Tillage and drainage impact on soil quality: I. Aggregate stability, carbon and nitrogen pools   总被引：1，自引：1，他引：0  

Muhammad Abid  Rattan Lal 《Soil & Tillage Research》2008,100(1-2):89-98

Effects of two tillage treatments, tillage (T) with chisel plough and no-till (NT), were studied under un-drained and drained soil conditions. Soil physical properties measured were bulk density (ρ_b), total porosity (ƒ_t), water stable aggregates (WSA), geometric mean diameter (GMD), mean weight diameter (MWD), organic carbon (OC) and total N concentrations in different aggregate size fractions, and total OC and N pools. The experiment was established in 1994 on a poorly drained Crosby silt loam soil (fine mixed, mesic, Aeric Ochraqualf) near Columbus, Ohio. In 2007, soil samples were collected (0–10, 10–20, and 20–30 cm) from all treatments and separated into six aggregate size classes for assessing proportions of macro (5–8, 2–5, 1–2, 0.5–1, 0.25–0.5) and micro (<0.25 mm) aggregates by wet sieving. Tillage treatments significantly (P ≤ 0.05) influenced WSA, MWD, and GMD. Higher total WSA (78.53 vs. 58.27%), GMD (0.99 vs. 0.68 mm), and MWD (2.23 vs. 0.99 mm) were observed for 0–10 cm depth for NT than T treatments. Relative proportion of macro-aggregates (>0.25-mm) was also more in NT than T treatment for un-drained plots. Conversely, micro-aggregates (<0.25-mm) were more in T plots for both drained and un-drained treatments. The WSA, MWD and GMD decreased with increase in soil depth. The OC concentration was significantly higher (P ≤ 0.05) in NT for un-drained (P ≤ 0.01) treatment for all soil depths. Within macro-aggregates, the maximum OC concentrations of 1.91 and 1.75 g kg⁻¹ in 1–2 mm size fraction were observed in NT for un-drained and drained treatments, respectively. Tillage treatments significantly (P < 0.01) affected bulk density (ρ_b), and total porosity (f_t) for all soil depths, whereas tillage × drainage interaction was significant (P < 0.01) for 10–20 and 20–30 cm depths. Soil ρ_b was negatively correlated (r = −0.47; n = 12) with OC concentration. Tillage treatments significantly affected (P ≤ 0.05) OC pools at 10–20 cm depth; whereas drainage, and tillage × drainage significantly (P ≤ 0.05) influenced OC pools for 0–10 cm soil layer. The OC pool in 0–10 cm layer was 31.8 Mg ha⁻¹ for NT compared with 25.9 Mg kg⁻¹ for T for un-drained treatment. In comparison, the OC pool was 23.1 Mg ha⁻¹ for NT compared with 25.2 Mg ha⁻¹ for T for the drained plots. In general, the OC pool was higher in NT system, coupled with un-drained treatment than in drained T plots. The data indicate the importance of NT in improving the OC pool.  相似文献   

Quantitative analysis of morphometry on Ribb and Gumara watersheds: Implications for soil and water conservation     

《国际水土保持研究(英文)》2019,7(2):150-157

Morphometric analysis is a quantitative measurement and mathematical analysis of landforms. It plays a significant role in understanding the geohydrological characteristics of a drainage basin in relation to the terrain feature and its flow patterns. It also helps to estimate the incidence of infiltration and runoff, and other related hydrological character of a watershed like erosion and sediment transport which has a strong implication for natural resource conservation. This study has attempted to quantify the morphometric characteristics of Guna- Tana watershed for proper implementation of soil and water conservation practices. ASTER (DEM) was used for extracting morphometric parameters. The watershed covers a total area of 3601.5 km² and it has a basin length of 78.89 km. It has been tried to generate morphometric parameters which account basin drainage network, geometry, drainage texture, and relief characteristics together with hypsometric characteristics. The morphometric analysis of drainage density of the study watershed is 0.49 km/km² which indicates the basin is highly permeable and result with better underground water storage capacity. Ruggedness number is 0.02 that implies the area is less prone to soil erosion. In addition, it has stream frequency of 0.32 and form factor 0.57 which indicates slightly elongated basin shape. Comparative analysis of its sub watersheds Gumara and Ribb was also undertaken. Therefore, practicing soil and water conservation in the watershed could enhance/strengthen the water storage capacity, prevent sediment loss and related natural resource from the watershed that rehabilitate its productivity.  相似文献   

Topographical thresholds for ephemeral gully initiation in intensively cultivated areas of the Mediterranean   总被引：2，自引：0，他引：2  

L. Vandekerckhove  J. Poesen  D. Oostwoud Wijdenes  T. de Figueiredo 《CATENA》1998,33(3-4)

Ephemeral gullying is an important erosion process in Mediterranean areas suffering from land degradation because of increased drought and human impact. An ephemeral gully is formed when a hydraulic threshold for incision into a resistant soil surface is exceeded. The flow intensity at the soil surface of any landscape position is controlled by topographical parameters, such as local slope (S) and drainage-basin area (A). The objective of this study was to investigate to what extent one could use field measurements of S and A to predict the location of ephemeral gully initiation in intensively cultivated Mediterranean environments. Two relatively homogeneous study areas in Southeast Spain and Northeast Portugal with widespread ephemeral gullying were selected. S and A were measured by standard methods at the initiation point of 50 ephemeral gullies in each study area. The relationship between S and A was statistically investigated. On a double logarithmic scale, the S and A data showed considerable scatter. Orthogonal regression resulted in the threshold relationship S=aA^−b with b=0.133 for Spain, and b=0.226 for Portugal. The analysis also showed that S and A were weakly correlated for the Spanish dataset, and more strongly correlated for the Portuguese dataset. The correlation was considerably strengthened by including additional information on planform curvature and on tillage direction relative to the gully direction. Greater soil stoniness and the presence of a less permeable horizon generally increased the threshold level in both study areas. The threshold relationships resulting from this study were compared with literature data. The indices A_cS and ln(A_c/S) were applied to our study sites but neither relationship individually described the general trend between the data of S and A. Therefore, an alternative index, A_c^bS, with 0.133≤b≤0.226, according to the empirical trend between drainage basin area and local slope, was proposed to describe the topographical threshold conditions for ephemeral gully initiation in similar Mediterranean areas.  相似文献   

海涂围垦区降渍脱盐的试验研究     

俞双恩  刘才良  邵孝候 《灌溉排水学报》1994,(4)

针对五四农场新围垦区存在的渍害问题，进行了两年的田间试验。结果表明，控制内河水位，实施暗管排水具有明显的降渍脱盐，增产效果，将大麦受渍时间缩短为３天，１ｍ土体含盐量由试验前的０．２３５％降到０．１５％以下，大麦增产２０％以上。  相似文献   

Nitrogen and water use efficiency of zucchini squash for a plastic mulch bed system on a sandy soil   总被引：2，自引：0，他引：2  

Lincoln Zotarelli  Michael D. Dukes  Johannes M. Scholberg  Travis Hanselman  Kristen Le Femminella  Rafael Muñoz-Carpena 《Scientia Horticulturae》2008

Zucchini squash (Cucurbita pepo L.) is an economically important vegetable crop in Florida. Typically, it is intensively managed with high inputs of fertiliser and irrigation water. Our objectives were to evaluate the interaction between fertilisation rates and irrigation treatments, and to quantify nitrate leaching in a plastic mulched/drip irrigated zucchini squash production systems. Three studies were carried out. The first study evaluated different depth placement of drip and fertigation lines on plant growth and fruit yield. Treatments included SUR (both irrigation and fertigation drip lines placed on the surface); S&S (both lines buried 0.15 m deep); and SDI (irrigation line placed 0.15 m below the fertigation line on the surface). The second and third studies compared three different N-rates and different soil moisture sensor-based irrigation strategies. Nitrate-N leaching was monitored by zero tension drainage lysimeters and soil samples. N leaching increased when irrigation and N-rates increased, with values ranging from 2 to 45 kg ha⁻¹ of N. Use of SDI increased yields by 16% compared to the S&S treatment, and reduced nitrate leaching by 93% while increasing the water use efficiency by 75% compared to a fixed 2-h irrigation event per day treatment. Application of N above the standard recommended rate of 145 kg ha⁻¹ did not increase yield, although yields were reduced at the lowest N-rate. The use of soil moisture sensors for automatic irrigation control reduced irrigation application and minimized nitrogen leaching. In addition, combining the soil moisture controlled SDI system that had surface applied fertigation resulted in similar or higher yields, while reducing both water use and potential N leaching because of improved nutrient retention in the root zone.  相似文献   

Assessment and simulation of water and nitrogen transfer under furrow irrigation   总被引：3，自引：0，他引：3  

D. Crevoisier  J.C. Mailhol  P. Ruelle 《Agricultural Water Management》2008,95(4):354-366

The objective of this study is to simulate water and nitrogen transfers under two furrow irrigation technologies (every furrow irrigation (EFI) and alternative furrow irrigation (AFI)) on Chromic Luvisol in Sofia region, Bulgaria. A bi-dimensional water and solutes transport modeling approach, HYDRUS-2D model [Simunek, J., Sejna, M., Van Genuchten, M.T., 1999. The HYDRUS-1D and HYDRUS-2D codes for estimating unsaturated soil hydraulic and solutes transport parameters. Agron Abstr. 357] is adopted in order to consider the technology of irrigation and fertilization. The model is calibrated in six steps using detailed data observed in two cropped lysimeters. The data consist of water and nitrogen (N) profiles below ridge and furrow bed, precipitation, drainage and water/N uptake by plant. Hydrological components of the soil are derived from laboratory: water retention data (step (i)) and adjusted to field conditions when EFI is approximated by one-dimensional (step (ii)). Then a two-dimensional water flow is adopted in model simulations for parameter calibration and verification, under EFI (step (iii)) and under AFI technology (step (iv)). This model calibration and validation is then used to calibrate the solute transport parameters, that is the aim of step (v) and step (vi). EFI and particularly AFI technologies points out the necessary 2D model using for the N transfer simulation under specific fertilizer applications. Thus, this calibrated model allows predicting the impact of furrow irrigation practices and distribution uniformity on drainage and nitrogen leaching under the studied conditions.  相似文献   

Effect of irrigation water salinity on transpiration and on leaching requirements: A case study for bell peppers     

Alon Ben-Gal  Eviatar Ityel  Lynn Dudley  Shabtai Cohen  Uri Yermiyahu  Eugene Presnov  Leah Zigmond  Uri Shani 《Agricultural Water Management》2008,95(5):587-597

Maximization of crop yields when the salinity of irrigation water is high depends on providing plant transpiration needs and evaporative losses, as well as on maintaining minimum soil solution salinity through leaching. The effect of the amount of applied irrigation water was studied regarding transpiration, yields, and leaching fractions as a function of irrigation water salinity. Bell pepper (Capsicum annum L. vars. Celica and 7187) in protected growing environments in the Arava Valley of Israel was used as a case study crop to analyze water quantity–salinity interactions in a series of lysimeter, field and model simulation experiments. Leaching fraction was found to be highly influenced by plant feedback, as transpiration depended on root zone salinity. Increased application of saline irrigation water led to increased transpiration and yields. The higher the salinity level, the greater the relative benefit from increased leaching. The extent of leaching needed to maximize yields when irrigating with saline water may make such practice highly unsustainable.  相似文献   

泥浆土壤特性动态检测(英文)     

《（《农业科学与技术》）编辑部》2008,(4)

[Objective] The research aimed to provide basic files and theoretical guidance for constructing sluicing-siltation dam using soil with high clay content soil.[Method] The soils of Dagou basin near Xiwu Village of Baishui County,Shaanxi Province were taken as experimental materials.pvc pipes with same height and diameter were used to construct testing model for dynamically determining settlement,shear strength,wet density of grouting bulk under 2 different grouting speeds(15 cm/d and 25 cm/d).[Result] Under different grouting speeds,general change trend was similar during grouting course.The subsidence,deformation,shear strength and wet density increased with the increase of grouting speed.Five or six days after grouting,daily displacement under 25 cm/d grouting speed was fewer than that under 15 cm/d grouting speed.[Conclusion] The increase of grouting speed could shorten the time for reaching the same subsidence,deformation,shear strength and wet density and increased displacement at the initial stage of grouting,however,with the increase of grouting time,lower grouting bulk was bad for displacement at later grouting period because it was near impermeable layer.  相似文献   

浅谈市政排水管道工程的总体规划及施工管理     

李智 《林业科技情报》2013,45(3):38-39

从排水管道工程的各个阶段出发，分别阐述其施工措施，并从规划、质量管理的角度提出相应办法。排水系统是城市市政设施得以正常使用的重要环节之一，科学合理的设计排水系统，不仅关系到城市的经济建设，也关系到城市未来的发展。  相似文献   

Micronutrients Losses from Soil under Subsurface Drainage System     

《Communications in Soil Science and Plant Analysis》2012,43(17):2546-2559

The drainage system, although it reclaims waterlogged soils, poses a potential threat to leaching of valuable nutrients. To assess the micronutrient losses from such system established more than two decades ago in the plains of northwestern Pakistan, drainage waters were periodically analyzed for selected micronutrients. The inputs of micronutrients in irrigation waters were also determined. The micronutrient removal in drainage water was 1.39 to 9.79 times greater than micronutrient inputs in irrigation waters and fertilizers. Among micronutrients, the removal of copper (Cu) and manganese (Mn) in drainage water was greater than iron (Fe) and zinc (Zn). The concentrations of micronutrients generally changed with cropping (sampling time), increased with soil depth, and were invariably negative on the nutrient balance sheet, suggesting that these nutrients are continuously depleted from the system in drainage water. These nutrients therefore must be replenished in soil through an appropriate means for optimum crop yields under the given drainage–irrigation–cropping system.  相似文献