砂姜黑土钙质结核剖面分布特征及其对土壤持水性的影响

2021-06-01 14:29陈雪娇魏翠兰周明华李保国
农业工程学报 2021年6期
关键词:钙质黑土结核

谷 丰,陈雪娇,魏翠兰,周明华,李保国

·农业水土工程·

砂姜黑土钙质结核剖面分布特征及其对土壤持水性的影响

谷 丰1,2,陈雪娇3,魏翠兰2,4,周明华1,李保国2※

(1. 中国科学院水利部成都山地灾害与环境研究所,中国科学院山地表生过程与生态调控重点实验室,成都 610041;2. 中国农业大学土地科学与技术学院,农业农村部华北耕地保育重点实验室,自然资源部农用地质量与监控重点实验,北京 100193;3. 四川大学建筑与环境学院,成都 610065;4. 江苏开放大学环境生态学院,南京 210036)

钙质结核是砂姜黑土重要的成土特征,直接影响土壤结构和水分运移,但目前关于钙质结核对土壤持水性作用机制的研究主要集中在实验室尺度,而且报道较少。基于此,该研究在田间尺度上研究了钙质结核剖面垂直分布特征及其对土壤持水性的影响。结果表明:钙质结核主要分布在20 cm以下的土层,其含量和粒径均随土层深度的增加呈现增大趋势,>80~100 cm土层钙质结核质量分数可达11.42%。2~5、>5~8、>8~30 mm的钙质结核饱和含水率分别为0.25、0.22和0.20 cm3/cm3,均远低于土壤饱和含水率。土壤饱和含水率、田间持水量和萎蔫点均随钙质结核含量的提高而逐渐降低。但是含钙质结核土层土壤有效持水量与钙质结核含量呈现显著正相关关系,钙质结核有利于改善砂姜黑土黏重的土壤质地。研究结果可为深入了解砂姜黑土水分运动规律及中低产田改良提供理论依据。

土壤;含水率;颗粒;砂姜黑土;钙质结核;空间分布;持水性;水分特征曲线

0 引 言

砂姜黑土是中国主要的中低产田类型之一,总面积约为400万hm2,主要分布于山东、河南、江苏、安徽和湖南等地[1]。土壤剖面中明显的姜状钙质结核,以及暗色黑土层是砂姜黑土的主要特征[2]。钙质结核又称石灰结核或砂姜,它由分散的碳酸盐与土壤颗粒在硅酸、二氧化物、三氧化物、铁和锰等吸附性物质的表面胶结而成[3]。钙质结核主要分布于砂姜黑土20 cm以下土层[1],其含量随土层深度的增加逐渐升高,同时具有强烈的空间变异性,变异系数甚至可以超过100%[4-6]。作为粒径较大的粗粒介质(粒径大于2 mm),钙质结核不仅能导致土壤的非均质性,而且会严重影响土壤结构发育[7-9]。

土壤持水性质是计算土壤水分和养分运移的关键,也是制定精准灌溉措施的基础。粗粒介质自身孔隙及其对土壤结构的影响必然会引起土壤持水性质的变化。研究表明[10-11],土壤有效持水量随土壤粗粒介质含量的增加而降低。粗粒介质内部孔隙也可持有一定水分,但其含水率可能低于土壤[10,12],也可能高于土壤[13],这与粗粒介质的类型、尺寸、孔隙度以及风化程度等密切相关。

因此,钙质结核的存在不仅直接影响砂姜黑土的持水、蓄水能力,而且可能降低土壤耕性,甚至限制作物根系的生长和发育[14]。Gu等[15]在实验室条件下研究了钙质结核对土壤持水性的影响,结果表明,土壤田间持水量、萎蔫含水率和有效持水量均随钙质结核含量的增加而显著降低。目前,关于田间尺度下钙质结核对土壤持水性影响的报道尚少。基于此,本研究选择典型砂姜黑土农田为试验区,通过田间调查,研究田间尺度下钙质结核在土壤剖面中的垂直分布,结合室内分析探究钙质结核对砂姜黑土土壤持水性质的影响,以期为砂姜黑土的改良利用提供理论依据。

1 材料与方法

1.1 试验区概况

试验区位于安徽省阜阳市临泉县(115°16'30''E,32°59'05''N)(图1)。临泉县地处淮北平原西部,地势平坦,海拔31~40 m;属暖温带半湿润季风性气候,多年(1955—2004年)平均气温约为15 ℃,平均降雨量为913 mm。试验区土壤类型为砂姜黑土,土壤质地类型为黏壤土。当地传统的耕作方式为冬小麦-夏玉米轮作,熟制为一年两熟。

1.2 土壤样品采集

试验田长150 m,宽50 m,面积为0.75 hm2。根据前期调查结果(图2),钙质结核广泛分布于试验田中,且空间变异性较强[5]。随机挖取3个1 m深的土壤剖面,按照每20 cm一层,0~100 cm土层共分为5层。用铁铲在各层采集土壤样品,风干后测定土壤颗粒组成、有机质、钙质结核质量含量及不同粒径钙质结核的持水性。与此同时,用环刀(100 cm3)在每个土层分别采集3个原状样品,用于测定土壤容重和水分特征曲线。

1.3 指标测定和计算方法

1.3.1 土壤基本理化性质

风干土样过2 mm筛后,采用沉降法[16]测定土壤颗粒组成;采用外加热法[17]测定土壤有机质含量。

1.3.2 钙质结核粒径分级、含量及密度

称取一定量风干土壤样品(0,g),筛分出粒径大于2 mm的钙质结核,再分别通过5、8 mm筛,将钙质结核进一步分为粒径为2~5、>5~8 、>8~30 mm的样品。用自来水将钙质结核表面残留土粒冲洗干净,置于105 ℃下烘干至恒质量,采用式(1)计算钙质结核含量。

式中CW(=1,2,3)分别表示粒径为2~5、>5~8、>8~30 mm钙质结核含量(%,质量分数)和烘干质量(g);为土壤样品的风干含水率,g/g。钙质结核总含量total为以上3个粒级钙质结核含量之和(1+2+3),%。

将各粒级钙质结核(质量为,g)放入去离子水中,浸泡24 h,待充分饱和后取出。利用排水法测定钙质结核体积(,g),计算钙质结核密度(ρ=/,g/cm3)。

1.3.3 土壤水分特征曲线测定方法

将土壤原状样品饱和后,采用离心机法[18]测定土壤水分特征曲线。

不同转速(300、500、700、1 000、2 000、3 000、5 000、7 000和8 700 r/s)下土壤基质势(cm)[18-20]为

式中为重力加速度,本文取值981 cm/s2;为离心机转子角速度,r/s;为水的密度,g/cm3;1和2分别代表自由水面和土壤样品重心与离心机转子中心的距离,cm。

测定完成后,土壤样品在105 ℃下烘干至质量恒定,计算土壤容重和各转速下的土壤含水率。

1.3.4 钙质结核水分特征曲线测定方法

采用沙箱法和压力板法测定2~5、>5~8、>8~30 mm钙质结核的水分特征曲线[12]。首先,将钙质结核埋入细砂(粒径小于1 mm)并装填入100 cm3环刀中,以保证钙质结核与沙箱或压力板之间的水力连通性;然后将装填好的样品用去离子水饱和24 h以上;最后,将样品放入沙箱或压力板中测定不同基质势下的钙质结核含水率。共设定13个基质势梯度,分别为-5、-10、-20、-40、-60、-80、-100、-300、-500、-1 000、-3 000、-5 000和-15 000 cm。

1.3.5 水分特征曲线拟合方法

在Excel 2016软件中应用规划求解功能对水分特征曲线测定值进行拟合,得到最优拟合参数。本研究采用的水分特征曲线模型为van Genuchten模型[21],公式如下

式中是含水率,cm3/cm3;θθ分别为饱和含水率和残余含水率,cm3/cm3;为测定样品的基质势,cm;为土壤进气值的倒数,1/cm;为模型曲线形状参数,无量纲。

土壤重力水含量(Gravitational-water Content,GC)、田间持水量(Field Capacity,FC)、萎蔫含水量(Wilting Point,WP)和有效持水量(Available Water Holding Capacity,AWHC)的计算方法:将土壤水分特征曲线中-330 cm和-15 000 cm基质势下的土壤含水率作为土壤FC和WP[22]。GC为土壤饱和含水率与田间持水量的差值,AWHC为FC和WP的差值。

1.4 统计分析

在Excel 2016软件中进行数据整理,通过SPSS25.0软件进行单因素方差分析(Analysis of Variance,ANOVA),由最小显著性差异法(Least-Significant Difference,LSD)表示指标间差异的显著性,并采用Pearson相关性检验分析钙质结核含量与土壤性质之间的相关性。

2 结果与分析

2.1 土壤基本理化性质

试验区土壤剖面中0~20 cm为耕作层,土壤颜色较深,结构较为松散,以团粒和块状为主(图3)。20 cm以下土壤紧实度明显增加,其中>20~40 cm为犁底层,>40~80 cm为过渡层,土壤呈现黄白并夹杂黑色,主要土壤结构呈现棱柱状。当土壤深度大于80 cm时,土壤颜色以黄白色为主,这些变化与土壤容重、有机质以及钙质结核的含量分布密切相关。表层以下土壤(>20~100 cm)容重为1.57~1.61 g/cm3,显著高于表面耕作层容重(1.23 g/cm3)(表1),因此土壤紧实度增加。试验区土壤有机质含量总体偏低(表1),在全国第二次土壤普查养分分级标准中属于第4~6级,与其他研究中砂姜黑土有机质含量类似[23]。其中,0~20 cm土层有机质含量约为11.40 g/kg,比其他土层高86%~136%,这可能是导致其土壤颜色深于底层土壤的原因之一[23]。

注:同一列不同小写字母表示差异性显著(<0.05),下同。

Note: Different lowercase letters in the same column indicate significant differences (<0.05), the same below.

土壤中黏粒、粉粒和砂粒质量分数分别约为30.56%~39.75%、39.88%~45.34%和18.67%~24.45%(表1),在美国制土壤质地分类标准中属于粉质黏土。从剖面看,不同粒径的土壤颗粒在不同深度土壤中的分布不尽一致(表1)。例如,黏粒(粒径小于0.002 mm)含量随着土壤深度的增加而显著减少,耕层(0~20 cm)和犁底层(>20~40 cm)的黏粒含量分别是底层(>80~100 cm)土壤的1.30倍和1.27倍。0~40 cm土层中粉粒(0.002~0.05 mm)质量分数介于39.88%到42.64%之间,显著低于深度为>40~100 cm的土壤(44.70%~45.34%)。对于砂粒(0.05~2 mm)而言,其含量也随着土壤深度的增加而呈上升趋势。各土层中,底层(>80~100 cm)土壤砂粒质量分数(24.45%)最大,与>60~80cm差异不显著,但比其他各层(0~60 cm)土壤高20%~31%。总体而言,试验区0~100 cm土壤主要以黏粒和粉粒为主,砂粒质量含量较低。研究表明,砂姜黑土黏粒质量分数较高(>30%),土壤水分有效库容较小,且因黏土矿物以2∶1型的蒙脱石为主,这是导致砂姜黑土胀缩性强、宜耕性差的原因之一[24-25]。

2.2 钙质结核垂直分布特征

试验田表层(0~20 cm)土壤中钙质结核含量极低,仅有少量2~5 mm钙质结核散落分布(表2),质量分数仅占土壤的0.02%。但是随着土层深度的增加,钙质结核含量呈现上升趋势,其在>60~80 cm土层中的质量分数约为3.73%,而在>80~100 cm土层中的质量分数高达11.42%。可见,砂姜黑土钙质结核主要分布于60 cm以下土壤。相比于0~40 cm土层,>60~100 cm土壤中各粒径钙质结核的含量均最高,尤其是在>80~100 cm时,大颗粒(>8~30 mm)钙质结核的质量分数可以达到8.04%,这与钙质结核的发育过程有关。研究表明,钙质结核主要形成于干湿交替作用下地下水中的碳酸盐和成土母质中的碳酸钙(CaCO3)的淋溶及凝结作用[26]。大粒径钙质结核的形成对土壤环境条件要求苛刻,且需长时间的积累[6,27]。底层土壤受地下水的影响较多,可能有利于大粒径钙质结核的形成。0~20 cm土壤中各粒径钙质结核含量均较低,一方面是由于与深层土壤相比,表层土壤受地下水影响较小,另一方面,也可能与当地农民在长期耕作过程中对钙质结核的清理有关[6]。

2.3 土壤水分特征曲线及持水特征

土壤含水率随土壤基质势的增加而逐渐降低,各层土壤的水分特征曲线差异明显(图4)。表层(0~20 cm)土壤的饱和含水率(θ)显著高于>20~100 cm土壤(表 3),这主要是由于表层土壤受耕作影响较大,土壤容重较低(表1)。由于>20~100 cm土壤长期受到机械压实作用,且存在一定量的钙质结核,其容重显著高于表层土壤,饱和含水率低。对于>20~100 cm间的各层土壤而言,其θ值差异并不显著(>0.05)。此外,van Genutchen模型的拟合参数(、、θ)在表层(0~20 cm)土壤与20 cm以下土层之间也表现出显著的差异性(表 3)。例如,值在0~20 cm时最高,表明表层土壤大孔隙数量较多[28];相比于其他土层,表层土壤的值最大,这说明当土壤基质势降低时,土壤更容易失水[29],因此水分特征曲线的斜率也更大。

表2 不同深度土壤剖面钙质结核含量

表层土壤(0~20 cm)重力水远远大于>20~100 cm,这与表层土壤大孔隙数量较多有关。表层以下(>20~100 cm)土壤重力水随土层深度的增加呈现升高趋势。有研究指出,粗颗粒(粒径>2 mm)的加入会使土壤细土与粗颗粒之间形成大孔隙,从而增加混合样品的大孔隙数量[7,29-30]。Gargiulo等[9]也发现向变性土中添加粗颗粒,不仅引起大孔隙数量的增多,而且导致了土壤裂隙的形成。

注:采用 van Genutchen模型拟合,下同。

与重力水的变化趋势不同,土壤田间持水量和萎蔫点均随着土层深度的增加呈现先升高后降低的趋势,并且在>20~40 cm层达到最大值(表3)。随着土层深度的增加,土壤有效持水量逐渐升高。相比于0~60 cm土层,>60~100 cm土壤的有效持水量值提高了43%~120%,这可能与土壤黏粒含量的降低有关(表1)。

表3 不同深度砂姜黑土水力学特性参数

2.4 钙质结核水分特征曲线及持水特征

在以往的研究中,钙质结核的含水率和水力学特征通常被忽略。本研究结果显示,高基质势情况下(基质势为-10~0 cm),小粒径钙质结核的含水率要高于大粒径钙质结核(图5)。2~5、>5~8、>8~30 mm的钙质结核饱和含水率分别为0.25、0.22和0.20 cm3/cm3。这主要是因为小粒径钙质结核的容重较低(表4),孔隙度较大,能够保持更多的水分。当基质势低于-20 cm时,不同粒级钙质结核的含水率差别不大。由表4可知,基于van Genutchen 模型的钙质结核水分特征曲线拟合的决定系数(2)不小于0.95,具有较好的拟合效果。不同粒径钙质结核水分特征曲线值由大到小为2~5、>5~8、>8~30 mm。随着钙质结核粒径的增大,其饱和含水率和残余含水率值均显著降低,这主要与小粒径钙质结核密度较低、孔隙度较高有关。在小粒径钙质结核的形成过程中,较低的土壤溶液结晶度是造成其低密度的主要原因[26]。

2.5 钙质结核对砂姜黑土持水能力的影响

因表层土壤极易受耕作的影响,且钙质结核含量极低,本研究仅选取>20~100 cm土壤,对其钙质结核含量及其他土壤性质进行相关性分析(表5)。结果表明,随着钙质结核含量的增多,土壤持水性能,如饱和含水量、FC、WP以及残余含水率等均呈现下降趋势。其中,钙质结核总含量total与FC、WP之间分别具有极显著(<0.01)和显著(<0.05)的负相关关系,这可能是由于钙质结核密度显著高于常规土壤容重,导致土壤持水性降低。此外,在所有基质势范围内(-15 000~0 cm),钙质结核含水率均低于原状土壤(图 4~图5),这也是造成砂姜黑土具有较低持水性的重要原因之一。Gu等[15]的研究结果表明,土壤含水率随着钙质结核含量的增多而逐渐降低。Tetegan等[11]、Ceacero等[8]和付同刚等[31]在其他含粗粒介质土壤如砾石土壤的研究中也得到了类似的结果。

表4 不同粒径钙质结核水力学特性参数

除>8~30 mm外,其他粒径(2~5和>5~8 mm)钙质结核含量以及钙质结核总量均与土壤AWHC呈现显著的正相关关系(<0.05,表5)。这与之前人工装填土壤的研究结果表现不一致[15],是因为钙质结核引起的FC的减少量低于WP的减少量,二者的差值,即AWHC随着钙质结核含量的增加而增多。可见,相比于FC,钙质结核对土壤WP的负作用更强。除自身持水特性之外,钙质结核还可能通过影响土壤质地来改变土壤的持水性能。各粒级钙质结核及其总量均与土壤砂粒含量呈显著正相关,而与黏粒含量间具有显著的负相关关系(<0.05,表5),这可能是由于砂姜黑土砂粒中含有少量粒径小于2 mm的钙质结核。钙质结核凝结的同时可能将土壤颗粒结合在一起,提高了土壤砂粒含量。一般而言,壤质土壤AWHC要高于砂质和黏质土壤[32]。因此,小颗粒钙质结核的增多可能有助于改善砂姜黑土黏重的土壤质地。由于钙质结核主要分布在耕层以下土壤中,深耕可能是改良砂姜黑土耕层结构、提高土壤AWHC并促进作物根系生长的有效措施之一。

表5 20~100 cm土壤钙质结核含量与其他土壤性质间相关系数

注:**表示在0.01水平下相关性显著;*表示在0.05水平下相关性显著。

Note: ** indicates significant correlations at the 0.01 level, * indicates significant correlations at the 0.05 level.

从土壤水分特征曲线van Genutchen模型拟合参数及持水参数上看,和以及GC均与钙质结核含量之间的相关系数大于0(=0.12~0.64)。这表明钙质结核具有增加土壤大孔隙的潜力,其原因可能有以下几个方面:1)钙质结核与土壤细土之间容易形成大孔隙[29];2)钙质结核等粗颗粒在变性土开裂过程中起到开裂点的作用[9],使土壤裂隙或大孔隙数量增多;3)钙质结核在土壤中可充当骨架,减少压实作用[18];4)钙质结核含量高的土层其砂粒含量也较高,从而增加了土壤大孔隙的数量。

总体上看,较高的黏粒含量是造成砂姜黑土耕层土壤(0~20 cm)持水能力较差,土壤AWHC较低的主要原因。而对于耕层以下土壤(>20 cm)而言,机械压实作用和大量钙质结核导致土壤容重较高,土壤持水量偏低。钙质结核对砂姜黑土持水性的影响主要集中在耕层以下土壤。随着钙质结核含量的增加,土壤饱和含水率、FC和WP均降低,但AWHC显著提高。这可能是由于小粒径钙质结核本身持水量较高,同时其性质与砂粒类似。可见,钙质结核对砂姜黑土持水性的影响并非完全负面,钙质结核,特别是小粒径钙质结核可通过改善土壤质地等性质来提高土壤有效持水量。

为便于土壤持水性质的评估,前人研究往往研发土壤转换函数,通过土壤质地、有机质、容重等基础理化性质便捷地获取土壤持水参数[33-34],而未考虑钙质结核。基于本文研究结果,钙质结核对土壤持水性具有不可忽视的影响,以后需综合考虑钙质结核含量和粒径参数研发土壤转换函数模型,为砂姜黑土土壤持水性的准确评估提供技术理论依据,从而为中低产田改良提供科学支撑。

3 结 论

本研究以典型砂姜黑土区土壤剖面为研究对象,探讨了土壤持水性及其对钙质结核空间分布的响应特征,主要结论有:

1)土壤饱和含水率在0~20 cm土层达到最高,而>20~100 cm各土层之间差异不显著;土壤重力水含量随着土层深度呈现先下降后升高的趋势;土壤田间持水量和萎蔫点的趋势与之相反;土壤有效持水量随土层深度呈现逐渐升高趋势。

2)钙质结核含量随深度增加而增加,0~20 cm土壤中钙质结核质量分数仅为0.02%,而>80~100 cm钙质结核质量分数高达11.42%。

3)钙质结核降低了砂姜黑土土壤持水性。虽然钙质结核本身可持有少量水分,但其含水率远低于土壤,大粒径钙质结核含水率低于小粒径钙质结核。

4)小粒径钙质结核可有效改善砂姜黑土黏重的土壤质地,提高土壤砂粒含量,提高土壤有效持水量。

本研究对于评估砂姜黑土的持水性质、制定精确的灌溉措施、提高农业生产力具有重要意义。

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Distribution of calcareous concretion in soil profile and their effects on soil water retention in calcic vertisol

Gu Feng1,2, Chen Xuejiao3, Wei Cuilan2,4, Zhou Minghua1, Li Baoguo2※

(1.,,,610041,; 2.,,,,,,100193,; 3.,,610065,; 4.,,210036,)

Calcic vertisol is a typical kind of low-yield field with a total area of about 4 million hm2in China. Calcareous concretion with particle size larger than 2 mm has been one of the representative characteristics of calcic vertisol. The limitation of soil available water is an important reason for crop failure in this region. Therefore, the curve of soil water retention dominates the estimation of available water content. However, most studies focused on the effects of calcareous concretion on soil water retention of calcic vertisol mainly under laboratory conditions. It is lacking that under field conditions. In this study, both field surveys and laboratory experiments were conducted to explore the effect of calcareous concretion distribution in 0-1 m soil profile on soil water retention. Firstly, the spatial distribution of calcareous concretion was investigated in the study plot with 150 m length, 50 m width, and 1 m depth. After then, soil profiles (0-1 m soil depth) were chosen to divide into 5 layers with a 20 cm interval. Disturbed and undisturbed soil samples were collected in each layer. Physicochemical properties were evaluated to measure the distribution of soil particle size, size and content of calcareous concretion, bulk densities of soil, and calcareous concretions. Meanwhile, the curves of soil water retention were determined usinghigh speed centrifuge. A pressure plate method was conducted to measure water retention curves in calcareous concretion. The results showed that the mass contents of clay, silt, and sand were 30.56%-39.75%, 39.88%-45.34%, and 18.67%-24.45%, respectively, which belonged to silty clay soil in the classification standard of the United States Department of Agriculture (USDA). Clayey particles decreased, but sandy particles increased significantly with the increase of soil depth. Calcareous concretion was mainly distributed in the soil depth of >20-100 cm, where the content and size increased as soil depth increased. Calcareous concretions content in the surface soil (0-20 cm) was very low (with mass content 0.02%), where only a few calcareous concretions of 2-5 mm were discovered. The maximum content of calcareous concretion was detected at > 80-100 cm (up to 11.42%), where the calcareous concretion content was 8.04% in the size of >8-30 mm. Soil bulk density ranged from 1.23-1.61 g·cm-3. The densities of calcareous concretions were 2.01, 2.21, and 2.23 g/cm3with the size of 2-5 mm, >5-8 mm, and >8-30 mm, respectively. Soil bulk density increased along with the calcareous concretion content increasing. Water retention curves of soil and calcareous concretion were well fitted by the van Genuchten model, with the determination coefficient larger than 0.95. The saturated water content of surface soil (0-20 cm) was significantly higher than that of 20-100 cm soil. Nevertheless, the Gravitational-water content in the surface soil (0-20 cm) was much larger than that in the soil of > 20-100 cm, which was related to macropores formed during tillage. In the subsurface (>20-100 cm), soil gravitational-water content and available water-holding capacity increased with the increase of soil depth, but the field capacity and wilting point decreased. Calcareous concretion maintained a non-negligible amount of water, 0.25, 0.22, and 0.20 cm3/cm3in the particles with the size of 2-5 mm, >5-8 mm, and >8-30 mm, respectively. But the water-holding capacities of calcareous concretion were significantly lower than that of soil. The effects of calcareous concretion on water-holding capacity mainly occurred in the subsurface soil. Soil saturated water content, field capacity, and wilting point decreased with increasing calcareous concretion. Interestingly, calcareous concretion content was positively correlated with the soil sand content, but negatively correlated with the soil clay content. Calcareous concretion can bind soil particles together to prevent sand weathering, and thereby effectively improve soil texture. More calcareous concretion led to higher sand contents, and thus increased the available water-holding capacity in soil. This finding can provide a theoretical basis to accurately assess the soil water-holding capacity in calcic vertisol for precision irrigation and high crop productivity.

soils; soil moisture; particles; calcic vertisol; calcareous concretion; spatial distribution; water retention; water characteristic curve

谷丰,陈雪娇,魏翠兰,等. 砂姜黑土钙质结核剖面分布特征及其对土壤持水性的影响[J]. 农业工程学报,2021,37(6):73-80.doi:10.11975/j.issn.1002-6819.2021.06.010 http://www.tcsae.org

Gu Feng, Chen Xuejiao, Wei Cuilan, et al. Distribution of calcareous concretion in soil profile and their effects on soil water retention in calcic vertisol[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(6): 73-80. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2021.06.010 http://www.tcsae.org

2020-11-24

2021-01-19

国家重点研发计划项目(2016YFD0300801);国家水体污染控制与治理科技重大专项(2017ZX07101001)

谷丰,博士,研究方向为土壤结构与水分运动。Email:guf@imde.ac.cn

李保国,教授,博士生导师,研究方向为土壤过程定量化。Email:Libg@cau.edu.cn

10.11975/j.issn.1002-6819.2021.06.010

S152.7+1

A

1002-6819(2021)-06-0073-08

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