共查询到20条相似文献，搜索用时 859 毫秒
1.
基于CT扫描技术研究有机无机肥长期配施对土壤物理特征的影响 总被引：1，自引：1，他引：0
2.
《Soil Use and Management》2018,34(1):101-110
Carbon sequestration in agricultural soils may help to reduce global greenhouse gas concentrations, but building up soil carbon levels requires accumulating organic matter faster than it is lost via heterotrophic respiration. Using field and laboratory studies, this study sought to elucidate how tillage, the below‐ground incorporation of cover crop residue, and soil macroporosity affect soil respiration and residue decomposition rates. In the field, residue from a cover crop mixture of barley (Hordeum vulgare ) and crimson clover (Trifolium incarnatum ) was placed into litter bags that were left on the surface versus incorporated into the soil at three depths (4, 8 or 12 cm), while the laboratory study compared surface‐placed versus incorporated litter (8 cm depth). To assess tillage effects on cover crop decomposition, the field study simulated no‐till and conventional tillage treatments, while the laboratory and field studies both included treatments in which artificial soil macropores were created. The field study showed that conventional tillage and the presence of macropores enhanced soil respiration, while in the laboratory study, incorporating cover crop residue resulted in higher soil respiration and faster litter decomposition rates. Additionally, the laboratory measurements showed that macropores increased soil respiration in wet conditions, likely by enhancing oxygen diffusion. Thus, organic matter incorporation and macropores may represent important factors that affect soil respiration and carbon dynamics. 相似文献
3.
4.
It has been suggested that surface applications of animal manure can ameliorate both top and subsoil acidity. For that reason, the effects of surface incorporation (0–5 cm) of a high rate of poultry manure to an acid soil on pH and exchangeable and soluble Al in the top‐ and subsoil were investigated in a leaching column study. During the experimental period of 108 d, columns received a total of 875 mm with leaching events occurring after 9, 37, 58, and 86 d. Incorporation of poultry manure into the surface 5 cm resulted in a large rise in pH measured in both 1M KCl and in soil solution. This liming effect was attributed primarily to the substantial CaCO3 content of poultry manure. In the 15–45 cm layer, pHKCl was not significantly different between poultry manure and control treatments but surprisingly, soil‐solution pH was substantially less in the poultry‐manure treatments. Exchangeable Al was significantly less in poultry manure than in control in all soil layers although the effect was most marked in the 0–5 cm layer. However, although concentrations and activities of monomeric Al (Almono), and the proportion of total Al present as Almono, in soil solution were lower under poultry manure than in control in the 0–5 cm layer, the reverse was, in fact, the case in lower soil horizons. This was attributed to a soluble‐salt effect, originating from the large cation content of poultry manure, displacing exchangeable Al3+ and H+ back into soil solution. Indeed, electrical conductivity and concentrations of Ca2+, Mg2+, K+, and Na+ in soil solution were substantially higher in the poultry‐manure than in the control treatments at all soil depths. Poultry‐manure applications also resulted in substantial increases in the concentrations of Ca2+, Mg2+, K+, Na+, Almono, NH , and NO in leachates, particularly at the fourth leaching. It was concluded that although surface application of poultry manure can raise soil pH in the topsoil, increases in soluble‐salt concentrations in soil solution can greatly modify this effect in the subsoil. 相似文献
5.
Iris Vogeler Rainer Horn Holger Wetzel Julia Krümmelbein 《Soil & Tillage Research》2006,88(1-2):193-204
To study the effect of different soil tillage practices and the consequences of soil deformation on the functioning of the pore system, we performed unsaturated leaching experiments (by applying a suction of −10 kPa) on undisturbed soil columns from the Ap-horizon of a luvisol derived from glacial till (agricultural site at Hohenschulen, North Germany). We compared two different tillage practices (conventionally tilled to 30 cm depth, and conservational chiselled to a depth of 8 cm-Horsch system) with respect to soil strength, pore connectivity and their effect on the fate of surface-applied fertilisers. The soil strength was measured by determining the precompression stress value (PCV). The conventionally tilled topsoil had a PCV of 21 kPa at a pore water potential of −6 kPa, while the conservation treatment resulted in a slightly higher PCV of 28 kPa, suggesting a slowly increasing soil strength induced by the formation of aggregates under reduced tillage practice.
The leaching experiments were modelled using the convection dispersion equation (CDE) and a modified version of the mobile–immobile approach (MIM), which included three water fractions: mobile, immobile and totally immobile water. From the CDE mobile water fractions (θm) ranging from 47 to 67% were found, and θm was slightly higher in the ploughed seedbed compared to the conservation-tilled one. This could be due to higher aggregation in the latter one. Dispersivities were relatively large, ranging from 44 to 360 mm, but no difference was found for the treatments. The MIM could simulate the drop in concentration when leaching was interrupted, but overall did not improve the simulation, despite the larger number of fitting parameters.
Compacting the soil with loads of 70 kPa prior to the leaching experiment did not affect solute transport in the conservational tilled soil. In the conventional-tilled soil, however, the dispersivity decreased and the mobile water content increased compared to the non-compacted soil, suggesting that the former one is less prone to deformation by mechanical loads. 相似文献
6.
M. Carof S. De Tourdonnet Y. Coquet V. Hallaire & J. Roger-Estrade 《Soil Use and Management》2007,23(3):230-237
We studied soil hydraulic conductivity (K) and porosity in five combinations of soil tillage and cover crop management systems. Treatments were winter wheat (Triticum aestivum L.) grown on a conventionally tilled soil (CT), on a no‐till soil (NT), and on an NT with three different cover crops: red fescue (Festuca rubra L.; Fr), bird's‐foot‐trefoil (Lotus corniculatus L.; Lc) and alfalfa (Medicago sativa L.; Ms). Measurements were made on a loamy soil in Grignon, France, in November 2004, May 2005 and October 2005. K and mean size of hydraulically active pores were measured in situ at three water potentials (?0.6, ?0.2 and ?0.05 kPa) at the soil surface and at 10 cm depth. In November 2004 and May 2005, pore space was described using 2D image analysis of pores on undisturbed soil samples in the 0–10 cm layer and in the 10–20 cm layer. The major differences were caused by soil tillage that created two heterogeneous soil layers and increased K in the 0–10 cm layer relative to NT. The effects of cover crop on K and porosity were not affected by the root type: there were no major differences between the grass cover crop (fibrous‐root type) and the leguminous ones (tap‐root type). However, we recorded larger functional pores and more tubules in the no‐till treatments with a cover crop, compared with the no‐till treatment without cover crop; this was probably the result of root activity. Although these changes generally did not result in larger values of K, they participated in the maintenance of soil structure and K over time. 相似文献
7.
This study evaluated the effect of 13 years of swine‐manure application on the changes in soil hydraulic properties, and as associated physicochemical properties, with a focus on heavy metal mobility. Various soil hydraulic properties were measured, including soil water retention (SWR), saturated field hydraulic conductivity (Kfs) and unsaturated field hydraulic conductivity (Kfunsat) using a disc infiltrometer. Heavy metal mobility was evaluated with a sequential extraction procedure. At 0–30 cm soil depth in the heavily manured plot (SMhigh plot), SWR at 0 to ?100 kPa was significantly larger than in plots amended with a standard amount of manure (SMstd plot) or with chemical fertilizer (CF plot). Kfs and Kfunsat values in both manure‐amended plots were less than in the CF plot under dry soil conditions but greater than those of the CF plot under wet soil conditions. Furthermore, Kfs and Kfunsat did not necessarily increase with manure application rates. On the other hand, high‐mobility metal fractions, such as the exchangeable fraction of Zn, and the CH3CO2Na‐extractable fraction of Zn and Mn, and the metal–organic complex fractions of Zn, Cu and Mn, increased with the greater manure application rate. In addition, low‐mobility metal fractions, the organically bound fractions of Zn, Cu and Mn in the high SM plot and the easily reducible metal oxide fraction of Mn in both manure‐amended plots were probably affected and released into high‐mobility fractions. This indicated that manure application changed the soil redox conditions by improving the soil structure, depending on the water content of soil pores. Despite the reduction of Kfs and Kfunsat by heavy manure application, the transport of high‐mobility metal fractions with either surface water flow or infiltration water flow could be controlled by soil water content at the beginning of a rain or irrigation event. 相似文献
8.
Soil macropore dynamics affected by tillage and irrigation for a silty loam alluvial soil in southern Portugal 总被引：5，自引：0，他引：5
Soil tillage can have a significant effect on soil porosity and water infiltration. This study reports field measurements of near saturated hydraulic conductivity in an undisturbed soil under two tillage treatments, conventional tillage (CT) and minimum tillage (MT). The objective was to determine effective macro and mesoporosities, porosity dynamics during the irrigation season, and their contribution to water flow. Field observations were performed during the 1998 maize (Zea mays L.) cropping season in an Eutric Fluvisol with a silty loam texture, located in the Sorraia River Watershed in the south of Portugal. Infiltration measurements were done with a tension infiltrometer. At each location an infiltration sequence was performed corresponding to water tensions (φ) of 0, 3, 6 and 15 cm. Five sets of infiltration measurements were taken in both treatments in the top soil layer between May and September. One set of measurements was done at the depth of 30 cm at the bottom of the plowed layer in the CT plot. After 5 years of continuous tillage treatments the results show that regardless of the tillage treatment, saturated conductivity values K(φ0) were several times larger than near saturation conductivity K(φ3). This indicates that subsurface networks of water conducting soil pores can exist in both CT and MT maize production systems. In CT, the moldboard plow created macro and mesoporosity in the top soil layer while breaking pore continuity at 30 cm depth. This porosity was partially disrupted by the first irrigation, resulting in a significant decrease of 45% in the macropore contribution to flow. Later in the season, the irrigation effect was overlaid by the root development effect creating new channels or continuity between existing pores. In MT macroporosity contribution to flow did not show significant differences in time, representing 85% of the total flow. In both the treatments, macropores were the main contributing pores to the total flow, in spite of the very low macroporosity volumes. 相似文献
9.
《Soil & Tillage Research》1988,12(1):37-51
The temporal variability of soil porosity, especially macropores (> 50 μm), and associated porosity factors such as pore continuity, percent water-filled pore space (%WFPS), and earthworm numbers and biomass were determined over 3 years under direct-drilling and mouldboard ploughing. The study was conducted on a Charlottetown fine sandy loam, an Orthic Podzol with a humid to perhumid soil-moisture regime.Differences in soil porosity between tillage systems were mainly confined to the surface 0–8-cm soil depth. Fissures (> 300 μm), or large pores, were reduced under direct drilling compared with mouldboard ploughing, but subject to regeneration over the winter period. The absence of soil loosening caused the volume of macropores to fall below 10% during the growing season. Tillage had a residual effect on soil porosity, maintaining the volume of macropores between 11 and 18%. Differences between tillage and ice-induced porosity influenced the degree of macropore regeneration. In general, water-storage pores were similar between tillage systems. A close relationship (r2 = 0.832) was observed between dry bulk density and macroporosity under both tillage systems. The relationship between macroporosity and pore continuity (Ksat), which differed between tillage systems, indicated that a macroporosity of between 8 to 10% (v/v) would maintain adequate soil permeability. In contrast, the %WFPS, which was closely related (R2 = 0.952) to macroporosity and soil water content, indicated that the volume of macropores should exceed 14% to provide an optimum level of air-filled pore space.Under humid soil-moisture regimes, the use of macroporosity as an index of critical soil structure or limiting density needs to be based both on adequate soil permeability and on water-filled pore space. Although direct drilling maintained adequate functional porosity, the need for an optimum aerobic environment may necessitate loosening of the surface soil on an annual basis. 相似文献
10.
稻麦轮作条件下长期不同土壤管理对供氮能力的影响 总被引：3，自引：0，他引：3
通过种植了 25季的长期定位试验研究了稻麦轮作条件下不同土壤耕作方式和培肥制度对土壤供氮能力的影响。结果表明 ,不论免耕还是耕翻 ,0～5cm土壤的氮素释放均较持久 ,5～15cm土壤的氮素释放耕翻较免耕持久。休闲的 0～5cm土壤在免耕条件下其氮素矿化势和短期矿化氮量均远远高于耕翻 ,5～15cm和 15～30cm土壤在免耕和耕翻间则相差不大。施肥的3个处理 0～ 5cm土壤氮素矿化势和短期矿化氮量有免耕高于耕翻的趋势 ,而 5～ 15cm土层免耕明显低于耕翻 ,15～ 30cm土壤免耕与耕翻没有差异。有机肥与化肥配施的免耕与耕翻土壤中 25季作物吸氮量几乎无差异 ,不施肥和单施化肥处理的免耕土壤中作物吸氮量低于耕翻土壤。免耕条件下 ,有机肥配施化肥土壤的供氮能力仅低于休闲土壤 ,不施肥土壤最低 ;耕翻条件下 ,有机肥配施化肥土壤的供氮能力最高。各培肥处理间的差异主要表现在 0～ 5cm土层。 相似文献
11.
《Soil Science and Plant Nutrition》2013,59(4):546-557
Abstract Soil carbon sequestration in agricultural lands has been deemed a sustainable option to mitigate rising atmospheric CO2 levels. In this context, the effects of different tillage and C input management (residue management and manure application) practices on crop yields, residue C and annual changes in total soil organic C (SOC) (0–30 cm depth) were investigated over one cycle of a 4-year crop rotation (2003–2006) on a cropped Andisol in northern Japan. For tillage practices, the effects of reduced tillage (no deep plowing, a single shallow harrowing for seedbed preparation [RT]) and conventional deep moldboard plow tillage (CT) were compared. The combination of RT, residue return and manure application (20 Mg ha?1 in each year) increased spring wheat and potato yields significantly; however, soybean and sugar beet yields were not influenced by tillage practices. For all crops studied, manure application enhanced the production of above-ground residue C. Thus, manure application served not only as a direct input of C to the soil, but the greater crop biomass production engendered enhanced subsequent C inputs to the soil from residues. The SOC contents in both the 0–5 cm and 5–10 cm layers of the soil profile were greater under RT than under CT treatments because the crop residue and manure were densely incorporated into the shallow soil layers. Comparatively, neither tillage nor C input management practices had significant effects on annual changes in SOC content in either the 10–20 cm or 20–30 cm layers of the soil profile. When soil C sequestration rates, as represented by annual changes in total SOC (0–30 cm), were assessed on a total soil mass basis, an anova showed that tillage practices had no significant effect on total C sequestration, but C input management practices had significant positive effects (P ≤ 0.05). These results indicate that continuous C input to the soil through crop residue return and manure application is a crucial practice for enhancing crop yields and soil C sequestration in the Andisol region of northern Japan. 相似文献
12.
Johnson Kayode Adesodun Florence Alaba Olowokere Adewole Oladipupo Ismail Ayodeji Obaloluwa Adekunle Juliana Abimbola Osore 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):14-22
Short-term effect of organic and inorganic amendments on soil physical quality (SPQ) is marked when dealing with tropical soils which are naturally exposed to a high risk of water erosion. This study assessed the suitability of Tithonia diversifolia (Mexican Sunflower) when incorporated as green manure (GM) and also composted with poultry manure (PM) and other organic-based and inorganic fertilizers to improve some hydraulic properties of an Alfisol subject to excessive drainage. Treatments applied include fresh T. diversifolia (GM), PM, T. diversifolia composted with PM, organo-mineral fertilizers (OMF), neem fertilizer (NF), inorganic fertilizer (20-10-10 NPK), and control in a randomized complete block design and replicated four times. Soil samples were collected at 0–20 cm depth to determine near steady-state infiltration rates (Is), sorptivity, transmissivity, saturated hydraulic conductivity (Ks), macroporosity (MacP), microporosity (MicP), air capacity (AC), and relative water capacity (RWC). The Is rates were significantly (P ≤ 0.05) reduced to optimum range with the addition of the organic fertilizers over very high value (128.7 cm hr?1) observed for control. Whereas, Ks was enhanced in the order: GM > compost (CP) > NF > inorganic fertilizer > control > organo-mineral fertilizer > PM. Sorptivity and transmissivity were highest in control and inorganic fertilizer plots, indicating that the addition of organic fertilizers lowered these parameters while MacP, MicP, AC, and RWC were generally increased with the addition of organic-based and inorganic fertilizers. Specifically, NF increased MicP by 34% over control. Values for RWC which were within the optimum range (0.60–0.70) were only obtained with NF (0.74), OMF (0.72), NPK (0.70), and GM (0.60). The SPQ parameters assessed in this study were enhanced by the addition of fresh T. diversifolia applied as GM and CP compared to other treatments. Therefore, T. diversifolia usually burned by farmers should instead be incorporated into the soil as manure. 相似文献
13.
Soil structure and the effect of management practices 总被引：7，自引：0，他引：7
To evaluate the impact of management practices on the soil environment, it is necessary to quantify the modifications to the soil structure. Soil structure conditions were evaluated by characterizing porosity using a combination of mercury intrusion porosimetry, image analysis and micromorphological observations. Saturated hydraulic conductivity and aggregate stability were also analysed.
In soils tilled by alternative tillage systems, like ripper subsoiling, the macroporosity was generally higher and homogeneously distributed through the profile while the conventional tillage systems, like the mouldboard ploughing, showed a significant reduction of porosity both in the surface layer (0–100 mm) and at the lower cultivation depth (400–500 mm). The higher macroporosity in soils under alternative tillage systems was due to a larger number of elongated transmission pores. Also, the microporosity within the aggregates, measured by mercury intrusion porosimetry, increased in the soil tilled by ripper subsoiling and disc harrow (minimum tillage). The resulting soil structure was more open and more homogeneous, thus allowing better water movement, as confirmed by the higher hydraulic conductivity in the soil tilled by ripper subsoiling. Aggregates were less stable in ploughed soils and this resulted in a more pronounced tendency to form surface crust compared with soils under minimum tillage and ripper subsoiling.
The application of compost and manure improved the soil porosity and the soil aggregation. A better aggregation indicated that the addition of organic materials plays an important role in preventing soil crust formation.
These results confirm that it is possible to adopt alternative tillage systems to prevent soil physical degradation and that the application of organic materials is essential to improve the soil structure quality. 相似文献
14.
This study was conducted to investigate the impact of land use (dryland farming, grassland and irrigated farming) on bulk density, (ρb) and relative bulk density (ρb‐rel), and to study the relationships between ρb and ρb‐rel, respectively, and soil organic matter content (OM) and soil texture at 100 locations in calcareous soils of central Iran. The ρb–rel was expressed as the ratio of ρb to a reference bulk density, ρbef. By considering ρb‐ref an inherent soil property that is dependent on soil texture but not on OM, the combined effects of OM due to land use and compaction (due to agricultural machinery) on the degree of compactness could be explored. Multiple linear regression was used to derive pedotransfer functions for predicting ρb and ρb‐rel. It was found that ρb‐rel is strongly affected by OM, and a strong correlation was obtained between ρb‐rel and the ratio of OM to clay content. The predictive performance of the multiple regression models was poorest for irrigated farming, which might be explained by intensive soil disturbance by tillage in irrigated farming. The main effect of land use was on OM, and consequently, the degree of compactness was mainly controlled by OM. The greatest OM and least ρb‐rel were measured in irrigated farming. Dryland farming had the least OM and the greatest ρb‐rel. 相似文献
15.
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
16.
F. Curran Cournane R. W. Mcdowell R. P. Littlejohn D. J. Houlbrooke L. M. Condron 《Soil Use and Management》2011,27(3):376-384
Agriculture is a major source of phosphorus (P) and suspended sediment (SS) losses to aquatic ecosystems promoting eutrophication. Mechanical soil loosening equipments such as topsoil looseners or aerators have been reported to improve the physical quality and infiltration of soils susceptible to livestock damage resulting from treading. We hypothesized that soil aeration would significantly decrease the volume of surface runoff and consequent losses of P and SS compared with non‐aerated soil (control) in cattle‐grazed pasture on a poorly structured silt‐loam soil. Hydrologically isolated plots (2 m long × 1 m wide × 0.15 m deep) were installed in aerated and control plots to collect surface runoff following irrigation or rainfall and analysed for P and SS losses for 1 year. Soil physical properties [% macroporosity, bulk density, saturated hydraulic conductivity (Ksat) and unsaturated hydraulic conductivity (Kunsat at ?1kPa)] were measured in the aerated and control treatments and taken before each irrigation event (n = 12). Six months after mechanical aeration was employed, but before cattle grazing commenced, no significant differences in soil physical quality were found between aerated and control treatments, with the exception of a minor increase in Kunsat for the control plots. This lack of treatment difference continued after grazing and was largely attributed to the re‐settling of the poorly structured and dispersive soil. Flow‐weighted mean concentrations and annual loads of dissolved reactive P (DRP) on the mechanically aerated soil (2.24 kg DRP/ha) were approximately double those from the control treatment (1.20 kg DRP/ha). However, no significant differences were observed between treatments for surface runoff volumes and losses of total P and total SS, which may reflect the similar soil physical conditions exhibited between treatments throughout most of the trial. As observed elsewhere, time (days) since grazing or fertilizer application was found to influence P and/or SS losses. We conclude that aeration did not decrease P and SS losses. Any changes in soil physical properties such as macroporosity were short‐lived and therefore unlikely to influence surface runoff and subsequent P and SS losses for this soil type. 相似文献
17.
《Communications in Soil Science and Plant Analysis》2012,43(15-16):2383-2390
Abstract Our goal was to determine if anion‐exchange membranes (AEMs), which can be placed in situ in soils and act as anion exchangers, were better soil nitrate (NO3‐) assessment tools than soil extraction. During winter 1993–1994 we compared NO3‐ in the surface of tilled and non‐tilled soils that were subjected to rye cover crop and fallow winter coverage treatments. Estimates of soil solution concentrations of NO3‐ based on KC1 extracts of the AEMs were between 1 to 5 fold higher than concentrations based on soil extracts. Both methods of NO3‐ assessment documented a general decline in NO3‐ availability during the winter; however, only the AEM NO3‐ data produced statistically significant results. AEM data suggested that the combination of fall tillage and winter fallowing increased soil NO3‐ contents and led to more potential for loss of NO3‐ during the 1993–1994 winter than reduced tillage practices or planting a rye cover crop. 相似文献
18.
《Communications in Soil Science and Plant Analysis》2012,43(17-18):2869-2885
Abstract Conventional management practices have been associated with increased soil erosion and organic matter loss and the contamination of surface and ground water. Alternative agriculture systems which minimize external chemical inputs and degradation of soil and water resources represent alternatives to conventional management practices. Four different management practices were compared on an alluvial silty loam soil cultivated to grow corn (Zea mays L.). The effects of conventional and reduced tillage and of different chemical inputs on the distribution of phosphorus (P) concentration and on soil porosity were investigated. Results showed that the highest P content was detected in the topsoil (0–10 cm) of the minimum tilled plots even though the amount of P fertilizer added was much lower than the amount added in the conventionally tilled plots. The total porosity was significantly higher in the minimum tilled soil and was related only to the tillage technique. Since the higher porosity was mainly due to the higher proportion of elongated and regular pores, the minimum tilled soil appeared to be more resistant to physical stresses and characterized by a higher biological activity. 相似文献
19.
F. Zehetner I. Djukic R. Hofmann L. Kühnen G. Rampazzo‐Todorovic M. H. Gerzabek G. Soja 《Soil Use and Management》2015,31(4):528-533
The farming practices in vineyards vary widely, but how does this affect vineyard soils? The main objective of this study was to evaluate the effects of vineyard management practices on soil organic matter and the soil microbial community. To this end, we investigated three adjacent vineyards in the Traisen valley, Austria, of which the soils had developed on the same parent material and under identical environmental/site conditions but were managed differently (esp. tillage, fertilizer application, cover crops) for more than 10 yrs. We found that topsoil bulk density (BD) decreased with increasing tillage intensity, while subsoil BD showed the opposite trend. Soil organic carbon (SOC) stocks in 0–50 cm depth increased from 10 kg m?2 in an unfertilized and frequently tilled vineyard to 17 kg m?2 in a regularly fertilized but less intensively tilled vineyard. Topsoil microbial biomass per unit SOC, estimated by the sum of microbial phospholipid fatty acids (PLFAs), followed this trend, albeit not statistically significantly. Principal component analysis of PLFA patterns revealed that the microbial communities were compositionally distinct between different management practices. The fungal PLFA marker 18:2ω6,9 was highest in the vineyard with the lowest amount of extractable Cu (by 0.01 m CaCl2), and the bacterial‐to‐fungal biomass ratio was positively correlated with extractable Cu. Our results indicate that tillage and fertilizer application of vineyards can strongly affect vineyard soil properties such as BD and SOC stocks and that the application of Cu‐based fungicides may impair soil fungal communities. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(5-6):585-599
Abstract Exchangeable NH4, organic N, and fixed NH4, were followed in three soil layers (0–25, 25–50, and 50–75 cm) of plots under conventional and minimum tillage in a 10—year field experiment. The main effect of both tillage treatments was a marked increase of fixed NH4 during the first two years which was attributed to the heavy application of N fertilizers because soils were not fertilized prior to the experiment. Due to spatial variability of soil composition, a statistically significant increase over the 10—year was observed for total and fixed NH4 only in the surface layer of conventionally tilled soils, probably due to thorough mixing caused by intense cultivation. In this layer the organic N pool did not appear to vary with the years, while the fixed NH4 pool was influenced by N fertilization. A general trend was a uniform increase of the ratio between fixed NH4 and total N. Under conventional tillage, the trend was similar for the three soil layers while the reduced amount of fixed NH4 present in the upper soil layers (0—25 and 25–50 cm) was assumed to be caused by root absorption. Under minimum tillage, the increase of fixed NH4 ratio was limited to the first 50 cm of soil, and was less pronounced in the top layer where maximum root accumulation is generally expected to be present. The data support the importance for crops of the fixed NH4 pool. 相似文献