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1
Udoh, B. T., and T. O. Ibia. "Fertility capability classification for agricultural land use planning in the beach sands area of Akwa Ibom State, Nigeria." Agro-Science 21, no. 2 (June 22, 2022): 74–78. http://dx.doi.org/10.4314/as.v21i2.8.
Повний текст джерелаАнотація:
Soil survey and fertility capability classification (FCC) were carried out in an area mostly underlain by the beach ridge sands (BRS) parent material in Akwa Ibom State, Nigeria. The study applied the FCC in agricultural land use planning for efficient land management and optimal agricultural productivity of the beach soils. Field and laboratory data were obtained from 40 pedons located across eight Local Government Areas on the BRS parent material. From the results of field and laboratory studies, 11 FCC units were identified in the area. Based on similarities in certain soil profile characteristics, the 11 FCC units were grouped into four agro-ecological units (AEUs): (i) poorly drained FCC units with sandy topsoil over sandy subsoil, grouped to form AEU-A, covered 65.00% of study area; (ii) well drained FCC units with sandy topsoil over sandy subsoil, formed AEU-B and covered 22.50% of study area; (iii) poorly drained FCC units with sandy topsoil over loamy subsoil or loamy top- and sub- soils, formed AEU-C and covered 7.50% of study area; (iv) well drained FCC units with sandy topsoil over loamy subsoil, which formed AEU-D, occupied 5.00% of study area. The result of this study has shown that FCC can be employed as a simple but efficient tool in agricultural land use planning. Major soil profile characteristics used to differentiate land units within the beach sands area of Akwa Ibom State are drainage and texture.
2
Liu, Ying, Yangnan Guo, Linli Long, and Shaogang Lei. "Soil Water Behavior of Sandy Soils under Semiarid Conditions in the Shendong Mining Area (China)." Water 14, no. 14 (July 7, 2022): 2159. http://dx.doi.org/10.3390/w14142159.
Повний текст джерелаАнотація:
The soil water behavior of sandy soils was studied under semiarid conditions in the Shendong mining area (China). The soil water content (θ) was measured under different depths and topographies using an HH2 moisture meter. The infiltration process was studied using a Guelph soil permeameter. A set of hydrodynamic variables was calculated in the laboratory. The θ of the first 20 cm was the lowest and increased with depth. The content of soil water increased from the top slope to the bottom slope. The infiltration experiments showed that the steady state infiltration rate was >40 mm h−1 in most cases. Owing to the higher contents of sand and soil macropores at the top of the slope and the top 0–20 cm of surface soil, the initial infiltration rate and steady infiltration rate were higher. The average available water capacity was 18.28%, which was consistent with the predominance of a sandy textural fraction. The results of a soil water retention curve and a rainfall simulation experiment showed that there was a low soil water retention capacity throughout the whole profile. This study contributes to the understanding of several aspects of the soil water behavior of sandy soils and provides key information for environmental management and land reclamation under semiarid conditions in the Shendong mining area.
3
Chaichi, Mohammad Reza, Marcus Turcios, and Mina Rostamza. "The influence of surfactant and organic matter content on wetting pattern of different non-water repellent soils." Soil Research 54, no. 7 (2016): 880. http://dx.doi.org/10.1071/sr15153.
Повний текст джерелаАнотація:
Non-ionic surfactants have been well researched as a tool to ameliorate water repellent conditions. However, few studies have evaluated the risks and benefits of non-ionic surfactant applications in wettable soil. The objective of this study was to evaluate the effects of a surfactant in modifying the wetting pattern in soils of different textures and organic matter contents. The experimental treatments consisted of (1) four different soil textures including sandy, sandy loam, sandy clay loam and silt loam, (2) four different organic matter contents (0.2, 0.7, 1.2 and 1.7% by weight), and (3) irrigation water treatments with or without surfactant (IrrigAid Gold). The experiment was carried out in Plexiglas boxes with one drip emitter under the soil surface. The results demonstrated the superiority of surfactant application on increasing water distribution in the soil profile for all soil textural classes. Silt loam texture had the highest side wetted area and wetting depth 45min after the initiation of irrigation. Upward capillary water movement and top wetted area significantly decreased in the surfactant treatment across all soil textures except in sandy soil. As organic matter content increased, top wetted area decreased. These findings clarified the potential ability of surfactant in increasing water infiltration in non-repellent soil in an in vitro system.
4
SONNEVELD, M. P. W., and J. J. H. VAN DEN AKKER. "Quantification of C and N stocks in grassland topsoils in a Dutch region dominated by dairy farming." Journal of Agricultural Science 149, no. 1 (July 27, 2010): 63–71. http://dx.doi.org/10.1017/s0021859610000535.
Повний текст джерелаАнотація:
SUMMARYEstimates on soil organic carbon (SOC) and nitrogen (N) stocks in soils cannot be directly calculated from routine soil analyses, since these often lack measurements on soil bulk density (Bd). Hence, flexible pedotransfer functions are required that allow the calculation of SOC stocks from gravimetrically determined SOC contents. The present paper aimed to: (1) quantify SOC and N stocks in grassland topsoils for a Northern Dutch region dominated by dairy farming and (2) analyse the relationships between SOC and bulk density at the field level. As estimates of SOC and N stocks are potentially affected by soil compaction, the combined measurements on soil bulk density and soil organic matter (SOM) were also evaluated with respect to critical limits for soil compaction using soil density (Sd) for sandy soils and packing density (Pd) for clay soils. The SOC and Bd measurements were done in the upper 0·1–0·2 m of grasslands at 18 dairy farms, distributed across sandy, clay and peat soils. Both farm data and grassland management data were collected. Non-linear regressions were used to analyse relationships between Bd and SOM. Significant non-linear relationships were found between gravimetric SOC contents and bulk density for the 0–0·1 m layer (R2=0·80) and the 0·1–0·2 m layer (R2=0·86). None of the fields on sandy soils or clay soils indicated signs for limited rooting in the topsoil although some fields appear to approach the critical limit for compaction for the 0·1–0·2 m layer. Stocks of SOC in the top 0·2 m at farm level were highest in the peat soils (21·7 kg/m2) and lowest in the sandy soils (9·0 kg/m2). Similarly, N stocks were highest for farms on peat soil (1·30 kg/m2) and lowest for farms on sandy soil (0·60 kg/m2). For the sandy soils, the mean SOC stock was significantly higher in fields with shallow groundwater tables.
5
Chan, KY, and JA Mead. "Surface physical properties of a sandy loam soil under different tillage practices." Soil Research 26, no. 3 (1988): 549. http://dx.doi.org/10.1071/sr9880549.
Повний текст джерелаАнотація:
The infiltration behaviour and physical properties of a hardsetting sandy loam soil at Cowra, N.S.W., following 2 years of different tillage treatments are reported. Soil that had not been cultivated for 25 years was also investigated at an adjacent pasture site. Infiltration of simulated rainfall at the end of the wheat-growing season gave moisture profiles that were quite different for cultivated, direct drilled and pasture soils. The moisture profile for the cultivated soil suggested the presence of an impeded layer which retarded the movement of infiltrated rain to the subsoil. Porosity measurements confirmed the presence of a layer with significantly fewer macropores (> 300 �m diameter) at the 50-100 mm depth in the cultivated soil, when compared with the direct drilled soil. The old pasture soil had significantly higher porosity (> 300 �m diameter) in the top 100 mm. Aggregate stabilities and organic carbon contents were measured in narrow increments to 150 mm depth for the three different soils, and revealed that a surface 25 mm layer of high organic carbon and highly stable macro-aggregates was present in the pasture and direct drilled soils but absent in the cultivated soil. The unstable surface layer in the conventionally cultivated soil was a consequence of the mixing and inverting action of cultivation and was not due to a net loss of organic carbon from the profile. The organic carbon content of the pasture soil was not significantly different from the direct drilled soil below 50 mm; however, it was significantly lower than the conventionally cultivated soil between 50 and 150 mm depth. These results indicate a need to adopt tillage practices that can preserve the top 25 mm layer of such fragile soils.
6
Nørnberg, P., L. Sloth, and K. E. Nielsen. "Rapid changes of sandy soils caused by vegetation changes." Canadian Journal of Soil Science 73, no. 4 (November 1, 1993): 459–68. http://dx.doi.org/10.4141/cjss93-047.
Повний текст джерелаАнотація:
Development of Typic Haplorthods in a heathland area in Denmark responded over a short period of time (decades) to changes of vegetation. Part of the heath, Hjelm Hede, was left undisturbed and was invaded by trees, mainly oak and a few aspen and conifers. Another part of the heath was planted with Norway and Sitka spruce 60–70 yr ago. The soils under heath, oak and spruce were studied. Major differences were found, some visible in the field and others detectable in the laboratory. Under oak, relative to heath, horizon boundaries were less distinct, pH increased in the top horizons, organic carbon and C/N ratio decreased, and iron and aluminum contents in the upper B horizons decreased. Compared with the original heath podzol, the soil under spruce had a lower pH in the O, E and upper B horizons, higher organic carbon content and C/N ratio in the top horizons, increased cementation, and a placic horizon. However the pyrophosphate-extractable iron and aluminum content was significantly lower than in any of the other soils. The soil under oak showed "depodzolization" features, whereas the soil under spruce was increasingly podzolized, though the podzolization mechanism might be different from that under heath. Analyses of phenolic compounds in the soil water were consistent with these conclusions. The three main components of substituted benzoic acids were gallic acid, protocatechuic acid and coumaric acid, which are all strongly complexing agents believed to take part in the podzolization process. Generally, the highest concentrations were found under spruce and the lowest under oak.Key words: Vegetation-induced soil changes, Spodosols, phenolic compounds
7
Emerson, W. W., and D. McGarry. "Organic carbon and soil porosity." Soil Research 41, no. 1 (2003): 107. http://dx.doi.org/10.1071/sr01064.
Повний текст джерелаАнотація:
The %C within the top sandy 0.15 m of a sodic Hydrosol under native trees consisted of a constant %C in uncharged organic matter and a %C in negatively charged organic matter decreasing linearly with depth, as did the specific volume of the soil. The kaolinitic clay present was strongly bonded together. In an adjoining canefield cleared 10 years earlier, incorporation of burnt cane residues to 0.35 m had more than doubled the CEC of the soil, but had not generated structural porosity. The clay in the top 0.15 m remained strongly bonded together. The rate of increase in the specific volume of the sandy soil under trees with %C was twice that reported for surface aggregates of a silty soil from rotation plots on a Chromosol, and of sectioned clay cores from a Ferrosol under softwood scrub.The rate of increase in the specific volume of pores ≤30 μm diameter with %C was measured by the water retention of aggregates at 10 kPa suction, and was 50% more for the sandy soil than for the silty soil. The difference is ascribed to the dominance of mycorrhizal fungi under trees compared with bacteria under grass. Both agents are presumed to link particles together through acidic polysaccharide gel. Subsequent air-drying then leaves pores stable to wetting and drying. It is suggested that the increase in the plastic limit of silty soils is mainly due to pores stabilised in this way. Pores in decomposing plant residues coated with inorganics could also contribute.
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Blyth, E. M., and C. C. Daamen. "The accuracy of simple soil water models in climate forecasting." Hydrology and Earth System Sciences 1, no. 2 (June 30, 1997): 241–48. http://dx.doi.org/10.5194/hess-1-241-1997.
Повний текст джерелаАнотація:
Abstract. Several simple soil water models with four layers or less, typical of those used in GCMS, are compared to a complex multilayered model. They are tested by applying a repeating wetting/drying cycle at different frequencies, and run to equilibrium. The ability of the simple soil models to reproduce the results of the multilayer model vary according to the frequency of the forcing cycle, the soil type, the number of layers and the depth of the top layer of the model. The best overall performance was from the four layer model. The two layer model with a thin top layer (0.1 m) modelled sandy soils well while the two layer model with a thick top layer (0.5 m) modelled clay soils well. The model with just one layer overestimated evaporation during long drying periods for all soil types.
9
Dirgėlienė, Neringa, Šarūnas Skuodis, and Elijus Vasys. "The behaviour of stress variation in sandy soil." Open Geosciences 14, no. 1 (January 1, 2022): 13–23. http://dx.doi.org/10.1515/geo-2020-0336.
Повний текст джерелаАнотація:
Abstract This research article represents the recompacted dense sand sample behaviour and stress distribution in the direct shear box. In Lithuania, sand is quite common on a construction site, in general about 32%. To reduce the influence of the shear box design on the experimentally determined values of the soil strength parameters, it is necessary to know the regularities of the change of the normal load acting in the shear plane. Three different normal stresses of 50, 100, and 200 kPa were applied to the dense sand in the direct shear boxes during experimental and numerical simulation. The results showed an obvious evidence of non-uniformity of stress for standard and raised specimens. The numerical analysis exhibited that when the sample is loaded only with a vertical load, approximately 75% of that load is transferred to the sample bottom, 84% to the shear plane, and 95% to the top. At the end of the shear test, the vertical force in the shear plane reaches maximum, the normal stress is higher by 13.5% than applied on the sample top. The shear strength of sandy soils were influenced by box size and sample height too. The improved shear box apparatus allows to estimate the vertical load at shear plane.
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Kesteren, A. R. van. "Soil erodibility relationships on drumlin deposits in the Cape Caribou River area, Labrador." Canadian Journal of Soil Science 80, no. 4 (November 1, 2000): 577–80. http://dx.doi.org/10.4141/s00-002.
Повний текст джерелаАнотація:
Universal soil loss equation (USLE) soil erodibility (K) factors were computed from drumlin soils in the Cape Caribou River area, Labrador. Soil erodibility variation was investigated, using Mann-Whitney and Kruskal-Wallis tests, for three stratifications: (i) topographic position (TOP), (ii) mineral soil horizon (HOR), and (iii) soil texture (TEX). Topographic position with two substrata, drumlin summits (SUM) and drumlin side slopes (SID), was not significant. Horizons A, B and C and textural classes loamy sands (LS), sandy loams (SL) and loams (L) were significant. A log linear likelihood chi-square (G2) model was applied to investigate relationships of HOR and TEX. Partitioning of the G2 statistic revealed both significant and non-significant cells in the cross tabulation. Some sampling considerations for the determination of K factors are discussed. It is concluded that accepted field methods could enhance K factor determination in Labrador forest soil environments. Key words: Soil erodibility, K factor, drumlins, Labrador
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Alghamdi, Abdulaziz G., Bandar H. Aljohani, and Anwar A. Aly. "Impacts of Olive Waste-Derived Biochar on Hydro-Physical Properties of Sandy Soil." Sustainability 13, no. 10 (May 14, 2021): 5493. http://dx.doi.org/10.3390/su13105493.
Повний текст джерелаАнотація:
In this study, waste olive leaves and branches were pyrolyzed to produced biochar, and their impacts on physical and chemical properties of a sandy soil were evaluated. Pyrolytic temperatures of 300 °C, 400 °C, and 500 °C were used for biochar production. After evaluating the physio-chemical properties, the produced biochars were added to the top 10 cm layer of the soil at rates of 0%, 1%, 3%, and 5% in a column experiment at 25 °C. Biochar was mixed with a sandy soil into the top 10 cm of the columns. For all treatments, cumulative evaporation was reduced; however, treatments with 5% biochar prepared at the highest temperatures showed the highest impact. The available water contents were increased by 153.33% and 151.11% when olive branch-derived biochar and olive leaves-derived biochars produced at 500 °C were applied at 5% rate, respectively. No impact of available water was observed for 1% biochar contribution. Biochar application decreased both cumulative infiltration and infiltration rate. Biochar pyrolyzed at 500 °C most intensely improved hydro-physical properties of a sandy soil. However, its application as a soil supplement in arid environments should be adopted with constraints due to its high pH (9.69 and 9.29 for biochar pyrolyzed at the highest temperatures) and salinity (up to electrical conductivity = 5.07 dS m−1). However, the salinity of biochar prepared from olive branches (5%, pyrolyzed at 500 °C) was low (0.79 dS m−1); therefore, it can be used safely as a supplement in saline and acidic soils, but with restriction in alkaline soils.
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Sharma, P. K., S. K. De Datta, and C. A. Redulla. "Root Growth and Yield Response of Rainfed Lowland Rice to Planting Method." Experimental Agriculture 23, no. 3 (July 1987): 305–13. http://dx.doi.org/10.1017/s001447970001718x.
Повний текст джерелаАнотація:
SUMMARYField experiments were conducted on two soils (clay loam and sandy loam) with varying texture and water table depth to study the effects of two planting methods (dry seeding and transplanting) on the root growth and grain yield of rainfed lowland rice. About 75% of the roots were found in the top 10 cm soil. Root length density at the flowering stage and grain yield in the sandy loam soil, with a water table deeper than 1.5 m, were less in dry-seeded than in transplanted rice, probably because of the greater moisture stress in dry-seeded rice between late tillering and harvest. In the clay loam soil, with the water table mostly at the soil surface, there was no difference in grain yield between dry-seeded and transplanted rice.
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Liu, Siyi, Jiangye Li, Aizhen Liang, Yan Duan, Haibin Chen, Zhuyun Yu, Ruqin Fan, Haiyang Liu, and Hong Pan. "Chemical Composition of Plant Residues Regulates Soil Organic Carbon Turnover in Typical Soils with Contrasting Textures in Northeast China Plain." Agronomy 12, no. 3 (March 21, 2022): 747. http://dx.doi.org/10.3390/agronomy12030747.
Повний текст джерелаАнотація:
Soil organic carbon (SOC) turnover plays a pivotal role in achieving C neutrality, promoting C retention and increasing soil fertility. Residue biochemistry and soil texture essentially determine SOC distribution (including CO2 mineralization and stock in soil) in farmland. However, less is known about allocation of residue-C with contrasting biochemistry and the fate of residue-C in soil under two different textures. This study was conducted in a 61-day aerobic incubation with two Black soils with distinct texture (clay loam vs. sandy loam) in Northeast China. Chemical composition of seven residue parts (soybean roots, leaves, and stems and maize roots, leaves and top and bottom stem parts) was characterized using solid-state 13C nuclear magnetic resonance spectroscopy. The results showed that leaves of both two crops contained significantly higher nitrogen (N), carbonyl and aryl concentrations and lower carbon (C) and lignin concentrations than other parts, resulted in faster decomposition in soils, especially in the clay loam. Stems contained higher O-alkyl and di-O-alkyl concentrations, C/N and lignin/N, while roots contained higher aromaticity. Maize top stem parts with larger slow C pool and longer half-life had higher contribution to SOC accumulation than other parts. Soil textures also induced great impact on SOC turnover. The clay loam favored SOC sequestration due to significantly longer half-life of slow C pool than the sandy loam. Generally, the alkyl/O-alkyl ratio showed the most significant correlation with SOC, CO2 emission and soil biochemical factors in the clay loam; whereas in sandy loam, the lignin/N was the pivotal indicator for SOC accumulation. This study provides insights into the differences in chemical composition among various residue parts, and highlights the significant effects of both residue chemical composition and soil texture on residue decomposition and SOC accumulation.
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Adams, Jason W., and Rodney G. Lym. "Quinclorac and Aminocyclopyrachlor Movement in Sandy Soils." Invasive Plant Science and Management 8, no. 3 (September 2015): 269–75. http://dx.doi.org/10.1614/ipsm-d-14-00070.1.
Повний текст джерелаАнотація:
AbstractThe Sheyenne National Grassland (SNG) is a native tall grass and mixed grass prairie located in southeastern North Dakota. Approximately half of the SNG has been invaded by leafy spurge (Euphorbia esulaL.) and control methods have been limited. Many herbicides cannot be utilized at the SNG due to sandy soils (> 80%) and shallow groundwater, nor can they be applied near the western prairie fringed orchid (Platanthera praeclaraSheviak and Bowles), a federally listed threatened plant found on the SNG. Quinclorac and aminocyclopyrachlor were considered for use on the SNG but potential to enter the groundwater was unclear. Movement of quinclorac and aminocyclopyrachlor was evaluated in 70 cm soil columns that simulated field conditions from five ecological sites. Quinclorac leached further following the heavy rainfall event of 15 cm in 48 h compared to the annual precipitation of 51 cm applied over 9 wk. Quinclorac leached approximately 45 cm into the soil profile averaged over all soil types and both precipitation events but never exceeded 65 cm regardless of soil type. Aminocyclopyrachlor leaching was greater than quinclorac and moved through all soil types into the leachate following both watering regimes. Desorption of both herbicides was incomplete. Approximately 10 and 32% of applied aminocyclopyrachlor and quinclorac, respectively, remained in the top 5 cm of soil regardless of soil type or watering regime. Quinclorac but not aminocyclopyrachlor was considered suitable for use at the SNG to control leafy spurge and has the added benefit of not harming the western prairie fringed orchid.
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Stanila, Anca-Luiza, Iulian Ratoi, Aurelia Diaconu, and Catalin Cristian Simota. "The Results Obtained on Production of Alfalfa on Sandy Soils of Field Dabuleni by Administration of Loess and Chemical Fertilizers." Revista de Chimie 71, no. 2 (March 3, 2020): 30–34. http://dx.doi.org/10.37358/rc.20.2.7887.
Повний текст джерелаАнотація:
Recovery sandy soils top was a major concern, sandy soil cultivation with the crop plants had the main goal need to increase the agricultural production. Sands in southern Oltenia offers less favorable conditions of plant life, which is why the range of cultivated plants is much lower than in other areas.Seed plants that require small and early seed (alfalfa) are affected by the negative effect of the wind, which blows away the sand particles, lesion rooted young plants or compromising their culture. On sandy soils in southern Oltenia (Field Dabuleni), forage crops help to improve physical, hydro-chemical properties, change the living conditions for plants, animals and humans, create an ecological balance that preserves the environment, partly destroyed by abolishing plantations of Robinia pseudocacia and leveling dunes relief for arranging irrigation.Among perennial leguminous pure culture, alfalfa is the most valuable forage plant feed all animal species, both for its output, especially for forage quality. Achieving quality parameters alfalfa is conditional, namely the establishment of the following technologies, namely: mowing standing of the optimal phenological stages of the plant, the establishment range of mowing or the number of harvest in a year.
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Kravets, Svyatoslav, Vladimir Suponyev, Valery Shevchenko, Alexander Yefymenko, and Vitaliy Ragulin. "Determination of the regularities of the soil punching process by the working body with the asymetric tip." Eastern-European Journal of Enterprise Technologies 2, no. 1 (110) (April 20, 2021): 44–51. http://dx.doi.org/10.15587/1729-4061.2021.230256.
Повний текст джерелаАнотація:
The presence of analytical dependencies describing the process of static soil puncture by a working body with a conical asymmetric tip is necessary to create installations with the ability to control the trajectory of the soil puncture. The paper considers the features of the process of interaction of an asymmetric conical tip with the ground. Analytical relationships were obtained to determine its reactions during a static puncture, the deviation of the head trajectory from a straight line, to determine the size of the soil compaction zone and the magnitude of the destructive force that acts on adjacent communications and other underground objects. It was found that with an increase in the value of the displacement of the top of the cone, for example, from its axis from 0.02 m to 0.08 m with a borehole diameter of 0.2 m, the value of soil resistance increases almost four times. The greatest resistance is achieved when piercing a hard sandy sand. It was found that with an increase in the displacement of the tip of the tip cone, the deviation of the trajectory increases. The piercing head achieves the greatest deviation from the straight trajectory of movement with a sharper cone and a greater asymmetric deviation of its top, and, for example, in hard sandy loam can be up to 0.17 m with a span of 10 m. It was found that the size of the soil destruction zone will be almost 1.8 times larger than the tip in the form of a symmetrical cone and reaches from 8 to 12 borehole diameters, depending on the type of soil. The maximum pressure on adjacent objects can reach from 0.06 MPa in hard-plastic clay to 0.09 MPa in hard sandy loam. The calculated dependences obtained for determining the power and technological parameters depending on the geometric dimensions of the asymmetric tip of the working body can be used to create installations with a controlled static puncture for use in the most common soil conditions.
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MAREI, A. S., H. R. SOLTAN, A. MOUSA, and A. KHAMIS. "Leaching and mobility of carbofuran from granular and alginate controlled release formulations." Journal of Agricultural Science 134, no. 4 (June 2000): 405–12. http://dx.doi.org/10.1017/s0021859699007741.
Повний текст джерелаАнотація:
Controlled release (CR) formulations can significantly influence the fate of carbofuran in the environment. The influence of three alginate-encapsulated CR formulations compared with the granular formulation (G10%) on the mobility of carbofuran in sandy clay loam soil and sandy loam soil was investigated. In flooded soil the leaching potential of the three alginate controlled release formulations tested was decreased more than nine times (not more than 3%) compared with the G10% (28%). Most of the released carbofuran was confined to the top 0–5 cm of the soil column followed by the second 5–10 cm layer and the least was found in the fourth section (15–20 cm). The data obtained for a sandy loam soil irrigated by drip irrigation showed that the greatest proportion of carbofuran leached through the columns was from the G10% (52%) compared with 3–4% from CR formulations over a 30-day period. The carbofuran concentrations found in different soil depths showed similar trends to those for the flooded soil. Based on the residue levels recorded within the 20 cm depth, the relative retention ratio of carbofuran in sandy clay loam versus sandy loam soil was 1·2[ratio ]1 for the controlled release formulations and 1·9[ratio ]1 for the G10%.
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Balah, Mohammed A., Sayed A. Dahroug, Zidane H. Zidan, and Abdel-Rahman Gamal Aldin. "Effect of some Additives on the hydrolysis, persistence and the downward Movement of Glyphosate and Fluazifop-butyl Herbicides." Al-Mukhtar Journal of Sciences 32, no. 2 (December 31, 2017): 102–10. http://dx.doi.org/10.54172/mjsc.v32i2.152.
Повний текст джерелаАнотація:
The first objective was to determine the effect of additives and water type on the degradation of glyphosate and fluazifop-butyl herbicides. Both glyphosate and fusillade were strongly hydrolysed in hard water more than Nile water and distilled water. Most additives were decreased glyphosate persistence in all types of water. Glyphosate plus glue was more persistent than glyphosate alone and when mixed with the following additives (urea, glycerine, dioleate, monoleate, paraffin and mineral oil), respectively. Fusilade alone was more persistent than its mixture with the additives rape seed oil, mineral oil, paraffin oil, dioleate and monoleate, respectively. The second objective was to deal with the effect of additives soil texture interactions on persistance and leaching of glyphosate and fluazifop-butyl herbicides. Persistence of glyphosate in clay soil was lower than in sandy soil. Most additives increased half life of glyphosate in clay soil, while glyphosate additive mixtures decreased its stability in sandy soil. Fluazifop-butyl was rapidly dissipated in clay soil more than the sandy soil. Whereas most of the used adjuvant decreased fluazifop-butyl half life in each soil. Glyphosate was not detected in the soil leachate of clay and sandy soil column. The majority of glyphosate and fluazifop-butyl amount was located in the top layer of soil column followed by fewer amounts in the successive layers. Whereas glyphosate and fluazifop-butyl could be transferred from the sub- surface to the following layer from sandy soil with some additives (surfactants) to the following layer. Meanwhile fusillade with surfactants was detected in sandy soil column leaching with non significant amount.
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Sorenson, Brent A., Donald L. Wyse, William C. Koskinen, Douglas D. Buhler, William E. Lueschen, and Michael D. Jorgenson. "Formation and Movement of14C-Atrazine Degradation Products in a Sandy Loam Soil Under Field Conditions." Weed Science 41, no. 2 (June 1993): 239–45. http://dx.doi.org/10.1017/s0043174500076128.
Повний текст джерелаАнотація:
Formation and distribution of14C-atrazine degradation products in the top 120 cm of soil were determined over 16 mo under field conditions in an Estherville sandy loam. After 16 mo, 78% of applied14C was still present in the soil. By 2 mo after treatment (MAT),14C had moved to the 30- to 40-cm depth; however, movement to depths greater than 40 cm was not observed. Greater than 98% of the14C remaining in the soil profile after 16 mo was in the top 20 cm. Twenty-seven percent of the14C applied was atrazine 16 MAT. Atrazine was the predominant14C-compound in soil below 10 cm. Hydroxyatrazine (HA) was the major degradation product in the top 10 cm of soil. The proportion of14C as HA in the top 10 cm increased from 15% 2 MAT to 37% 16 MAT. Deethylatrazine (DEA) was the predominant degradation product at the 10- to 30-cm depth and accounted for up to 23% of the14C present in the 10- to 20-cm depth. Deisopropylatrazine (DIA) accounted for less than 6% of the radioactivity recovered at any soil depth. The proportion of DEA and DIA increased while the proportion of HA decreased as soil depth increased, indicating that DEA and DIA are more mobile in soil than HA. Detection of HA at depths greater than 10 cm appears to be due to in situ degradation of atrazine previously moved to that soil depth. The large amount of14C remaining in the soil 16 MAT suggests that a large pool of atrazine and its degradation products are present in the soil for an extended period following application and have the potential to contaminate ground water.
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Lichner, L., T. Orfánus, K. Novákova, M. Šír, and M. Tesař. "The impact of vegetation on hydraulic conductivity of sandy soil." Soil and Water Research 2, No. 2 (January 7, 2008): 59–66. http://dx.doi.org/10.17221/2115-swr.
Повний текст джерелаАнотація:
The objective of this study was to assess the impact of vegetation on the hydraulic conductivity of sandy soil at the locality Mláky II at Sekule (southwest Slovakia). The measurements were taken on the surface of a meadow (Meadow site), a 30-year old Scots pine (Pinus sylvestris) forest (Forest site) and a glade (Glade site). In the glade, the measurements were also taken in the depth of 50 cm (Pure sand) to reduce the influence of vegetation on the soil properties. It was found that the unsaturated hydraulic conductivity k<sub>r</sub>(−2 cm) as reduced due to the soil water repellency increased in the same order: Forest soil < Glade soil ≈ Meadow soil < Pure sand, similarly as decreased the water drop penetration time t<sub>p</sub>: Forest soil > Glade soil ≈ Meadow soil > Pure sand, which could refer to an inverse proportionality between the capillary suction and hydrophobic coating of the soil particles. The saturated hydraulic conductivity K<sub>s</sub> increased in the following order: Meadow soil < Glade soil ≈ Forest soil < Pure sand; more than two-times higher K<sub>s</sub> at both the Forest and Glade sites than that at the Meadow site could be the result of both the patchy growth of vegetation with some areas of bare soil at the Glade site and the macropores (dead roots) in more homogeneous humic top-layer at the Forest site. The share B<sub>r</sub> of flux through the pores with radii r longer than approximately 0.5 mm decreased in the order: Forest soil » Meadow soil > Glade soil » Pure sand, revealing the prevalence of preferential flow through macropores (dead roots) in the Forest site and a negligible share of macropores in the Pure sand.
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Hassink, J., and J. J. Neeteson. "Effect of grassland management on the amounts of soil organic N and C." Netherlands Journal of Agricultural Science 39, no. 4 (December 1, 1991): 225–36. http://dx.doi.org/10.18174/njas.v39i4.16533.
Повний текст джерелаАнотація:
The effects of different management systems on soil organic N and C contents were studied on a sandy and loamy soil given various amounts of N fertilizers under rotational grazing, in the Netherlands. Differences in total soil N and C between grazed and mown fields were also investigated. On the loamy soil grazed plots N accumulated at 245 kg/ha per year, irrespective of the rate of applied N. Four years after the experiment was initiated both soil N and C contents were considerably higher under grazing than under mowing. The C/N ratio of soil organic matter was higher without N fertilizer application, especially in the top 5 cm. The amount of N returned to the soil by grazing was 71% and 57% in the sandy and the loamy soil, resp. (Abstract retrieved from CAB Abstracts by CABI’s permission)
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Cheng, Qi Yun, and Yong Gang Li. "Finite Element Analysis of the Soil Pressure in Sandy Soil at the Top of Pipe Culvert." Applied Mechanics and Materials 744-746 (March 2015): 1077–81. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1077.
Повний текст джерелаАнотація:
ANSYS is an engineering analysis software with a multiple analysis ability.It can be used to solve the structure, fluid, electric, electromagnetic fields and collision problems and so on.So it has been widely used in varied fields.Circular culvert is commonly used for water hydraulic structure in hydraulic engineering.The paper focuses on the study of culvert soil pressure at the top of the circle under the sand in the northern of China by using the Ansys finite element analysis software.Research shows that:When the elastic modulus and Poisson's ratio changes,the soil pressure distribution shape doesn’t obviously change;While the soil pressure and the relative height of precipitation have a certain relationship with the two indicators.
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Brennan, R. F., and M. D. A. Bolland. "Soil and tissue tests to predict the sulfur requirements of canola in south-western Australia." Australian Journal of Experimental Agriculture 46, no. 8 (2006): 1061. http://dx.doi.org/10.1071/ea04206.
Повний текст джерелаАнотація:
The sulfur (S) requirements of canola (Brassica napus L.) grown in rotation with spring wheat (Triticum aestivum L.) and lupin (Lupinus angustifolius L.) in south-western Australia are not known. This study, involving 59 experiments, was conducted from 1993 to 2003 to determine soil and tissue test values for canola grain production below which S deficiency is likely. Extraction of S from soil using 0.25 mol KCl/L at 40°C (KCl-40 procedure) for the top 10 cm of soil is the standard soil test for S in the region. We measured KCl-40 values for soil samples collected at soil depths of 0–10, 10–20 and 20–30 cm and related the values to canola grain yield responses to applied fertiliser S measured at the end of the growing season. Total S measured in dried shoots at about 90 days after sowing (DAS) was related to shoot yields at 90 DAS and grain yields. In addition, the concentration of oil in canola grain was measured to see if applications of S affected oil concentrations. Soil test S was higher in the subsoil than in the top 10 cm of soil at about half the sites comprising sandy duplex soils with larger capacities to sorb sulfate in the subsoil. Significant grain yield responses to applied S occurred for soil test values <7 mg/kg to 30 cm. At many sites when soil test S was <7 mg/kg in the top 10 cm of soil, shoots showed grain yield responses to applied S, but canola roots eventually accessed sufficient S in the subsoil for grain production, so that no grain yield responses to applied fertiliser S occurred. Therefore, tissue test values for dried shoots at 90 DAS poorly predicted S deficiency for grain production. Responses of shoots and grain to applied S occurred for S concentrations in shoots <4 g/kg. We conclude that shallow soil tests and early tissue testing may both overestimate the magnitude of an S deficiency for grain production of canola grown in sandy WA soils. Deeper soil tests need to be seriously considered. Applications of fertiliser S mostly had no consistent effect on concentrations of oil in canola grain.
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Mota, Jaedson Cláudio Anunciato, Carlos Eduardo Linhares Feitosa, Lucas de Sousa Oliveira, José Israel Pinheiro, Alfredo Mendonça de Sousa, Thiago Leite de Alencar, Márcio Godofrêdo Rocha Lobato, Alexandre dos Santos Queiroz, and Ícaro Vasconcelos do Nascimento. "Pipette Method: Errors Resulting From Aliquot Collection Depth in Soil Clay Quantification." Journal of Agricultural Science 11, no. 2 (January 15, 2019): 244. http://dx.doi.org/10.5539/jas.v11n2p244.
Повний текст джерелаАнотація:
Granulometry represents the relative proportions of the fractions that compose the soil, being an important agronomic tool to infer mean values of density, water availability and cation exchange capacity, besides being useful in soil classification. Among the methods employed to determine the fractions composing the soil, those which consider the separation by sedimentation for the clay fraction still have problems in the analytical protocol, which are directly responsible of errors in the results obtained. Given the above, this study aimed to evaluate the best pipette immersion depth to collect the aliquot containing only clay, to calculate and discuss the errors associated with collection of the aliquot containing clay fraction in soil granulometric analysis. Samples for granulometric analysis were collected in the superficial layer and top of the B horizon of an Argissolo Amarelo, corresponding to the textural classes sandy loam and sandy clay. Regardless of soil textural class, the depth h = 5 cm established in the calculation using the Stokes’s equation leads to overestimation and underestimation of clay and silt fractions in the soil. The collection should be performed with the pipette tip positioned at h/2 = 2.5 cm.
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Salgado, M., M. T. Collins, F. Salazar, J. Kruze, G. Bölske, R. Söderlund, R. Juste, et al. "Fate ofMycobacterium aviumsubsp.paratuberculosisafter Application of Contaminated Dairy Cattle Manure to Agricultural Soils." Applied and Environmental Microbiology 77, no. 6 (January 14, 2011): 2122–29. http://dx.doi.org/10.1128/aem.02103-10.
Повний текст джерелаАнотація:
ABSTRACTDetails regarding the fate ofMycobacterium aviumsubsp.paratuberculosis(basonym,Mycobacterium paratuberculosis) after manure application on grassland are unknown. To evaluate this, intact soil columns were collected in plastic pipes (lysimeters) and placed under controlled conditions to test the effect of a loamy or sandy soil composition and the amount of rainfall on the fate ofM. paratuberculosisapplied to the soil surface with manure slurry. The experiment was organized as a randomized design with two factors and three replicates.M. paratuberculosis-contaminated manure was spread on the top of the 90-cm soil columns. After weekly simulated rainfall applications, water drainage samples (leachates) were collected from the base of each lysimeter and cultured forM. paratuberculosisusing Bactec MGIT ParaTB medium and supplements. Grass was harvested, quantified, and tested from each lysimeter soil surface. The identity of all probableM. paratuberculosisisolates was confirmed by PCR for IS900and F57 genetic elements. There was a lag time of 2 months after each treatment beforeM. paratuberculosiswas found in leachates. The greatest proportions ofM. paratuberculosis-positive leachates were from sandy-soil lysimeters in the manure-treated group receiving the equivalent of 1,000 mm annual rainfall. Under the higher rainfall regimen (2,000 mm/year),M. paratuberculosiswas detected more often from lysimeters with loamy soil than sandy soil. Among all lysimeters,M. paratuberculosiswas detected more often in grass clippings than in lysimeter leachates. At the end of the trial, lysimeters were disassembled and soil cultured at different depths, and we found thatM. paratuberculosiswas recovered only from the uppermost levels of the soil columns in the treated group. Factors associated withM. paratuberculosispresence in leachates were soil type and soil pH (P< 0.05). ForM. paratuberculosispresence in grass clippings, only manure application showed a significant association (P< 0.05). From these findings we conclude that this pathogen tends to move slowly through soils (faster through sandy soil) and tends to remain on grass and in the upper layers of pasture soil, representing a clear infection hazard for grazing livestock and a potential for the contamination of runoff after heavy rains.
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Bob, Joel, and Patrick S. Michael. "Nutrient dynamics under unmanaged rubber, cocoa, and oil palm plantations in a sandy soil under humid lowland tropical climatic conditions." International Journal of Environment 11, no. 1 (June 20, 2022): 46–61. http://dx.doi.org/10.3126/ije.v11i1.45839.
Повний текст джерелаАнотація:
Changes in land use are an important issue in many farms that affect soil biological, chemical, and physical properties temporarily under cropping cycles or when the land is permanently allocated to perennial tree crops, e.g., in agroforestry. This study investigated the changes in sandy soil chemistry induced by three perennial tree crops (rubber, cocoa, and oil palm) growing in 30-year-old unmanaged and abandoned plantations and the surrounding grasslands dominated by cogon grass. A disruptive approach was used to collect soil samples from the top 60 cm under all the tree crops and in the grassland soils. A 500-gram sample of each soil originating from under each tree crop and the grassland were carefully packed into pre-labeled paper bags in triplicate (n=3) and sent to the laboratory for analysis of a selected number of primary and secondary macronutrients, micronutrients, and other soil parameters. The results showed N, K, Mg, Cu, Zn, and S were generally deficient in the sandy soil. A tree crop-specific soil organic matter, organic carbon, carbon stock contents, and water holding capacity measured were high under rubber and cocoa only. The variation in pH, electrical conductivity, bulk density, total porosity, and particle composition were generally similar except that the sand composition was lower in the soils under rubber and oil palm.
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Meda, Anderson R., Marcos A. Pavan, Marcelo E. Cassiolato, and Mário Miyazawa. "Dolomite lime’s reaction applied on the surface of a sandy soil of the Northwest Paraná, Brazil." Brazilian Archives of Biology and Technology 45, no. 2 (June 2002): 219–22. http://dx.doi.org/10.1590/s1516-89132002000200014.
Повний текст джерелаАнотація:
Low Ca and Mg are serious limitations to crop production in sandy soils of the northwest Paraná, Brazil. Thus soil samples of an Oxisol collected in this region were packed into 30cm long columns. Dolomite lime (2.0, 0.84, 0.30, and < 0.30 mm screen) was added on soil surface, then leached with deionized water. Thereafter, the columns were dismantled and the soil cut into 5cm segments for chemical analysis. Dolomite lime increased pHCaCl2,, KCl-exchangeable Ca and Mg and residual CO3 mostly in the top surface layers. Surface dolomite lime had no effect on pH, Ca, Mg, and CO3 in the leachate, independent on the lime particle size. These results indicated that surface dolomite lime application had no effect on subsoil composition and mostly of the calcium and magnesium carbonates are still unreacted on the soil surface.
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Mahi, Shuaibu, Abubakar Yusuf, and Garba Lawal. "Geoelectrical Assessment of Groundwater Potential within Zamfara and its Environs, Northwestern Nigeria." Caliphate Journal of Science and Technology 4, no. 1 (February 10, 2022): 54–70. http://dx.doi.org/10.4314/cajost.v4i1.8.
Повний текст джерелаАнотація:
Groundwater potential assessment was carried out within Zamfara environs, Northwestern Nigeria using geoelectrical technique with a view of solving the problem of incessant failure of boreholes in the study area. A total of one hundred and eighty-three (183) vertical electrical soundings (VES) were used to identify potential groundwater bearing zones capable of sustaining economic development of the study area. Two hydrogeological units were investigated (basement rock units and sedimentary rock unit), using Omega resistivity meter Model No. 122, to measure and record the resistance of the subsurface by Schlumberger configuration. The data obtained were interpreted quantitatively and qualitatively using the partial curve matching and computer iteration techniques to generate the first order geoelectric parameters. Generally, the VES result from the basement rock units revealed, four geoelectric layers which correspond to lateritic top soil, weathered basement (clay), partially fractured layer/fractured layer and fresh basement. The weathered/fractured layer was identified as the water bearing layer, within the basement rock units of the study area. From geospatial analysis of both weathered thickness/fracture thickness layers, South and Northeastern part tends to be the most prospective area with the best hydrogeologic conditions for borehole siting within the basement rock units. Consequently, three geo-electric layers were delineated from VES result obtained from Gundumi formation, which correspond to sandy clayey top/gravelly sandy top soil, second layer are mostly silty-clay/compacted sandstone/sandy gravel layers, the third layer were majorly saturated sandstone in some instances silty clay. However, the aquiferous layer is saturated sandstone/sandy gravel layer. The Dar Zarrouk result revealed excellent groundwater potential within the Gundumi formation. The values of coefficient anisotropy obtained from Gundumi rock units range from 0.44 to 3.79, which implies moderate saturation of groundwater. This is an indication that the aquifers of the Gundumi formation is more promising and it can be tap for both domestic and agricultural uses.
Keywords: Vertical electrical sounding; Fractured layer; Saturated Sandstone; Basement rock units; Gundumi formation
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Azooz, R. H., and M. A. Arshad. "Soil water drying and recharge rates as affected by tillage under continuous barley and barley-canola cropping systems in northwestern Canada." Canadian Journal of Soil Science 81, no. 1 (February 1, 2001): 45–52. http://dx.doi.org/10.4141/s00-029.
Повний текст джерелаАнотація:
In areas of the northwestern Canadian Prairies, barley and canola are grown in a short growing season with high rainfall variability. Excessively dry soil in conventional tillage (CT) in dry periods and excessively wet soil in no-tillage (NT) in wet periods could cause a significant decrease in crop production by influencing the availability of soil water. The effects of CT, NT and NT with a 7.5-cm residue-free strip on the planting rows (NTR) on soil water drying (–dW/dt) and recharge (dW/dt) rates were studied in 1992 and 1993 during wet and dry periods to evaluate the impact of NTR, NT and CT systems on soil moisture condition. The soils, Donnelly silt loam and Donnelly sandy loam (both Gray Luvisol) were selected and soil water content by depth was measured by time domain reflectometry. Water retained at 6 matric potentials from –5 to –160 kPa were observed. In the field study, –dW/dt was significantly greater in CT than in NT in the silt loam for the 0- to 30-cm layer during the first 34 d after planting in 1992. The 0- to 30-cm soil layer in CT and NTR dried faster than in NT during a period immediately following heavy rainfall in the silt loam in 1993. The drying coefficient (–Kd ) was significantly greater in CT and NTR than in NT in the silt loam soil in 1993 and in the sandy loam soil in 1992 in the top 30-cm depth. The recharge coefficient (Kr) was significantly greater in NT and NTR than in CT for the silt loam soil. The NTR system increased the –dW/dt by 1.2 × 10-2 to 12.1 × 10-2 cm d-1 in 1992 and 1993 in the silt loam soil and by 10.2 × 10-2 cm d-1 in 1993 in the sandy loam soil as compared with NT. The dW/dt was 8.1 × 10-2 cm d-1 greater in NTR in 1992 and 1993 in the silt loam soil and was 1.9 × 10-2 greater in NTR in 1992 than in CT in the sandy loam soil. The laboratory study indicated that NT soils retained more water than the CT soils. The NTR practice maintained better soil moisture conditions for crop growth than CT in dry periods than NT in wet periods. Compared with NT, the NTR avoided prolonged near-saturated soil conditions with increased soil drying rate under extremely wet soil. Key words: Water drying, water recharge, water depletion, wet and drying periods, hydraulic properties, soil capacity to retain water
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H. O., Nwankwoala, and Omemu S. O. "Baseline Monitoring of Elemental Contamination Levels in Soil Samples in Elebele Community, Bayelsa State, Nigeria." Engineering Management Research 8, no. 1 (April 30, 2019): 20. http://dx.doi.org/10.5539/emr.v8n1p20.
Повний текст джерелаАнотація:
This study evaluated the physico-chemical properties of the soil and water in Elebele Community in Ogbia Local Government Area of Bayelsa State, Nigeria. Standard sampling and analytical methods were employed. The predominant soils of the region are mainly sandy-loam and clayey-loamy. The soil physico-chemical properties were in good status as they were not toxic. Soil particle size distribution (sand silt and clay) was observed as follows: sand content ranged between 50.6%-86.2% with a mean of 64.5% at the surface soil while the subsurface soil ranged between 35%-80.2% with a mean of 60.2%. Silt on the other hand ranged between 7.8%-36% and a mean of 25.1% at the surface and ranged between 12.8-49.6% and mean of 25.4% at the subsurface while clay ranged between 3.4%-16% and mean of 9.4% at the surface and also ranged between 7%-16% and mean value of the soil. However, the soil physical properties were relativity good for sustainability. Also, the metals studied were detected in all the sites. Generally the concentrations of the metals were highest at the top soils. This is expected since the top soil is the point of contact. The metal levels in all the sites were significantly higher than the levels observed in the control sites. Sources of heavy metals in soils like inorganic fertilizers and pesticides need to be controlled.
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Lu, Chih Wei, Meen Wah Gui, and Bing Yang Chang. "Numerical Analysis for Earth Structure Sitting on Liquefiable Soils in Roller Boundary." Advanced Materials Research 287-290 (July 2011): 1911–14. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1911.
Повний текст джерелаАнотація:
In this paper, the authors predict responses of an earth structure due to a dynamic vibration using a 3-dimensional soil-water coupled dynamic analysis. The earth structure sitting on three types of ground which are consisted of liquefiable and un-liquefiable layers is found to settle the most in the ground of which the loose sandy layer is at the top. It shows the most dam settlement occurs in the ground type of which the loose sandy layer is at the bottom. A relative better seismic stability of the earth structure is found to sit on the ground of which the loose sandy layers underlie in the middle.
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Abd El-Azeim, Mohieyeddin M., Ahmad M. Menesi, Mahmoud M. Abd El-Mageed, Joanna Lemanowicz, and Samir A. Haddad. "Wheat Crop Yield and Changes in Soil Biological and Heavy Metals Status in a Sandy Soil Amended with Biochar and Irrigated with Drainage Water." Agriculture 12, no. 10 (October 19, 2022): 1723. http://dx.doi.org/10.3390/agriculture12101723.
Повний текст джерелаАнотація:
The current research aims to study the impacts of adding corncob biochar to a sandy soil irrigated with drainage water on wheat productivity, heavy metals fate, and some soil properties that reflect healthy soil conditions. This research consists of two separate experiments under field (lysimeters) and pot incubation conditions conducted on sandy soil irrigated with drainage water and treated with corncob biochar at the rate of 0.0, 1, 2, and 3% as mixing or mulching. Results specified that drainage water electrical conductivity value (5.89 dS m−1) lies under the degree of restriction on use of “Severe”, indicating that nonstop irrigation with such drainage water may cause a severe salinity problem in soil in the long run. A comparison of heavy metal concentrations of biochar-treated soils with the control showed that total heavy metals had accumulated significantly in the topsoil layer. Most of the available heavy metal concentrations in all soil leachate fractions were below the method detection limits. Mean concentrations of Ni, Cd, and Pb in wheat crops were far below the concentrations considered phytotoxic to wheat plants. More than 90% of the Ni, Cd, and Pb contained in the drainage water of the Al-Moheet drain were significantly present (p ≤ 0.05) and adsorbed by biochar in the top 20 cm of soil lysimeters, indicating the high biochar adsorptive capacity of heavy metals. Total counts of bacteria and fungi gradually and significantly increased over the soil incubation time despite irrigation with contaminated drainage water. Soil resistance index (SRI) values for microbial biomass were positive throughout the experiment and increased significantly as the application rate of corncob biochar increased. These results indicated the high feasibility of using corncob biochar at a rate of 3% to temporarily improve the health of sandy soil despite irrigation with drainage water.
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Sutanto, Anthonius Steven, Paulus Pramono Rahardjo, and Aswin Lim. "Influence of Pre-Stressing on Tieback Retaining Wall for Sandy Soils Excavations." Journal of the Civil Engineering Forum 7, no. 3 (August 31, 2021): 253. http://dx.doi.org/10.22146/jcef.61564.
Повний текст джерелаАнотація:
Pre-stressed ground anchor systems or tieback systems are commonly used at wide and irregular-shaped excavations, with the advantage of lower cost and ease of construction compared to the braced excavations, but they come with the drawback on permits for excavations near buildings and tunnels. Research on tieback systems in sands was generally conducted. However, the studies on the correlation between the retaining wall deflection and pre-stress force are few. The objectives of this paper are to study the influence of pre-stress force, depth of excavation, wall embedment length, and soil shear strength that is represented by soil friction angle on the deflection and soil pressure acting on the retaining wall. The parametric study was conducted on an excavation in sand using the finite element method with the Hardening soil model. The results showed that a 50 kN/m increase in pre-stress force reduced the wall deflection on top of the wall by 0.005–0.083% of excavation depth. However, the pre-stressing influence in reducing wall deflection at excavations became less significant along with the sand density increase due to higher friction angle contribution to excavation stability. Moreover, the pre-stress force needed for stabilization of the wall with long embedment length is smaller than those on the wall with shorter embedment length, since the embedment length increase of 0.25 times of excavation depth reduces wall top deflection by 0.002–0.095% of excavation depth. Also, the increase of soil density reduces the need for wall embedment length, so at dense sand, the embedment length of 0.5 times of excavation depth is sufficient to support the excavation.
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Brennan, R. F., and M. D. A. Bolland. "Soil and tissue tests to predict the potassium requirements of canola in south-western Australia." Australian Journal of Experimental Agriculture 46, no. 5 (2006): 675. http://dx.doi.org/10.1071/ea04218.
Повний текст джерелаАнотація:
The predominantly sandy soils of south-western Australia have become potassium (K) deficient for spring wheat (Triticum aestivum L.) production due to the removal of K from soil in grain and hay. The K requirements of canola (rape, Brassica napus L.) grown in rotation with wheat on these soils are not known and were determined in the study reported here. Seed (grain) yield increases (responses) of canola to applications of fertiliser K occurred at sites where Colwell soil test K values (top 10 cm of soil) were <60 mg/kg soil. Grain yield responses to applied K occurred when concentrations of K in dried shoots were <45 g/kg for young plants 7 and 10 weeks after sowing and <35 g/kg for 18 weeks after sowing. Application of fertiliser K had no significant effects on either oil or K concentrations in grain.
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M, CHANDRAKALA. "Soil heterogeneity: A comparative assessment of soils from two different AESR, southern India." Annals of Plant and Soil Research 24, no. 1 (February 1, 2022): 29–33. http://dx.doi.org/10.47815/apsr.2021.10119.
Повний текст джерелаАнотація:
A comparative study was carried out to assess the nature and characteristics of soils from two agro-ecological sub regions (AESU and AESR) from two states of South India. Using sentinel-2 satellite data, google imagery and top sheet, a detailed soil survey was taken up in AESU and AESR. Major soils from upland as well as from lowlands were compared to assess the soils heterogeneity. Results showed that there was a high heterogeneity between properties of soils AESU and AESR. Variability existed in climatic conditions (tropical humid region in AESU and semiarid condition in AESR), physiographic (valley plain to gently, very gently, moderate, steep and very steep slopes in AESU and levelled to gently and very gently slopes in AESR ), geology (charnockite and granite gneiss in AESU whereas granite gneiss in AESR), land use (rubber, paddy, coconut in AESU and paddy, mango, pigeon pea, groundnut in AESR), soil classification (Ultisols and Alfisols in AESU whereas Alfisols and Inceptisols in AESR) and land capability (soil and water conservation measures must in AESU and slope was manageable with agronomic management practices in AESR). Soils varied in texture (clay, sandy clay and clay loam in AESU whereas sandy clay loam to sandy loam in AESR), consistency and depth of soils (shallow to very deep in AESU and shallow to deep in AESR). Clay content (32.9 to 63.5%) was dominant fraction in AESU whereas sand (52.1 to 72.1%) was in AESR. Soil acidity (strongly acid to very strongly acid) was a major problem (both hydrogen and aluminium saturation) in AESU whereas slightly acidic to neutral and slightly alkaline in AESR. Organic carbon content was high (up to 25.9 gkg-1) in AESU whereas it was up to 10.0 gkg-1 in AESR. Base saturation was <35% in AESU and >75% up to 100% in AESR. Calcium carbonate equivalent is >5% in AESR and not a problem in AESU. CEC was low (<12 cmol (p+) kg–1) in AESU and good (>12 cmol (p +) kg–1) in AESR.
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M, *CHANDRAKALA. "Soil heterogeneity: A comparative assessment of soils from two different AESR, southern India." ANNALS OF PLANT AND SOIL RESEARCH 24, no. 1 (February 1, 2022): 29–35. http://dx.doi.org/10.47815/apsr.2022.10119.
Повний текст джерелаАнотація:
A comparative study was carried out to assess the nature and characteristics of soils from two agro-ecological sub regions (AESU and AESR) from two states of South India. Using sentinel-2 satellite data, google imagery and top sheet, a detailed soil survey was taken up in AESU and AESR. Major soils from upland as well as from lowlands were compared to assess the soils heterogeneity. Results showed that there was a high heterogeneity between properties of soils AESU and AESR. Variability existed in climatic conditions (tropical humid region in AESU and semiarid condition in AESR), physiographic (valley plain to gently, very gently, moderate, steep and very steep slopes in AESU and levelled to gently and very gently slopes in AESR ), geology (charnockite and granite gneiss in AESU whereas granite gneiss in AESR), land use (rubber, paddy, coconut in AESU and paddy, mango, pigeon pea, groundnut in AESR), soil classification (Ultisols and Alfisols in AESU whereas Alfisols and Inceptisols in AESR) and land capability (soil and water conservation measures must in AESU and slope was manageable with agronomic management practices in AESR). Soils varied in texture (clay, sandy clay and clay loam in AESU whereas sandy clay loam to sandy loam in AESR), consistency and depth of soils (shallow to very deep in AESU and shallow to deep in AESR). Clay content (32.9 to 63.5%) was dominant fraction in AESU whereas sand (52.1 to 72.1%) was in AESR. Soil acidity (strongly acid to very strongly acid) was a major problem (both hydrogen and aluminium saturation) in AESU whereas slightly acidic to neutral and slightly alkaline in AESR. Organic carbon content was high (up to 25.9 gkg-1) in AESU whereas it was up to 10.0 gkg-1 in AESR. Base saturation was <35% in AESU and >75% up to 100% in AESR. Calcium carbonate equivalent is >5% in AESR and not a problem in AESU. CEC was low (<12 cmol (p+) kg–1) in AESU and good (>12 cmol (p +) kg–1) in AESR.
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Summers, RN, NR Guise, DD Smirk, and KJ Summers. "Bauxite residue (red mud) improves pasture growth on sandy soils in Western Australia." Soil Research 34, no. 4 (1996): 569. http://dx.doi.org/10.1071/sr9960569.
Повний текст джерелаАнотація:
Red mud is a finely crushed, iron-rich, alkaline residue, obtained by digesting bauxite with caustic soda to remove the alumina. The remnant alkalinity of red mud is equivalent to 11% pure calcium carbonate. Phosphorus leaching from infertile sandy soils has resulted in eutrophication of estuaries and has caused algal blooms. Red mud has been shown to reduce leaching of phosphorus from sandy soil. This research was undertaken to determine the effect of red mud on pasture growth and uptake of heavy metals. Red mud, either untreated or treated with gypsum, was applied at rates of 0, 10, 20, 40, and 80 t/ha to a subterranean clover and ryegrass hay paddock. There were 3 replicates of each treatment and a completely randomised design was used. The experimental design was 5 rates of red mud x 2 untreated and treated with gypsum x 3 replicates, resulting in 30 plots. Plant growth, and nutrient and heavy metal composition of the plant tops, were measured. An application of 40 t/ha of red mud increased hay (mainly subterranean clover and ryegrass) production by 24% and increased soil pH in the top 10 cm by 1.0 unit from 3.5 (1 : 5 soil : 0.1 M CaCl2). The increase in production was probably because of the liming effect of the remnant alkali in the red mud, which may have potential as a replacement for crushed limestone. Sodium carbonate, the predominant alkali in red mud, is more soluble than calcium carbonate from crushed limestone and has the potential to change the pH of the soil more rapidly. The soil was top-dressed with red mud, without disturbing the existing pasture, resulting in changes to the pasture production and nutrient composition consistent with a change in soil pH throughout the rooting depth. If crushed limestone is not mixed into the soil it may take many years to increase the pH of the soil; however, this mixing results in extra cost from re-seeding and an initial depression in yield. Although much more red mud is needed than lime, the cost is comparable when the haulage distance is less than about 30 km. In previous trials, at red mud application rates > 500 t/ha, gypsum was mixed into the red mud to reduce salinity and pH. At these rates, the red mud had overwhelmed the buffering capacity of the soil. The gypsum reduced the pH by changing the sodium carbonate in the red mud to calcium carbonate, thus changing the pH from > 10 to about 8.5. However, amendment of the red mud with gypsum when applied at rates < 80 t/ha proved unnecessary in this experiment, probably because the proportion of soil was sufficient to alter the pH of the red mud. When red mud is applied to acidic infertile sands, manganese application as manganese sulfate may be necessary, because the rise in pH may rapidly induce manganese deficiency in plants. Care should be taken to monitor other nutrients which have their availability for plants affected by pH (e.g. copper, zinc, and molybdenum). Red mud did not elevate the concentrations of heavy metals in the soil, hay, or fresh plant tissue.
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Ziyara, Hayder M., and Bushra S. Albusoda. "Experimental and numerical study of the bulb's location effect on the behavior of under-reamed pile in expansive soil." Journal of the Mechanical Behavior of Materials 31, no. 1 (January 1, 2022): 90–97. http://dx.doi.org/10.1515/jmbm-2022-0010.
Повний текст джерелаАнотація:
Abstract In this experimental and numerical analysis, three varieties of under-reamed piles comprising one bulb were used. The location of the bulb changes from pile to pile, as it is found at the bottom, center, and top of the pile, respectively. PLAXES 3D was used to conduct the research. In expansive soil, the under-reamed piles were 350 mm long, with the pile tip in dense sandy soil. The experiment was carried out in both saturated and unsaturated circumstances. The influence of the bulb location on the pile's bearing capacity for vertical and lateral loads, as well as the amount of swelling pressure and upward movement owing to swelling, was investigated. The results showed that in the unsaturated state, the bulb at the top of the pile gives bearing that is higher than the bulb at the bottom of the pile and near to the bulb in the center. In the case of unsaturated soil, the closer the bulb is to the top, the larger the bearing capacity, whereas in the event of swelling, the bearing capacity is highest when the bulb is in the middle of the pile. The same is true of the pile's upward movement, which is greater when the bulb is at the top than when it is at the bottom.
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Stupenko, O., P. Vytrykhovs’kyy, and V. Hirnyk. "137Cs accumulation in the yield of agricultural crops depending on the impact of agrochemical factors." Agroecological journal, no. 1 (March 17, 2016): 140–45. http://dx.doi.org/10.33730/2077-4893.1.2016.248211.
Повний текст джерелаАнотація:
We summarized the results of long-term research of fertili zing system and chemical melioration on radio cesium transition info yield of agricultural crops. The effect of such heavy fertilizer elements as magnesium and sulfur, participating in the nitrogen, phosphoric and carbohydrate metabolism in plants, on the crop formation and quality is studied. The influence of liming, level of providing soil with phosphorus and potassium, doses of nitrogen fertilizers in top-dressing, on buildup of radionuclide in crop yields is shown. The influence of the complex nitrogen-free fertilizer «Ekoplant» and its inclusion doses on the straw flax crop is defined. It has been shown the possibility of using the angustifolins lupine on sod-podzolic sandy soils with 10 Ci/km2 radio cesium contamination. It has been shown the dependence of radionuclide accumulation on perennial grasses hay harvest that were grown on sod-podzolic sandy soils of Polissia with 10 Ci/km2 radio cesium contamination.
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Jongmans, A. G., and R. Miedema. "Geogenesis and pedogenesis of well drained brown soils on the youngest Late Weichselian Meuse terrace in North Limburg, Netherlands." Netherlands Journal of Agricultural Science 34, no. 1 (February 1, 1986): 91–102. http://dx.doi.org/10.18174/njas.v34i1.16819.
Повний текст джерелаАнотація:
The Meuse terraces of Late Weichselian and Holocene age can be subdivided into 4 levels. The youngest Late Weichselian terrace occurs partly along and close to the present-day Meuse. On recent soil maps the well drained brown soils, occupying the highest positions of this terrace level, have been indicated as Plaggepts. This implies the presence of a plaggen epipedon of more than 50 cm thick. Three characteristic soil profiles were studied macromorphologically and micromorphologically and samples were analysed for particle size distribution and selected chemical properties. It is concluded that the brown top-soils are due to periodic Holocene sedimentation followed by homogenization. The sandy loam and finer-textured Late Weichselian subsoils have a clear argillic horizon. These soils should be classified as Alfisols (Luvisols) rather than Plaggepts. (Abstract retrieved from CAB Abstracts by CABI’s permission)
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Wang, Huanyuan, Wei Tong, Jinbao Liu, Jichang Han, and Siqi Liu. "Soil wind erosion resistance analysis for soft rock and sand compound soil: A case study for the Mu Us Sandy Land, China." Open Geosciences 14, no. 1 (January 1, 2022): 824–32. http://dx.doi.org/10.1515/geo-2022-0390.
Повний текст джерелаАнотація:
Abstract Mixtures of soft rock and sand have been applied extensively in the Mu Us Sandy Land (MUSL, also known as the Mu Us Desert) to limit the loss of top soil by wind erosion. In this study, the efficacy of sand-fixing technology was investigated in a series of experiments. The sand-fixing effect of seven different mixtures (ratios) on soft rock and sand was evaluated in a wind tunnel. The results indicated that the MUSL soils are susceptible to wind erosion, as the textural composition of sand is dominated by coarse particles. MUSL soils dominated by silt and clay particle sizes are more resistant to wind erosion. Each soft rock and sand combination experiences severe wind erosion. However, wind erosion was significantly reduced when soft rock and sand were mixed. An increase in particle size was associated with an increase in the resistance of soft rock and sand mixtures to wind erosion. The ability to resist wind erosion was greatest when the ratio of soft rock and sand was between 1:2 and 1:5. This study provided data to support the approaches to sand-fixing commonly used at present in the MUSL. The results of this study have important practical significance for the improvement of agricultural land potential in dry sandy areas.
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Lewis, DC, AL Clarke, and WB Hall. "Accumulation of plant nutrients and changes in soil properties of sandy soils under fertilized pasture in southeastern South-Australia .II. Total sulfur and nitrogen, organic carbon and pH." Soil Research 25, no. 2 (1987): 203. http://dx.doi.org/10.1071/sr9870203.
Повний текст джерелаАнотація:
The accumulation of total sulfur in sand over clay soils growing improved pastures was measured in three areas of the south-east of South Australia. Accumulation rates in the top 10 cm of soil ranged from 4.6 to 6.3 kg ha-1 yr-1 and in the 10-30 cm layer from 1.3 to 3.7 kg ha-1 yr-1. Assuming all of this sulfur came from applied single superphosphate, the recoveries of applied sulfur in the sand layer were 42, 63 and 57% for the Hundreds of Coles, Willalooka and Senior respectively. Using a 'balance sheet' approach, the calculated annual maintenance superphosphate rates, that will supply sufficient sulfur, ranged from 110 to 250 kg ha-1. Total soil nitrogen accumulation rates were 55, 48 and 37 kg ha-1 yr-1 for the Hundreds of Coles, Willalooka and Senior respectively. The enhanced nitrogen accretion in Coles was attributed to improved legume production resulting from both increased superphosphate dressings and higher average annual rainfall in that area. Organic carbon levels were highly correlated with pasture age, with increases in the top 10 cm of soil ranging from 0.022% to 0.034% per year. Soil pH was highly correlated with pasture age, with decreases as large as 0.036 units per year in the top 10 cm and 0.025 units per year in the 10-30 cm layer measured in the Hundred of Willalooka.
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NEMEATA ALLA, H. E. A., and S. A. M. HELMY. "RESPONSE OF SUGAR BEET TO SANDY SOIL AMENDED BY ZEOLITE AND POTASSIUM SULFATE FERTILIZATION." SABRAO Journal of Breeding and Genetics 54, no. 2 (June 30, 2022): 447–57. http://dx.doi.org/10.54910/sabrao2022.54.2.20.
Повний текст джерелаАнотація:
Two field experiments were carried out on a private farm at Wadi El-Natrun (latitude of 30.48° N and longitude of 30.50° E), Beheira Governorate, Egypt, in the 2019–2020 and 2020–2021 seasons, to find out the effect of adding zeolite as a soil conditioner and potassium fertilizer on growth, yield, and quality of sugar beet crop (Beta vulgaris L. var. saccharifera) grown in sandy soil conditions. The present work included 12 treatments, which were the combinations of four zeolite levels (Zero, 476, 952, and 1,428 kg ha-1), and three levels of potassium in the form of potassium sulfate (119, 178.5, and 238 kg K2SO4 ha-1), which were added as a soil application. The treatments were arranged in a complete block design in a split plot with four replications. The results showed that higher values of the photosynthetic pigments, root diameter, fresh and foliage weights plant-1, as well as, sucrose and extracted sugar percentages, quality index, yields of the root, top, and sugar ha-1, were obtained by adding 1,428 kg zeolite, compared with the other levels of zeolite, in both seasons. However, sodium, alpha-amino N contents in the root, and sugar lost to molasses% were insignificantly affected by zeolite rates in both seasons. Application of 238 kg K2SO4 ha-1 significantly resulted in the highest values of photosynthetic pigments, root dimensions, sucrose%, and root potassium content. In addition, extracted sugar %, quality index, root, top, and sugar yields ha-1 were increased compared with the other lower K-sulphate levels in both seasons. On the contrary, sugar lost to molasses% was insignificantly affected by applied potassium sulfate in both seasons. The maximum values of root diameter, fresh weight, yields of root and top ha-1 in both seasons, and also sugar yield in the second season were produced from the interaction between applying 1,428 kg zeolite and 238 kg potassium sulfate ha1.
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Song, Lining, Jiaojun Zhu, Jinxin Zhang, Ting Zhang, Kai Wang, Guochen Wang, and Jianhua Liu. "Effect of Drought and Topographic Position on Depth of Soil Water Extraction of Pinus sylvestris L. var. mongolica Litv. Trees in a Semiarid Sandy Region, Northeast China." Forests 10, no. 5 (April 28, 2019): 370. http://dx.doi.org/10.3390/f10050370.
Повний текст джерелаАнотація:
Drought and topographic position are the most important factors influencing tree growth and survival in semiarid sandy regions of Northeast China. However, little is known about how trees respond to drought in combination with topographic position by modifying the depth of soil water extraction. Therefore, we identified water sources for 33-year-old Mongolian pine (Pinus sylvestris L. var. mongolica Litv.) trees growing at the top and bottom of sand dunes by comparing stable isotopes δ2H and δ18O in twig xylem water, soil water at various depths and groundwater during dry and wet periods. Needle carbon isotope composition (δ13C) was simultaneously measured to assess water use efficiency. Results showed that when soil moisture was low during the dry period, trees at the top used 40–300 cm soil water while trees at the bottom utilized both 40–300 cm soil water and possibly groundwater. Nevertheless, when soil moisture at 0–100 cm depth was higher during the wet period, it was the dominant water sources for trees at both the top and bottom. Moreover, needle δ13C in the dry period were significantly higher than those in the wet period. These findings suggested that trees at both the top and bottom adjust water uptake towards deeper water sources and improve their water use efficiency under drought condition. Additionally, during the dry period, trees at the top used shallower water sources compared with trees at the bottom, in combination with significantly higher needle δ13C, indicating that trees at the bottom applied a relatively more prodigal use of water by taking up deeper water (possibly groundwater) during drought conditions. Therefore, Mongolian pine trees at the top were more susceptible to suffer dieback under extreme dry years because of shallower soil water uptake and increased water restrictions. Nevertheless, a sharp decline in the groundwater level under extreme dry years had a strong negative impact on the growth and survival of Mongolian pine trees at the bottom due to their utilization of deeper water sources (possibly groundwater).
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Horowitz, Menashe, and Clyde L. Elmore. "Leaching of Oxyfluorfen in Container Media." Weed Technology 5, no. 1 (March 1991): 175–80. http://dx.doi.org/10.1017/s0890037x00033479.
Повний текст джерелаАнотація:
Bentgrass was used to bioassay oxyfluorfen in leaching experiments done in columns of soilless potting media and soils, with herbicide incorporated into the upper 2 to 4 cm. Depth of herbicide leaching increased in order in the following soils: peat and sand (1:1) mix, Stockton clay soil, Yolo fine sandy loam soil, and redwood bark and sand (3:1) mix. Depth of leaching was not related to soil organic matter content. Equilibration experiments showed that peat adsorbed 4 to 5 times more oxyfluorfen than redwood bark. Less leaching was observed in potting mixtures containing peat than bark. Raising the oxyfluorfen dose from 20 to 200 ppmw increased the depth of leaching and concentration of herbicide in the leachate, while a 10-fold increase in water volume had only a limited effect. Twenty ppmw of oxyfluorfen incorporated in the top of a peat-containing potting medium has a low risk of leaching out of the container.
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Bolland, M. D. A., D. G. Allen, and Z. Rengel. "Response of annual pastures to applications of limestone in the high rainfall areas of south-western Australia." Australian Journal of Experimental Agriculture 42, no. 7 (2002): 925. http://dx.doi.org/10.1071/ea01169.
Повний текст джерелаАнотація:
The yield response of long-term pastures growing on acidified soil to applications of limestone (0, 2.5, 5.0, 7.5 and 10.0 t/ha with adequate magnesium fertiliser, and 0 and 5 t/ha with no magnesium fertiliser) was measured in 5 field experiments on different representative soils of the high rainfall areas of south-western Australia. After application, limestone was incorporated 1 cm deep in 3 experiments, 3 cm deep in 1 experiment, and 7 cm in another experiment. The pastures comprised subterranean clover (Trifolium subterraneum), and annual and Italian ryegrass (Lolium rigidum and L. multiflorum), the dominant species found in intensively grazed dairy and beef pastures of the region. Yields were measured when ryegrass plants had 3 leaves per tiller, which is when pastures in the region are grazed to maximise utilisation by cattle.Subsoil acidity was a problem at 4 of the 5 sites, and was so severe at 1 site that, despite having the lowest soil pH to 50 cm depth, there was no yield response to limestone incorporated to 3 cm deep. Applications of fertiliser magnesium had no significant effect on pasture production, soil pH, aluminium and manganese, or concentration of magnesium in dried herbage in any of the 5 experiments. Increasing amounts of limestone consistently: (i) increased soil pH, by between 1–2 pH units in the top 5 cm of soil, and 0.5–1.0 of a pH unit in the 5–10 cm soil profile; and (ii) decreased, by up to 84–98%, the amount of exchangeable aluminium in the 0–5 and 5–10 cm soil profiles. During 3 years (1998–2000) there were: (i) no yield responses to limestone for a total of 9 assessments on a sand, or 11 assessments on a sandy gravel; (ii) 2 significant (P<0.05) yield responses to limestone, from a total of 8 assessments on a loamy clay and from 9 assessments on a loam; (iii) 9 significant yield responses from a total of 13 assessments on a sandy loam (2 from 5 assessments in 1998, 3 from 4 assessments in 1999, and all 4 assessments in 2000). The sandy loam had the largest amount of exchangeable aluminium in the top 5 cm of soil [about 1.6 cmol(+)/kg, accounting for 35% of the exchangeable cations]. Increasing limestone applications did not induce deficiency or toxicity of any nutrient elements in subterranean clover or ryegrass dried herbage and, for dried herbage of bulk samples of both species, had no effect on dry matter digestibility, metabolisable energy and concentration of crude protein.
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Reynolds, W. Daniel, Craig F. Drury, Gary W. Parkin, John D. Lauzon, Joseph K. Saso, Tiequan Zhang, Kui Liu, et al. "Solute dynamics and the Ontario nitrogen index: I. Chloride leaching." Canadian Journal of Soil Science 96, no. 2 (June 1, 2016): 105–21. http://dx.doi.org/10.1139/cjss-2015-0069.
Повний текст джерелаАнотація:
The nitrogen (N) index for humid temperate southern Ontario, Canada (Ontario N index) incorporates previous and current crop type, fertilizer and (or) manure management, and hydrologic soil group (HSG) to estimate risk for contamination of tile drainage water and groundwater by nitrate leached below the primary crop root zone (top 60 cm of soil). The Ontario N index has received limited ground-truthing, and the leaching component was assessed using chloride tracer (ClTR) on five soils (one sandy loam, two loams, and two clay loams) representing four HSG-based risk levels (HSG-A, high risk; HSG-B, medium risk; HSG-C, low risk; HSG-D, very low risk). A square-wave pulse of ClTR was applied to the soil surfaces in fall 2007 as KCl, and movement and loss of ClTR was tracked over 1–1.2 years using monthly soil core samples collected from the top 60–80 cm. For all five soils, 60–96% of ClTR was leached out of the primary crop root zone (below 60 cm depth) during the noncropping period (October 2007 to March 2008 inclusive), and >80% was leached out of the root zone within 1 year. The percentage of ClTR that leached did not correlate with precipitation or HSG designation, but produced significant (P < 0.05) power function regressions with minimum and harmonic mean saturated soil hydraulic conductivity (Ksat) measured in the top 50–60 cm. ClTR leaching rate appeared to be controlled primarily by Ksat in a manner consistent with infiltration and solute transport theory. It was consequently proposed that solute leaching loss versus Ksat relationships may improve N index risk estimates for both southern Ontario and other humid temperate regions.
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Abd-Elaty, Ismail, Lorenzo Pugliese, Martina Zelenakova, Peter Mesaros, and Abdelaziz El Shinawi. "Simulation-Based Solutions Reducing Soil and Groundwater Contamination from Fertilizers in Arid and Semi-Arid Regions: Case Study the Eastern Nile Delta, Egypt." International Journal of Environmental Research and Public Health 17, no. 24 (December 15, 2020): 9373. http://dx.doi.org/10.3390/ijerph17249373.
Повний текст джерелаАнотація:
Intensive agriculture requires increasing application of fertilizers in order to sustain food production. Improper use of these substances in combination with increasing seawater intrusion results in long-term and nonpoint soil and groundwater contamination. In this work, a 3-D groundwater and solute transport numerical model was created to simulate the effect of excessive fertilizers application along the Bahr El Baqar drain system, in the eastern Nile Delta, Egypt. The geotechnical properties of the soils, hydrologic parameters, and unconfined compressive strength were determined at different sites and used as input parameters for the model. Model results showed that silty clay soils are able to contain the contaminations and preserve the groundwater quality. Nevertheless, sandy soils primarily located at the beginning of the Bahr El Baqar drain allow leakage of fertilizers to the groundwater. Thus, fertilizer application should be properly managed in the top sandy layers to protect the groundwater and soil, as increasing aquifer by excess irrigation water increased the groundwater contamination in confined layers due to the high value of cumulative salt for the current situation while the unconfined zone decreased groundwater and soil contamination. A mass transport 3-D multi-species (MT3D) model was set to identify the optimal measure to tackle soil and groundwater contamination along the Bahr El-Baqar drain system. A potential increase of the abstraction rates in the study area has a positive impact in reducing the transfer of fertilizer contamination to groundwater while it has a negative impact for soil contamination. The scenario analysis further indicated that the installation of a drainage network decreases the groundwater and soil contamination. Both solutions are potentially effective for protection against nonpoint contamination along the Bahr El Baqar drain system. However, a more sustainable management approach of fertilizer application is needed to adequately protect the receptors located further downstream in the Nile Delta.
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Chae, Joon, Seok Tae Park, Ji Hyun Cho, and Chan Hee Lee. "Interpretation of Construction Procedure and Physicochemical Characteristics for Soil Layers from Sowangneung (Small Royal Tomb) of Ssangneung (Twin Tombs) in Iksan, Korea." Journal of Conservation Science 37, no. 6 (December 31, 2021): 748–66. http://dx.doi.org/10.12654/jcs.2021.37.6.13.
Повний текст джерелаАнотація:
The Iksan Ssangneung (twin tombs), a pair of tombs comprising the Daewangneung (large royal tomb) and the Sowangneung (small royal tomb), were constructed in the typical style of stone tunnel and chamber tombs in the Baekje Kingdom during the Sabi period (538 to 660 AD) of ancient Korea. Soil layers exposed during excavation of Sowangneung in a trench east of the tomb are: the bottommost layer, the ground level layer, the Panchuk (rammed earth) layer of the Baekje, the layer created by a grave robbery, and soil recovered during the Japanese colonial period. Soil samples were obtained by segmenting an easy stratigraphic horizon into sub categorized soil layers, and their material properties were analyzed; they are composed mainly of sandy loam based on the particle size distributions. In the site foundation, loamy sand is packed in the bottommost layer, and sandy loam with high sand and silty sand fills most of the overlying layer. The central and topmost portion of the Baekje layer is composed of loam with high clay content. All soil layers show geochemical behaviors similar to those of the bottommost layer. X-ray diffraction analysis verified kaolinite in all layers, also observed in soil layers displaying high crystallinity. Kaolinite and halloysite were identified by scanning electron microscopy. Thus, we conclude that the Baekje layer of the Sowangneung is composed of sandy loam containing kaolin procured from near the site. An impermeable middle to upper layer was created using viscous loam. The top of the tomb was closed tightly.
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Alkhasha, Arafat, Abdulrasoul Al-Omran, and and Abdulaziz G. Alghamdi. "Effect of Water Quality and Date Palm Biochar on Evaporation and Specific Hydrological Characteristics of Sandy Soil." Agriculture 10, no. 7 (July 15, 2020): 300. http://dx.doi.org/10.3390/agriculture10070300.
Повний текст джерелаАнотація:
Experiments were conducted in a soil laboratory using transparent columns (5 and 40 cm in diameter and length, respectively) to evaluate the effects of water quality (i.e., fresh or saline water) with the addition of biochar on soil moisture characteristics. Soil and biochar were gently combined and added into the top 10 cm of each column at a rate of 2%, 4%, 6%, and 8% (w/w). The results show a decrease in cumulative evaporation by 29.27%, 16.47%, 14.17%, and 14.61% with freshwater, and by 21.24%, 12.22%, 21.08%, and 12.67% with saline water for B1, B2, B3, and B4, respectively, compared with unamended soil (B1, B2, B3 and B4 represent the treatments with the biochar rate of 2, 4, 6, and 8%, respectively). Cumulative infiltration was reduced by 34.38%, 43.37%, 58.89%, and 57.07% with freshwater, and by 30.18%, 44.38%, 54.44%, and 49.11% with saline water for B1, B2, B3, and B4, respectively. The infiltration rate was reduced by 32.73%, 42.17%, 57.82%, and 56.85% with freshwater, and 42.09%, 54.6%1, 62.68%, and 58.41% with saline water for T1, T2, T3, and T4, respectively, compared with the control. The saturated hydraulic conductivity of B1 decreased significantly by 92.8% and 67.72% with fresh and saline water, respectively. Biochar, as a soil conditioner, could be used in arid conditions with fresh and saline water to enhance the hydrological properties of sandy soils.