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Recent research has demonstrated the ability of a fenclorim seed treatment to reduce rice (Oryza sativa L.) injury to acetochlor. However, all studies were conducted on silt loam soils and have not evaluated rice tolerance or weed control on clay soils. Experiments were initiated in 2021 and 2022 at the Northeast Research and Extension Center near Keiser, AR, to determine rice response and the effectiveness of delayed‐preemergence (DPRE)‐applied microencapsulated (ME) acetochlor (1.1, 1.7, and 2.3 lb ai acre−1) when applied to a clay soil with and without a fenclorim seed treatment at 0 or 2.5 lb ai 1000‐lb−1 of seed. Averaged over the fenclorim seed treatment, acetochlor at 1.1 and 1.7 lb ai acre−1 caused similar injury levels to rice; however, barnyardgrass [Echinochloa crus‐galli (L.) P. Beauv.] control increased at 1.7 lb ai acre−1, eliciting 19% injury to rice and 82% barnyardgrass control at 28 days after emergence (DAE). Palmer amaranth (Amaranthus palmeri S. Watson) control ranged from 82% to 93%. Additionally, fenclorim did not influence barnyardgrass or Palmer amaranth control, but it did reduce rice injury and increase shoot density, plant height, and rough rice grain yield. At 14 and 28 DAE, fenclorim at 2.5 lb ai 1000‐lb−1 of seed (averaged over acetochlor rates) reduced visible rice injury from 61% to 13% and 40% to 8%, respectively. Results from this study indicate ME acetochlor could be successfully applied to rice grown on a clay soil when a fenclorim seed treatment is used, providing producers a new site of action for use in U.S. rice production. Plain Language Summary: Rice producers in the Southern United States need new effective herbicides to control problematic weeds. Research has shown that acetochlor (Warrant herbicide), while not labeled, could be used to control barnyardgrass in rice, but crop tolerance is a concern. Fenclorim has been used as an herbicide safener seed treatment to reduce rice injury to microencapsulated acetochlor, but this research was conducted on medium textured soils (silt loam). Rice tolerance has not been demonstrated on clay soils and heavier soils tend to bind more herbicide, which would mean higher rates are needed for adequate control. We observed good crop tolerance with acetochlor at 1.7 lb ai/acre (4.5 pt/A warrant) and a fenclorim seed treatment. This rate also demonstrated up to 82% barnyardgrass and Palmer amaranth control 28 days after the rice emerged. If a microencapsulated acetochlor were to become labeled in rice, producers could use it as an alternative residual herbicide option within a program. [ABSTRACT FROM AUTHOR]

Lack of attention to rural healthcare for livestock in the southeastern United States has led to a focus on small ruminant farming, mainly using sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don], a drought-resistant forage species with nutraceutical benefits. Climate change has increased land availability for SL cultivation, further expanding the potential of this bioactive (anti-parasitic) legume. This study aims to create a geospatial engineering and technology-assisted model for identifying suitable SL production areas for supporting profitable small ruminant farming. The cultivation of SL depends on specific weather conditions and soil properties, with minimum requirements for temperature and rainfall, non-clay soil with reduced bulk density, and open land cover. The main objective was to develop an automated geospatial model using ArcGIS Pro ModelBuilder to assess SL production suitability. This model also aimed to identify appropriate locations for small ruminant production in Georgia in the southeastern United States, characterized by increasing temperature fluctuations. A web-based geographic information system (webGIS) platform was developed using the ArcGIS Online dashboard interface, allowing agriculturalists to access decision support for SL production suitability tailored to their land. This forage production suitability analysis, conducted in the context of climate change, offers valuable guidance for pasture managers in other nations with similar environmental attributes, promoting global adaptability and resilience. [ABSTRACT FROM AUTHOR]

• A relationship between soil carbon, soil clay, and median soil aggregate size is derived. • A model of eroded sediment aggregation responsive to land management is proposed for RUSLE2. • Modeled macro-aggregation changes over time are compared to published observations. Land management that improves soil quality is known to increase the amount of water-stable soil aggregates, but many current soil erosion models do not consider land management effects when estimating the size distribution of eroded sediment. Our objective was to develop a method to improve eroded sediment size estimates in response to alternative land management practices using information available within the RUSLE2 model and its database. We conducted a literature search identifying 274 soil aggregate size distributions where soil clay and soil organic carbon were also reported. The median value and log-normal standard deviation were estimated for each distribution. Median value was found to be linearly related to soil clay fraction and quadratically related to soil carbon content. However, the 10% of samples with observed median aggregate sizes greater than 3 mm were all underestimated by the regression model. All these samples were collected from soils under land use described as grass, pasture, or forest. To then determine whether incorporating management impacts on size distribution could better fit field data than this simple approach based purely on clay and carbon, algorithms termed MAS (Model of Aggregated Sediment) were derived and applied with default values in the RUSLE2 soil erosion model to estimate a coarser sediment size distribution at the point of detachment for land management with increased biomass inputs and reduced tillage disturbances. The MAS estimates of macroaggregated sediment (>0.212 mm) mirrored fragment size observations made over 10 yr when cropland was converted to prairie in the central U.S.A. Thus, MAS estimated dynamic land management effects on aggregation better than regression relationships based solely on soil clay and carbon contents. More aggregate and sediment size datasets that include historical land use information will be needed to fully assess the generality of the MAS algorithms and parameter estimates. [ABSTRACT FROM AUTHOR]

The aim of this work is to determine viscoelastic behavior parameters of soil pastes and micromonoliths of natric and vertic horizons in the profile of Vertic Solonetz from the Kamennaya Steppe (Voronezh oblast, Russia) and to use rheological properties to explain the formation of three irregular alteration structures with different wavelengths and deformation patterns of the soil mass. The rheological parameters of six soil horizons were determined by the amplitude sweep tests using an MCR-302 rheometer with parallel plates. The general features of viscoelastic behavior of soil pastes and micromonoliths, the correlation between the storage modulus G'LVR in the linear range of viscoelastic behavior of pastes and micromonoliths with their moisture, the distribution of rheological properties in the soil profile, and the relationship between the content of exchangeable sodium and the integral Iz used for the evaluation of structural stiffness are discussed. Rheological properties of Vertic Solonetz are compared with published data on Vertisols from Brazil, Russia, and USA and on saline clay alluvial soil from Spain. A hypothesis of formation of the profile of Vertic Solonetz with the gilgai microtopography as dependent on the rheological characteristics of the viscoelastic behavior of the studied soil horizons is proposed. [ABSTRACT FROM AUTHOR]

Coastal Plain soils of the southeastern United States are highly degraded, with low soil organic carbon (C), meager soil fertility, and poor soil structure. We tested the effectiveness of clay soil amendment to promote the formation of soil aggregates, improve organic C stability, and enhance nutrient availability in field. Subsurface clay soils (B horizon, 25% clay) were applied (∼25 T ha–1) to the top of the soil surface, followed by the planting of winter cover crop mixtures. Crop growth and nutrient uptake and relevant soil biogeochemical properties were analyzed at the end of the winter season. Additions of subsurface clay soils prompted the formation of water-stable macroaggregates (250–2000 mm) from 32 to 54% and increased mean weight diameter of the aggregates from 390 to 592 mm. Additions of subsurface clay soils increased clay content from 1.5 to 3.8% but did not change soil texture, pH, water holding capacity, and bulk density. The stock of dissolved organic nitrogen was not affected by the amendment, whereas nitrate leaching from field was reduced by 61% because of clay soil application. Clay soil additions inhibited the activities of C-cycling (N-acetyl-β-glucosaminidase, β-d-cellubiosidase, β-glucosidase, and β-xylosidase) and N-cycling (leucine aminopeptidase) enzymes but did not modify soil microbial community level substrate utilization patterns, resulting in a 63% reduction in C turnover rate and 19% increases in concentrations of labile organic C. Our results indicated that subsurface clay soil amendment can improve soil structure, nutrient availability, and the stability of labile C in the field, at least in the short term, and may be a promising management alternative to enhance the productivity and sustainability of the degraded Coastal plain soils. [ABSTRACT FROM AUTHOR]

A brief review of world experience in mapping the mineralogical composition of soils is given; in particular, the results gained in Great Britain (England and Wales), Canada, the United States, Australia, Hungary, the former Soviet Union, and Russia are analyzed. In the majority of countries, the composition of clay minerals was the only object of mapping, except for the United States, for which the data on the mineral composition of coarse fractions were included. This publication is aimed at the analysis of the experience in mapping the mineralogical composition of soils in Moldova—a small country with steppe and forest-steppe landscapes—and elucidates the achievements and problems in this area. Unlike other countries, where the associations of clay mineral were the object of mapping, the specific mineralogical composition of soils and parent materials in Moldova, together with the development and application of appropriate analytical methods and databases, made it possible to compile the maps reflecting the contents of individual minerals both in the clay and coarse fractions. For the first time, digital maps of the contents of various minerals in soils of Moldova were developed on the basis of data of quantitative X-ray diffractometry and their statistical analysis. A close relationship was found between the content of certain minerals and the particle-size distribution data, which permitted us to perform mapping of the mineralogical composition of soils with due account for their textures. As an example, digital maps of the contents of clay minerals (smectite and illite) in the A horizon and in the parent material of Moldavian chernozems and forest soils on a scale of 1 : 3 M are presented. Statistical data on the contents of these minerals in the soils of different textures are discussed. The content of smectite varies within 6–43%, and the content of illite varies within 3–16%. Their distribution in the soil profiles attests to a statistically reliable difference between the contents of these minerals in the A horizon and in the parent material. The mapping procedure is described, and the areas of the practical application of such maps are specified. [ABSTRACT FROM AUTHOR]

Many challenges currently facing agriculture require long-term data on landscape-scale hydrologie responses to weather, such as from the Goodwater Creek Experimental Watershed (GCEW), located in northeastern Missouri, USA. This watershed is prone to surface runoff despite shallow slopes, as a result of a significant smectitic clay layer 30 to 50 cm deep that restricts downward flow of water and gives rise to a periodic perched water table. This paper is the first in a series that documents the database developed from GCEW. The objectives of this paper are to (i) establish the context of long-term data and the federal infrastructure that provides it, (ii) describe the GCEW/Central Mississippi River Basin (CMRB) establishment and the geophysical and anthropogenic context, (iii) summarize in brief the collected research results published using data from within GCEW, (iv) describe the series of papers this work introduces, and (v) identify knowledge gaps and research needs. The rationale for the collection derives from converging trends in data from long-term research, integration of multiple disciplines, and increasing public awareness of increasingly larger problems. The outcome of those trends includes being selected as the CMRB site in the USDA-ARS Long-Term Agro-Ecosystem Research (LTAR) network. Research needs include quantifying watershed scale fluxes of N, P, K, sediment, and energy, accounting for fluxes involving forest, livestock, and anthropogenic sources, scaling from near-term point-scale results to increasingly long and broad scales, and considering whole-system interactions. This special section informs the scientific community about this database and provides support for its future use in research to solve natural resource problems important to US agricultural, environmental, and science policy. [ABSTRACT FROM AUTHOR]

Abstract: A red clay subsoil is commonly found in the soils of the Driftless Area of Wisconsin, USA. The red clay is buried by a layer of loess and occurs on uplands underlain by dolostone. It is assumed to have derived from the impurities of the weathered dolostone. The red clay has implications for groundwater recharge and lateral flow of water through the landscape as well as the fixation of excess phosphorus from animal manure and inorganic fertilizers. Here we have produced digital soil maps at different levels of probability of the red clay presence, the depth to the red clay, and its thickness. Five hundred and sixty-one soil observations were made in a 7000ha study area and were used to investigate the relationship of the red clay to landscape characteristics and short range soil variability. Soil observations and environmental data were used to create digital soil maps using regression models and kriging. Compared to the described soil series for the study area it was found that the red clay is less red, about 10cm thinner and contains 15% less clay. At 60% probability, the model predicts 2600ha with red clay compared to 3300ha from the Soil Survey Geographic database (SSURGO), 2000ha with a 30 to 55cm loess cover (vs. 1600ha from SSURGO) and 1700ha with greater 15cm red clay thickness (vs. 3300ha from SSURGO). It is concluded that SSURGO overestimates the total area with red clay and the thickness of the clay. This study also showed how a clay subsoil can be mapped at different levels of probability. [Copyright &y& Elsevier]

Since 1993, the Red River of the North Valley in North Dakota (ND) and Minnesota (MN), in the USA has experienced increased annual rainfall which has caused localized seasonal soil waterlogging and inhibited crop yield potential in the unique, high water table clay soils of the region. Subsurface (tile) drainage has been increasingly considered by farmers to help reduce excess water in the crop root zone. Producers desire to manage the water table for optimizing yield and trafficability of the field. The objective of this research was to evaluate differences in soil penetration resistance and water table depth between subsurface (drained) and non-subsurface drained treatments (undrained), using water control structures, in fallow, and cropped soybean (Glycine max L. Merr.) and wheat (Triticum aestivum L. emend. Thell.) cultivars on a Fargo-Ryan silty clay soil near Fargo, ND, USA in 2009 and 2010. The experimental design was a randomized complete block in a split-plot arrangement with four replicates. The whole plot treatments were drained and undrained (control structures opened and closed, respectively). Soil penetrometer readings and water table depth were measured weekly. Yields of each crop were not different comparing drained and undrained treatments in 2009 and 2010. The depth averaged drained penetration resistance was 1,211 kPa compared with 1,097 kPa for undrained treatment, averaged across 2009 and 2010. The depth-averaged drained penetration resistance values for fallow, soybean, and wheat were 1,077, 1,137, and 1,420 kPa, respectively. The undrained values for fallow, soybean and wheat were 1,001, 1,021, and 1,267 kPa, respectively, all significantly lower than the drained treatments, indicating that the drained soil is capable of a higher load carrying capacity compared to the undrained soil. The average depth to the water table was greater on drained soil compared to the undrained soil both early and late in the growing season. Forty two percent of the variation in the penetration resistance can be explained by the level of the water table below the surface. Water control structures can be used to manage the water table level and soil penetrations resistance. The ability for land managers to enter drained fields with farm equipment earlier will likely extend the length of the growing season and potentially increase crop yields in this region. [ABSTRACT FROM AUTHOR]

Abstract: Local, field-scale, VisNIR-DRS soil calibrations generally yield the most accurate predictions but require a substantial number of local calibration samples at every application site. Global to regional calibrations are more economically efficient, but don''t provide sufficient accuracy for many applications. In this study, we quantified the value of augmenting a large global spectral library with relatively few local calibration samples for VisNIR-DRS predictions of soil clay content (clay), organic carbon content (SOC), and inorganic carbon content (IC). VisNIR models were constructed with boosted regression trees employing global, local+global, and local spectral data, using local samples from two low-relief, sedimentary bedrock controlled, semiarid grassland sites, and one granitic, montane, subalpine forest site, in Montana, USA. The local+global calibration yielded the most accurate SOC predictions for all three sites [Standard Error of Prediction (SEP)=3.8, 6.7, and 26.2 g kg−1]. This was similarly true for clay (SEP=95.3 and 102.5 g kg−1) and IC (SEP=5.5 and 6.0 g kg−1) predictions at the two semiarid grassland sites. A purely local calibration produced the best validation results for soil clay content at the subalpine forest site (SEP=49.2 g kg−1), which also had the largest number of local calibration samples (N =210). Using only samples from calcareous soils in the global spectral library combined with local samples produced the best SOC and IC results at the more arid of the two semiarid sites. Global samples alone never achieved more accurate predictions than the best local+global calibrations. For the temperate soils used in this study, the augmentation of a large global spectral library with relatively few local samples generally improved the prediction of soil clay, SOC, and IC relative to global or local samples alone. [Copyright &y& Elsevier]

The purpose of this study is to evaluate the adequacy of the 100-year discharge along with the Froehlich bridge abutment scour equation adopted by the U.S. Federal Highway Administration (FHwA) in predicting abutment scour for bridge design purposes in South Carolina streams. The analysis utilized bridge properties, stream cross-sectional and hydraulic data, local flood frequency equations, a one-dimensional steady river flow computer model (WSPRO), and procedures recommended by the FHwA for predicting abutment scour. A method was developed to identify the single stream-discharge at each bridge that can cause the abutment scour that was observed at 73 bridge abutments. Analysis of the results revealed that for one-third of the abutments in the sandy soil region of South Carolina, the flow rates required to produce the observed scour depths had return periods greater than 100 years. Although for bridges in the region dominated by clay soil, the return periods were significantly smaller than 100 years. [ABSTRACT FROM AUTHOR]

Abstract  The studies of excavations in soft clayey soils are normally based on undrained total stress analyses. A better approach consists of taking into account the effects of consolidation during the excavation-bracing process and after the completion of the construction by means of coupled finite element analyses in effective stresses. In this paper, the geotechnical behaviour of a braced excavation in the soft soils of San Francisco (USA) is analysed, both during and after the construction period. Numerical analyses are performed with a finite element program, which incorporates the Biot consolidation theory (coupled formulation of the water flow and equilibrium equations) and soil constitutive relations simulated by the p-q-θ critical state model. Numerical results are compared with field results. [ABSTRACT FROM AUTHOR]

A new irrigation scheduling tool called the UGA EASY Pan (Evaporation-based Accumulator for Sprinkler-enhanced Yield) allows remote observation of evaporation that can be correlated with crop water use. The pan was developed at the University of Georgia and was evaluated in Mississippi for low frequency irrigation of cotton in clay soils. To establish a baseline trigger level for irrigation, granular matrix soil water sensors were placed at three depths and four stations in a 3-ha field planted in a Sharkey series clay soil. Stoneville BXN 47 was planted for the 2002 and 2003 seasons and Stoneville 4892 BR was planted for 2004. Pan use and temporal adjustment criteria were developed during the 2003 season and further evaluated using data from 2004 and the previous year (2002). Irrigation was initiated based on field manager recommendations without assistance from scheduling aids so that pan readings could be associated with the field manager's irrigation decisions. Recommendations were made for temporal adjustment of the pan taking into account increased evapotranspiration based on sensor data analyzed post-season. To account for increased crop water demand in 2003 and 2004, a recommendation was made for a second adjustment approximately 97 days after planting (DAP) or 28 days after white bloom. This additional adjustment was also verified to be suitable to signal irrigation 112 DAP (43 days after white bloom) in 2003 that coincided with a trigger signal from sensor readings. Based on subsequent analysis of sensor readings as a baseline reference, one irrigation could have been delayed and another eliminated for 2003 (a 25% water savings), and the first irrigation could have been eliminated for 2004 (a 33% water savings) if pan recommendations had been followed to schedule irrigation. [ABSTRACT FROM AUTHOR]

Understanding the processes controlling Pu mobility in the subsurface environment is important for estimating the amount of Pu waste that can be safely disposed in vadose zone burial sites. To study long-term Pu mobility, four 52-L lysimeters filled with sediment collected from the Savannah River Site near Aiken, South Carolina were amended with well-characterized solid Pu sources (PuIIICl3, PuIV(NO3)4, PuIV(C2O4)2, and PuVIO2(NO3)2) and left exposed to natural precipitation for 2-11 years. Pu oxidation state distribution in the Pu(III) and Pu(IV) lysimeters sediments (a red clayey sediment, pH = 6.3) were similar, consisting of 0% Pu(III), >92% Pu(IV), 1% Pu(V), 1% Pu(VI), and the remainder was a Pu polymer. These three lysimeters also had near identical sediment Pu concentration profiles, where >95% of the Pu remained within 1.25 cm of the source after 11 years; the other 5% of Pu moved at an overall rate of 0.9 cm yr-1. As expected, Pu moved more rapidly through the Pu(VI) lysimeter, at an overall rate of 12.5 cm yr-1. Solute transport modeling of the sediment Pu concentration profile data in the Pu(VI) lysimeter indicated that some transformation of Pu into a much less mobile form, presumably Pu(IV), had occurred during the course of the two-year study. This modeling also supported previous laboratory measurements showing that Pu(V) or Pu(VI) reduction was 5 orders of magnitude faster than corresponding Pu(III) or Pu(IV) oxidation. The slow oxidation rate (1 × 10-8 hr-1 t½ = 8000 yr) was not discernible from the Pu(VI) lysimeter data that reflected only two years of transport but was readily discernible from the Pu(III) and Pu(IV) lysimeter data that reflected 11 years of transport. [ABSTRACT FROM AUTHOR]

This article focuses on the recovery and distribution of biosolids-derived trace metals in a clay loam soil. Land application of biosolids increases metal concentrations in soils. The U.S. Environmental Protection Agency (EPA) developed a risk assessment method to evaluate the potential negative effects of pollutants in biosolids. The U.S. EPA 40 CFR Part 503 was promulgated as the Standards for the Use and Disposal of Sewage Sludge. The Part 503 rule permits long-term application of biosolids to agricultural land with the assumption that the soil accumulation of trace metals from biosolids meeting ceiling concentrations will not cause environmental or health hazards during or after the application period. The concept of long-term metal immobilization in soil has been challenged when mass balance calculations at a number of land application studies were unable to account for up to ha! of biosolids-applied trace metal.

Questions concerning the classification of mineral clayey soils in Russia and foreign countries are examined, since classification principles differ considerably in Russian and foreign practices. As standards most frequently employed in common designs, the ASTM (United States) and BS (Great Britain) standards are cited as examples of foreign standards. [ABSTRACT FROM AUTHOR]

Clay soils are difficult to manage to obtain a soybean [Glycine max (L.) Merr.] stand, especially when dry. A novel production system, recently observed on several farms in Arkansas, consists of bedding the dry clayey soil with disk-bedders, broadcasting the soybean seed over the surface, re-bedding the seedbed to cover the seed, rolling the beds to flatten the tops and finally furrow irrigating immediately thereafter. Typically this planting system provides a stand of soybean within 4 to 6 days after irrigation and is designated as “hipped” after the common reference of a disk-bedder as a hipper. Studies were conducted on Sharkey soil at Keiser, AR from 1998 to 2000 for comparing this “hipped” system to more widely used planting methods. On dry clayey soils, a randomized complete block design with three replications was used to compare full-season soybean under a conventional 96-cm row system, drilled-planting into a stale seedbed, and the “hipped” system. A similar study for double-cropped wheat-soybean involved straw management (burn or leave) coupled with no-till drill, tilled drill, and “hipped” systems. Other small studies on the “hipped” system were conducted to investigate the sensitivity to planting depth, soybean plant population, and suitability for obtaining a stand on other crops such as cotton [Gossypium hirsutum (L.)] and grain sorghum [Sorghum bicolor (L.) Moench]. The “hipped” system worked well for obtaining stands of soybean, cotton, and grain sorghum. In essence the “hipped” system 1) provides insurance against poor planting conditions; 2) allows for a reduction in the uncertainty of planting and stand establishment time required; 3) can be used to achieve high plant populations; 4) requires a relatively higher seeding rate in double-crop than full-season systems; 5) shows promise for situations when wheat stubble burning becomes curtailed especially if planting can occur early to lead to improved canopy coverage and 6) leads to yield reductions in fields where depth of seed placement cannot be controlled easily. [ABSTRACT FROM AUTHOR]

Applications of the aquifer storage and recovery (ASR) technology can cause land subsidence due to the net compression of one or more semi-pervious clay beds. In order to estimate the potential risk of aquifer system deformation in response to an injecting-pumping scheme, a one-dimensional analytical solution based on a conceptual sandwich model is solved. The analytical solution corresponds to boundary and initial conditions. The boundary condition comprises linear and periodic strains changing with time. The periodic strain is assumed to be a sinusoidal function of time. The solution is analyzed for a unit column of an idealized compressible semi-pervious layer. A complete mathematical description includes an initial condition, two sets of boundary conditions and a governing equation that is expressed directly in terms of the vertical displacement of the skeletal frame. The saturated aquifer system is assumed to behave like nonlinear poroelastic material (both recoverable and non-recoverable). The two idealized aquifers (one above the modeled semi-confining bed and the other beneath) can be pumped independently of each other. The analytical solution is analyzed and applied to estimate the potential risk of land subsidence caused by ASR applications at Las Vegas, Nevada, USA and the results are satisfactory. Estimate and prediction of land subsidence using the analytical solution provide a first-estimate type of guideline for city and regional planning and the exploration of water resources. [ABSTRACT FROM AUTHOR]

The article reports on the soil persistence and mobility in cornfields of flumetsulam applied at low doses. The triazolopyrimidine sulfonanilide herbicide flumetsulam is used efficiently in the U.S. for the efficient control of weeds and grasses in corn and soybean. Roots and leaves of plants absorb it. When flumetsulam was incorporated in clay soil and incubated in the laboratory, its soil half-life was 246 days. Much different soil persistences have thus been reported for flumetsulam on account of the different conditions of the experiments. Flumetsulam being not yet in use in Belgium and Europe, this work studied the persistence and the mobility of flumetsulam in the soil of corn fields.

Assesses the potential of the reduced-runoff surface irrigation method for clay soils to limit tailwater runoff and evaluates its impact on crop production and soil salinity throughout an alfalfa hay production cycle in Imperial Valley, California. Background on water conservation efforts in the area; Information on related studies; Research methodology; Results and discussion; Summary and conclusions.

Analyzes crystalline and amorphous phases of the clay fraction of agriculturally important Hawaiian surface soils using x-ray diffraction and Rietveld method. Quantification of the phyllosilicates; Estimation of amorphicity; Mineral phase quantification; Optimal spike addition; Rietveld refinement of soil diffraction patterns.

Investigates bromide leaching on a Piedmont toposequence. Soil properties associated with increasing clay content; Modification of the soil-based leaching classification system; Susceptibility of footslopes to leaching losses; Comparison of groundwater depth between foot and linear slopes.

Determines the effect of clay crack flow on tail water quality and crack flow's contribution to salt leaching conducted on farm fields in Brawley, California. Soil sampling; Experiments conducted on each soils; Sampling of surface water.

Examines how suspended clays alter the trophic interactions that govern composition and density of the zooplankton community in a small eutrophic lake in North Carolina. Use of enclosure in a complete, triplicated, cross-classified design; Release of crustacean zooplankton from visual planktivores due to turbidity; Predation as the main governing factor.

Studies the deposition of clayey diamicton of the Oak Creek Formation by the Lake Michigan Lobe of the Laurentide Ice Sheet during the late Wisconsin deglaciation. Basis for the interpretation of basal; Interpretation of basal deposition.

Eight-year-old Loblolly pine (Pinus taeda) plots located in South Carolina were evaluated using high resolution aircraft multispectral scanner data to determine if biomass could be accurately measured. Sixteen pine plots located on both sandy and clay soils were treated with 0, 180, or 360 kg. (approximately 0, 400, or 800 lb.) of nitrogen per plot. Indices of biomass from remote sensing data were significantly correlated with in situ biomass measurements made in each plot. A ratio of infrared (9 - 1.1 μm) and red ( 65-70 μm) channels yielded the best correlation. The indices were not sensitive to differences in soil type (sandy or clay). [ABSTRACT FROM AUTHOR]

The article focuses on the clay work by elementary pupils in the U.S. Clay is considered as a medium that appeals most strongly to the younger children. In the first grade, students began their clay work through modeling animals like horses, cows and chicken. The second grade students, in relation with their study on human foods, have modeled fruits and vegetables. They also modeled trains, wagons and boats which represent the transportation of food product. Students in the higher grade did more complex clay work. They based their works on Greek history and literature. The objective of this activity was to awaken the sense of proportion and craftsmanship of school children.

Reestablishing shrub canopy cover after disturbance in semi‐arid ecosystems, such as sagebrush steppe, is essential to provide wildlife habitat and restore ecosystem functioning. While several studies have explored the effects of landscape and climate factors on the success or failure of sagebrush seeding, the influence of soil properties on gradients of shrub canopy structure in successfully seeded areas remains largely unexplored. In this study, we evaluated associations between soil properties and gradients in sagebrush canopy structure in stands that had successfully reestablished after fire and subsequent seeding treatments. Using a dataset collected across the Great Basin, USA, of sagebrush stands that had burned and reestablished between 1986 and 2013, we tested soil depth and texture, soil surface classification, biological soil crusts plus mean historical precipitation, solar heatload, and fire history as modeling variables to explore gradients in sagebrush canopy structure growth in terms of cover, height, and density. Deeper soils were associated with greater sagebrush canopy structure development in terms of plant density and percent cover, coarser textured soils were associated with greater sagebrush cover and density, and more clayey soils were typically associated with greater height. Biological crust presence was also positively associated with enhanced sagebrush canopy growth, but adding more demographically or morphologically explicit descriptions of biocrust communities did not improve explanatory power. Increasing heatload had a negative effect on sagebrush canopy structure growth, and increased mean annual precipitation was only associated with greater sagebrush height. Given that conservation and restoration of the sagebrush steppe ecosystems has become a priority for land managers, the associations we identify between gradients in post‐fire sagebrush canopy structure growth and field‐identifiable soil characteristics may improve planning of land treatments for sagebrush restoration and the understanding of semi‐arid ecosystem functioning and post‐disturbance dynamics. [ABSTRACT FROM AUTHOR]