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1.
田间原位不同深度入渗试验是表达土壤分层状态、展示土层物理分异以及定量土壤剖面水功能变化的关键。为了探究不同深度水稻土的入渗能力及保水作用,该研究以华东稻麦轮作区小农户长期机械化耕整模式下代表地块的土层分异为目标,设计田间原位不同深度入渗试验。在试验地块内开挖7个不同深度的入渗坑并在坑底进行入渗试验,然后渗透48 h分层测取土壤含水率,研究不同坑底深度（坑深）土壤的入渗能力和入渗后各土层含水率的变化。结果表明,不同深度入渗试验准确表达了不同坑深土壤的水分入渗及土层持水分异,同时也能清晰地鉴别出犁底层所在位置和厚度,犁底层始于15 cm深,且耕作层与犁底层分异明显,耕作层平均紧实度为1 005.79 kPa,犁底层平均紧实度为1 910.73 kPa;土壤剖面分析表明,耕作层土壤形态疏松,根系分布稠密,犁底层土壤容重大,孔隙度小,透水性差,心土层土壤铁锰斑点较多,结构性差;土壤入渗参数随坑深的增加而减少,其中0～15 cm坑深范围内平均的平均入渗速率和累计入渗量分别为>20～30 cm的17.04倍和18.06倍;通过对比初始含水率和渗透48 h后含水率,得到坑深在15 cm范围内的... 相似文献
2.
耕翻和秸秆还田深度对东北黑土物理性质的影响 总被引：6，自引：4，他引：2
为了明确耕翻和秸秆还田深度对土壤物理性质的影响,在东北黑土区中部进行了6 a的耕翻和秸秆还田定位试验,设置了免耕(D0)、浅耕翻(0～20 cm)(D20)、浅耕翻+秸秆(D20S)、深耕翻(0～35 cm)(D35)、深耕翻+秸秆(D35S)、超深耕翻(0～50 cm)(D50)和超深耕翻+秸秆(D50S)7个处理开展研究,秸秆还田处理将10 000 kg/hm2秸秆均匀地还入相应的耕翻土层。结果表明,耕翻和秸秆还田深度是影响土壤物理性质的重要农艺措施。与初始土壤相比,免耕显著增加了0～20cm土层土壤容重,减少了孔隙度、持水量、饱和导水率和0.25mm水稳性团聚体的含量(WAS0.25)(P0.05),而对20～50 cm土层没有显著影响(P0.05)。在0～20 cm土层,除了D50处理显著降低了WAS0.25含量以外,D20,D35和D50处理对各项土壤物理指标均没有显著影响;而D20S和D35S处理则显著改善了该层各项土壤物理指标。在20～35 cm土层,D35、D35S、D50和D50S处理显著改善了该土层各项土壤物理指标(除了2014年的容重)。在35～50cm土层,D50和D50S处理对各项土壤物理指标改善效果显著,特别是相应土层通气孔隙度和饱和导水率显著增加。研究结果表明耕翻配合秸秆对土壤物理指标的改善效果优于仅耕翻处理。综合评分结果也表明D35S和D50S处理分别对20～35 cm和35～50 cm土层土壤物理性质的改善效果最好,说明在质地黏重的黑土上深翻耕或者超深翻耕配合秸秆还田通过土层翻转秸秆全层混合施用能够显著改善全耕作层土壤的物理性质,增加耕层厚度,扩充土壤的水分库容,提高黑土的水分调节能力。 相似文献
3.
《Communications in Soil Science and Plant Analysis》2012,43(7):908-916
Tillage depth influences the soil–water–plant ecosystem, thereby affecting crop yield and quality. The effects of tillage depth on soil physical properties and sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study composed of two tillage depths [10 cm, referred to as shallow (ST), and 20 cm, referred to as deep (DT)] was conducted on a Lihen sandy loam soil in spring 2007 at the Agricultural Research Service (ARS) irrigated research farm near Williston, North Dakota. Soil bulk density (ρb), gravimetric water content (θw), and saturated hydraulic conductivity (Ks) were measured three times during the growing season at four depth increments to 40 cm deep. Samples were taken approximately 0.5 m apart within the crop row of irrigated sugarbeet. Soil air-filled pore volume (εa) was calculated from soil bulk density and water content data. Soil penetration resistance (PR) was also measured in 2.5-cm increments to a depth of 35 cm. Roots were hand-harvested from each plot, and each sample consisted of the roots within an area consisting of two adjacent rows 1.5 m long. Soil ρb was greater in ST than in DT, whereas Ks was greater with DT than with ST. Soil PR was significantly greater in ST than in DT at the 0- to 20-cm depth. Soil θw and εa were slightly greater in DT than those under ST. Although tillage depth had no significant effect on sugarbeet population, root yield, or sucrose content, a small difference in sucrose yield between two depths of tillage may be attributed to reduced ρb, increased water intake, improved aeration, and increased response to nitrogen uptake under DT than under ST. It was concluded that tillage depth enhanced soil physical quality and had little effect on sugarbeet yield or quality. 相似文献
4.
Advances in the development of non-residual herbicides have increased the interest in minimum tillage systems as an alternative to conventional cultivation. This study compared the effects of conventional tillage (CT), minimum tillage (MT) and zero-till (ZT) with continuous winter wheat, winter wheat-summerfallow, and winter wheat-barley-summerfallow on various properties of a Brown Chernozemic loam. Saturated hydraulic conductivity (HC), soil moisture retention, bulk density (BD) and infiltration rate of the soil were measured. The effects of crop rotation by tillage or crop rotation on these soil physical properties were not significant after 8 years of tillage. In general, the BD of the soil under ZT was greater than that under CT in the tillage zone and was lower below the tillage zone. The HC of ZT soil was less than that of CT soil in the tillage zone and greater below the tillage zone. Infiltration rates were not different among the tillage treatments. Although significant differences in some soil properties occurred among tillage treatments, these differences were likely to be too small to affect crop production. 相似文献
5.
不同耕作深度对红壤坡耕地耕层土壤特性的影响 总被引：2，自引：0，他引：2
红壤坡耕地不同耕作深度对耕层质量和作物产量具有重要影响。以江西红壤坡耕地示范区耕层为研究对象,从土壤属性角度,对红壤坡耕地不同耕作深度处理下垂直深度土壤水分、容重、孔隙度、土壤紧实度、土壤抗剪强度、土壤有机质、有效磷和速效钾等进行分析。结果表明:(1)不同耕作深度对土壤孔隙度、饱和含水量和田间持水量的影响为免耕翻耕20 cm翻耕10 cm常规耕作翻耕30 cm,对容重的影响为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作比较,翻耕30 cm使土壤饱和含水量、田间持水量和土壤孔隙度分别提高了18.17%,12.67%,5.94%,土壤容重降低6.90%。(2)不同耕作深度下土壤紧实度表现为翻耕30 cm翻耕10 cm翻耕20 cm免耕常规耕作,土壤抗剪强度表现为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作对照,翻耕30 cm使土壤紧实度和抗剪强度分别降低27.07%和24.82%。(3)土壤有机质含量以翻耕20 cm处理下最高(13.48 g/kg),免耕处理含量最低(9.39 g/kg),土壤速效养分主要集中分布在0-20 cm土层,但20-40 cm土层中翻耕处理较免耕处理有不同程度的增加,以翻耕20 cm和常规耕作表现显著。(4)主成分分析结果表明,翻耕30 cm处理对红壤坡耕地土壤的综合改善效果最好。研究结果可为红壤坡耕地耕层土壤改善和合理耕层构建提供技术参考。 相似文献
6.
耕作与覆盖措施对黄土塬区春玉米田土壤水气传输的影响 总被引：1，自引：1，他引：1
7.
Land-use effects on organic matter and physical properties of soil in a southern Mediterranean highland of Turkey 总被引：12，自引：0，他引：12
Forest and grassland soils in highlands of southern Mediterranean Turkey are being seriously degraded and destructed due to extensive agricultural activities. This study investigated the effects of changes in land-use type on some soil properties in a Mediterranean plateau. Three adjacent land-use types included the cultivated lands, which have been converted from pastures for 12 years, fragmented forests, and unaltered pastures lands. Disturbed and undisturbed soil samples were collected from four sites at each of the three different land-use types from depths of 0–10 cm and 10–20 cm in Typic Haploxeroll soils with an elevation of about 1400 m. When the pasture was converted into cultivation, soil organic matter (SOM) pool of cultivated lands for a depth of 0–20 cm were significantly reduced by, on average 49% relative to SOM content of the pasture lands. There was no significant difference in SOM between the depths in each land-use type, and SOM values of the forest and pasture lands were almost similar. There was also a significant change in soil bulk density (BD) among cultivation (1.33 Mg m−3), pasture (1.19 Mg m−3), and forest (1.25 Mg m−3) soils at depth of 0–20 cm. Only for the pasture, BD of the depth of 0–10 cm was significantly different from that of 10–20 cm. Depending upon the increases in BD and disruption of pores by cultivation, total porosity decreased accordingly. Cultivation of the unaltered pasture obviously increased the soil erodibility measured by USLE-K factor for each soil depth, and USLE-K factor was approximately two times greater in the cultivated land than in the pasture indicating the vulnerability of the cultivated land to water erosion. The mean weight diameter (MWD) and water-stable aggregation (WSA) were greater in the pasture and forest soils compared to the cultivated soils, and didn’t change with the depth for each land-use type. Aggregates of >4.0 mm size were dominant in the pasture and forest soils, whereas the cultivated soils comprised aggregates of the size ≤0.5 mm. I found that samples collected from cultivated land gave the lowest saturated hydraulic conductivity values regardless of soil depths, whereas the highest values were measured on samples from forest soils. In conclusion, the results showed that the cultivation of the pastures degraded the soil physical properties, leaving soils more susceptible to the erosion. This suggests that land disturbances should be strictly avoided in the pastures with the limited soil depth in the southern Mediterranean highlands. 相似文献
8.
Tillage effects on near-surface soil hydraulic properties 总被引：1，自引：0，他引：1
J. G. Benjamin 《Soil & Tillage Research》1993,26(4):277-288
The processes for the formation of porosity are thought to differ between tilled and non-tilled cropping systems. The pores are created primarily by the tillage tool in the tilled systems and by biological processes in non-tilled systems. Because of the different methods of pore formation, the pore size distribution, pore continuity and hydraulic conductivity functions would be expected to differ among tillage systems. The objective of this study was to determine effects of three tillage systems — mold-board plow (MP), chisel plow (CP), and no-till (NT) — on hydraulic properties of soils from eight long-term tillage and rotation experiments. Tillage effects on saturated and unsaturated hydraulic conductivity, pore size distribution, and moisture retention characteristics were more apparent for soils with a continuous corn (CC) rotation than for either a corn-soybean (CS) rotation or a corn-oats-alfalfa (COA) rotation. Pore size distributions were similar among tillage systems for each soil except for three soils with a CC rotation. The MP system increased volume of pores >150 μm radius by 23% to 91% compared with the NT system on two of the soils, but the NT system increased the volume of the same radius pore by 50% on one other soil. The NT system had 30 to 180% greater saturated hydraulic conductivity than either the CP or MP systems. The NT system with a CC rotation showed a greater slope of the log unsaturated hydraulic conductivity; log volumetric water content relationship on two of the soils indicating greater water movement through a few relatively large pores for this system than for either the CP or MP systems. 相似文献
9.
《Soil & Tillage Research》1988,11(1):1-18
With the increasing use of conservation tillage, many questions about the long-term effects of tillage system on soil physical properties have been raised. Studies were conducted to evaluate saturated hydraulic conductivity (KSAT), macropore characteristics and air permeability of two silty soils as affected by long-term conservation tillage systems in the state of Indiana. Measurements were taken during the tenth year of a tillage study on a Chalmers silty clay loam (Typic Haplaquoll) and the fifth year of a study on a Clermont silt loam (Typic Ochraqualf). Tillage systems were moldboard plow, chisel, ridge till-plant, and no-till in a rotation of corn (Zea mays L.) and soya beans (Glycine max L.). Saturated hydraulic conductivity was measured on large soil columns (25 × 25 × 40 cm) before spring tillage, and macropore size and continuity were assessed with staining techniques. Intact soil cores (8 cm diam × 10 cm) were collected in early July in the row and non-trafficked interrow at three depths (10–20, 20–30, and 30–40 cm) and were analyzed for air permeability (Kair), air-filled porosity and bulk density. Saturated hydraulic conductivity values were in the order plow > chisel > ridge till > no-till for the Chalmers soil and were significantly greater in the plow treatment than in the other 3 tillage systems on the Clermont soil. Differences in KSAT between the 2 soils were generally greater than differences among tillage systems, and coefficients of variation were lower for treatments that did not include may fall tillage operations. At the 10-cm depth on the Chalmers soil, the chisel treatment had the greatest number of stained cylindrical channels, whereas for the Clermont soil the ridge till had the greatest number at this depth. Although the no-till treatment had similar or fewer total channels, it had the most continuous channels from the 10-cm depth to the 20- and 30-cm depths on both soils. Tillage system, row position and depth all affected Kair. On the Chalmers soil, plow, chisel and ridge systems had lower Kair between rows than in the row at the 10–20-cm depth, whereas no-till had constant Kair in the row and between the row. On the Clermont soil, ridge till had the highest Kair of all treatments at the 10–20-cm depth, and no-till had the highest Kair of all treatments at the 20–30-cm depth. 相似文献
10.
耕作方式对土壤水分入渗、有机碳含量及土壤结构的影响 总被引：14，自引：6，他引：14
为探明不同耕作方式对土壤剖面结构、水分入渗过程等的作用机理,采集田间长期定位耕作措施(常规耕作、免耕、深松)试验中的原状土柱(0~100 cm)及0~10 cm、10~20 cm、…、90~100 cm环刀样、原状土及混合土样,通过室内模拟试验进行了0~100 cm土层土壤入渗过程和饱和导水率的测定,分析了不同土层的土壤有机碳含量、土壤结构特征及相互关系。结果表明:从土柱顶部开始供水(恒定水头)到水分全部入渗到土柱底部的时间为:常规耕作免耕深松;土柱土壤入渗速率和累积入渗量为:深松免耕常规耕作;土柱累积蒸发量为:常规耕作免耕深松。土壤的饱和导水率表现为:0~10 cm和50~60 cm土层,免耕深松常规耕作;20~50 cm和60~100 cm土层,深松免耕常规耕作。随土层的加深,0.25 mm水稳性团聚体含量和土壤有机碳含量均表现为先增加(10~20 cm)再降低的趋势。在0~40 cm土层和80~100 cm土层,均以深松处理0.25 mm水稳性团聚体含量最高。在60 cm以上土层,土壤有机碳含量表现为:免耕深松常规耕作,而60 cm土层以下土壤有机碳显著降低,均低于4 g·kg?1,且在70 cm以下土层,常规耕作免耕深松。综上,耕作措施能够改变土壤有机碳含量,改善土壤结构,促进土壤蓄水保墒;深松更利于水分就地入渗,而免耕则更利于有机碳的提升和水分的储存,其作用深度在0~60 cm土层。 相似文献
11.
Abstract. A rotation trial of four years' pasture followed by two years' arable was used to study the effect of cropping on the morphological and hydraulic properties of soil. An adjacent paddock in grass for the past 35 years was included as a permanent pasture reference. Initial infiltration and field saturated hydraulic conductivity ( K fs ) were least for cultivated soil and increased with increasing time under pasture. This could be explained by the contrasting porosities of resin-impregnated blocks of undisturbed soil which had been infiltrated with methylene blue dye. Small K fs values for cultivated soil resulted mainly from a thin surface crust, although pore discontinuity at the depth of the cultivation pan (130 mm) could also have contributed. Greater K fs values under short-term pasture resulted primarily from water flowing through biogenic pores connected to the surface. The greatest K fs values were in soil that had been under pasture for 35 years (P35). This was attributed to flow through biogenic pores and fissures associated with the strongly-developed subangular blocky structure. The amount of water that infiltrated the two- and four-year pasture soils (P2 and P4) under ponding was 2.5 and 5 times greater, respectively, than the soil that had been cultivated for two years (C2).
As irrigation duration cannot be varied under the border-dyking system used on the Canterbury Plains, the interval between irrigations must be varied if the same total amount of water is to be applied to each of these soils through the season. The interval should be less for the cultivated soil than for those under pasture, and should increase with increasing time under pasture (i.e. P35 > P4 > P2 > C2). 相似文献
As irrigation duration cannot be varied under the border-dyking system used on the Canterbury Plains, the interval between irrigations must be varied if the same total amount of water is to be applied to each of these soils through the season. The interval should be less for the cultivated soil than for those under pasture, and should increase with increasing time under pasture (i.e. P35 > P4 > P2 > C2). 相似文献
12.
Physical properties of field soil vary both spatially and temporally. Because so little information is available concerning the changes in magnitude of soil physical properties as functions of soil depth, distance normal to a crop row, and time, they have largely been ignored in model development. The purpose of this study was to evaluate quantitatively the spatial and temporal variability imposed by several tillage operations on several soil physical properties. Three tillage treatments, replicated 4 times in a randomized complete block design, were (1) conventionally-disked 3 times before planting, (2) full width strip chisel plowed to a 27-cm depth, and (3) in-row-subsoiled plus bedding. Soil physical properties measured were cone index (CI), weight percentage water (Pw), bulk density (Db), soil water characteristic curve, saturated hydraulic conductivity (Ksat) and soil settling. These properties were measured 3 times: immediately after planting soybeans (Glycine max (L.) Merr.) on 16 May; on 3 June; on 8 July 1977. Soil properties were measured at the 0–14, 14–28, and 28–41-cm soil depths at 3 positions relative to the row i.e., in the row, in the trafficked interrow, and in the non-trafficked interrow. Significant differences due to tillage treatment were found for Db, CI, and the soil water characteristic. The greatest spatial variation occurred in the 0–14-cm depth and decreased with depth. Significant differences for most variables were also found for the tillage by depth and tillage by position interactions. All properties exhibited significant temporal variation. 相似文献
13.
The effects of deep tillage on soil physical properties and maize yields were evaluated on a loamy sand soil in which the bulk density distribution did not show a distinct root-limiting soil zone. Sub-soiling, mould-board ploughing and deep digging to 45 cm were compared with conventional tillage with and without irrigation. The tillage operations slightly decreased the bulk density of soil at all working depths. Sub-soiling and deep digging decreased the soil penetration resistance in the 20–40-cm layer to one-tenth of that in the control. They induced deeper and greater rooting and increased profile water use compared with conventional tillage. Sub-soiling, mould-board ploughing and deep digging increased plant height by 30–35 cm and yielded 80–100% more stover and 70–350% more grain than the control in different experiments. 相似文献
14.
为了明确农业生产过程中耕作方式对田间土壤孔隙结构及土壤水分运动特性的影响,以广西农地蔗田为研究对象,基于土壤切片技术分析研究免耕和垄耕2种典型耕作方式蔗田的田间土壤孔隙结构特征,并结合土柱模拟入渗试验,探究土壤孔隙结构对土壤水分运动的影响,进一步揭示孔隙结构与土壤水分运动特性之间的相互作用关系。结果表明：随着土层深度的增加,免耕蔗田孔隙形态以聚集的团块状分布为主,垄耕蔗田孔隙形态以条状分布为主。与免耕蔗田相比,垄耕蔗田的土壤总孔隙度和>2.5 mm孔径的孔隙度分别增加32.5%和21.9%。垄耕蔗田在局部土层深度范围内显著增加上下土层孔隙的变异度(p<0.05),显著降低土壤孔隙的连通性(平均邻近指数为0.448)(p<0.05),土壤孔隙形态相对规则(平均成圆率为0.335)。对于土壤水分运动特性,免耕蔗田总体的土壤饱和导水率和质量流率显著高于垄耕蔗田(p<0.05),初始含水率显著低于垄耕蔗田(p<0.05),质量流率随时间变化强度相对较大,提高水流入渗能力。垄耕降低土壤孔隙结构连通性,使水分蓄存在表层土壤中,一定程度上可降低土壤水分的入渗现象,改变蔗... 相似文献
15.
轮耕对土壤物理性状和冬小麦产量的影响 总被引：25，自引：12，他引：25
针对华北地区土壤连续单一耕作存在的主要问题,进行了土壤轮耕效应的研究。试验选择冬小麦夏玉米玉两熟区连续5 a免耕田,设置免耕、翻耕和旋耕3种轮耕处理（即免耕一免耕,免耕一翻耕和免耕一旋耕）,冬小麦播种前进行耕作处理。研究结果表明：多年免耕后进行土壤耕作（翻耕、旋耕）可以显著降低土壤体积质量;旋耕显著降低0～10 cm土壤体积质量,翻耕则降低0～20 cm体积质量;随时间变化各处理土壤体积质量差异逐渐降低。翻耕、旋耕均显著增加了0～10 cm土壤总孔隙,同时翻耕显著增加了10～20 cm土壤总孔隙;翻耕、旋耕显著提高了5～10 cm毛管孔隙。0～10 cm土壤饱和导水率表现为旋耕＞翻耕＞免耕,翻耕、旋耕在5%水平上显著高于免耕;10～20、20～30 cm土层均表现为翻耕＞旋耕＞免耕,且10～20 cm翻耕5%水平上显著高于免耕;饱和导水率与体积质量呈显著线性负相关。翻耕、旋耕有效穗数与免耕相比分别提高了24.1%、22.3%;冬小麦的实际产量表现为：旋耕＞翻耕＞免耕,翻耕、旋耕分别比免耕增产11.8%、16.9%。总之,长期免耕后进行土壤耕作有利于改善土壤物理性状,提高作物产量。 相似文献
16.
Soil Hydraulic Properties: Influence of Tillage and Cover Crops 总被引：1，自引：0，他引：1
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. 相似文献
17.
《Communications in Soil Science and Plant Analysis》2012,43(17-18):2945-2958
In Indian Punjab, rice–wheat is a dominant cropping system in four agro‐ecosystems, namely undulating subregion (zone 1), Piedmont alluvial plains (zone 2), central alluvial plains (zone 3), and southwestern alluvial plains (zone 4), varying in rainfall and temperature. Static and temporal variabilities in soil physical and chemical properties prevail because of alluvial parent material, management/tillage operations, and duration of rice–wheat rotation. A detailed survey was undertaken to study the long‐term effect of rice–wheat rotation on soil physical (soil separates, bulk density, modulus of rupture, saturated and unsaturated hydraulic conductivities, soil water content, and suction relations) and chemical (organic carbon, pH, electrical conductivity) properties of different textured soils (sandy clay loam, loam, clay loam, and silty clay loam) in these four zones of Punjab. Soil samples (of 0‐ to 30‐cm depth) from 45 sites were collected during 2006 and were analyzed for physical and chemical properties. The results showed that sand content and pH increased whereas silt and organic carbon decreased significantly from zones 1 to 4. Compared to other textures, significantly greater organic carbon, modulus of rupture, and pH in silty clay loam; greater bulk density in clay loam, and greater saturated hydraulic conductivity in sandy clay loam were observed. Irrespective of zone and soil texture, in the subsurface soil, there was a hard pan at 15–22.5 cm deep, which had high soil bulk density, modulus of rupture, more silt and clay contents (by 3–5%) and less organic carbon and hydraulic conductivity than the surface (0–15 cm) layer. These properties deteriorated with fineness of the soil texture and less organic carbon content. Continuous rice–wheat cropping had a deleterious effect on many soil properties. Many of these soils would benefit from the addition of organic matter, and crop yields may also be affected by the distinct hardpan that exists between 15 and 22.5 cm deep. 相似文献
18.
不同机械深耕的改土及促进作物生长和增产效果 总被引：2，自引：0，他引：2
长期不合理耕作导致土壤结构性能恶化、土壤耕性变差,限制作物根系下扎、影响土壤生产潜力发挥。为了改善土壤耕层构造,该试验采用自主研发的改土机械ES-210型深松犁和前置式心土(亚表层)耕作犁进行深耕,以灭茬旋耕(常规耕作)为对照,进行大区耕作对比试验。结果表明:1)深松、亚表层耕作处理与对照相比,耕层土壤固相率分别降低1.6%~3.3%、2.8%~4.5%,液相、汽相相对增加,三相比更趋于合理化;打破犁底层,降低耕层土壤硬度,其中20~35 cm土层效果更为明显;耕层土壤有效水含量上升1.1%~1.2%、0.9%,束缚水(无效水)含量下降0.4%~1.1%、0.5%~0.9%。2)深松、亚表层耕作处理比对照根长增长,其中甜菜增长5.1%、2.9%,大豆增长11.5%、13.2%;干物质积累量增加,其中甜菜增加2.3%~4.1%、3.1%~4.8%,大豆增加7.8%~10.0%、10.4%~13.6%;3)深松、亚表层耕作处理与对照相比,其中甜菜增产8.5%、12.6%;大豆增产5.0%、6.1%;深松及亚表层耕作改土处理分别比对照增收1003.3、1454.4元/hm2,其中收益大小为亚表层耕作处理深松处理对照。可见,采用ES-210深松犁及心土耕作犁深耕改土,改变了土壤耕层构造,起到扩库增容的效果;改善了作物根系生长环境,提高了作物产量,为今后农业耕作机械的发展提供了技术支撑。 相似文献
19.
Conversion of natural forest to intensive cultivation makes to soil susceptible to flooding, declining fertility and loss of organic matter (OM) and reduced water movement into and within the soil. We studied infiltration rates and related soil penetrating indicators of forested and cultivated soils in humid tropical coastal plain sands in Southern Nigeria. Results showed that mean-weight diameter (MWD) and water stability of aggregates were higher in forested than cultivated soils. Stable aggregates > 1.00 mm were 16.5% and 31.1% respectively, for cultivated and forested soils at 0–15 cm depth, indicating formation of more macro-aggregates in forested soil. Soil disturbance through cultivation decreased hydraulic conductivity and increased bulk density of the soil. Infiltration rate attained after 2 hours was higher in forested soil. Temporary infiltration rate of 178 mm hr?1 at initial time in cultivated soil was followed by very low infiltration rate of 7 mm hr?1 after 2 hours. Soil organic matter (SOM), saturated hydraulic conductivity, MWD and total sand correlated positively with infiltration rates are r = 0.76, 0.61, 0.57 and 0.51 respectively. Changes in these parameters are dependent on surface soil disturbance by cultivation. Cultivation of forest decreased infiltration rates and water transmission properties of the soil. 相似文献
20.
Kripal Singh Ashish Kumar Mishra Bajrang Singh Rana P. Singh Dharani Dhar Patra 《Land Degradation \u0026amp; Development》2016,27(2):223-230
Tillage modifies soil structure and has been suggested as a practice to improve physical, hydrological and chemical properties of compacted soils. But little is known about effect of long‐term tillage on physicochemical soil properties and crop yield on sodic soils in India. Our objective was to investigate the effect of different tillage regimes on crop yield (wheat and paddy rice) and physicochemical properties of sodic soils. Two sodic sites under conventional tillage for 5 (5‐YT; 5‐year tillage) and 9 (9‐YT; 9‐year tillage) years were selected for this study. Changes in crop yield and physicochemical soil properties were compared with a control, sodic land without any till history, that is, 0‐year tillage/untilled (0‐YT). Five replicated samples at 0‐ to 10‐cm and 10‐ to 20‐cm soils depths were analysed from each site. In the top, 0‐ to 10‐cm soil depth 5‐YT and 9‐YT sites had higher particle density (Pd), porosity, water holding capacity, hydraulic conductivity, organic carbon, total nitrogen (Nt), available nitrogen (Navail), phosphorus (Pavail) and exchangeable calcium (Exch. Ca++) than 0‐YT, whereas bulk density (Bd), C : N ratio and CaCO3 were significantly lower. Bd, pH, EC and CaCO3 increased significantly with depth in all the lands, whereas Pd, porosity, water holding capacity, hydraulic conductivity, organic carbon, Nt, Navail, Pavail and Exch. Ca++ decreased. We conclude that continuous tillage and cropping can be useful for physical and chemical restoration of sodic soils. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献