太原东山试验林场土壤理化性质及饱和导水率的坡向分异规律研究

为了探究太原东山试验林场不同坡向条件土壤性质及饱和导水率变化的规律,选取东山林场无植被覆盖裸地和油松林地的阳坡、阴坡、半阴半阳坡共6个样地进行土壤采样,测定了土壤基本性质及养分含量,并用环刀分层取土,测定土壤饱和导水率,对比分析了土壤性质、养分及饱和导水率的坡向分异规律。结果表明:坡向对土壤密度无影响;裸地土壤含水率表现为阴坡 > 半阴半阳坡 > 阳坡;油松林地土壤含水率、土壤养分元素含量、土壤饱和导水率表现为阳坡 > 半阴半阳坡 > 阴坡,阳坡表层土壤（0—30 cm）石砾含量少于其他坡向,总孔隙度高于其他坡向。坡向对土壤性质及饱和导水率的影响是通过植被产生作用。在今后对林地土壤性质及水分入渗的研究中不能忽略坡向的影响。     

容重对土壤饱和水分运动参数的影响

通过石蜡固定容重方法测定了4种土壤不同容重下的饱和重量含水量与饱和导水率，分析了容重对这两个土壤饱和水分运动参数的影响。结果表明：饱和重量含水量随容重的增加而减小，与容重成反比关系．饱和导水率随着容重的增加呈现幂函数形式递减。这些结果将为构建变容重土壤水分运动创新性理论体系提供适当的定量关系，有利于实现土壤水资源的合理利用。     

不同改良剂对滨海盐渍土水盐特性的影响

针对滨海盐渍土盐分含量高和土壤导水性能差的问题,采用禾康盐碱土改良剂、康地宝盐碱土改良剂、金满田生物菌剂、腐殖酸和石膏5种土壤改良剂,通过田间小区试验,分析测定了土壤含水量、土壤盐分含量、pH值、容重和饱和导水率等指标,并测定了作物收获产量,筛选适宜于改良研究区滨海盐渍土水盐特性的改良剂.试验结果表明:(1)土壤水分含量变化极大地影响着土壤的含盐量,土壤含水量与土壤含盐量呈极显著线性负相关关系.(2)腐殖酸在抑制滨海盐渍土盐分和降低土壤容重方面效果最佳,经腐殖酸(300 kg/hm2)处理后,0-5,5-20和20-40 cm土层盐分含量较CK分别减少了29.2％,32.6％和25.9％,土壤容重较CK减少了10.2％,土壤孔隙度和饱和导水率较CK也相对提高.(3)5种改良剂不同程度提高了作物的产量,以腐殖酸处理作物增产效果最为明显,玉米和油菜产量较CK分别增加了104.8％和41.6％.     

鹫峰地区不同植被群落土壤性质及饱和导水率特征

为了探究鹫峰国家森林公园不同植被群落土壤性质及饱和导水率的特征,对鹫峰地区6种不同植被群落林区进行土壤取样,测定土壤基本性质与养分元素含量,并用环刀分层取土进行水分穿透试验,测定土壤饱和导水率,对比分析不同植被群落土壤性质、土壤养分及饱和导水率特征。结果表明:鹫峰地区不同植被群落土壤石砾含量及土壤分形维数表现为裸地矮型草本矮型灌木乔木林混交林;土壤密度、土壤含水率、土壤孔隙度、土壤饱和导水率及表层(0—30cm)土壤全氮、速效钾、速效磷含量均表现为混交林纯林灌木林草本裸地。在今后的人工林营建中,要优先考虑适宜的混交林,因为其对土壤的改良以及水源涵养能力的提高有最优效果。     

不同根系构型草本与灌木复合对土壤饱和导水率的影响因素分析及模拟

[目的] 探究不同根系构型草本与灌木复合时的根土性质的差异对土壤饱和导水率的影响,并综合考虑根系和土壤性质建立估算土壤饱和导水率的经验方程,为黄土高原植被恢复后的水文模型建立提供理论参考。[方法] 选取不同根系构型草本与灌木的混合样地,分别为柠条锦鸡儿加冰草(须根系)和柠条锦鸡儿加铁杆蒿(直根系)。采用双环刀法测定不同样地土壤饱和导水率。[结果] 样地类型和土层深度对土壤饱和导水率的影响达到显著水平,两者对土壤饱和导水率影响的因子贡献率分别为26%和52%。直根系铁杆蒿与柠条锦鸡儿混合样地的土壤饱和导水率高于须根系冰草与柠条锦鸡儿混合样地,并且不同样地的土壤饱和导水率随土层深度的增加均表现出降低的趋势。根长密度、团聚体以及土壤容重能够较好地模拟土壤饱和导水率,其拟合精度R²可以达到0.86。[结论] 直根系草本与灌木复合时较须根系草本与灌木复合相比具有更高的饱和导水率。在不同样地中,根长密度、团聚体以及土壤容重是影响饱和导水率的主要因素。     

施肥和地膜覆盖对黄土旱塬土壤理化性质和冬小麦产量的影响

【目的】研究黄土高原旱作农业区施肥等措施对耕层土壤理化性质和作物农艺性状的影响,为保持土壤适度生产力,选择适合黄土塬区可持续发展的新型增产措施提供理论基础。【方法】通过设在渭北旱塬的多年田间定位试验,选取不施肥空白对照、施氮磷肥、施氮磷钾肥、氮磷肥加生物炭、氮磷肥加生育期地膜半覆盖和氮磷肥加夏闲期地膜半覆盖共6个处理,所有处理均在冬小麦收获后和播种前进行翻耕。分析了不同处理耕层土壤理化性质、冬小麦产量及农艺指标。【结果】与对照相比,施氮磷肥显著提高了耕层土壤饱和导水率,降低耕层土壤紧实度,显著增加冬小麦生育期耗水量,提高水分利用效率和降雨利用效率,显著提高了耕层土壤中有机质、全氮、硝态氮、铵态氮、全磷、有效磷等养分的含量,连续三年提高冬小麦的产量均在一倍左右。与氮磷肥处理相比,增施钾肥处理增加了冬小麦拔节期耕层土壤紧实度,却显著降低了收获期土壤容重、增加了总孔隙度,并显著提高了水分利用效率,在一定程度上增加了耕层土壤全氮、有机质含量,使冬小麦的叶面积指数显著增加,连续三年冬小麦平均产量达4500 kg/hm2;增施生物炭处理耕层土壤容重降至最低为1.16 g/cm3,增加了土壤总孔隙度,导致饱和导水率最大为0.049 cm/min,提高了水分利用效率;耕层土壤中的有机质、全氮、全磷、有效磷的含量有一定增加,冬小麦的产量有所提升;施氮磷肥基础上的生育期地膜半覆盖与夏闲期地膜半覆盖,均显著降低了耕层土壤饱和导水率,增加了土壤紧实度,提高了冬小麦水分利用效率,耕层土壤中有机质、铵态氮、速效钾的含量有所增加,全磷含量降低,土壤pH下降,除去受灾年份,冬小麦平均产量在4700～4800 kg/hm2之间。【结论】与对照相比,长期施用氮磷化肥显著提高冬小麦的产量,却导致土壤pH下降。在施氮磷肥的基础上增施生物炭,可以显著改善土壤物理化学性质,增加冬小麦产量,但其经济投入过高。在施氮磷肥的基础上,增施钾肥与生育期地膜半覆盖,改善了耕层土壤养分状况,有一定的经济效益,是适宜黄土塬区的冬小麦增产措施。     

有机物料对黑土氮素转化的影响

通过室内好气培养试验,研究了短期内添加不同有机物料对黑土氮素转化的影响。结果表明,与对照处理相比,添加2%和4%猪粪显著提高了土壤的铵态氮和硝态氮含量,猪粪添加量越高,土壤无机氮含量越高,且随着培养的进行逐渐上升。而添加2%和4%秸秆显著降低了土壤的铵态氮和硝态氮含量,秸秆添加量越高,土壤无机氮含量越低,且随着培养的进行逐渐下降。添加猪粪显著增加了土壤的净氮矿化量,而添加秸秆显著降低了土壤净氮矿化量,使无机氮发生了固定。有机物料氮矿化残留率随添加量的增加而增大,培养7天后猪粪有机氮的分解残留率要远小于秸秆。由此可见,有机物料对黑土氮素转化的影响因其种类和施用量的不同而异,实际农业生产中应合理施用。     

生物质炭对旱地红壤理化性状和作物产量的持续效应

以江西进贤旱地红壤为供试土壤,连续3a观测施用生物质炭(0t/hm2,2.5t/hm2,5t/hm2,10t/hm2,20t/hm2,30t/hm2和40t/hm2)后土壤容重、孔隙度、饱和导水率、土壤pH、有机碳、阳离子交换量及油菜和红薯产量的变化。结果表明:生物质炭连续3a降低土壤容重,提高了土壤孔隙度和土壤饱和导水率,提升了土壤pH,增加了土壤有机碳和阳离子交换量;油菜和红薯产量均随生物质炭施用量的增加而增加,且红薯产量增幅大于油菜。随种植年限的延长,作物产量增幅越大。高施用量(40t/hm2)处理在旱地红壤上的改良效果和增产效应最好,施用生物质炭后第3a其土壤容重下降了0.17g/cm3,土壤孔隙度和饱和导水率分别增加了11.71%和126.57%,土壤pH、有机碳和阳离子交换量分别提高了7.25%,47.88%和44.61%,油菜和红薯产量分别增加了1.23t/hm2和14.83t/hm2。在连续3a内,旱地红壤施用生物质炭对改善土壤理化性状,维持作物增产具有持续效应,为生物质炭在红壤地区的大规模推广应用提供了科学依据。     

渭北旱塬管理措施对冬小麦地土壤剖面物理性状的影响

【目的】研究黄土高原旱作农业区不同施肥覆盖措施对冬小麦地0—40 cm土壤剖面物理性质的影响,可为保持良好的土壤物理性状,探求适合渭北旱塬可持续的田间管理措施提供参考。【方法】基于设在渭北旱塬15年的田间定位试验,选取NP (N 150 kg/hm^2+P 75 kg/hm^2)、NPK (NP+K 30 kg/hm^2)、NPB (NP+biochar 14.0t/hm^2)、NPFFT (NP配合地膜夏闲期覆盖)、NPFGT (NP配合地膜生育期覆盖)和NPFWT (NP配合地膜全年覆盖)共6个处理。于2017年冬小麦收获期采集剖面土样,对0—10 cm、10—20 cm、20—30 cm和30—40 cm土层土壤含水量、土壤容重、饱和导水率和水稳定性团聚体等相关土壤物理性质进行测定与分析。【结果】与NP相比,NPK处理降低了收获期0—20 cm土壤容重,增加了耕层土壤总孔隙度和0—40 cm土层> 2 mm水稳定性团聚体含量,0—10 cm土层> 2 mm水稳定性团聚体含量显著提高了1.3倍(P <0.05);NPB处理,收获期耕层土壤容重降低,土壤总孔隙度增加,表层土壤饱和导水率显著降低27.9%,剖面土壤含水量和> 2 mm水稳定性团聚体含量均增加,且表层> 2 mm水稳定性团聚体含量显著提高了1.0倍;NPFFT处理收获期剖面土壤含水量降低,耕层土壤容重增加,总孔隙度降低;NPFGT处理收获期耕层土壤容重和剖面土壤含水量均增加,耕层总孔隙度降低,剖面土壤饱和导水率降低,尤其表层显著降低60.2%;NPFWT处理收获期耕层土壤容重增加,总孔隙度降低,表层土壤饱和导水率降低,但10—40 cm土壤饱和导水率平均提高57.5%,剖面土壤含水量、> 2 mm水稳定性团聚体含量、平均重量直径和几何平均直径均增加。受当地传统耕作深度的影响,不同施肥覆盖措施对土壤容重、饱和导水率和孔隙度的影响主要集中在0—20 cm土层,对20—40 cm土层影响较小。【结论】在氮磷肥配施的基础上,增施钾肥、生物炭和地膜全年覆盖均有利于改善试验农田土壤物理性质,但从经济投入和对土壤物理性状改良程度方面考虑,增施钾肥和地膜全年覆盖这两种处理是保持渭北旱塬良好土壤剖面物理性质的有效措施。     

长期耕作对典型黑土水力性质的影响

为揭示长期耕作对黑土耕地水文退化的作用,以典型黑土区不同纬度带的未经机械耕作的林地与长期耕作的耕地土壤进行对比,研究沟垄耕作对土壤垂直和水平方向物理性质和水力性质的影响。结果表明：长期耕作使得总体物理与土壤水力性质严重退化,与林地土壤相比,耕地土壤质地未发生变化,有机质含量显著降低,容重从1.03（0.84~1.17）g·cm-3显著提高至1.31（1.20~1.46）g·cm-3,穿透阻力显著增加,持水供水与导水性显著降低,有效含水量从0.19（0.14~0.23）cm3·cm-3降至0.15（0.10~0.21）cm3·cm-3。物理质量指数S值从0.061（优）降至0.025（差）。长期沟垄耕作使得犁底层的饱和导水率（6.61 cm·d-1）仅为耕作层的1/10.。耕作导致耕作层垂直方向导水率（64.67 cm·d-1）低于水平方向（82.84 cm·d-1）。犁底层的穿透阻力（897.04 kPa）为耕作层的1.89倍,造成了耕作层与犁底层水力性质分层。长期耕作导致的耕地土壤水力性质分层和方向分异是促进耕地坡面径流“沟渠效应”而加速侵蚀退化的重要原因。     

Assessment of Properties of a Harkey Soil under Organic and Conventional Farming Systems

Farming practices involving less intense chemical use are becoming popular in the United States primarily because of environmental concerns related to the use of chemicals in conventional farming systems. Physical and chemical soil properties were assessed on four farms, one conventional farm and three organic farms 3 (OF3), 6 (OF6), and 9 (OF9) years after certification. All farms were located in Doña Ana County of southern New Mexico, sited on Harkey soil (coarse silty, mixed, calcareous, thermic typic Torrifluvents). OF3, OF6, and OF9 were planted to cotton (Gossypium arboreum L.), chile (Capsicum annuum), and alfalfa (Medicago sativa) in 2006, respectively, and the conventional farm was planted to cotton. Core and bulk soil samples were collected from each farm at three different locations and three depths during September 2005, June 2006, and November 2006. Clay content was positively correlated with field capacity, wilting point, and available water capacity (AWC) and negatively correlated with transmission pore volume (VTP) and sand content at most depths. The one-way analysis of means of soil physical and chemical properties separately by depth showed that bulk density (ρ_b) was greater in November 2006 samples than in September 2005 and June 2006 samples in OF9 and was lowest in the conventional farm. In general, saturated hydraulic conductivity (K_s), volume of storage pores, effective porosity, AWC, and VTP showed little variation and were not related to the amount of time under organic farming. Soil pH and electrical conductivity (EC) were greater in the organic farms, and EC values mostly increased with increasing amount of time under organic farming. The greatest EC (2.6 dS m^?1) in OF9 indicated that 9 years of manure application has raised soil salinity only slightly. Although no evidence on significant improvement of soil quality due to organic farming was observed, with regard to soil storage and transport properties and soil salinity, the organic farming system is sustainable for this region.     

不同有机材料覆盖对土壤保水效果的影响

[目的]研究不同有机材料覆盖对土壤水分蒸发量、土壤含水量的影响,并筛选出保水效果最佳的材料。[方法]以木片、树皮及经过堆腐的园林废弃物为研究对象,进行模拟蒸发及桶装控制试验。[结果]不同粒径的园林废弃物覆盖均能降低土壤水分日蒸发量,日蒸发量从大到小依次为CK,3～5 cm粒径(M_3)、0～1 cm粒径(M_1)、1～3 cm粒径(M_2)。在连续蒸发14 d后,M_2,M_1,M_3和CK的土壤水分累积蒸发量分别为193.0,269.5,304.0和1 037.0 g,与CK相比,分别减少了81.4%,74.0%,70.7%;不同有机材料覆盖均能提高土壤含水量。除了雨季之外,不同土层土壤含水量从高到低依次表现为:木片覆盖(M_4)树皮覆盖(M_5)1～3 cm粒径园林废弃物覆盖(M_2)CK。土壤含水量的年变化整体呈现出双峰趋势,一年中4—5月含水量较低,6—8月含水量较高,不同土层土壤含水量的年变化趋势基本一致。M_4,M_5,M_2和CK的0—40 cm土层土壤年平均含水量分别为32.9%,30.3%,27.4%,26.8%。[结论]木片为保水效果最好的有机材料,其次是树皮和园林废弃物。     

The Effects of Long‐term Fertiliser Applications on Soil Organic Carbon and Hydraulic Properties of a Loess Soil in China

Based on a 28‐year in situ experiment, this paper investigated the impacts of organic and inorganic fertiliser applications on soil organic carbon (SOC) content and soil hydraulic properties of the silt loam (Eumorthic Anthrosols) soils derived from loess soil in the Guanzhong Plain of China. There were two crop (winter wheat and summer maize) rotations with conventional tillage. The treatments included control without fertiliser application, organic manure application (M), chemical fertiliser application (NP), and the application of organic manure with chemical fertiliser (MNP). The results showed that the 28‐year organic manure applications (M and MNP) significantly (p < 0·05) increased SOC content at surface layer (0–10 cm), but the effect of chemical fertilisers alone on SOC was not significant. Organic manure treatments (M and MNP) apparently improved soil hydraulic properties. Compared with control, field capacity and total porosity significantly (p < 0·05) increased while soil bulk density significantly (p < 0·05) decreased for organic manure applications. The M and MNP treatments increased soil water retentions by 3·2–10·8%, which was dependent of suction tensions. However, the NP treatment had no significantly impact on soil water retention compared with control. Neither organic nor inorganic fertiliser applications significantly changed saturated hydraulic conductivity. However, a clear difference was observed for unsaturated hydraulic conductivity between the M and the control at 0–5 cm. Overall, long‐term applications of organic manuring increased SOC content and amended soil hydraulic properties. However, the effects of chemical fertilisers on these soil properties were limited. Copyright © 2015 John Wiley & Sons, Ltd.     

河西走廊荒漠区土壤物理性质沿降水梯度的变化

土壤质量、土壤蓄水保肥能力和土壤养分吸收利用与土壤物理性质有密切联系。在甘肃省河西走廊民乐县至高台县自东向西的天然降水梯度上,选择荒漠区的7个研究点对土壤表层(0—20cm)和亚表层(20—40cm)分别采集42个土壤样品,在野外采用张力入渗仪测定饱和导水率,室内采用常规方法对土壤容重、孔隙度、颗粒组成等项目进行了测定。结果表明,在360～100mm的降水梯度上,荒漠土壤粉粒和黏粒含量降低,砂粒含量增加;伴随着土壤的粗粒化,引起土体的风散和结构的破坏,使土壤容重增加、孔隙度降低、持水性能下降等一系列物理性质的恶化。土壤表层、亚表层饱和导水率Ksat和变异系数Cv分别为70.0%和86.3%,均是土壤表层和亚表层各物理性质中变异系数最高的。     

Soil Hydraulic Properties: Influence of Tillage and Cover Crops

Understanding the effects of cover crops and tillage on soil physical properties is important for determining soil productivity. This study was conducted at Lincoln University's Freeman Center, USA to evaluate the effects of tillage and cover crop management on soil hydraulic properties. The field site included three replicate blocks in a randomized complete block design with each plot measuring 21.3 m in length and 12.2 m in width. Treatment factors were tillage at two levels(moldboard plow tillage vs. no tillage) and cover crop at two levels(cereal rye(Secale cereal) cover crop vs. no cover crop). Soil samples were collected in late spring/early summer from each treatment at 10-cm depth increments from the soil surface to a depth of 40 cm using cores(76.2-mm diameter and 76.2-mm length). Soil bulk density was 13% lower with tillage compared with no-tillage. Volumetric water content was significantly higher at 0.0 and -0.4 k Pa pressures with tillage compared with no tillage. Tillage increased the proportion of coarse mesopores by 32% compared with no tillage, resulting in 87% higher saturated hydraulic conductivity(K_(sat)). Cover crop increased the proportion of macropores by 24% compared with no cover crop; this can potentially increase water infiltration and reduce runoff. As a result of higher macroporosity, Ksat was higher under cover crop compared with no cover crop. This study demonstrated that tillage can benefit soil hydraulic properties in the short term, but these effects may not persist over time. Cover crops may slightly improve soil hydraulic properties, but longer term studies are needed to evaluate the long-term effects.     

生物炭配合深松对土壤团聚体及有机碳的影响

[目的] 分析施加生物炭配合深松对农田耕层土壤容重、土壤结构稳定性及有机碳的影响,为土壤结构改良提供科学合理的调控措施和理论依据。[方法] 基于冬小麦—夏玉米轮作体系,2017—2019年大田试验期间,在小麦季设置生物炭施用量分别为0,3 000,6 000 kg/hm²(B₀,B₁和B₂)的3个处理,在玉米季设置传统贴茬播种(P)和深松耕作播种(S)2个耕作处理,共计B₀P,B₁P,B₂P,B₀S,B₁S,B₂S 6个处理。[结果] ①两个轮作后,相同耕作方式下,土壤容重随生物炭用量的增加而降低,其中B₂S较B₀S显著降低(13.59%);同一施炭水平下,各处理土壤容重呈现出深松＜传统的特征,深松容重整体较传统低4.95%。②连续施加生物炭配合深松耕作两年后,B₂S处理下的有机碳含量达到最高,比B₀P显著增加(42.15%),比B₂P增加1.03%。③两个轮作后,随生物炭用量的增加机械性团聚体含量(DR_0.25)、水稳性团聚体含量(WR_0.25)、平均重量直径(MWD)呈上升趋势,相反土壤团聚体破坏率(PAD)及土壤不稳定团粒指数(ELT)呈逐渐下降趋势,且表现为B₂S处理均优于其他各处理的特征,表明高添加量生物炭配合深松耕作较传统耕作能更有效地提高团聚体稳定性。[结论] 小麦季基施6 000 kg/hm²生物炭并配合玉米季深松有利于提高土壤团聚体稳定性,改善华北平原农田土壤结构。     

滨海盐渍土土壤物化性质与水动力学性质变异

为分析不同梯度盐渍土土壤的物理性质与水动力学性质变异状况,在江苏沿海连云港市徐圩新区开展了试验研究。对5种不同盐渍化级别土壤进行取样,测定其pH、EC_e、容重、总孔隙度、含水率和饱和导水率等,分析不同级别滨海盐渍土壤物化特性参数和水动力学性质变化规律。结果表明:(1)不同级别盐渍土0—50 cm剖面土壤EC_e先变小后增大,但40—50 cm剖面EC_e明显大于0—10 cm剖面。非盐渍土和极重度盐渍土0—50 cm剖面土壤EC_e变化较小,轻度盐渍土、中度盐渍土、重度盐渍土的0—50 cm剖面土壤EC_e值变化较大。(2)土壤EC_e和容重呈极显著负相关关系,与毛管孔隙度、非毛管孔隙度、总孔隙度、含水率、毛管持水量、田间持水量、最大持水量呈极显著正相关关系。土壤孔隙度和持水量呈极显著正相关关系。(3)极重度盐渍土饱和导水率明显小于其他级别的盐渍土,且0—20 cm剖面土壤饱和导水率大于20—50 cm剖面。研究结果可为滨海盐渍土水盐管理和生态环境建设提供理论参考依据。