Infiltration in reclaimed mined land ameliorated with deep tillage treatments

Reclamation of mined land with heavy machinery can result in soil compaction. Compaction increases soil bulk density and reduces porosity, water infiltrability, root elongation and crop productivity. Mine operators have used deep tillage equipment to alleviate the compaction problem. The main objectives of this study were to examine (1) the effect on infiltration in reclaimed surface mined land of a deep tillage treatment, and (2) the subsequent changes in infiltration after the amelioration. The experiment was conducted at the Horse Creek Mine near Conant, Perry County, IL, USA. The soil was classified as Schuline series, which is a fine, loamy, mixed, mesic, Typic Udorthents. The treatments included tillage depths of 20 (as a control), 40, 60 and 80 cm. Infiltrometers and runoff plots were installed to evaluate infiltration and rainfall-runoff relationships affected by the treatments. Results indicated that the steady infiltration rates of the 40- and 60-cm tillage treatments were lower than that of the control treatment successively during the experimental period for 3 years. Results also revealed that the 80-cm tillage treatment increased infiltration and reduced surface runoff most. Even though the beneficial effects declined over a 3-year test period, the 80-cm tillage is recommended in the amelioration of soil compaction because tillage depths less than 80 cm did not enhance water infiltration rate much.     

Long-Term Effects of Different Passages of Vehicular Traffic on Soil Properties and Carbon Storage of a Crosby Silt Loam in USA

The passage of vehicles with heavy axle loads causes soil compaction, and this adversely affects soil properties and crop yield.The adverse effects can persist for several years due to significant changes in key soil properties. However, the mechanisms of the aforementioned effects are not well understood for conservation agriculture(CA)(e.g., no-till(NT)) wherein the use of heavy machinery is considerably common. Therefore, known compaction forces(0 Mg load for compaction(NT-0, control), two passages of 2.5 Mg water wagon axle load(NT-2), and four passages of 2.5 Mg water wagon axle load(NT-4)) were applied to all the plots annually for 20 consecutive years. The experiment was established in 1997 at the Waterman Agricultural and Natural Resources Laboratory(WANRL), Ohio State University, Columbus, Ohio. Each treatment was replicated thrice. Soil samples were obtained in November2016 to determine the effects of variations in the axle load and vehicular passages on carbon(C) and nitrogen(N) storage and selected soil properties of a Crosby silt loam soil under NT-based corn-soybean rotation with residue retention in Central Ohio, USA. Three locations were also randomly selected in an adjoining natural woodlot(WL) soil plot and sampled(30 m away from the compaction field) to compare the effects of vehicular traffic on soil under NT with WL soil. Results revealed that soil bulk density(ρb) and total porosity at 0–10 and 10–20 cm depths were not affected by the passages of vehicular traffic for 20 years under the NT system.The penetration resistance(PR)(1.86 and 2.03 MPa at 0–10 and 10–20 cm soil depths, respectively) was significantly higher under NT-4 compared with that under other treatments. Saturated hydraulic conductivity at 0–10 and 10–20 cm soil depths ranged from19.7 to 31.4 and 18.5 to 29.5 mm d~(-1), respectively, across all the treatments. The proportion of macroaggregates( 0.25 mm) and microaggregates( 0.25 mm), mean weight diameter and geometric mean diameter of aggregates, pH, electrical conductivity, and C and N contents and storage did not differ significantly between the treatments at either of the sampling soil depths. The data indicated that 2 to 4 passages of vehicles with 2.5 Mg of axle load did not cause significant compaction of the Crosby silt loam under NT compared with that under natural WL. Therefore, the continuous cultivation of row crops with NT and residue retention is feasible with passages of vehicular traffic for well-drained soils in Central Ohio.     

Axle load and tillage effects on the shrinkage characteristics of a Mollic Ochraqualf in northwest Ohio

Cracking due to soil shrinkage is a complex process whose effect on soil properties, crop growth and water quality are not adequately understood. The intensity of cracking depends on soil characteristics and management. The effect of three axle loads and three tillage methods on shrinkage characteristics and cracking behavior were studied for a heavy-textured lake bed soil in northwest Ohio. The three axle load treatments were 0, 10 and 20 Mg, and the three tillage treatments were no till (NT), chisel plowing (CP) and moldboard plowing (MP). Cracking area increased from 1.75% in July to 12.27% in September, was maximum in the NT treatment, and increased with increase in axle load. The no till and 30 Mg axle load caused significantly higher cracking than other axle load and tillage treatment combinations. Shrinkage of compressed soil cores under laboratory conditions showed that a bulk density of 1.5 Mg/m³ had the lowest total shrinkage volume. A combination of no till and heavy axle load increased the cracking area and accentuated adverse effects on soil structure.     

不同轮耕模式对旱地土壤结构及入渗蓄水特性的影响

为了探索免耕与深松隔年轮耕对土壤结构及入渗蓄水性能的影响,2007-2010年在宁南旱区采用免耕/深松/免耕、深松/免耕/深松与连年翻耕3种耕作模式,对土壤体积质量、团聚体、入渗率及水分利用效率等方面的影响进行了研究。结果表明:与连年翻耕相比,免耕/深松/免耕、深松/免耕/深松处理使0～60cm各土层土壤体积质量平均降低3.5%、6.2%(P<0.05);使0～20cm土层>0.25mm机械稳定性团聚体数量平均分别增加10.3%(P<0.05)和20.3%(P<0.01),>20～40cm土层分别平均增加17.2%(P<0.05)和23.6%(P<0.01)。免耕/深松/免耕处理0～10cm和>30～40cm土层的水稳性团聚体稳定率分别比连年翻耕提高35.1%和45.8%(P<0.05),深松/免耕/深松处理>10～20cm和>20～30cm土层水稳性团聚体稳定率分别提高101.7%和61.7%(P<0.01)。不同轮耕模式显著增强了土壤的入渗性能,提高对土壤水分的有效利用及降水利用率,免耕/深松/免耕、深松/免耕/深松处理降雨入渗率较连年翻耕分别提高35.2%和15.3%(P<0.05),水分利用效率平均提高7.2%和7.7%(P<0.05),降水生产效率平均提高9.6%和10.7%(P<0.05)。     

不同耕作深度对红壤坡耕地耕层土壤特性的影响

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。     

Influence of basin‐based conservation agriculture on selected soil quality parameters under smallholder farming in Zimbabwe

The research was carried out to determine the effect of basin‐based conservation agriculture (CA) on selected soil quality parameters. Paired plots (0.01 ha) of CA and conventional tillage based on the animal‐drawn mouldboard plough (CONV) were established between 2004 and 2007 on farm fields on soils with either low (12–18% – sandy loams and sandy clay loams) or high clay levels (>18–46% – sandy clays and clays) as part of an ongoing project promoting CA in six districts in the smallholder farming areas of Zimbabwe. We hypothesized that CA would improve soil organic carbon (SOC), bulk density, aggregate stability, soil moisture retention and infiltration rate. Soil samples for SOC and aggregate stability were taken from 0 to 15 cm depth and for bulk density and soil moisture retention from 0 to 5, 5 to 10 and 10 to 15 cm depths in 2011 from maize plots. Larger SOC contents, SOC stocks and improved aggregate stability, decreased bulk density, increased pore volume and moisture retention were observed in CA treatments. Results were consistent with the hypothesis, and we conclude that CA improves soil quality under smallholder farming. Benefits were, however, greater in high clay soils, which is relevant to the targeting of practices on smallholder farming areas of sub‐Saharan Africa.     

Deforestation and land-use effects on soil degradation and rehabilitation in western Nigeria. I. Soil physical and hydrological properties

Assessments of the effects of deforestation, post-clearance tillage methods and farming systems treatments on soil properties were made from 1978 through 1987 on agricultural watersheds near Ibadan, southwestern Nigeria. These experiments were conducted in two phases: Phase I from 1978 through 1981 and Phase II from 1983 to 1987, with 1 year (1982) as a transition phase when all plots were sown with mucuna (Mucuna utilis). There were six treatments in Phase I involving combinations of land clearing and tillage methods: (1) manual clearing with no-till (MC-NT); (2) manual clearing with plough-till (MC-PT); (3) shear-blade clearing with no-till (SB-NT); (4) tree-pusher/root rake clearing with no-till (TP-NT); (5) tree-pusher/root-rake clearing with plough-till (TP-PT); (6) traditional farming (TF). The six treatments were replicated twice in a completely randomized design. The traditional treatment of Phase I was discontinued during Phase II. The five farming systems studied during Phase II with a no-till system in all treatments were: (1) alley cropping with Leucaena leucocephala established on the contour at 4-m intervals; (2) and (3) fallowing with Mucuna utilis on severely degraded and moderately degraded watersheds, respectively, for 1 year followed by maize-cowpea rotation for another; (4) and (5) ley farming involving establishment of pasture in the first year on severely and moderately degraded plots, respectively, controlled grazing in the second year, and growing maize (Zea mays)-cowpea (Vigna unguiculata) in the third year. All treatments, imposed on watersheds of 2–4 ha each, were replicated twice. The soil properties analyzed were particle size distribution, total aggregation and mean weight diameter of aggregates, soil bulk density, penetrometer resistance, water retention characteristics, infiltration capacity and saturated hydraulic conductivity. These properties were measured under the forest cover in 1978, and once every year during the dry season thereafter during Phases I and II. Prior to deforestation, mean soil bulk density was 0·72 Mg m⁻³ and 1·30 Mg m⁻³, soil penetration resistance was 32·4 KPa and 90·7 KPa, and mean weight diameter of aggregates was 3·7 mm and 3·2 mm for 0–5 cm and 5–10 cm depths, respectively. The infiltration rate was excessive (54–334 cm hr⁻¹) and saturated hydraulic conductivity was rapid (166–499 cm hr⁻¹) under the forest cover. Furthermore, water transmission properties varied significantly even over short distances of about 1 m. Deforestation and cultivation increased soil bulk density and penetration resistance but decreased mean weight diameter of aggregates. One year after deforestation in 1980, mean soil bulk density was 1·41 Mg m⁻³ for 0–5 cm depth and 1·58 Mg m⁻³ for 5–10 cm depth. Soil bulk density and penetration resistance were generally higher for NT than for PT methods, and the penetration resistance was extremely high in all treatments by 1985. During Phase II, soil bulk density was high during the grazing cycle of the ley farming treatment. Sand content at 0–5 cm depth increased and clay content decreased with cultivation duration. Soon after deforestation, saturated hydraulic conductivity and equilibrium infiltration rate in cleared and cultivated land declined to only 20–30 per cent of that under forest. Mean saturated hydraulic conductivity following deforestation was 46·0 cm hr⁻¹ for 0–5 cm depth and 53·7 cm hr⁻¹ for 5–10 cm depth. Further, infiltration rate declined with deforestation and cultivation duration in all cropping systems treatments. During Phase I, mean infiltration rate was 115·8 cm hr⁻¹ under forest cover in 1978, 20·9 cm hr⁻¹ in 1979, 17·4 cm hr⁻¹ in 1980 and 20·9 cm hr⁻¹ in 1981. During Phase II, mean infiltration rate was 8·5 cm hr⁻¹ in 1982, 11·9 cm hr⁻¹ in 1983, 11·0 cm hr⁻¹ in 1984, 11·3 cm hr⁻¹ in 1985 and 5·3 cm hr⁻¹ in 1986. Infiltration rate was generally high in ley farming and mucuna fallowing treatments. Natural fallowing drastically improved the infiltration rate from 19·2 cm hr⁻¹ in 1982 to 193·2 cm hr⁻¹ in 1986, a ten-fold increase within 5 years of fallowing. High-energy soil water retention characteristics in Phase I were affected by those treatments that caused soil compaction by mechanized clearing and no-till systems. Soil water retention at 0·01 MPa potential in 1979 was 19·2 per cent (gravimetrics) for SB, 17·9 per cent for TP, 15·9 per cent for MC and 17·8 per cent for TF methods. With regards to tillage, soil water retention was 17·8 per cent for NT compared with 16·8 per cent for PT. During Phase II, water retention characteristics were not affected by the farming system treatments. Mean soil water retention (average of 4 years' data from 1982 to 1986) at 0·01 MPa for 0–5 cm depth was 16·6 per cent for alley cropping, 16·7 per cent for mucuna fallowing and 16·8 per cent for ley farming. Mean soil water retention for 1·5 MPa suction was 9·3 per cent for alley cropping, 8·7 per cent for mucuna fallowing, and 9·3 per cent for ley farming. Water retention at 1·5 MPa suction correlated with the clay and soil organic carbon content.     

Effects of tillage depth on infiltration characteristics of two bangladesh soils having ploughpans

Ploughpans, caused by puddling of soil for rice cultivation for years, are bound to affect soil water balance and the utilization of the stored soil water by dry-land crops. Loosening of the pan by increasing the plough depth is likely to increase utilization of sub-soil water and recharge of the soil profile. The effects of different tillage regimes on infiltration of two Bangladesh soils with ploughpans were studied. Cumulative infiltration rates were increased in both Sonatala and Modhupur soils owing to increase in depth of tillage. Cumulative infiltration and infiltration rates were much higher in the grey floodplain sandy loam soil compared with the red terrace clay loam soil. The cumulative infiltration of Sonatala soil in no-tillage, 7.5, 15.0 and 22.5 cm tillage depth plots were 18.8 cm in 400 min, 31.0 cm in 400 min, 36.3 cm in 300 min and 43.3 cm in 150 min, respectively. The total amount of water entering into Modhupur soil in 400 min was 14.3, 21.0, 35.5, 46.9 and 50.7 cm in no-tillage, 7.5, 12.5, 17.5 and 22.5 cm tillage depth plots, respectively. Results further revealed that although the initial infiltration was higher and different in different tillage treatments, it decreased with time and tended to be more or less similar for all the tillage depths at the end of the study period. This was true for both the soils.     

耕翻和秸秆还田深度对东北黑土物理性质的影响

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。     

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

  【目的】  良好的土壤物理和水力学性质是土壤肥力可持续的基础。研究黄土高原旱作农业区长期不同耕作、覆盖措施对土壤水气传输性质的影响,为黄土塬区可持续的农田管理提供参考。  【方法】  基于设在渭北旱塬始于2002年的田间定位试验,选取传统耕作 (CT)、传统耕作+秸秆覆盖 (TS)、传统耕作+地膜覆盖 (TP)、传统耕作+全膜覆盖 (TWP)、免耕 (NT)、免耕+秸秆覆盖 (NS)、免耕+地膜覆盖 (NP)、免耕+生草覆盖 (NG) 共8个处理。于2019年春玉米收获期采集剖面土样,对0—10、10—20、20—30和30—40 cm土层土壤质量含水量、容重、导气率、相对气体扩散率和饱和导水率进行测定与分析。  【结果】  与CT处理相比,TS处理显著增加了0—40 cm土壤平均质量含水量,降低了0—40 cm各层土壤导气率,增加了各层土壤相对气体扩散率,表层 (0—10 cm) 土壤饱和导水率显著降低了75.9%;TP处理收获期耕层 (0—20 cm) 土壤容重增加,土壤总孔隙度显著降低,在0—10 cm土层,土壤导气率显著提高了54.1%;TWP处理耕层土壤容重显著增加,土壤总孔隙度显著降低,剖面0—40 cm土壤导气率和饱和导水率分别平均增加了64.8%和111.2%,尤其是表层土壤导气率显著提高了99.5%。与NT处理相比,NS处理耕层土壤容重降低,总孔隙度增加,表层土壤质量含水量、相对气体扩散率和饱和导水率分别显著提高了14.8%、25.3%和446.4%;NP处理耕层土壤容重增加,总孔隙度降低,表层土壤质量含水量和饱和导水率分别显著增加3.5%和145.2%,土壤导气率显著降低33.7%;NG处理耕层土壤容重降低,总孔隙度增加,表层土壤质量含水量显著提高了11.3%,土壤相对气体扩散率显著降低了42.1%。相同覆盖条件下与传统耕作比较,免耕处理能够降低下层20—40 cm土壤容重,增加土壤总孔隙度,提高土壤持水性,虽然降低了表层0—10 cm土壤导气率,但提高了土壤相对气体扩散率和饱和导水率。  【结论】  免耕秸秆覆盖可降低耕层土壤容重,增加总孔隙度,并且显著提高耕层土壤相对气体扩散率和饱和导水率,增加下层土壤导气率,是免耕处理组中最佳处理。传统耕作全膜覆盖可提高耕层土壤导气率、相对气体扩散率和饱和导水率,是传统耕作组中最佳处理,可有效保持渭北旱塬良好的土壤水气传输能力。     

Permanent raised beds improved soil structure and yield of spring wheat in arid north‐western China

In arid north‐western China, soil degradation, limited water and subsequent yield decline, largely as a result of excessive tillage and residue removal practices, are the main factors limiting further development of local agriculture. The effects of permanent raised beds (PRB), no‐till (NT) and traditional tillage (TT) on soil structure and yield were investigated in a wheat (Triticum aestivum L.) – maize (Zea mays L.) cropping system from 2004 to 2009 in the Hexi Corridor of Gansu Province, China. PRB and NT had more macro‐aggregates (>0.25 mm, +2.7%), a better distribution of pore size classes and improved hydraulic conductivity, whereas TT soils were dominated by micro‐aggregates and micro‐porosity. In PRB, soil bulk density decreased significantly by 6.3 and 7.0% for the 0‐ to 10‐cm and 20‐ to 30‐cm depths relative to TT. The PRB mean crop yields increased by 4.2% and water use efficiency improved by 21.3% compared with TT because of greater soil moisture and improved soil physical and chemical status. These improvements in soil properties, yield and water use are of considerable importance for soil regeneration, food security and sustainable agriculture in arid regions, such as north‐western China.     

Tillage Effects on Crop Yield and Physicochemical Properties of Sodic Soils

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 (N_t), available nitrogen (N_avail), phosphorus (P_avail) 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, N_t, N_avail, P_avail 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.     

Infiltration patterns into two soils under conventional and conservation tillage: influence of the spatial distribution of plant root structures and soil animal activity

The characteristics and properties of the soil macropore system may cause different infiltration behavior under different tillage practices. To evaluate the effect of a specific tillage system on infiltration and percolation with particular regard to the influence of crop structure and soil animal activity dye tracer irrigation experiments were conducted in a silty (Luvisol) as well as in a sandy loam soil (Podzolluvisol). The spatial distribution of water flow paths was experimentally examined at four square areas of 0.49 m², under conservation and conventional tillage. Natural rainstorms were simulated by irrigating the plots with 2.8×10⁻³ M methylene blue solutions. For both soils the root crowns of the agricultural crop, wormcasts and stained soil sections as well as macroscopic conduits were traced on plastic sheets. The investigated soil depths were 0, 5, 10 and 20 cm for the both soils. For the Luvisol, the 30, 40, 50, 80 and 120 cm depths were also studied.For the Luvisol, the conservation tillage plot revealed pronounced vertical connectivity and continuity of the macropore network (maximum depth of stained pores=120 cm), while at the conventional tillage plot, continuous macropores were observed to soil depths of 50 cm, but mainly restricted to the ploughed topsoil (0–30 cm soil depth).For the Podzolluvisol, at the conservation tillage site extensive mulch residues prevented water transport beneath 5 cm soil depth. In contrast, at the conventionally tilled site stained water reached a depth of 20 cm. For all investigated plots on both soil types, the location of the root crowns of agricultural crop and of wormcasts was not related to percolation patterns.The results suggest that conservation tillage on silty soils under agricultural landuse could induce an increased water retention capacity reducing the significance of fast runoff components.     

田间原位试验分析长期机械作业下稻麦轮作地块土壤入渗性能

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...     

The effect of tillage type and cropping system on earthworm communities, macroporosity and water infiltration

To test the assumption that changes to earthworm communities subsequently affect macroporosity and then soil water infiltration, we carried out a 3 year study of the earthworm communities in a experimental site having six experimental treatments: 2 tillage management systems and 3 cropping systems. The tillage management was either conventional (CT; annual mouldboard ploughing up to −30 cm depth) or reduced (RT; rotary harrow up to −7 cm depth). The 3 cropping systems were established to obtain a wide range of soil compaction intensities depending on the crop rotations and the rules of decision making. In the spring of 2005, the impact of these different treatments on earthworm induced macroporosity and water infiltration was studied. During the 3 years of observation, tillage management had a significant effect on bulk density (1.27 in CT and 1.49 mg m⁻³ in RT) whereas cropping system had a significant effect on bulk density in RT plots only. Tillage management did not significantly affect earthworm abundance but significantly influenced the ecological type of earthworms found in each plot (anecic were more abundant in RT). On the contrary cropping system did have a significant negative effect on earthworm abundance (104 and 129 ind. m⁻² in the less and most compacted plots, respectively). Significantly higher numbers of Aporrectodea giardi and lower numbers of Aporrectodea caliginosa were found in the most compacted plots. CT affected all classes of porosity leading to a significant decrease in the number of pores and their continuity. Only larger pores, with a diameter superior to 6 mm, however, were adversely affected by soil compaction. Tillage management did not change water infiltration, probably because the increase in macroporosity in RT plots was offset by a significant increase in soil bulk density. However, cropping system had a significant effect on water infiltration (119 vs 79 mm h⁻¹ in the less and most compacted plots, respectively). In RT plots, a significant correlation was observed between larger macropores (diameter > 6 mm) and water infiltration illustrating the potential positive effect of earthworms in these plots.     

Plant-water relations,crop growth and grain yield of spring barley in relation to tillage methods

The influence of tillage methods on plant water status was measured in spring barley on a sandy loam soil (Wighill series) in 1976. Three methods of tillage were used: direct drilling, tine cultivation to 12.5 cm depth, and moldboard plowing to 20 cm depth. Soil bulk density was higher in the 0–5 and 5–10 cm layers of the direct-drilled plots. Soil strength was also higher in the direct-drilled plots to 22.8 cm depth compared with plowed plots, and to 15.2 cm depth compared wiht tine-cultivated plots. Thje only significant effect on soil water content (measured to 90 cm depth) was between 80 and 114 days from planting when extraction from the 0–10 cm depth was greater in the direct-drilled plots compared with the plowed plots, and at 20 cm depth greater in plowed plots than in direct-drilled plots. There were no significant differences between tillage methods in leaf water potential, above-ground dry matter produced, and grain yield.     

深松35 cm可改善潮棕壤理化性质并提高小麦和玉米产量

【目的】我国传统耕作深度一般为20 cm,长期不变的翻耕深度降低耕层厚度,增加了犁底层厚度,影响作物的生长。研究小麦—玉米一年两季的种植模式下深松耕作的效果,为大田耕作管理提供技术支持。【方法】田间试验在山东烟台潮棕壤上进行。设计4个耕作处理,分别为常规翻耕20 cm (CK)、深松30 cm、深松35 cm、深松40 cm。小麦播种前进行耕作处理,所有处理均结合耕作一次性基施腐殖酸复合肥 (N–P₂O₅–K₂O=18–10–12) 1125 kg/hm2。玉米免耕,在拔节期追施一次化肥。于小麦、玉米收获期取0—10 cm、10—20 cm、20—30 cm及30—40 cm土层土壤样品,测定土壤速效养分含量与土壤容重,计算三相比,并调查小麦、玉米产量。【结果】与CK相比,深松30 cm、35 cm、40 cm小麦季分别增产10.9%、15.3%和15.5%,玉米季分别增产12.0%、14.9%和9.4%(P < 0.05);10—40 cm土层土壤容重降低了0.03～0.18 g/cm3。其中,小麦季0—10 cm土层中CK处理土壤容重显著低于各深松处理,深松35 cm处理0—10 cm与10—20 cm土层土壤容重显著高于其他各处理;玉米季0—10 cm与10—20 cm土层土壤容重最低的处理为深松35 cm,且显著低于其他处理。小麦季深松30 cm处理各土层土壤三相比 (R值) 在13.2～15.9之间,总体最小,玉米季则以深松40 cm三相比值总体最小,在6.03～8.81之间。深松处理增加了20—40 cm土层有效养分含量,其中深松35 cm处理的20—40 cm土层有效磷和速效氮含量增加最为明显,分别为0.56～37.4 mg/kg与31.9～77.8 mg/kg;速效钾各土层的增加则以深松30 cm最为显著,为24.3～100 mg/kg;有机质含量以深松40 cm增加量最大,为0.95～0.69 g/kg。【结论】深松耕作可显著降低当季土壤容重,增加当季与下一季作物产量,提高土壤耕层以下20—40 cm土层的养分有效性,综合各机械能耗与耕作效果,以深松35 cm最佳。     

耕作措施对土壤物理性状的影响

耕作措施对0~20cm土壤容重影响较大,深层影响较小。稳定入渗率呈现出强烈的时间变异性,从整个生育期看,翻耕都表现出较高的稳定入渗率,随时间的变化,差异减小;不同负压下,翻耕稳定入渗率最高,免耕次之,铁茬最低,不同时期变化趋势一致;翻耕大孔隙较其它两耕作措施多,翻耕后,土壤大孔隙增多,比免耕和铁茬处理高65%左右,达到5%水平差异显著,免耕与铁茬差异不显著。随着时间的推移,不同耕作措施大孔隙比例有所下降,中小孔隙比例增加,大孔隙数目翻耕仍最高,从显著性看,与免耕和铁茬在5%水平显著。     

Improvement of the physical fertility of a degraded Alfisol with planted and natural fallows under humid tropical conditions

Abstract. Topsoil (0–15 cm) bulk density, aggregate stability, soil dispersibility, water retention and infiltration were measured between 1989 and 1996 on an Alfisol under rehabilitation in southwestern Nigeria. The planted leguminous species were Pueraria phaseoloides, Senna siamea, Leucaena leucocephala, Acacia leptocarpa and A. auriculiformis. Also, plots with natural fallow and maize/cassava intercropping were included. Level (minimum) and mound tillage with hoes was adopted for the cultivated areas under study after 4 and 6 year fallow periods. Under fallow, the soil bulk density decreased from1.56 to 1.11 t m73.The continuously cropped treatment (level tillage) had significantly higher bulk density than the fallowed subplots after 6 years. Mean soil penetrometer resistance ranged from 75 to 157 kPa for fallowed plots and from 192 to 295 kPa for the continuously cropped (level tillage) subplot. Surface soilwater contentswere similar for all the treatments during the soil strength measurements. Although soil aggregates were generally of low stability and not well formed, they were improved by fallowing.
Soil structural improvement by planted fallows was similar to that by natural fallow, but the trees were more promising for long-term fallow (>6 years) than the herbaceous P. phaseoloides. However, the improvement in soil structure after 4 or 6 year fallow could not be maintained in subsequent cropping. Furthermore, the significant improvement in soil bulk density caused by A. auriculiformis and natural fallow was more rapidly lost on the cultivated subplots compared with other fallow treatments. Thus, soil structure recovery under a fallow does not imply a sustained improvement when stress is applied to this soil. Post-fallow soil management options such as residue incorporation and tillage to ameliorate compaction or soil strength will be necessary to enhance the improvements by fallow species.     

Wheel traffic impact on soil conditions as influenced by tillage system in Central Anatolia

The increased limiting effects of soil compaction on Central Anatolian soils in the recent years demonstrate the need for a detailed analysis of tillage system impacts. This study was undertaken to ascertain the effects of seven different tillage systems and subsequent wheel traffic on the physical and mechanical properties of typical Central Anatolian medium textured clay loam soil (Cambisol), south of Ankara, Turkey. Both tillage and field traffic influenced soil bulk density, porosity, air voids and strength significantly except the insignificant effect of traffic on moisture content. Traffic affected the soil properties mostly down to 20 cm. However, no excessive compaction was detected in 0–20 cm soil depth. The increases of bulk density following wheel traffic varied between 10–20% at 0–5 cm and 6–12% at 10–15 cm depth. In additions, traffic increased the penetration resistance by 30–74% at 0–10 cm and 7–33% at 10–20 cm. Less wheel traffic-induced effects were found on chisel tilled plots, compared to ploughed plots. Soil stress during wheel passage was highly correlated with soil strength. Also, both tillage and traffic-induced differences were observed in mean soil aggregate sizes, especially for mouldboard ploughed plots. The obtained data imply that chisel+cultivator-tooth harrow combination provides more desirable soil conditions for resisting further soil compaction.