失防治和评价提供科学依据。

1 研究区概况

遂宁水土保持试验站(E 105°28′51″，N 30°21′51″)位于川中丘陵区，属涪江一级支流琼江流域，海拔288~331 m。亚热带湿润季风气候，年均温18.2 ℃，年均降水量902 mm，年均蒸发量897.2 mm，年均无霜期296 d。土壤为红棕紫色土，呈中性到微碱性，由侏罗系遂宁组砂、页、泥岩风化形成，土壤松散、结构性差，土壤抗冲和抗蚀能力均弱^[7]。坡耕地种植植物有玉米(Zea mays)、红苕(Ipomoea batatas)、小麦(Triticum aestivum)、胡豆(Vicia faba)、黄花(Hemerocallis citrina Baroni)、油桃(Amygdalus persica)等。

2 材料与方法 2.1 试验区布设

试验站内设置6个标准径流小区(水平投影长20 m，宽5 m)，正南坡向，小区四边均砌水泥围墙。其中10°小区4个、15°小区2个，小区下端设集流槽和径流观测池。

2.2 降雨等级划分与观测方法

结合每次降雨历时和降雨量，依据国家气象局颁布的降雨等级标准，划分为小雨(light rain，LR)，中雨(moderate rain，MR)，大雨(heavy rain，HR)，暴雨(rainstorm，RS)，大暴雨(large rainstorm，LRS)，特大暴雨(extraordinary rainstorm，ERS)^[2]。

按《水土保持试验规程》(SL 419—2007)观测降雨量、径流量等数据^[8]。并计算径流深(mm)、径流系数、产沙量(t/km²)、含沙量(kg/m³)^[9]。数据用Excel和SPSS 20.0软件分析。

2.3 不同耕作种植模式划分

1989—2016年，为保证耕种措施在时段内的一致性，确保各小区之间的可比性，选取4个时段进行研究(表 1)。2006—2008年，新银合欢(Leucaena leucocephala)植物篱于2006年3月栽植，篱带间距9 m，每带2行，行距0.4 m，株距0.2 m，株高0.7 m，每年春季修剪。2013—2016年，新银合欢和香根草(Vetiveria zizanioides)植物篱于2010年4月移栽，篱带间距6.5 m，每带2行，行距0.4 m或0.5 m，株距0.2 m，株高0.8 m。

表 1 4个时段耕作种植模式对比 Tab. 1 Contrast of tillage and crop patterns in four periods

时段 Period	小区 Plot	坡度 Slope/(°)	耕作方式 Tillage patterns	作物类型 Crop patterns
1991—1993	R1	10	等高沟垄两端加档Contour ridge and furrow closed at both ends
	R2	10	沟垄(30°)一端加档Ridge and furrow with 30°to horizontal and closed one end	玉米-红苕Zea mays-Ipomoea batatas
	R3	10	沟垄(20°)一端加档Ridge and furrow with 30°to horizontal and closed one end
	R4	10	等高沟垄一端加档Contour ridge and furrow closed at one end
	R5	15	等高沟垄两端加档Contour ridge and furrow closed at both ends
	R6	15	等高沟垄一端加档Contour ridge and furrow closed at one end
2004—2005	T1	10	横坡垄作Cross ridge	黄花Hemerocallis citrina Baroni
	T2	10	顺坡垄作Downhill ridge	黄花Hemerocallis citrina Baroni
	T3	10	横坡垄作Cross ridge	玉米-红苕Zea mays-Ipomoea batatas
	T4	10	顺坡垄作Downhill ridge
	T5	15	横坡垄作Cross ridge
	T6	15	顺坡垄作Downhill ridge
2006—2008	P1	10	横坡Cross slope	玉米-红苕Zea mays-Ipomoea batatas
	P2	10	顺坡新银合欢植物篱Downhill slope, Leucaena leucocephala as planting hedgerows	玉米-红苕Zea mays-Ipomoea batatas
	P3	10	横坡Cross slope	油桃Amygdalus persica
	P4	10	顺坡新银合欢植物篱Downhill slope, Leucaena leucocephala as planting hedgerows	油桃Amygdalus persica
	P5	15	横坡Cross slope	玉米-红苕Zea mays-Ipomoea batatas
	P6	15	顺坡新银合欢植物篱Downhill slope, Leucaena leucocephala as planting hedgerows	玉米-红苕Zea mays-Ipomoea batatas
2013—2016	H1	10	横坡Cross slope	玉米Zea mays
	H2	10	顺坡新银合欢植物篱Downhill slope, Leucaena leucocephala as planting hedgerows	玉米Zea mays
	H3	10	休闲地Fallow land	荒草Weeds
	H4	10	顺坡香根草植物篱Downhill slope, Vetiveria zizanioides as planting hedgerows
	H5	15	横坡香根草植物篱Cross slope, Vetiveria zizanioides as planting hedgerows	玉米Zea mays
	H6	15	顺坡Downhill slope	玉米Zea mays

表 1 4个时段耕作种植模式对比 Tab. 1 Contrast of tillage and crop patterns in four periods

3 结果与分析 3.1 4个时段降雨等级分布情况

如表 2所示，4个时段的侵蚀性降雨累计72场。1991—1993年集中于6—8月，约占总降雨量的90%；其中大雨居多，占总次数的64%。2004—2005年则集中于7—8月，占总降雨量的63%；且以暴雨、大雨居多，占总次数的88%。2006—2008年集中于6月和8月，约占总降雨量的52%；并以暴雨为主，占总次数的64%。2013—2016年集中于6—7月，约占总降雨量的60%；以大、暴雨为主。10月仅出现1次侵蚀性降雨，小雨和中雨几乎不产流产沙，大、暴雨为侵蚀性降雨主要表现，故应针对大、暴雨加强6—8月水土保持工作。

表 2 4个时段侵蚀性降雨分布及特征 Tab. 2 Distribution and characteristics of erosive rainfall in four periods

时段 Period	降雨等级 Rain level	月份(每月降雨次数) Month(Number of rainfall events in every month)	累计降雨量 Accumulated rainfall/mm
1991—1993	ERS	6月June(1)、8月August(1)	480.90
	LRS	8月August(1)	152.90
	RS	6月June(1)、7月July(1)、8月August(1)、9月September(1)	276.40
	HR	5月May(2)、6月June(3)、7月July(4)、8月August(5)	348.20
	MR	7月July(1)	14.10
2004—2005	LRS	7月July(1)、8月August(1)	237.10
	RS	6月June(2)、7月July(2)、8月August(2)、9月September(2)	366.70
	HR	5月May(1)、6月June(3)、7月July(1)、8月August(1)	171.20
2006—2008	LRS	5月May(1)、6月June(1)	163.80
	RS	5月May(1)、6月June(1)、7月July(1)、8月August(4)、9月September(2)	464.40
	HR	6月June(2)、9月September(1)	103.60
2013—2016	ERS	6月June(1)	287.40
	LRS	5月May(1)、7月July(2)	335.30
	RS	5月May(1)、7月July(3)、8月August(3)、9月September(2)、10月October(1)	541.00
	HR	5月May(1)、6月June(4)、7月July(1)	212.10
Notes：ERS stands for extraordinary rainstorm，LRS stands for large rainstorm，RS stands for rainstorm, HR stands for heavy rain, and MR stands for moderate rain. The same below.

表 2 4个时段侵蚀性降雨分布及特征 Tab. 2 Distribution and characteristics of erosive rainfall in four periods

3.2 降雨等级对沟垄耕作的产流产沙影响

由表 3可知，该时段有5种降雨等级，中、大暴雨均为1场，不进行方差分析。各小区的径流深在特大暴雨与大、暴雨间均差异显著(P < 0.05)。径流系数在R1、R2、R5小区特大暴雨与大、暴雨均存在显著差异；在R4、R6小区特大暴雨与大雨间差异显著。产沙量在所有小区中，特大暴雨与大、暴雨间均差异显著。含沙量在除R2外的其余小区中，特大暴雨与大、暴雨均差异显著，R2小区各降雨等级无显著差异(P>0.05)。

表 3 1991—1993年不同降雨等级下各小区产流产沙特征 Tab. 3 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 1991-1993

指标Index	小区Plot	ERS	LRS	RS	HR	MR
径流深 Runoff depth/mm	R1	36.83±44.44aA	6.74	0.03±0.05bA	0.00bC	0.00
	R2	165.00±147.34aA	114.68	18.12±19.23bA	3.88±4.01bA	0.29
	R3	138.85±183.93aA	98.87	13.48±15.73bA	2.74±4.30bAB	0.20
	R4	103.47±138.21aA	74.51	10.12±17.19bA	1.39±2.66bBC	0.15
	R5	123.26±162.51aA	5.21	0.07±0.15bA	0.06±0.18bC	0.00
	R6	133.28±176.38aA	96.89	11.02±18.62bA	1.52±2.90bBC	0.20
径流系数 Runoff coefficient	R1	0.14±0.16aA	0.04	0.00bA	0.00bC	0.00
	R2	0.63±0.49aA	0.75	0.21±0.20bA	0.16±0.17bA	0.02
	R3	0.51±0.67aA	0.65	0.15±0.17aA	0.12±0.19aAB	0.01
	R4	0.38±0.50aA	0.49	0.11±0.20abA	0.06±0.12bBC	0.01
	R5	0.46±0.59aA	0.03	0.00bA	0.00bC	0.00
	R6	0.49±0.64aA	0.63	0.13±0.21abA	0.07±0.13bBC	0.01
产沙量 Sediment yield/(t·km^-2)	R1	221.00±298.40aC	6.20	0.00bB	0.00bC	0.00
	R2	3 129.18±1 194.19aA	587.20	451.75±524.50bA	56.06±78.93bA	15.58
	R3	2 834.99±1 166.46aA	477.93	210.48±241.87bAB	37.05±57.20bAB	3.56
	R4	1 336.40±472.77aABC	113.40	111.00±148.56bAB	19.49±40.04bBC	2.20
	R5	557.52±743.10aBC	0.00	0.00bB	0.07±0.27bC	0.00
	R6	2 540.43±795.40aAB	514.20	120.25±162.97bAB	17.41±38.48bBC	3.06
含沙量 Sediment concentration/(kg·m^-3)	R1	4.09±3.17aA	0.92	0.00bB	0.00bB	0.00
	R2	26.17±16.13aA	5.12	14.80±13.10aA	13.73±18.58aA	53.72
	R3	121.18±152.12aA	4.83	11.28±5.99bAB	10.70±17.39bA	17.80
	R4	148.02±202.29aA	1.52	8.97±12.77bAB	6.67±10.59bAB	14.67
	R5	4.19±0.50aA	0.00	0.00bB	0.10±0.39bB	0.00
	R6	120.30±153.12aA	5.31	8.53±11.88bAB	5.83±7.53bAB	15.30
注:表中为均值±标准差；同一指标下不同小写字母表示同一行内达到显著性差异(P＜0.05)，不同大写字母表示同列内达到显著性差异(P＜0.05)。下同。Notes: The data before and after“ ± ”are the mean and standard deviation，different lowercase letters represent significant differences in the same row (P＜0.05)，different capital letters represent significant differences in the same column (P＜0.05) under the same index. The same below.

表 3 1991—1993年不同降雨等级下各小区产流产沙特征 Tab. 3 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 1991-1993

10°小区，同降雨等级下，径流深、径流系数、产沙量均为：R2>R3>R4>R1，含沙量在特大暴雨：R4>R3>R2>R1。径流深、径流系数在大雨下R1与R2、R3差异显著。产沙量在大雨、大暴雨下R1与R2、R3也差异显著。在15°对照小区、相同措施不同坡度对照小区，所有指标在同降雨等级下均差异不显著。

3.3 降雨等级对横坡垄作的产流产沙影响

由表 4可知，各小区径流深、产沙量、含沙量均表现为大暴雨>暴雨>大雨；而径流系数在T1小区：暴雨>大暴雨>大雨，T3~T6小区：暴雨>大雨>大暴雨，可能与前期土壤含水量有关。径流深、径流系数在同小区各降雨等级间均差异不显著。产沙量在所有小区中大暴雨与大、暴雨差异显著，大暴雨下T2~T6小区平均产沙量为暴雨的4.2~22.2倍，为大雨的20.5~126.8倍。含沙量在所有小区中大暴雨与大雨差异显著，除T3小区外大暴雨与暴雨间差异显著。

表 4 2004—2005年不同降雨等级下各小区产流产沙特征 Tab. 4 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2004-2005

指标Index	小区Plot	LRS	RS	HR
径流深Runoff depth/mm	T1	5.98±2.07aAB	2.86±4.61aB	1.01±1.58aB
	T2	10.11±4.71aAB	3.25±5.01abB	1.59±2.70bAB
	T3	4.74±1.85aB	4.57±5.98aAB	2.03±3.16aAB
	T4	11.16±4.58aAB	10.38±12.37aAB	6.17±7.31aAB
	T5	7.75±1.48aAB	7.06±9.41aAB	2.78±4.73aAB
	T6	17.03±8.79aA	13.21±14.88aA	7.40±7.99aA
径流系数Runoff coefficient	T1	0.05±0.00aCD	0.06±0.09aB	0.03±0.05aB
	T2	0.08±0.01aBC	0.07±0.10aB	0.04±0.07aB
	T3	0.04±0.00aD	0.10±0.12aAB	0.06±0.09aB
	T4	0.09±0.01aB	0.21±0.24aAB	0.19±0.19aAB
	T5	0.07±0.01aBCD	0.15±0.18aAB	0.08±0.13aAB
	T6	0.14±0.03aA	0.28±0.31aA	0.23±0.22aA
产沙量Sediment yield/(t·km^-2)	T1	37.38±29.71aA	1.39±1.96bB	0.00bB
	T2	59.61±52.69aA	2.68±3.59bB	0.47±0.78bB
	T3	33.73±27.49aA	6.58±7.36bB	1.36±2.22bB
	T4	524.70±439.06aA	123.78±136.65bA	25.58±34.93bAB
	T5	55.50±37.12aA	10.35±9.50bB	1.75±2.93bB
	T6	704.22±567.03aA	149.09±159.13bA	32.55±40.60bA
含沙量Sediment concentration/(kg·m^-3)	T1	5.74±2.98aB	1.31±2.46bB	0.00bB
	T2	5.25±2.76aB	0.62±1.07bB	0.10±0.16bB
	T3	6.48±3.27aB	3.33±3.56abB	0.22±0.35bB
	T4	42.52±21.88aA	12.97±11.24bA	4.68±2.67bA
	T5	6.83±3.49aB	2.99±2.69bB	0.21±0.33cB
	T6	37.81±13.79aA	15.11±13.48bA	5.85±4.27bA

表 4 2004—2005年不同降雨等级下各小区产流产沙特征 Tab. 4 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2004-2005

10°小区，同降雨等级下，各指标整体表现为顺垄>横垄，而黄花小区在大暴雨、暴雨表现为横垄>顺垄。T3与T4小区的径流系数和产沙量分别在大暴雨和暴雨下差异显著。T4小区含沙量是T3的3.9~21.3倍，且差异显著。同降雨等级下T2小区产沙量和含沙量显著小于T4小区。T5与T6小区径流系数和产沙量分别在大暴雨和大、暴雨下差异显著；含沙量在各降雨等级下均差异显著。

3.4 降雨等级对植物篱定植初期的产流产沙影响

由表 5可知，小区各指标整体趋势：大暴雨>暴雨>大雨。P1、P3、P5小区的径流深和径流系数在大暴雨与大雨间差异显著；产沙量和含沙量在P3、P4小区下大暴雨与大雨间差异显著，P4小区大暴雨与暴雨间也存在显著差异。

表 5 2006—2008年不同降雨等级下各小区产流产沙特征 Tab. 5 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2006-2008

指标Index	小区Plot	LRS	RS	HR
径流深Runoff depth/mm	P1	6.40±2.18aA	3.12±2.49abB	0.00bC
	P2	16.05±14.66aA	7.11±5.71aAB	2.94±1.23aB
	P3	8.91±5.39aA	3.74±3.30abB	0.00bC
	P4	2.75±2.35aA	3.09±2.43aB	0.00aC
	P5	9.94±5.37aA	4.02±2.58bB	0.00cC
	P6	27.41±29.31aA	10.98±9.64aA	4.80±1.80aA
径流系数Runoff coefficient	P1	0.08±0.02aA	0.05±0.04aB	0.00bC
	P2	0.19±0.17aA	0.13±0.11aAB	0.08±0.03aB
	P3	0.11±0.06aA	0.06±0.06abB	0.00bC
	P4	0.03±0.03aA	0.05±0.04aB	0.00aC
	P5	0.12±0.06aA	0.07±0.05aB	0.00bC
	P6	0.33±0.35aA	0.21±0.18aA	0.14±0.04aA
产沙量Sediment yield/(t·km^-2)	P1	42.98±11.67aA	25.71±51.42aB	0.00aC
	P2	317.88±354.60aA	262.40±317.83aA	12.92±7.74aAB
	P3	163.26±160.51aA	40.71±66.65abB	0.00bC
	P4	107.06±108.68aA	25.36±36.93bB	0.00bC
	P5	102.72±30.33aA	39.14±59.54aB	0.00aC
	P6	478.82±468.82aA	341.20±371.98aA	24.31±14.97aA
含沙量Sediment concentration/(kg·m^-3)	P1	6.81±0.50aA	4.48±7.57aB	0.00aB
	P2	16.67±6.87aA	42.86±58.12aA	4.17±0.82aA
	P3	15.76±8.48aA	5.79±8.53abB	0.00bB
	P4	88.33±115.23aA	4.95±6.70bB	0.00bB
	P5	11.14±2.97aA	6.58±8.45aB	0.00aB
	P6	19.45±3.70aA	37.96±45.17aA	4.68±1.55aA

表 5 2006—2008年不同降雨等级下各小区产流产沙特征 Tab. 5 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2006-2008

同降雨等级下各指标小区间表现为：P1 < P2，P3>P4，P5 < P6；在大雨下，P1和P2小区的径流深和径流系数差异显著；产沙量和含沙量在P3和P4小区差异不显著，而大、暴雨下P1与P2小区差异显著。15°小区各指标在大雨下均显著差异。相同措施不同坡度，P2与P6小区在大雨下的径流深和径流系数存在显著差异。

3.5 降雨等级对定植3年后植物篱的产流产沙影响

由表 6可知，该时段有4种降雨等级，特大暴雨仅1场，不进行方差分析。各小区在大暴雨下径流深是暴雨的3.0~3.6倍，是大雨的4.9~6.6倍；大暴雨下径流系数是暴雨的1.4~1.7倍，是大雨的1.4~2.0倍；大暴雨下产沙量为暴雨的8.8~36.9倍，为大雨的44.9~113.5倍；大暴雨含沙量为暴雨的2.4~7.5倍，为大雨的4.0~15.3倍。所有小区大暴雨下各指标与暴雨、大雨差异显著。

表 6 2013—2016年不同降雨等级下各小区产流产沙特征 Tab. 6 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2013-2016

指标Index	小区Plot	ERS	LRS	RS	HR
径流深runoff depth/mm	H1	38.46	24.00±9.96aA	7.01±4.44bAB	3.63±0.92bABC
	H2	31.28	17.15±8.54aA	4.82±2.03bB	2.98±0.93bC
	H3	45.64	25.20±9.21aA	7.06±3.77bAB	3.90±1.32bABC
	H4	29.63	15.83±8.46aA	4.89±2.09bB	3.22±0.95bBC
	H5	32.02	20.20±11.14aA	6.83±4.12bAB	4.08±1.23bAB
	H6	46.24	28.94±9.29aA	9.30±5.77bA	4.50±1.42bA
径流系数Runoff coefficient	H1	0.13	0.21±0.04aABC	0.13±0.07bAB	0.11±0.02bABC
	H2	0.11	0.15±0.04aC	0.09±0.02bB	0.09±0.02bC
	H3	0.16	0.22±0.03aAB	0.13±0.05bAB	0.11±0.04bAB
	H4	0.10	0.13±0.04aC	0.09±0.02bB	0.09±0.02bBC
	H5	0.11	0.17±0.06aBC	0.12±0.03bB	0.12±0.03bAB
	H6	0.16	0.25±0.02aA	0.17±0.08bA	0.13±0.03bA
产沙量Sediment yield/(t·km^-2)	H1	278.30	644.57±934.55aA	45.02±52.12bA	6.39±1.83bA
	H2	98.70	284.87±441.36aA	7.71±7.00bB	2.51±1.27bB
	H3	362.50	309.31±317.49aA	35.21±28.00bAB	6.89±3.61bA
	H4	83.20	191.00±290.77aA	7.75±7.04bB	2.50±1.11bB
	H5	121.50	328.63±517.91aA	22.56±40.57bAB	3.00±1.56bB
	H6	351.70	848.13±1 217.89aA	53.32±55.26bA	8.30±4.14bA
含沙量Sediment concentration/(kg·m^-3)	H1	7.24	21.32±29.35aA	5.14±3.07bA	1.81±0.47bB
	H2	3.16	12.20±17.98aA	1.63±1.44bB	0.80±0.39bB
	H3	7.94	10.85±10.65aA	4.56±1.97bA	1.64±0.73bB
	H4	2.81	8.53±12.03aA	1.60±1.46bB	0.74±0.33bB
	H5	3.79	11.93±17.98aA	3.67±6.13abAB	0.70±0.38bB
	H6	7.61	25.20±35.39aA	5.45±2.58bA	6.29±4.25bA

表 6 2013—2016年不同降雨等级下各小区产流产沙特征 Tab. 6 Characteristics of runoff and sediment yield in the plots under different rainfall levels during 2013-2016

10°小区，径流深和径流系数呈现：H3>H1>H2>H4；产沙量和含沙量呈现：H1>H3>H2>H4。径流深和径流系数在同降雨等级下H2和H4差异不显著，植物篱与无植物篱小区也差异不显著。产沙量和含沙量分别在大、暴雨和暴雨下，植物篱与无植物篱小区间差异显著。15°小区，在大暴雨、大雨下H6的径流系数是H5的1.5和1.4倍，在大雨下H6的产沙量和含沙量分别是H5的2.8和9倍，均达显著性水平。

4 讨论

坡耕地产流产沙与降雨等级和耕种措施密切相关^[2]。4类耕种模式中，等高沟垄加档在大雨下水土保持效应最明显。横坡垄作在大暴雨和暴雨下分别能有效减少径流系数和产沙量。由于垄沟内形成的细沟侵蚀及可能的瞬时坍塌使侵蚀动态变化过程波动性大于径流的波动性。随着降雨强度和水流强度增加，水层增厚，溅蚀动能减少，泥沙颗粒无附加

外力破坏黏聚力，仅靠剪切力，挟沙减小^[10]。黄花能有效减少水土流失，仅降雨等级较小时明显，降雨等级较大时植株、根系易受破坏。定植初期植物篱植株尚未长成，盖度小，未形成闭合带，篱墙密集度低，根系不发达，加上种植时翻动扰动大，短时间内未能发挥减流减沙作用，这与马星等^[9]研究基本一致，与杨帅等^[11]研究有一定差异；油桃小区林冠高大，根系发达，持水能力强，在各降雨等级下均具有较好的水土保持功能^[12]。植物篱经3~5年生长，其固土保水功能逐步体现，且在暴雨、大雨时效果最为突出，香根草为草本植物，根茎发达，丛数越多减流减沙作用越明显。

植物措施通过根系的生长与固持作用，以及植株对泥沙阻碍，使土壤大颗粒在篱带或植株前沉积^[7]，且更大的粗糙度可使黏土含量、沉积物分形维数发生改变，更好地控制其侵蚀力^[5]。垄作使径流汇集，快速入渗达到岩土界面形成蓄满产流；降雨击溅致使土壤结皮，使降雨后期土壤抗侵蚀能力增强，产沙正效应减弱，使垄沟机械阻拦更为有效^[10]。各类耕种模式通过对植被、土体、降雨因素综合调整，达到调水固土效果。采用国家气象局颁布的降雨等级，研究不同耕种措施的水土保持作用，更具实践性，对该区水土保持措施布置具有重要的现实指导价值。

5 结论

1) 侵蚀性降雨集中于6—8月，大、暴雨为主要降雨等级，坡耕地产流产沙量随降雨等级增大而增加。

2) 等高沟垄两端加档、横垄、油桃小区+植物篱、香根草植物篱在4个时段内减流减沙效果最佳，且减沙效应优于减流。

3) 种植黄花及植物篱措施在大雨下减沙效果最佳，而耕作措施在暴雨下的效果明显，不同措施在防治水土流失中存在降雨临界值。

6 参考文献

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