Journal articles on the topic 'Zone of improved soil'
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FARID, H. U., A. BAKHSH, N. AHMAD, A. AHMAD, and Z. MAHMOOD-KHAN. "Delineating site-specific management zones for precision agriculture." Journal of Agricultural Science 154, no. 2 (May 8, 2015): 273–86. http://dx.doi.org/10.1017/s0021859615000143.
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SUMMARYDelineating site-specific management zones within fields can be helpful in addressing spatial variability effects for adopting precision farming practices. A 3-year (2008/09 to 2010/11) field study was conducted at the Postgraduate Agricultural Research Station, University of Agriculture, Faisalabad, Pakistan, to identify the most important soil and landscape attributes influencing wheat grain yield, which can be used for delineating management zones. A total of 48 soil samples were collected from the top 300 mm of soil in 8-ha experimental field divided into regular grids of 24 × 67 m prior to sowing wheat. Soil and landscape attributes such as elevation, % of sand, silt and clay by volume, soil electrical conductivity (EC), pH, soil nitrogen (N) and soil phosphorus (P) were included in the analysis. Artificial neural network (ANN) analysis showed that % sand, % clay, elevation, soil N and soil EC were important variables for delineating management zones. Different management zone schemes ranging from three to six were developed and evaluated based on performance indicators using Management Zone Analyst (MZA V0·1) software. The fuzziness performance index (FPI) and normalized classification entropy NCE indices showed minimum values for a four management zone scheme, indicating its appropriateness for the experimental field. The coefficient of variation values of soil and landscape attributes decreased for each management zone within the four management zone scheme compared to the entire field, which showed improved homogeneity. The evaluation of the four management zone scheme using normalized wheat grain yield data showed distinct means for each management zone, verifying spatial variability effects and the need for its management. The results indicated that the approach based on ANN and MZA software analysis can be helpful in delineating management zones within the field, to promote precision farming practices effectively.
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Alafeena, Mustafa A., and Ala Nasir Aljorany. "Experimental Study on the Modulus of Subgrade Reaction for Sandy Soil Improved by Grouting Materials." Key Engineering Materials 857 (August 2020): 358–66. http://dx.doi.org/10.4028/www.scientific.net/kem.857.358.
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Many methods have been used for soil improvement at site, one of these methods is grouting. Cement grouted soils consist of particulate soil media and cementation agents. Such soils have been widely used to improve the shear strength and stiffness of weak soils and for preventing of water seepage through soils. The modulus of subgrade reaction may give a good indication about the soil bearing capacity and stiffness. This geotechnical parameter can be measured by using the plate load test. In this study, an experimental work is done to assess the improvement in the stiffness of sandy soils by injection two different cementing agents (cement and colloidal silica). The work includes plate loading tests with two different plate diameters (B= 150 and B= 250 mm). The effects of plate size, depth of the grouted zone (0-B and B-2B) as well as the effect of grouting material type on the performance of the grouted soil are investigated. The results show that the colloidal silica grout is more effective in increasing the modulus of sub grade reaction (ks) than the cement grout. Also, the use of plate with 150 mm diameter gives higher value of (ks) than that of 250 mm diameter. Furthermore, grout injection at depth (from 0 to B) gives a higher value of (ks) than that for deeper grouted zone.
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Wiseman, P. Eric, Susan Day, and J. Roger Harris. "Organic Amendment Effects on Soil Carbon and Microbial Biomass in the Root Zone of Three Landscape Tree Species." Arboriculture & Urban Forestry 38, no. 6 (November 1, 2012): 262–76. http://dx.doi.org/10.48044/jauf.2012.036.
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There is increasing interest in amending degraded soils with organic matter to improve soil quality, especially in urban areas where rehabilitation of damaged soils may enhance tree growth and provision of ecosystem services. To assess the potential of such organic amendments for producing a sustained alteration in soil biological characteristics, researchers studied the effects of three organic amendments incorporated into the root zone of three tree species on root development, soil carbon dynamics, and soil microbial biomass over one year beginning 20 months after amendment application. Soil amendment with leaf-based, and to a lesser extent, biosolids-based composts increased root length within the amended root zone of red maple (Acer rubrum), but not of pin oak (Quercus palustris) or chestnut oak (Q. montana). There was a concomitant increase in microbial biomass carbon for red maple. Across all species, sphagnum peat moss amendment reduced microbial biomass carbon by 47% compared to unamended root zones and suppressed maximum seasonal soil respiration relative to composts. In contrast, leaf-based compost increased microbial biomass carbon by 12% (P = 0.0989) compared to unamended root zones. Carbon/nitrogen ratios remained stable throughout most of the year except in the root zones of chestnut oak and pin oak amended with peat, where it declined 44%–85%. Total soil carbon was stable in all treatments, although unamended soils averaged about 40% lower than amended soils. Across all species and treatments, cumulative fine root length explained 19% of the variation in microbial biomass carbon. The study authors conclude that soil microbial activity can be increased by compost amendment of the root zone and that this increase is mediated to some degree by tree roots. In addition, stable C/N ratios suggest this alteration in the root zone may be sustainable. Further research may clarify whether compost amendment combined with tree planting can accelerate soil restoration.
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Tian, Siyuan, Luigi J. Renzullo, Albert I. J. M. van Dijk, Paul Tregoning, and Jeffrey P. Walker. "Global joint assimilation of GRACE and SMOS for improved estimation of root-zone soil moisture and vegetation response." Hydrology and Earth System Sciences 23, no. 2 (February 21, 2019): 1067–81. http://dx.doi.org/10.5194/hess-23-1067-2019.
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Abstract. The lack of direct measurement of root-zone soil moisture poses a challenge to the large-scale prediction of ecosystem response to variation in soil water. Microwave remote sensing capability is limited to measuring moisture content in the uppermost few centimetres of soil. The GRACE (Gravity Recovery and Climate Experiment) mission detected the variability in storage within the total water column. However, root-zone soil moisture cannot be separated from GRACE-observed total water storage anomalies without ancillary information on surface water and groundwater changes. In this study, GRACE total water storage anomalies and SMOS near-surface soil moisture observations were jointly assimilated into a hydrological model globally to better estimate the impact of changes in root-zone soil moisture on vegetation vigour. Overall, the accuracy of root-zone soil moisture estimates through the joint assimilation of surface soil moisture and total water storage retrievals showed improved consistency with ground-based soil moisture measurements and satellite-observed greenness when compared to open-loop estimates (i.e. without assimilation). For example, the correlation between modelled and in situ measurements of root-zone moisture increased by 0.1 (from 0.48 to 0.58) and 0.12 (from 0.53 to 0.65) on average for grasslands and croplands, respectively. Improved correlations were found between vegetation greenness and soil water storage on both seasonal variability and anomalies over water-limited regions. Joint assimilation results show a more severe deficit in soil water anomalies in eastern Australia, southern India and eastern Brazil over the period of 2010 to 2016 than the open-loop, consistent with the satellite-observed vegetation greenness anomalies. The assimilation of satellite-observed water content contributes to more accurate knowledge of soil water availability, providing new insights for monitoring hidden water stress and vegetation conditions.
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Kirkby, M. J. "Water in the critical zone: soil, water and life from profile to planet." SOIL 2, no. 4 (December 12, 2016): 631–45. http://dx.doi.org/10.5194/soil-2-631-2016.
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Abstract. Earth is unique in the combination of abundant liquid water, plate tectonics and life, providing the broad context within which the critical zone exists, as the surface skin of the land. Global differences in the availability of water provide a major control on the balance of processes operating in the soil, allowing the development of environments as diverse as those dominated by organic soils, by salty deserts or by deeply weathered lateritic profiles. Within the critical zone, despite the importance of water, the complexity of its relationships with the soil material continue to provide many fundamental barriers to our improved understanding, at the scales of pore, hillslope and landscape. Water is also a vital resource for the survival of increasing human populations. Intensive agriculture first developed in semi-arid areas where the availability of solar energy could be combined with irrigation water from more humid areas, minimising the problems of weed control with primitive tillage techniques. Today the challenge to feed the world requires improved, and perhaps novel, ways to optimise the combination of solar energy and water at a sustainable economic and environmental cost.
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Li, Chang Yu, Han Bing Liu, and Hai Bin Wei. "An Experimental Study on Engineering Properties of Rubber Particles-Improved Fly Ash Soil." Applied Mechanics and Materials 71-78 (July 2011): 3401–6. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.3401.
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In this paper, by studying the engineering properties of rubber particles-improved fly ash soil, the authors provide technical parameters for setting up cold-resistance layer in the seasonal frozen zone. In the experiment, rubber particles are mixed into the fly ash soil by mass of 0%, 1%, 2%, 3%, 5% and 7% and unconfined compressive strength testing, frost heave test, insulation test and thermal conductivity test. By analyzing the test results, the authors drew the conclusion that fly ash soil improved by rubber particles has a high compressive strength, a small amount of frost heave, good insulation performance, small thermal conductivity coefficient.Therefore, improved fly ash soil with rubber particles is one of the preferred materials to set up the cold resistance layer in seasonal frost zone.
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Li, Dayang, Zhongmin Liang, Binquan Li, Xiaohui Lei, and Yan Zhou. "Multi-objective calibration of MIKE SHE with SMAP soil moisture datasets." Hydrology Research 50, no. 2 (November 1, 2018): 644–54. http://dx.doi.org/10.2166/nh.2018.110.
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Abstract Root zone soil moisture plays an important role in water storage in hydrological processes. The recently launched Soil Moisture Active Passive (SMAP) mission has produced a high-resolution assimilation product of global root zone soil moisture that can be applied to improve the performance of hydrological models. In this study, we compare three calibration approaches in the Beimiaoji watershed. The first approach is single-objective calibration, in which only observed streamflow is used as a benchmark for comparison with the other approaches. The second and third approaches use multi-objective calibration based on SMAP root zone soil moisture and observed streamflow. The difference between the second and third approaches is the metric used to characterize the root zone soil moisture. The second approach applies the mean, which was commonly used in previous studies, whereas the third approach applies the hydrologic complexity μ, a dimensionless metric based on information entropy theory. These approaches are implemented to calibrate the distributed hydrological model MIKE SHE. Results show that the root zone soil moisture simulation is clearly improved, whereas streamflow simulation suffers from a slightly negative impact with multi-objective calibration. The hydrologic complexity μ performs better than the mean in capturing the features of root zone soil moisture.
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Nian, Ting Kai, Zhong Kai Feng, Peng Cheng Yu, and Hui Jun Wu. "Shear Test on Mixed Slide-Zone Soils of Landslide under Different Water Content." Advanced Materials Research 301-303 (July 2011): 1208–13. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1208.
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This study is based on a typical residual soil landslide adjacent to Daxishan Reservior in Dalian city of China. By drilling the original samples in the field and remodeling the copy samples in the laboratory, a series of geotechnical experiments are carried out by the improved direct shear apparatus to obtain the changing law between the shear strength and water content of the mixed slide-zone soils. Emphasis is given on the shear stress-strain behavior and the corresponding constitutive model under different water content for the soils. Especially, the typical fitting equation is achieved to reflect the state of shear stress-normal stress-water content, some strain softening and hardening behavior on the mixed slide-zone soils of landslide is also discussed in detail. The results indicate that the shear strength is significantly related to water content of mixed slide-zone soils of landslide. The bigger water content of slide-zone soil is, the smaller the shear strength of soils is. When water content of mixed slide-zone soils approaches to certain value (i.e., 15%), the curve of shear stress and displacement shows a remarkable softening behavior, and the shear strength has marked a peak value.
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Rebel, K. T., R. A. M. de Jeu, P. Ciais, N. Viovy, S. L. Piao, G. Kiely, and A. J. Dolman. "A global analysis of soil moisture derived from satellite observations and a land surface model." Hydrology and Earth System Sciences 16, no. 3 (March 16, 2012): 833–47. http://dx.doi.org/10.5194/hess-16-833-2012.
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Abstract. Soil moisture availability is important in regulating photosynthesis and controlling land surface-climate feedbacks at both the local and global scale. Recently, global remote-sensing datasets for soil moisture have become available. In this paper we assess the possibility of using remotely sensed soil moisture – AMSR-E (LPRM) – to similate soil moisture dynamics of the process-based vegetation model ORCHIDEE by evaluating the correspondence between these two products using both correlation and autocorrelation analyses. We find that the soil moisture product of AMSR-E (LPRM) and the simulated soil moisture in ORCHIDEE correlate well in space and time, in particular when considering the root zone soil moisture of ORCHIDEE. However, the root zone soil moisture in ORCHIDEE has on average a higher temporal autocorrelation relative to AMSR-E (LPRM) and in situ measurements. This may be due to the different vertical depth of the two products – AMSR-E (LPRM) at the 2–5 cm surface depth and ORCHIDEE at the root zone (max. 2 m) depth – to uncertainty in precipitation forcing in ORCHIDEE, and to the fact that the structure of ORCHIDEE consists of a single-layer deep soil, which does not allow simulation of the proper cascade of time scales that characterize soil drying after each rain event. We conclude that assimilating soil moisture, using AMSR-E (LPRM) in a land surface model like ORCHIDEE with an improved hydrological model of more than one soil layer, may significantly improve the soil moisture dynamics, which could lead to improved CO2 and energy flux predictions.
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Tian, Siyuan, Luigi J. Renzullo, Robert C. Pipunic, Julien Lerat, Wendy Sharples, and Chantal Donnelly. "Satellite soil moisture data assimilation for improved operational continental water balance prediction." Hydrology and Earth System Sciences 25, no. 8 (August 24, 2021): 4567–84. http://dx.doi.org/10.5194/hess-25-4567-2021.
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Abstract. A simple and effective two-step data assimilation framework was developed to improve soil moisture representation in an operational large-scale water balance model. The first step is a Kalman-filter-type sequential state updating process that exploits temporal covariance statistics between modelled and satellite-derived soil moisture to produce analysed estimates. The second step is to use analysed surface moisture estimates to impart mass conservation constraints (mass redistribution) on related states and fluxes of the model using tangent linear modelling theory in a post-analysis adjustment after the state updating at each time step. In this study, we assimilate satellite soil moisture retrievals from both Soil Moisture Active Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) missions simultaneously into the Australian Water Resources Assessment Landscape model (AWRA-L) using the proposed framework and evaluate its impact on the model's accuracy against in situ observations across water balance components. We show that the correlation between simulated surface soil moisture and in situ observation increases from 0.54 (open loop) to 0.77 (data assimilation). Furthermore, indirect verification of root-zone soil moisture using remotely sensed Enhanced Vegetation Index (EVI) time series across cropland areas results in significant improvements from 0.52 to 0.64 in correlation. The improvements gained from data assimilation can persist for more than 1 week in surface soil moisture estimates and 1 month in root-zone soil moisture estimates, thus demonstrating the efficacy of this data assimilation framework.
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Kelly, B. F. J., R. I. Acworth, and A. K. Greve. "Better placement of soil moisture point measurements guided by 2D resistivity tomography for improved irrigation scheduling." Soil Research 49, no. 6 (2011): 504. http://dx.doi.org/10.1071/sr11145.
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Soil moisture beneath irrigated crops has traditionally been determined using point measurement methods such as neutron probes or capacitance systems. These approaches cannot measure soil moisture at depths beyond the root-zone of plants and have limited lateral coverage. It is shown that surface two-dimensional electrical resistivity tomography (ERT) can be used to map the spatial heterogeneity in soil moisture throughout a field under irrigated cotton. The case study demonstrates that ERT provides a better understanding of the pathways of water migration, and provides spatial information on how water storage changes throughout the growing season. We conclude that ERT should be integrated into farm water management surveys to delineate zones of excessive water loss due to deep drainage and to improve the positioning of point measurement methods for measuring soil moisture, thereby improving irrigation scheduling.
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Kung, K.-J. S., and S. V. Donohue. "Improved Solute-Sampling Protocol in a Sandy Vadose Zone Using Ground-Penetrating Radar." Soil Science Society of America Journal 55, no. 6 (November 1991): 1543–45. http://dx.doi.org/10.2136/sssaj1991.03615995005500060007x.
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Heap, J. W., and A. C. McKay. "Managing soil-borne crop diseases using precision agriculture in Australia." Crop and Pasture Science 60, no. 9 (2009): 824. http://dx.doi.org/10.1071/cp08345.
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Field experiments in southern Australia examined the spatial distribution of soil-borne disease inoculum within paddocks using DNA-based soil assays. Paddocks were divided into zones using cluster analysis for a range of combinations of digital data layers. Inoculum levels differed among zones in 33–64% of the 108 cases examined, depending on the zone model used. It was concluded that zone models used for precision agriculture (PA) most commonly in Australia (viz. zones based on cluster analysis of grain yield maps, ECa, and elevation, and zones based on satellite biomass imagery) were most suitable for partitioning inoculum distribution within paddocks. Generally there was a correlation between pre-sowing levels of inoculum and crop root damage and shoot biomass; however, there was not always a strong correlation between inoculum level and grain yield. There was some evidence that damage/unit soil inoculum varied among zones, but difficulties in predicting this a priori suggest that the damage rate should be assumed to be equal among zones. It is suggested that crop managers divide paddocks into yield or management zones and test each zone before every crop, using an appropriate soil sampling protocol. The disease risk and yield potential for each zone should then be considered to decide whether differential management is feasible or warranted. A soil test based on one composite paddock sample gives a paddock average only, which in many cases gives insufficient information about varying inoculum levels for robust zone management. If testing of every zone is not possible, then zones with the highest risk to profit from disease damage should be tested, to minimise risk. As PA technologies and biological understanding of disease behaviour improve, crop managers will have greater opportunities to exploit the non-random spatial distribution of soil-borne disease inoculum in new and imaginative ways at the zone level.
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Erlandsson Lampa, Martin, Harald U. Sverdrup, Kevin H. Bishop, Salim Belyazid, Ali Ameli, and Stephan J. Köhler. "Catchment export of base cations: improved mineral dissolution kinetics influence the role of water transit time." SOIL 6, no. 1 (June 3, 2020): 231–44. http://dx.doi.org/10.5194/soil-6-231-2020.
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Abstract. Soil mineral weathering is one of the major sources of base cations (BC), which play a dual role in forest ecosystems: they function as plant nutrients and buffer against the acidification of catchment runoff. On a long-term basis, soil weathering rates determine the highest sustainable forest productivity that does not cause acidification. It is believed that the hydrologic residence time plays a key role in determining the weathering rates at the landscape scale. The PROFILE weathering model has been used for almost 30 years to calculate weathering rates in the rooting zone of forest soils. However, the mineral dissolution equations in PROFILE are not adapted for the saturated zone, and employing these equations at the catchment scale results in a significant overprediction of base cation release rates to surface waters. In this study, we use a revised set of PROFILE equations which, among other features, include retardation due to silica concentrations. Relationships between the water transit time (WTT) and soil water concentrations were derived for each base cation, by simulating the soil water chemistry along a one-dimensional flow path, using the mineralogy from a glacial till soil. We show how the revised PROFILE equations are able to reproduce patterns in BC and silica concentrations as well as BC ratios (Ca2+/BC, Mg2+/BC and Na+/BC) that are observed in the soil water profiles and catchment runoff. In contrast to the original set of PROFILE equations, the revised set of equations could reproduce the fact that increasing WTT led to a decreasing Na+/BC ratio and increasing Ca2+/BC and Mg2+/BC ratios. Furthermore, the total release of base cations from a hillslope was calculated using a mixing model, where water with different WTTs was mixed according to an externally modeled WTT distribution. The revised set of equations gave a 50 % lower base cation release (0.23 eq m−2 yr−1) than the original PROFILE equations and are in better agreement with mass balance calculations of weathering rates. Thus, the results from this study demonstrate that the revised mineral dissolution equations for PROFILE are a major step forward in modeling weathering rates at the catchment scale.
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Etuk, Etiese, Kingsley C. Ogboi, C. A. Nwadinigwe, and Wali Elekwachi. "A Comparative Analysis of Bioremediation of Hydrocarbon Polluted Soil in the Island Forest Ecosystem and the Low land Forest Ecosystem in the Niger Delta through Enhanced Natural Attenuation Process (ENAP)." Advances in Social Sciences Research Journal 8, no. 1 (January 17, 2021): 81–93. http://dx.doi.org/10.14738/assrj.81.9027.
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The Niger Delta region has witnessed environmental pollution arising from oil activities over the years of oil exploration and production. Soil fertility in both the Lowland Forest Ecological Zone and Island Forest Ecological Zone were investigated to establish the consequences of oil pollution on the soil and remedial actions to restore back quality and fertility of the soil. A suitable cost effective and environmentally friendly technology to handle the pollutions in the Niger Delta region can be found in Remediation by Enhanced Natural Attenuation Process (ENAP) which facilitates the activities of microorganisms to biodegrade the hydrocarbon impacted soil. The study compared the bio-physicochemical parameters of the oil spill polluted soil with particular reference to areas of oil production of the two Ecological Systems with those of the unaffected soil as well as their response to bioremediation interventions using ENAP. The results demonstrated significant decrease in the values of the key indicator parameter, the Total Petroleum Hydrocarbons (TPH). But for the unenhanced process, the result showed low level of reduction of TPH values for the polluted soils. A degradation trend was demonstrated with time leading to significant TPH reductions and improved key soil fertility indices. The result showed that the level of the nutrient status of soil in the region can be improved through the natural attenuation process.
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McKenzie, R. H., and E. Bremer. "Relationship of soil phosphorus fractions to phosphorus soil tests and fertilizer response." Canadian Journal of Soil Science 83, no. 4 (August 1, 2003): 443–49. http://dx.doi.org/10.4141/s02-079.
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Soil tests for available P may not be accurate because they do not measure the appropriate P fraction in soil. A sequential extraction technique (modified Hedley method) was used to determine if soil test P methods were accurately assessing available pools and if predictions of fertilizer response could be improved by the inclusion of other soil P fractions. A total of 145 soils were analyzed from field P fertilizer experiments conducted across Alberta from 1991 to 1993. Inorganic P (Pi) removed by extraction with an anion-exchange resin (resin P) was highly correlated with the Olsen and Kelowna-type soil test P methods and had a similar relationship with P fertilizer response. No appreciable improvement in the fit of available P with P fertilizer response was achieved by including any of the less available P fractions in the regression of P fertilizer response with available P. Little Pi was extractable in alkaline solutions (bicarbonate and NaOH), particularly in soils from the Brown and Dark Brown soil zones. Alkaline fractions were the most closely related to resin P, but the relationship depended on soil zone. Inorganic P extractable in dilute HCl was most strongly correlated with soil pH, reflecting accumulation in calcareous soils, while Pi extractable in concentrated acids (HCl and H2SO4) was most strongly correlated with clay concentration. A positive but weak relationship as observed between these fractions and resin P. Complete fractionation of soil P confirmed that soil test P methods were assessing exchangeable, plant-available P. Key words: Hedley phosphorus fractionation, resin, Olsen, Kelowna
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Juneja, Ashish, Bashir Ahmed Mir, and N. S. Roshan. "Effect of the Smear Zone around SCP Improved Composite Samples Tested in the Laboratory." International Journal of Geomechanics 13, no. 1 (February 2013): 16–25. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000169.
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Xu, Qingzhang, Bingru Huang, and Zhaolong Wang. "Photosynthetic Responses of Creeping Bentgrass to Reduced Root-zone Temperatures at Supraoptimal Air Temperature." Journal of the American Society for Horticultural Science 127, no. 5 (September 2002): 754–58. http://dx.doi.org/10.21273/jashs.127.5.754.
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High air and soil temperatures are major factors limiting growth of cool-season grasses. A previous study by the authors reported that a soil temperature reduction of only 3 °C when air temperature was maintained at 35 °C significantly improved shoot and root growth of creeping bentgrass [Agrostis stolonifera L. var. palustris (Huds.) Farw. (syn. A. palustris Huds.)]. This study was designed to investigate the responses of photosynthetic activities of creeping bentgrass to lowered root-zone temperatures from the supraoptimal level when shoots were exposed to high air temperature. Two cultivars of creeping bentgrass, `L-93' and `Penncross', were exposed to the following air/root-zone temperature regimes in growth chambers and water baths: 1) optimal air and soil temperatures (20/20 °C, control); 2) lowering soil temperature by 3, 6, and 11 °C from 35 °C at high air temperatures (35/32, 35/29, and 35/24 °C); and 3) high air and soil temperatures (35/35 °C). Soil temperature was reduced from 35 °C by circulating cool water (18 °C) in water baths at variable flow rates. Both cultivars had similar responses to high or low root-zone temperatures with high air temperature. High air and root-zone temperatures caused significant reductions in canopy photosynthetic rate (Pcanopy), single-leaf photosynthetic rate (Pleaf), leaf chlorophyll content, photochemical efficiency (Fv/Fm), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, beginning on day 1 of high air and soil temperature stress for Pcanopy and Pleaf, and day 7 for chlorophyll content, Fv/Fm, and Rubisco activity. The 3 °C reduction in root-zone temperature at high air temperature had no effect on those photosynthetic parameters, except chlorophyll content. Reducing root-zone temperature by 6 °C or 11 °C while maintaining air temperature at 35 °C significantly improved Pcanopy, Poleaf, leaf chlorophyll content, Fv/Fm, and Rubisco activity. Single leaf photosynthetic rate at 35/24 °C was not different from the control level, but Pcanopy at 35/24 °C was lower than the control level. A reduction in root-zone temperature enhanced canopy and single-leaf photosynthetic capacity even though shoots were exposed to supraoptimal air temperature, which could contribute to improved turfgrass growth.
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Lin, Hai, Muhannad T. Suleiman, Hanna M. Jabbour, and Derick G. Brown. "Bio-grouting to enhance axial pull-out response of pervious concrete ground improvement piles." Canadian Geotechnical Journal 55, no. 1 (January 2018): 119–30. http://dx.doi.org/10.1139/cgj-2016-0438.
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Bio-grouting is an environmentallly friendly, sustainable, and low-cost ground improvement technique, which mainly utilizes microbial-induced carbonate precipitation. Previous large-scale applications of MICP have encountered practical difficulties including bio-clogging, which resulted in a limited zone of cemented soil around injection points. The research presented in this paper focuses on evaluating the feasibility of cementing a limited soil zone surrounding permeable piles using MICP bio-grouting to improve the mechanical response of permeable piles under axial pull-out loading. Two instrumented pervious concrete piles (test units), one with and one without MICP bio-grouting, were subjected to pull-out loading at the Soil-Structure Interaction Facility at Lehigh University. The pervious concrete pile served as an injection point during the MICP bio-grouting. The mechanical responses of the test units and surrounding soil were analyzed, along with shear wave (S-wave) velocities, moisture, and CaCO3 contents of the surrounding soil. The results presented in this paper demonstrate that the limited MICP-improved zone, extending a radial distance of approximately 102 mm around pervious concrete piles, improved the load–displacement response, load transfer, and pile capacity under pull-out loading. The ratios between ultimate loads of the test units with and without MICP bio-grouting were 4.2. The average shaft resistance along the pile with MICP bio-grouting was up to 2.8 times higher than that of the pile without bio-grouting.
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Lin, H. S. "Earth's Critical Zone and hydropedology: concepts, characteristics, and advances." Hydrology and Earth System Sciences Discussions 6, no. 2 (April 27, 2009): 3417–81. http://dx.doi.org/10.5194/hessd-6-3417-2009.
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Abstract. The Critical Zone (CZ) is a holistic framework for integrated studies of water with soil, rock, air, and biotic resources in terrestrial environments. This is consistent with the recognition of water as a unifying theme for research on complex environmental systems. The CZ ranges from the top of the vegetation down to the bottom of the aquifer, with a highly variable thickness (from <0.001 to >10 km). The pedosphere is the foundation of the CZ, which represents a geomembrance across which water and solutes, as well as energy, gases, solids, and organisms are actively exchanged with the atmosphere, biosphere, hydrosphere, and lithosphere to create a life-sustaining environment. Hydropedology – the science of the behaviour and distribution of soil-water interactions in contact with mineral and biological materials in the CZ – is an important contributor to CZ research. This article reviews and discusses the basic ideas and fundamental features of the CZ and hydropedology, and suggests ways for their advances. An "outward" growth model, instead of an "inward" contraction, is suggested for propelling soil science forward. The CZ is the right platform for synergistic collaborations across disciplines. The reconciliation of the geological (or "big") cycle and the biological (or "small") cycle that are orders of magnitude different in space and time is a key to understanding and predicting complex CZ processes. Because of the layered nature of the CZ and the general trend of increasing density with depth, response and feedback to climate change take longer from the above-ground zone down to the soil zone and further to the groundwater zone. Interfaces between layers and cycles are critical controls of the landscape-soil-water-ecosystem dynamics, which present fertile grounds for interdisciplinary research. Ubiquitous heterogeneity in the CZ can be addressed by environmental gradients and landscape patterns, where hierarchical structures control the landscape complex of flow networks embedded in mosaics of matrices. Fundamental issues of hydropedology are linked to the general characteristics of the CZ, including (1) soil structure and horizonation as the foundation of flow and transport characteristics in field soils; (2) soil catena and distribution pattern as a first control of water movement over the landscape; (3) soil morphology and pedogenesis as signatures of soil hydrology and soil change; and (4) soil functional classification and mapping as carriers of soil hydrologic properties and soil-landscape heterogeneity. Monitoring changes in the crucible of terrestrial life (soil) is an excellent (albeit complex) environmental assessment, as every soil is a "block of memory" of past and present biosphere-geosphere dynamics. Our capability to predict the behaviour and evolution of the CZ in response to changing environment can be improved significantly if a global alliance for monitoring, mapping, and modeling of the CZ can be fostered.
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Kuzychenko, Yu. "Zones of introduction of main soil treatment systems for row crops in the conditions of the Central Pre-Caucasus." Agrarian Bulletin of the 194, no. 3 (April 1, 2020): 28–35. http://dx.doi.org/10.32417/1997-4868-2020-194-3-28-35.
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Abstract. The purpose of the research is to establish the areas of implementation, varying in time of application, of the primary tillage systems for row crops in various climatic zones of the Stavropol Territory. Methods. The analysis of changes in climatic factors and arable land under row crops over a 10-year period with the construction of graphical trends in increasing the area of arable land for corn and sunflower is carried out. Zones for the introduction of semi-steam and chaffinch main tillage for these crops were determined on the basis of calculations of the generalized indicator D, taking into account the choice of certain criteria indicators at each point of the survey. Results. Analysis of changes in the annual precipitation over the last 10 summer periods showed that the average decrease in precipitation is observed only in the extremely arid zone (1) – 22 mm, with an increase in precipitation in the arid zone (2) by 24 mm, in the zone of unstable moisture ( 3) by 21 mm, and in the zone of sufficient moisture (4) by 27 mm, which indicates the possibility of adjusting the time and, accordingly, determining the zones for introducing a semi-steam treatment or processing according to the type of improved late fallow for row crops according to spike crops . Analysis of the time series of areas for corn for grain showed a significant increase in area trends in the 2nd, 3rd and 4th zones by 2.9; 6.5 and 5.7 thousand ha, respectively. A significant increase in the area under sunflower was established only in the 2nd zone on 4.0 thousand ha, in the 3rd and 4th zones only a tendency to increase the area is noted. The scientific novelty. It is established that at the points of examination where Dfact. > 0.93 recommended main processing for occupied steam according to the half-pair system, if Dfact. in the range of 0.93–0.80, then the main processing of the type of improved late fallow is effective, with Dfact. <0.80 –the area is not recommended for row crops.
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Larsbo, Mats, Stephanie Roulier, Fredrik Stenemo, Roy Kasteel, and Nicholas Jarvis. "An Improved Dual-Permeability Model of Water Flow and Solute Transport in the Vadose Zone." Vadose Zone Journal 4, no. 2 (May 2005): 398–406. http://dx.doi.org/10.2136/vzj2004.0137.
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Dessureault-Rompré, Jacynthe, Bernie J. Zebarth, David L. Burton, and Cynthia A. Grant. "Depth distribution of mineralizable nitrogen pools in contrasting soils in a semi-arid climate." Canadian Journal of Soil Science 96, no. 1 (March 1, 2016): 1–11. http://dx.doi.org/10.1139/cjss-2015-0048.
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A better understanding of the depth distribution of soil mineralizable nitrogen (N) pools is important to improve prediction of net soil N mineralization. However, our understanding of the depth distribution of these N pools under the semi-arid conditions of western Canada is limited. This study examined the depth distribution of soil mineralizable N pools (kS, the rate constant of a nondepleting zero-order stable N pool, and NL, the size of a depleting first-order labile N pool) of six sites in western Canada chosen to vary with respect to soil zone, soil texture, and cropping system. The depth distribution of mineralizable N pools varied substantially among sites, indicating that this distribution needs to be considered in making predictions of net soil N mineralization. A single regression equation including soil total nitrogen (STN), Pool I (a labile mineralizable N pool determined through a 14-day aerobic incubation), and soil pH explained 67% of the variation in kS across sites and soil depths. In addition, 95% of the variation in NL was explained by a regression model with Pool I. Thus, although the depth distribution of soil mineralizable N pools can vary substantially among sites, the mineralizable N parameters can be adequately predicted across sites and soil depths from simple soil properties. Comparison with a study using surface soils under humid conditions in New Brunswick suggests that the relationship between NL and Pool I is applicable across a wide range of soils, climatic zones, and cropping systems, whereas the regression model to predict kS varied with climatic zone, perhaps reflecting different pedogenic processes stabilizing the organic matter in these climatic zones.
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Schepers, James S., Dennis D. Francis, and John F. Shanahan. "Relay Cropping for Improved Air and Water Quality." Zeitschrift für Naturforschung C 60, no. 3-4 (April 1, 2005): 186–89. http://dx.doi.org/10.1515/znc-2005-3-405.
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Abstract Using plants to extract excess nitrate from soil is important in protecting against eutrophication of standing water, hypoxic conditions in lakes and oceans, or elevated nitrate concentrations in domestic water supplies. Global climate change issues have raised new concerns about nitrogen (N) management as it relates to crop production even though there may not be an immediate threat to water quality. Carbon dioxide (CO2) emissions are frequently considered the primary cause of global climate change, but under anaerobic conditions, animals can contribute by expelling methane (CH4) as do soil microbes. In terms of the potential for global climate change, CH4 is ~ 25 times more harmful than CO2. This differential effect is minuscule compared to when nitrous oxide (N2O) is released into the atmosphere because it is ~ 300 times more harmful than CO2. N2O losses from soil have been positively correlated with residual N (nitrate, NO3 -) concentrations in soil. It stands to reason that phytoremediation via nitrate scavenger crops is one approach to help protect air quality, as well as soil and water quality. Winter wheat was inserted into a seed corn/soybean rotation to utilize soil nitrate and thereby reduce the potential for nitrate leaching and N2O emissions. The net effect of the 2001- 2003 relay cropping sequence was to produce three crops in two years, scavenge 130 kg N/ha from the root zone, produce an extra 2 Mg residue/ha, and increase producer profitability by ~ $ 250/ha.
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Meti, S., P. D. Lakshmi, M. S. Nagaraja, and V. Shreepad. "SENTINEL 2 AND LANDSAT-8 BANDS SENSITIVITY ANALYSIS FOR MAPPING OF ALKALINE SOIL IN NORTHERN DRY ZONE OF KARNATAKA, INDIA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3/W6 (July 26, 2019): 307–13. http://dx.doi.org/10.5194/isprs-archives-xlii-3-w6-307-2019.
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<p><strong>Abstract.</strong> Soil salinization is most common land degradation process occurring in deep vertisol of northern dry zone of Karnataka, India. Accurate and high resolution spatial information on salinization can assist policy makers to better target areas for interventions to avoid aggravation of soil degradation process. Digital soil mapping using satellite data has been identified as a potential means of obtaining soil information. This paper focuses on exploring possibility of using new generation medium resolution Landsat-8 and Sentinel-2 satellite data to map alkaline soils of Ramthal irrigation project area in north Karnataka. Surface soil salinity parameters of zone 20 were correlated with reflectance values of different band and band combination and traditional salinity indices and result has indicated that SWIR bands of both satellite showed significant negative correlation with soil pH, EC (r&thinsp;=&thinsp;&minus;0.39 to &minus;0.45) whereas visible and NIR bands did not show significant relation. However rationing of SWIR bands with visible blue band has significantly improved the correlation with soil pH and EC (r&thinsp;=&thinsp;+0.60 to +0.70). Traditional salinity index based on visible bands failed to show significant correlation with soil parameters. It is interesting to note that SWIR bands alone did not show significant correlation with soil sodicity parameters like exchangeable Na, SAR, RSC but band rationing with blue bands has significantly improved the correlation (r&thinsp;=&thinsp;0.45). High resolution soil salinity map was prepared using simple linear regression model and using this map will serve as base map for the policy makers.</p>
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Hanafy, S., and S. A. al Hagrey. "Ground-penetrating radar tomography for soil-moisture heterogeneity." GEOPHYSICS 71, no. 1 (January 2006): K9—K18. http://dx.doi.org/10.1190/1.2159052.
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Many ground-penetrating radar (GPR) studies incorporate tomographic methods that use straight raypaths for direct model reconstruction, which is unrealistic for media with gradually changing petrophysics. Ray-bending algorithms can sometimes lead to unreliable resolution, especially at interfaces of abrupt dielectric changes. We present an improved GPR tomography technique based on a combination of seismic tomographic methods and a finite-difference solution of the eikonal equation. Our inversion algorithm uses velocity gradient zones and bending rays that represent realistic geology in the subsurface. We tested the technique on theoretical and experimental models with anomalous bodies of varying saturations and velocity and applied it to data from a GPR field experiment that analyzed the root zones of trees. Synthetic results showed that the resolution of our technique is better than that of published methods, especially for local anomalies with sharp velocity contacts. Our laboratory experiments consisted of four objects buried in sand with various water saturations. The GPR tomogram could map the objects and determine their degree of saturation. The velocities are compatible with those of the complex refraction index method; their relationship to the water content fits a previously published empirical equation. Our original field experiment around a poplar tree could map the heterogeneous subsurface and distinguish a central low velocity beneath the tree from the peripheral negative anomaly of a refill. This zone reflects the whole root zone and is caused by its bulk water content of both the organic root network and its surrounding soils.
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Priori, Simone, Sergio Pellegrini, Nadia Vignozzi, and Edoardo A. C. Costantini. "Soil Physical-Hydrological Degradation in the Root-Zone of Tree Crops: Problems and Solutions." Agronomy 11, no. 1 (December 31, 2020): 68. http://dx.doi.org/10.3390/agronomy11010068.
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The diffusion of tree crops has continuously increased during the last decades all over the world. The market boost has favored the adoption of intensive and highly mechanized cultivation, often triggering the degradation of the soil physical-hydrological qualities, mainly through enhanced soil erosion and compaction. Several papers have been published on soil degradation and restoration strategies in specific perennial crops and environments. This review paper collects such studies showing the sensitivity of soil under tree crops to the degradation of their physical-hydrological qualities. Then it reports the state of the art on the methodologies used for the evaluation of the physical-hydrological qualities in the field and in the laboratory, also suggesting an improved methodology for estimating the actual available water capacity. Some updated and promising experiences to recover the physical-hydrological qualities of soil are then illustrated. In particular, subsoiling and placement of drainages, spreading of organic amendments, compost, biochar, using of cover crops, and biological inoculants. A key point in applying the restoration practices is that they should not only be specific for the soil and tree rooting system, but also tailored according to the ecosystem functions that need to be improved besides plant health and yield.
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Kassa Cholbe, Mesfin, Fassil Kebede Yeme, and Wassie Haile Woldeyohannes. "Fertility Status of Acid Soils under Different Land Use Types in Wolaita Zone, Southern Ethiopia." Applied and Environmental Soil Science 2020 (October 13, 2020): 1–9. http://dx.doi.org/10.1155/2020/3713967.
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Information on soil fertility status of acid soil of a particular area as affected by land use type is important for developing sound soil management systems for improved and sustainable agricultural productivity. The main objective of this study was to assess the fertility status and effect of land use change on soil physicochemical properties. In this study, adjacent three land use types, namely, enset-coffee, crop, and grazing land use were considered in four districts (i.e., Bolos Sore, Damot Gale, Damot Sore, and Sodo Zuria) of Wolaita Zone, southern Ethiopia. Soil samples were collected from a depth of 0–20 cm from each land use type of the respective districts for physicochemical analyses. The results showed that land use types significantly affected ( P ≤ 0.05 ) soil properties such as bulk density, available P, exchangeable potassium, exchangeable acidity, exchangeable bases (Na, K, Ca, Mg), exchangeable acidity, and CEC. Besides, soil pH, OC, and TN were influenced significantly ( P ≤ 0.05 ) both by districts and land use types. The very strongly acidic soils were found predominantly in the crop and grazing lands whereas a neutral acidity level was found in the enset-coffee land use type of four districts. In conclusion, the study proves that land use type change within the same geographic setting can affect the severity of soil acidity due to over cultivation and rapid organic matter decomposition. Finally, the study recommends an in-depth study and analysis on the root causes in aggravating soil acidity under crop and grazing land use types.
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Randall, Mark T., and Andrea Bradford. "Bioretention gardens for improved nutrient removal." Water Quality Research Journal 48, no. 4 (November 1, 2013): 372–86. http://dx.doi.org/10.2166/wqrjc.2013.016.
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Bioretention gardens are stormwater management practices capable of providing numerous water quantity and quality benefits. However, previous studies have reported inconsistent removal of nitrogen and phosphorus in these systems. This study used ten, vegetated, mesoscale (0.20 m3), bioretention cells in a field setting to provide a comparison of the nutrient removal capabilities of five, alternative bioretention designs. Applying a synthetic stormwater to the bioretention cells demonstrated that a sandy soil mix can provide a 75.5 and 53.4% reduction in concentrations of total phosphorus and total nitrogen, respectively. Phosphorus removal was found to be only slightly enhanced in bioretention cells where soil was amended with alum-based drinking water treatment residuals, a commercially available oxide-coated media, or a commercially available lanthanum-modified bentonite product. However, improvements in phosphorus removal were observed in some cells when elevated phosphorus loads were applied to evaluate longer term performance. In cells incorporating a permanently saturated zone containing shredded newspaper to promote denitrification, effluent concentrations of nitrate were reduced by >99%, however total nitrogen concentrations increased.
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Deb, Kousik, and Aparajita Behera. "Rate of Consolidation of Stone Column–Improved Ground Considering Variable Permeability and Compressibility in Smear Zone." International Journal of Geomechanics 17, no. 6 (June 2017): 04016128. http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000830.
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Rains, Dominik, Xujun Han, Hans Lievens, Carsten Montzka, and Niko E. C. Verhoest. "SMOS brightness temperature assimilation into the Community Land Model." Hydrology and Earth System Sciences 21, no. 11 (November 28, 2017): 5929–51. http://dx.doi.org/10.5194/hess-21-5929-2017.
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Abstract. SMOS (Soil Moisture and Ocean Salinity mission) brightness temperatures at a single incident angle are assimilated into the Community Land Model (CLM) across Australia to improve soil moisture simulations. Therefore, the data assimilation system DasPy is coupled to the local ensemble transform Kalman filter (LETKF) as well as to the Community Microwave Emission Model (CMEM). Brightness temperature climatologies are precomputed to enable the assimilation of brightness temperature anomalies, making use of 6 years of SMOS data (2010–2015). Mean correlation R with in situ measurements increases moderately from 0.61 to 0.68 (11 %) for upper soil layers if the root zone is included in the updates. A reduced improvement of 5 % is achieved if the assimilation is restricted to the upper soil layers. Root-zone simulations improve by 7 % when updating both the top layers and root zone, and by 4 % when only updating the top layers. Mean increments and increment standard deviations are compared for the experiments. The long-term assimilation impact is analysed by looking at a set of quantiles computed for soil moisture at each grid cell. Within hydrological monitoring systems, extreme dry or wet conditions are often defined via their relative occurrence, adding great importance to assimilation-induced quantile changes. Although still being limited now, longer L-band radiometer time series will become available and make model output improved by assimilating such data that are more usable for extreme event statistics.
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Rahayu, Rahayu, Jauhari Syamsiyah, and Laila Nikmatus Sa'diyah. "Aggregate stability of Alfisols root zone upon turfgrass treatment." SAINS TANAH - Journal of Soil Science and Agroclimatology 17, no. 1 (June 29, 2020): 50. http://dx.doi.org/10.20961/stjssa.v17i1.40455.
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<p>Soil degradation mostly occurs on land where a lack of surface coverage results in soil-aggregate destruction due to heavy rainfall. Turfgrass is an ornamental plant and covers the soil surface and, thus, potentially improves soil-aggregate stability. This study determined the potential of some summer grasses to improve soil-aggregate stability and was a pilot experiment using six turfgrass species: <em>Paspalum vaginatum</em>; middle-leaf <em>Zoysia sp.</em>; <em>Cynodon dactylon</em>; coarse-leaf <em>Zoysia sp.;</em> <em>Axonopus compressus</em>; <em>Zoysia matrella</em>. Turfgrasses were planted using stolons in a 0.6 m<sup>2</sup> plot unit with 5 cm x 5 cm space. Lawn maintenance included irrigation, fertilizing, and weeding. Soil characteristics were observed six months after planting and showed that turfgrass increased the soil-aggregate index from 42.3% to 83.0% in control, and carbon particles measuring 6.4 μm from 28.3% to 63.0%.</p>
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Sao, Davy, Hirotaka Saito, Tasuku Kato, and Jirka Šimůnek. "Numerical Analysis of Soil Water Dynamics during Spinach Cultivation in a Soil Column with an Artificial Capillary Barrier under Different Irrigation Managements." Water 13, no. 16 (August 9, 2021): 2176. http://dx.doi.org/10.3390/w13162176.
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Artificial capillary barriers (CBs) are used to improve root zone conditions as they can keep water and nutrients in the root zone by limiting downward percolation. Numerical analysis is one of the promising tools for evaluating CB systems’ performance during the cultivation of leafy vegetables. This study aims to investigate the effects of the CB system on soil water dynamics during spinach cultivation in a soil column under different irrigation scenarios using HYDRUS (2D/3D) by comparing uniform (UNI), line-source (LSI), and plant-targeted (PTI) irrigations combined with alternative irrigation schedules. Simulation results of volumetric soil water contents were generally corresponding to measured data. Simulation results with various hypothetical irrigation scenarios exhibited that the CB was an effective system to diminish percolation losses and improve the root zone’s soil water storage capacity. On the other hand, evaporation loss can be increased as more water is maintained near the surface. While this loss can be significantly minimized by reducing the water application area, the irrigation amount must be carefully defined because applying water in a smaller area may accelerate downward water movement so that the water content at the CB interface can reach close to saturation. In addition to the malfunction of the CB layer, it may also cause a reduction of plant root water uptake (RWU) because the root zone is too wet. Among evaluated irrigation scenarios, irrigating every two days with PTI was the best scenario for the spinach as water use efficiency was greatly improved.
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Wang, Cheng, Dan Bai, Yibo Li, Xinduan Wang, Zhen Pei, and Zuochao Dong. "Infiltration Characteristics and Spatiotemporal Distribution of Soil Moisture in Layered Soil under Vertical Tube Irrigation." Water 12, no. 10 (September 29, 2020): 2725. http://dx.doi.org/10.3390/w12102725.
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The limited quantity of irrigation water in Xinjiang has hindered agricultural development in the region and water-saving irrigation technologies are crucial to addressing this water shortage. Vertical tube irrigation, a type of subsurface irrigation, is a new water-efficient technology. In this study, field and laboratory experiments were conducted to analyze (1) the infiltration characteristics and spatiotemporal distribution of moisture in layered soil and (2) the water-saving mechanism of vertical tube irrigation. In the field experiments, we analyzed jujube yield, irrigation water productivity (IWP), and soil moisture in the jujube root zone. In the laboratory irrigation experiments, two soil types (silty and sandy loam) were selected to investigate homogeneous and layered soil, respectively. Cumulative infiltration, wetting body, and soil water moisture distribution were also analyzed. Relative to surface drip irrigation, vertical tube irrigation resulted in slightly lower jujube yields but higher savings in water use (47–68%) and improved IWP. The laboratory experiments demonstrated that layered soil had less cumulative infiltration, a larger ellipsoid wetted body, slower vertical wetting front migration (hindered by layer interface), and faster horizontal wetting front migration than homogenous soil had. The irrigation amount for vertical tube irrigation decreased in layered soil, and water content increased at the layer interface. Vertical tube irrigation in layered soil facilitates the retention of water in the root zone, prevents deep leakage, reduces irrigation amount, and improves the IWP of jujube trees. This study aids the popularization and application of vertical tube irrigation technology.
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Karpenko, N. P., D. K. Egemberdiev, and I. V. Glazunova. "Biomeliorant for the restoration of saline and degraded soils in the arid zone." IOP Conference Series: Earth and Environmental Science 1010, no. 1 (April 1, 2022): 012044. http://dx.doi.org/10.1088/1755-1315/1010/1/012044.
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Abstract The methods of gypsum application in degraded soils to increase and restore saline and degraded soils, to grow vegetables and fruits in the arid zone are considered in the paper. The issues of soil alkalinity reduction to increase soil fertility with the use of a new biomeliorant at standard of ST RK 2208-2012 containing phosphogypsum, calcium, sulfur and cattle manure with the addition of crushed camel thorn were studied. According to calculations this meliorant application reduces the loss of nitrogen and organic matter by 40%,, which being a highly effective fertilizer that improves the physico-chemical and biological properties of the soil, which contributes to an increase in crop yields. Field studies have shown that the joint anaerobic fermentation of phosphogypsum and manure, camel thorn led to intensive aggregation and the creation of favorable conditions of the soil structure for the crops. The results showed that the biomeliorant application into the soil led to a noticeable improvement in its structure, increases alkalinity, soils become more fertile and crop yields increase.
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Zhang, Zhong-Miao, Jun Yu, Guang-Xing Zhang, and Xin-Min Zhou. "Test study on the characteristics of mudcakes and in situ soils around bored piles." Canadian Geotechnical Journal 46, no. 3 (March 2009): 241–55. http://dx.doi.org/10.1139/t08-119.
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Constructing a bored pile produces a disturbed zone of soil adjacent to the pile, referred to as a “mudcake.” The physical properties of the mudcake are different from those of the surrounding soil. This paper reports research on bored piles in silt, clay, and sandy silt layers in Hangzhou, China. Laboratory tests were performed on samples of in situ soil, mudcake, and mudcake mixed with cement grout. The test results showed that mudcakes have a higher water content, higher void ratio, higher compressibility, lower friction, and lower shear strength than in situ soils. They also showed that mudcake properties could be improved by the addition of cement grout. Mudcakes form a weak, thin layer between a pile and a borehole wall, which can lead to a decrease in bearing capacity and an increase in settlement of the pile. Grouting improves the characteristics of mudcakes remarkably, thereby increasing the bearing capacity of piles, which is demonstrated by the case history in this paper.
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Lin, Shu, Dengfeng Fu, Zefeng Zhou, Yue Yan, and Shuwang Yan. "Numerical Investigation to the Effect of Suction-Induced Seepage on the Settlement in the Underwater Vacuum Preloading with Prefabricated Vertical Drains." Journal of Marine Science and Engineering 9, no. 8 (July 24, 2021): 797. http://dx.doi.org/10.3390/jmse9080797.
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Vacuum preloading combined with prefabricated vertical drains (PVDs) has the potential to improve the soft sediments under water, however, its development is partly limited by the unclear understanding of the mechanism. This paper aims to extend the comprehension of the influential mechanism of overlapping water in the scenario of underwater vacuum preloading with PVDs. The systematic investigations were conducted by small strain finite element drained analyses, with the separated analysis schemes considering suction-induced consolidation, seepage and their combination. The development of settlement in the improved soil region and the evolution of seepage flow from the overlapping water through the non-improved soil region into improved zone are examined in terms of the build-up of excess pore pressure. Based on the results of numerical analyses, a theoretical approach was set out. It was capable to estimate the time-dependent non-uniform settlement along the improved soil surface in response to the combined effects of suction-induced consolidation and seepage. The difference of underwater and onshore vacuum preloading with PVDs is discussed with some practical implication and suggestion provided.
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Choi, Hyun I., and Xin-Zhong Liang. "Improved Terrestrial Hydrologic Representation in Mesoscale Land Surface Models." Journal of Hydrometeorology 11, no. 3 (June 1, 2010): 797–809. http://dx.doi.org/10.1175/2010jhm1221.1.
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Abstract This study addresses several deficiencies in the existing formulations for terrestrial hydrologic processes in the Common Land Model (CLM) and presents improved solutions, focusing on runoff prediction. In particular, this paper has 1) incorporated a realistic geographic distribution of bedrock depth to improve estimates of the actual soil water capacity; 2) replaced an equilibrium approximation with a dynamic prediction of the water table to produce more reasonable variations of the saturated zone depth; 3) used an exponential decay function with soil depth for the saturated hydraulic conductivity to consider the effect of macropores near the ground surface; 4) formulated an effective hydraulic conductivity of the liquid part at the frozen soil interface and imposed a maximum surface infiltration limit to eliminate numerically generated negative or excessive soil moisture solution; and 5) examined an additional contribution to subsurface runoff from saturation lateral runoff or baseflow controlled by topography. To assess the performance of these modifications, runoff results from a set of offline simulations are validated at a catchment-scaled study domain around the Ohio Valley region. Together, these new schemes enable the CLM to capture well the major characteristics of the observed total runoff variations. The improvement is especially significant at peak discharges under high flow conditions.
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Kuril, Vasiliy, and Viktor Pryshlyak. "OPTIMIZATION OF PARAMETERS OF WORKING BODIES OF MACHINES FOR SUGAR BEET PRODUCTION." ENGINEERING, ENERGY, TRANSPORT AIC, no. 3(110) (October 30, 2020): 86–94. http://dx.doi.org/10.37128/2520-6168-2020-3-9.
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Existing technologies and modern technical means do not always provide the required quality of technological processes for growing sugar beets. Increasing requirements necessitate continuous improvement of existing and creation of new high-performance machines and units to ensure high-quality production technologies of sugar beet crops. Improved technological processes for the production of sugar beet crops are described in the article. Such technological processes include: loosening the compacted topsoil and destruction of the soil crust before the emergence of sugar beet shoots, loosening the soil after emergence, feeding sugar beets with increased soil hardness and low moisture content, inter-row soil cultivation with hilling plants in lines. As a result of research of technologies for inter-row processing of sugar beets in the system of crop care, the following ratio was established: the optimal depth and width of the strips for cutting the top layer of the soil, depending on the depth of placement of the sown seeds; the distance between the ribs of the roller, depending on the depth of cutting the soil; the maximum depth of soil loosening in the row zone and the row spacing zone, depending on the depth of sowing seeds and the placement of the root system of beets; the required depth of soil loosening in the aisles, depending on the specified optimal depth of application of mineral fertilizers in the aisles; the required distance from the conditional centerline of the beet rows to the zone of mineral fertilization in the aisles, etc. The use of optimized technological processes makes it possible to create the necessary conditions for the growth and development of sugar beet plants on heavy-textured soils and after a significant amount of precipitation and an increase in soil density. In addition, the proposed innovative technologies ensure the preservation and even increase of soil moisture, reduction of sparseness and contamination of crops, as well as losses and damage to sugar beet roots during harvesting. The research results can be used to improve and optimize zonal technologies and technical means for growing sugar beets in conditions of high density and insufficient soil moisture, as well as in the educational process in the preparation of future specialists from agricultural engineering for scientific project activities.
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Alzamily, Zaid Neamah, and Basim Sh Abed. "Comparison of Seepage Trough Zoned Earth dam Using Improved Light-Textured Soils." Journal of Engineering 28, no. 3 (March 1, 2022): 32–45. http://dx.doi.org/10.31026/j.eng.2022.03.03.
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Seepage through earth dams is one of the most popular causes for earth dam collapse due to internal granule movement and seepage transfer. In earthen dams, the core plays a vital function in decreasing seepage through the dam body and lowering the phreatic line. In this research, an alternative soil to the clay soil used in the dam core has been proposed by conducting multiple experiments to test the permeability of silty and sandy soil with different additives materials. Then the selected sandy soil model was used to represent the dam experimentally, employing a permeability device to measure the amount of water that seeps through the dam's body and to represent the seepage line. A numerical model was adopted using Geo-Studio software in the branch (SEEP/W) to simulate the experimental model, examined soils with different percentages of additives, and compared the numerical and experimental results to predict the innovation model of soil. It was found that the sandy type (C) soil model has a permeability very close to that of clay soil when using 10% cement kiln dust (CKD) and 5% cement as additives. Furthermore, soil type (C) was calibrated with the core soil of HIMREEN Earth dam, which is clay soil, as well as with the core soil of HADITHA Earth dam, which is composed of dolomite. The comparison between the results of the hypothetical simulated cases and the real cases were revealed a high agreement between the two cases according to the resulted of identical phreatic (seepage) lines and the calculated amount of seepages water from these cases.
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Ryabtseva, N. А. "ARGUMENTS OF SOIL PROTECTIVE CROP CULTIVATION TECHNOLOGY IN ZONE OF LOW MOISTURE." Vestnik of Ulyanovsk state agricultural academy, no. 3(50) (September 8, 2020): 47–52. http://dx.doi.org/10.18286/1816-4501-2020-3-47-52.
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In the article we show arguments for achieving the research goal- to get economically feasible crop yield growth of sunflower , spring barley and winter wheat in zone of low moisture of Rostov region against common and soil protective technology. The experiment was two-factorial: factor А – crop rotation link, factor B – crop cultivation technology. Soil protective technology with after harvesting and plant residues on soil surface affected moisture collection and conservation in soil at the cost of best preservation of snow cover, decrease of aeration. Soil protective technology allowed to preserve in the field from 84,5 to 95,1 % of plant residues, which increased show cover for 16,5-28,4%. Significant impact on soil density soil protective technology didn’t demonstrate. Compared to common, it helped to increase the number of earthworms in 4,3 times, which is the evidence of environmentally safe soil quality. Influence of soil protective technology on field emergence of studied cultures is established. Survival of cereal crops was higher for 2-5 %, and sunflower was lower for 5,4 %. All the cultures increased crop yield when using soil protective technology. Effect of transition to soil protective technology grew from year to year. Profitability raised in the first year for 11%, in the second for 13%, in the third for 36%. Spring barley and sunflower showed big response on this technology. Introduction of soil protective technology in average in years of experiments improved profitability for 20 %.
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Djaman, Koffi, Komlan Koudahe, Aminou Saibou, Murali Darapuneni, Charles Higgins, and Suat Irmak. "Soil Water Dynamics, Effective Rooting Zone, and Evapotranspiration of Sprinkler Irrigated Potato in a Sandy Loam Soil." Agronomy 12, no. 4 (March 31, 2022): 864. http://dx.doi.org/10.3390/agronomy12040864.
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Potato (Solanum tuberosum L.) is a very sensitive crop to water stress and timely irrigation water management improves tuber yield and quality. The objectives of this study were to (1) investigate soil water dynamics under potato crops across their root zone and (2) estimate potato crop evapotranspiration (ETa) under sprinkler irrigation on the sandy loam soil. The field experiment was conducted during the 2018 and 2019 growing seasons at the Navajo Farms within the Navajo Agricultural Products Industry, Farmington, NM. Two irrigation scheduling methods were evaluated as FAO-56 approach evapotranspiration-based scheduling and soil moisture sensing irrigation scheduling. Sentek capacitance soil moisture probe was used across four commercial potato fields in each year after calibration to the soil texture just after installation. Crop Evapotranspiration values estimated by the water balance method and the two-step approach were compared to the satellite-based models used in OpenET. The results showed that the potato’s effective rooting zone is the upper 40 cm soil layer. Potato plants extracted more than 50% of total water from the upper 15 cm of the soil profile and about 85% from the upper 40 cm of the soil profile. Little water amount was extracted from the 40–60 cm soil water. Potato crop seasonal evapotranspiration averaged 580 to 645 mm in 2018 and 2019, respectively. The Two-step approach ETa values of 795.5 and 832.7 mm in 2018 and 2019, respectively, were higher than the soil water balance estimated ETa. The satellite modeled ETa varied with field and years and ranged from 437 to 759 mm and averaged 570.4 mm for the 2016–2020 period. Soil moisture probe-based irrigation scheduling improved irrigation water management and the irrigation water use of potatoes in the semiarid climate.
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Rovira, AD. "Dryland mediterranean farming systems in Australia." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 801. http://dx.doi.org/10.1071/ea9920801.
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The mediterranean region of Australia extends from Geraldton in Western Australia across southern Australia into western and northern Victoria. This region experiences hot, dry summers and cool, wet winters, with 300-600 mm annual rainfall. In the dryland farming zone, the cereal-livestock farming system dominates and produces 30-35% of Australia's total agricultural production. The major soils in the region are deep, coarse-textured sands and sandy loams, duplex soils with coarse-textured sands over clay (generally low in nutrients and organic matter), and fine-textured red-brown earths of low hydraulic conductivity. Major soil problems in the region include sodicity, salinity, soil structural degradation, nutrient deficiencies, boron toxicity, acidity, waterlogging, inadequate nitrogen nutrition, water-repellence, and root diseases. These problems have been exacerbated by excessive clearing of trees, increased frequency of cropping, reduced area sown to pastures, declining pasture production, and a decline in nutrient levels. With improved soil management there is potential for increased productivity from dryland farming areas of the region and improved ecological sustainability.
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Zhou, Jizhong, Beicheng Xia, David S. Treves, L. Y. Wu, Terry L. Marsh, Robert V. O’Neill, Anthony V. Palumbo, and James M. Tiedje. "Spatial and Resource Factors Influencing High Microbial Diversity in Soil." Applied and Environmental Microbiology 68, no. 1 (January 2002): 326–34. http://dx.doi.org/10.1128/aem.68.1.326-334.2002.
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ABSTRACT To begin defining the key determinants that drive microbial community structure in soil, we examined 29 soil samples from four geographically distinct locations taken from the surface, vadose zone, and saturated subsurface using a small-subunit rRNA-based cloning approach. While microbial communities in low-carbon, saturated, subsurface soils showed dominance, microbial communities in low-carbon surface soils showed remarkably uniform distributions, and all species were equally abundant. Two diversity indices, the reciprocal of Simpson’s index (1/D) and the log series index, effectively distinguished between the dominant and uniform diversity patterns. For example, the uniform profiles characteristic of the surface communities had diversity index values that were 2 to 3 orders of magnitude greater than those for the high-dominance, saturated, subsurface communities. In a site richer in organic carbon, microbial communities consistently exhibited the uniform distribution pattern regardless of soil water content and depth. The uniform distribution implies that competition does not shape the structure of these microbial communities. Theoretical studies based on mathematical modeling suggested that spatial isolation could limit competition in surface soils, thereby supporting the high diversity and a uniform community structure. Carbon resource heterogeneity may explain the uniform diversity patterns observed in the high-carbon samples even in the saturated zone. Very high levels of chromium contamination (e.g., >20%) in the high-organic-matter soils did not greatly reduce the diversity. Understanding mechanisms that may control community structure, such as spatial isolation, has important implications for preservation of biodiversity, management of microbial communities for bioremediation, biocontrol of root diseases, and improved soil fertility.
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Kassa, Mesfin, Fassil Kebede, and Wassie Haile. "Forms and Dynamics of Soil Potassium in Acid Soil in the Wolaita Zone of Southern Ethiopia." Applied and Environmental Soil Science 2021 (October 26, 2021): 1–10. http://dx.doi.org/10.1155/2021/9917316.
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Quantity-intensity (Q/I) characteristics are among conventional approaches for studying potassium dynamics and its availability. This was assessed to determine availability in four districts: namely, Sodo Zuria, Damot Gale, Damot Sore, and Boloso Sore, at three different land use systems (enset-coffee, crop land, and grazing land). Fractionation and dynamics of K sources were studied in soil samples, which were collected from 0–20 cm depth of each land system. The study revealed that water extractable K (H2O-K) concentrations ranged from 0.13 to 0.34 cmolc kg−1 soils at enset-coffee and grazing land use systems, respectively, and had a mean value of 0.28 cmolc kg−1 soils ammonium acetate extractable (NH4OAC-K) and nitric acid extract (HNO3-K) had a mean value of 0.25 cmolc kg−1 soils. In this study, the means of nonexchangeable- and exchangeable-K concentrations were of 0.11 and 0.14 cmolc kg−1 soils for land use types. Significant correlations were found between soil properties and Q/I parameters and among equilibrium solution parameters and Q/I parameters. There was no significant variation among the mean quantity values of the soils. The soils had higher change in exchangeable-K and potential buffering capacity than the enset-coffee land use soils, and the cop land had the highest values for these parameters. However, the enset-coffee land use soils had higher K-intensity. Therefore, application of site specific soil fertility management practices and research can improve soil K status and Q/I parameters to sustain productivity soils.
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Gardner, WK, and GK McDonald. "Responses by wheat to lupin, soil amelioration and fertilizer treatments in a solodised solonetz soil." Australian Journal of Experimental Agriculture 28, no. 5 (1988): 607. http://dx.doi.org/10.1071/ea9880607.
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Disruption of the junction of the A-B horizons of a yellow duplex soil did not affect moisture extraction or grain yield of wheat grown in the Southern Wimmera, and it is unlikely that this zone represents a serious impediment to root growth. However, improving soil fertility, either by growing lupins or by placing nitrogen and phosphorus in the A2 horizon, did increase yields. Following lupins in 1983, wheat yield increased from 4.3 to 55 t/ha in 1984,andfrom 3.1 to3.7 t/ha in 1985. This response was greater than that due to deep placement of nitrogen and phosphorus (0.3 t/ha in 1984,0.4 t/ha in 1985), probably because of improved root growth as a result of less root disease. There were consistent responses to foliar applications of copper and interactions with other treatments; the greatest responses occurred in situations of improved nitrogen nutrition.
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Grau, Joan, Kang Liang, Jae Ogilvie, Paul Arp, Sheng Li, Bonnie Robertson, and Fan-Rui Meng. "Improved Accuracy of Riparian Zone Mapping Using Near Ground Unmanned Aerial Vehicle and Photogrammetry Method." Remote Sensing 13, no. 10 (May 20, 2021): 1997. http://dx.doi.org/10.3390/rs13101997.
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In agriculture-dominant watersheds, riparian ecosystems provide a wide array of benefits such as reducing soil erosion, filtering chemical compounds, and retaining sediments. Traditionally, the boundaries of riparian zones could be estimated from Digital Elevation Models (DEMs) or field surveys. In this study, we used an Unmanned Aerial Vehicle (UAV) and photogrammetry method to map the boundaries of riparian zones. We first obtained the 3D digital surface model with a UAV. We applied the Vertical Distance to Channel Network (VDTCN) as a classifier to delineate the boundaries of the riparian area in an agricultural watershed. The same method was also used with a low-resolution DEM obtained with traditional photogrammetry and two more LiDAR-derived DEMs, and the results of different methods were compared. Results indicated that higher resolution UAV-derived DEM achieved a high agreement with the field-measured riparian zone. The accuracy achieved (Kappa Coefficient, KC = 63%) with the UAV-derived DEM was comparable with high-resolution LiDAR-derived DEMs and significantly higher than the prediction accuracy based on traditional low-resolution DEMs obtained with high altitude aerial photos (KC = 25%). We also found that the presence of a dense herbaceous layer on the ground could cause errors in riparian zone delineation with VDTCN for both low altitude UAV and LiDAR data. Nevertheless, the study indicated that using the VDTCN as a classifier combined with a UAV-derived DEM is a suitable approach for mapping riparian zones and can be used for precision agriculture and environmental protection over agricultural landscapes.
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Batukaev, Abdul-Malik A., Anatoly P. Endovitsky, Andrey G. Andreev, Valery P. Kalinichenko, Tatiana M. Minkina, Zaurbek S. Dikaev, Saglara S. Mandzhieva, and Svetlana N. Sushkova. "Ion association in water solution of soil and vadose zone of chestnut saline solonetz as a driver of terrestrial carbon sink." Solid Earth 7, no. 2 (March 15, 2016): 415–23. http://dx.doi.org/10.5194/se-7-415-2016.
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Abstract. The assessment of soil and vadose zone as the drains for carbon sink and proper modeling of the effects and extremes of biogeochemical cycles in the terrestrial biosphere are the key components to understanding the carbon cycle, global climate system, and aquatic and terrestrial system uncertainties. Calcium carbonate equilibrium causes saturation of solution with CaCO3, and it determines its material composition, migration and accumulation of salts. In a solution electrically neutral ion pairs are formed: CaCO30, CaSO40, MgCO30, and MgSO40, as well as charged ion pairs CaHCO3+, MgHCO3+, NaCO3−, NaSO4−, CaOH+, and MgOH+. The calcium carbonate equilibrium algorithm, mathematical model and original software to calculate the real equilibrium forms of ions and to determine the nature of calcium carbonate balance in a solution were developed. This approach conducts the quantitative assessment of real ion forms of solution in solonetz soil and vadose zone of dry steppe taking into account the ion association at high ionic strength of saline soil solution. The concentrations of free and associated ion form were calculated according to analytical ion concentration in real solution. In the iteration procedure, the equations were used to find the following: ion material balance, a linear interpolation of equilibrium constants, a method of ionic pairs, the laws of initial concentration preservation, operating masses of equilibrium system, and the concentration constants of ion pair dissociation. The coefficient of ion association γe was determined as the ratio of ions free form to analytical content of ion γe = Cass∕Can. Depending on soil and vadose zone layer, concentration and composition of solution in the ionic pair's form are 11–52 % Ca2+; 22.2–54.6 % Mg2+; 1.1–10.5 % Na+; 3.7–23.8 HCO3−, 23.3–61.6 % SO42−, and up to 85.7 % CO32−. The carbonate system of soil and vadose zone water solution helps to explain the evolution of salted soils, vadose and saturation zones, and landscape. It also helps to improve the soil maintenance, plant nutrition and irrigation. The association of ions in soil solutions is one of the drivers promoting transformation of solution, excessive fluxes of carbon in the soil, and loss of carbon from soil through vadose zone.
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Lu, Yang, Jianzhi Dong, and Susan C. Steele-Dunne. "Impact of Soil Moisture Data Resolution on Soil Moisture and Surface Heat Flux Estimates through Data Assimilation: A Case Study in the Southern Great Plains." Journal of Hydrometeorology 20, no. 4 (April 1, 2019): 715–30. http://dx.doi.org/10.1175/jhm-d-18-0234.1.
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Abstract The spatial heterogeneity and temporal variation of soil moisture and surface heat fluxes are key to many geophysical and environmental studies. It has been demonstrated that they can be mapped by assimilating soil thermal and wetness information into surface energy balance models. The aim of this work is to determine whether enhancing the spatial resolution or temporal sampling frequency of soil moisture data could improve soil moisture or surface heat flux estimates. Two experiments are conducted in an area mainly covered by grassland, and land surface temperature (LST) observations from the Geostationary Operational Environmental Satellite (GOES) mission are assimilated together with either an enhanced L-band passive soil moisture product (9 km, 2–3 days) from the Soil Moisture Active Passive (SMAP) mission or a merged product (36 km, quasi-daily) from the SMAP and the Soil Moisture Ocean Salinity (SMOS) mission. The results suggest that the availability of soil moisture observations is increased by 41% after merging data from the SMAP and the SMOS missions. A comparison with results from a previous study that assimilated a coarser SMAP soil moisture product (36 km, 2–3 days) suggests that enhancing the temporal sampling frequency of soil moisture observations leads to improved soil moisture estimates at both the surface and root zone, and the largest improvement is seen in the bias metric (0.008 and 0.007 m3 m−3 on average at the surface and root zone, respectively). Enhancing the spatial resolution, however, does not significantly improve soil moisture estimates, particularly at the surface. Surface heat flux estimates from assimilating soil moisture data of different spatial or temporal resolutions are very similar.
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Ibrahim, P. A., A. Y. Adepoju, and E. D. Imolehin. "RESPONSE OF MAIZE (ZEA MAYS) TO TERRALLYT-PLUS (SOIL CONDITIONER) APPLICATION IN CENTRAL ZONE OF NIGERIA." Acta Agronomica Hungarica 48, no. 4 (January 1, 2001): 409–12. http://dx.doi.org/10.1556/aagr.48.2000.4.11.
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One of the known agricultural practices by which degraded soils can be restored and rehabilitated to an optimum level of productivity is by the use of synthetic organic materials, called soil conditioners. In a greenhouse experiment at the National Cereals Research Institute (NCRI), Badeggi, located in the Southern Guinea Savannah Agro-Ecological Zone (Lat. 9o45'N. Long 6o7'E, Alt. 70.57 metres above sea level) the soil conditioner Terrallyt-Plus was evaluated on soils from three locations within the Central Zone of Nigeria. The results obtained indicate that the addition of Terrallyt-Plus did not improve the yield of maize or the status of the soils.