Georgia Soils Research Articles

Nonefficacy of Postplant Nematicides in Vitis vinifera Wine Grapes in Georgia, U.S.A.

Plant parasitic nematodes (PPNs) are known to cause significant yield loss in vineyards across the world. Methods for PPN control are limited, and there is a need for development of treatments that provide long-term efficacy. Preplant fumigants provide ephemeral effects, so growers are searching for alternative, postplant nematicides to combat these pests. Two postplant nematicides, fluensulfone and spirotetramat, were evaluated for their efficacy on the three most abundant ectoparasitic PPN genera ( Helicotylenchus, Mesocriconema, Xiphinema) in a northern Georgia vineyard over a 2-year period. Nematode densities following treatment with either nematicide did not differ statistically from the untreated control. This strongly suggests that fluensulfone and spirotetramat are highly unlikely to provide useful levels of ectoparasitic PPN control on wine grapes in comparable Georgia soils.

Pollution of Kvemo Kartli Region (Georgia) Soils by Heavy Metals

Pollution of Kvemo Kartli Region (Georgia) Soils by Heavy Metals

Methylation protocol for the retrospective detection of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, indicative markers for the nerve agents sarin, soman and cyclosarin, at low levels in soils using EI-GC–MS

A practical and efficient protocol for the derivatization and detection by GC-EI-MS of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, key diagnostic degradation products of the nerve agents sarin, soman and cyclosarin respectively, in six different types of soil matrices is presented. The method involves the in situ conversion of the phosphonic acids to their respective methyl esters using trimethyloxonium tetrafluoroborate when present in the soils at low levels (10 μg g−1) without any prior extractions or soil preparation. The soils employed in our study were Nebraska EPA soil, Georgia soil, silt, Virginia type A soil, regular sand and Ottawa sand and were chosen for their vast differences in composition and physical features. Appealing attributes of the protocol include its rapidity (t < 30 min), mildness (ambient temperature), and practicality that includes the production of the phosphonic methyl esters that can be easily detected by GC-EI–MS and corroborated with the instrument's internal NIST spectral library or the Organisation for the Prohibition of Chemical Weapons (OPCW) central analytical database (OCAD v.21_2019). The overall efficacy of the protocol was then tested on a soil sample featured in the 44th OPCW PT that our laboratory participated in. After preparing the soil so as to give pinacolyl methylphosphonic acid at a 5 μg g−1 concentration, the acid was successfully methylated and detected by GC-EI-MS. The protocol's performance mirrors that of the universally employed diazomethane protocol but accomplishes this without any of the explosive hazards and time consuming reagent preparation commonly associated with it.

A Comparison of Diffusion-Conductimetric and Distillation-Titration Methods in Analyzing Ammonium- and Nitrate-Nitrogen in the KCl-Extracts of Georgia Soils

ABSTRACTSoil mineral (or inorganic) nitrogen (SMN), which primarily exists as exchangeable and soluble ammonium (NH4+) and the nitrate (NO3−) ions, represents readily available nitrogen for plant growth. Over the years a 2M potassium chloride (KCl) solution has become the extraction solution of choice for extracting SMN. In the research and service laboratories, either distillation-titration method (DTM) or colorimetric method (CM) is virtually the standard to measure NH4+- and NO3−-N in the 2M KCl soil extracts. However, being a time-consuming and labor intensive method, DTM generally has a very low throughput. Likewise, CM is affected by interferences from pH variation, color, turbidity, presence of organic species, and some other constituents in the extracts. In contrast, diffusion conductivity method (DCM) is a less expensive and high throughput one, which is also relatively free from common interferences. In this study, we, therefore, compared the extraction efficiency of various KCl concentrations and performance of diffusion conductivity method (DCM) with DTM in measuring NH4+-N and NO3−-N in KCl extracts of 32 agricultural soils of Georgia. A 0.2M KCl solution extracted statistically similar amounts of NH4+-N and NO3−-N as did 2M KCl, suggesting that a 10-fold dilute KCl solution than the standard 2M KCl might be good enough to extract and estimate the most of SMN. For the analyses of NH4+- and NO3−-N in the KCl extracts, the DCM produced results statistically similar to those produced by DTM. The deviation between the results given by DCM and DTM was no more than ±10%. Thus, DCM appears to be an attractive alternative to the labor intensive and time-consuming DTM for measuring NH4+- and NO3−-N in the KCl extract of soils in the research and service laboratories.

Evaluation of the FieldScout TDR300 for Determining Volumetric Water Content in Sandy South Georgia Soils

Although time domain refl ectometry (TDR) probes have been found to be accurate in most soils, the strength of the relationship between TDR values and soil water content can vary considerably from one soil to the next. This study examined the accuracy of water content measurements taken with a FieldScout TDR300 as compared to volumetric water content determined from samples of known volume. The primary soils sampled in the study are of the Albany, Chipley and Ousley series which have sand or loamy sand textures. Simple linear regression analysis was used to evaluate the relationship between TDR readings and volumetric water content. The slope of the regression line was 1.06 and the R 2 value was 0.70. These values lead to the conclusion that the FieldScout TDR300 provided reasonable estimations of soil water content in the soils investigated and would be appropriate to use in certain situations. However, the FieldScout TDR300 may not be appropriate for use in these soils if a high degree of water content accuracy is essential or if readings are needed from depth within the soil.

Efficiency of Commercial Agricultural-Grade Limestone

The University of Georgia (GA) lime recommendation equation includes a multiplier of 1.5 to account for agricultural (ag) lime that is less reactive than reagent-grade calcium carbonate (CaCO3). Research has not been conducted with ag lime to arrive at this multiplier with GA soils typical of the coastal plain or with ag limes available in GA. These ag limes may differ in their reactivity from others tested previously. The efficiency of five dolomitic ag limes were compared to reagent-grade CaCO3 on two GA soils with different pH-buffering capacities. Reactions other than acid neutralization by lime affected pH, especially in the soil with low pH-buffering capacity. Results from the soil with high pH-buffering capacity yielded multipliers of 1.17, 1.16, 1.48, 1.34, and 1.73 for ag limes 1 through 5, respectively, with an average multiplier of 1.38. Based on these results, continued use of a multiplier of 1.5 is appropriate.

Equilibration Reaction from Single Addition of Base to Determine Soil Lime Requirement

The University of Georgia Soil, Plant, and Water Laboratory (SPW) uses a single‐addition titration for estimating soil lime requirement. The lime requirement depends in part on a soil's pH buffering capacity (described as lime buffer capacity [LBC] in mg CaCO3 kg−1 per pH unit), which is estimated from the rise in soil pH after Ca(OH)2 is added and allowed to react for 30 min. The 30‐min reaction time has not been sufficient to reach equilibrium between the soil and Ca(OH)2, resulting in an underestimation of the LBC. As a corrective measure, the SPW adjusts the agricultural lime recommendations to account for the lack of equilibrium. This study investigated the rate of pH change after Ca(OH)2 is added to acid soils. Specifically, the objectives of this study were to: (i) determine the time in which the Ca(OH)2–treated samples reached pH equilibrium; and (ii) determine if a relationship exists between the LBC estimated from a 30‐min equilibration and the LBC estimated from the time in which the sample had reached an equilibrium pH. The 25 soils used in this study were equilibrated for up to 96 h. Results indicated that the soils had reached an equilibrium pH by 84 h after the addition of Ca(OH)2 The ratio (mean of 84‐ and 96‐h LBC/30‐min LBC) could be predicted with the equation 1.4742 + 0.0023(30‐min LBC) (r2 = 0.82). This relationship allows the current titration procedure with 30‐min equilibration time to be used to predict the equilibrium LBC, which in turn can be used to calculate more accurate lime recommendations.

Effect of Traffic Rate and Type on Soil Compaction in Sandy South Georgia Soils

Soil compaction is one of the largest problems faced by modern mechanized agricultural and forestry operations. This makes research in the area of soil compaction critical. This study was undertaken to see how different types and levels of traffic have influenced soil compaction in sandy soils at the Valdosta State University Lake Louise field station south of Valdosta, GA. Four different traffic patterns were investigated in this study. The first area has relatively high vehicular traffic, the second more moderate vehicular traffic, and the third area a relatively low level of vehicle traffic. The fourth area has experienced foot, horse, and ATV traffic, but full sized vehicles like cars and vans have not been used in the area. To study compaction, soil cores of known volume were taken at the soil surface and at 30-cm depths. These cores were taken both in the trafficked area (road, trail) and alongside the trafficked area at three locations for each treatment. Average soil bulk density values for the trafficked and untrafficked areas were statistically compared to determine the effects of traffic patterns on soil compaction. Results indicate that soils were more compacted along trafficked areas than in the corresponding untrafficked areas with the exception of the fourth area, which had experienced the lightest traffic load.

Evergreen in context

Evergreen in context

Evaluation of Loss On Ignition Method for Determining Organic Matter of South Georgia Soils

Soil Survey HorizonsVolume 50, Issue 3 p. 83-85 Article Evaluation of Loss On Ignition Method for Determining Organic Matter of South Georgia Soils John K. Luke, Corresponding Author John K. Luke kevinluke@mchsi.com ENVI-GEO, 2009 Baytree Road, Valdosta, GA, 31602Search for more papers by this authorEric C. Brevik, Corresponding Author Eric C. Brevik Eric.Brevik@dsu.nodak.edu Departments of Natural Sciences and Agriculture and Technical Studies, Dickinson State University, Dickinson, ND, 58601Search for more papers by this authorGary L. Wood, Corresponding Author Gary L. Wood lwood@valdosta.edu Dep. of Chemistry, Valdosta State University, Valdosta, GA, 31698Search for more papers by this author John K. Luke, Corresponding Author John K. Luke kevinluke@mchsi.com ENVI-GEO, 2009 Baytree Road, Valdosta, GA, 31602Search for more papers by this authorEric C. Brevik, Corresponding Author Eric C. Brevik Eric.Brevik@dsu.nodak.edu Departments of Natural Sciences and Agriculture and Technical Studies, Dickinson State University, Dickinson, ND, 58601Search for more papers by this authorGary L. Wood, Corresponding Author Gary L. Wood lwood@valdosta.edu Dep. of Chemistry, Valdosta State University, Valdosta, GA, 31698Search for more papers by this author First published: 04 August 2015 https://doi.org/10.2136/sh2009.3.0083Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume50, Issue3Fall 2009Pages 83-85 RelatedInformation

Large scale measurements of soil moisture for validation of remotely sensed data: Georgia soil moisture experiment of 2003

A series of soil moisture experiments were conducted in 2003 (SMEX03) to develop enhanced datasets necessary to improve spatiotemporal characterization of soil moisture and to enhance satellite-based retrievals. One component of this research was conducted in South Central Georgia of the US, from June 17th to July 21st (SMEX03 GA). This study analyzes measurements of soil moisture and temperature collected during SMEX03 GA. A network of in situ soil moisture measurement devices, established to provide validation data for the satellite collections and for long-term estimation of soil moisture conditions throughout the region, provided continuous measurements at 19 sites. Additional soil moisture and temperature validation data were collected daily from 49 field sites. These sites represented a diversity of land covers including forest, cotton, peanut, and pasture. Precipitation that occurred prior to June 22nd and from June 29th through July 2nd produced drying conditions from June 23rd to June 28th and gradual wetting from June 29th through July 2nd. Soil moisture in the top 0–1 cm of the soil was found to be more responsive to precipitation and to have greater variability than soil moisture at the 0–3 or 3–6 cm layers. Within different land covers, soil moisture followed the same trends, but varied with land use. Pasture sites were consistently the wettest while row-crop sites were normally the driest. Good agreement was observed between soil moisture measurements collected with the in situ network and the 49 SMEX sites. For the study period, soil moisture across the entire 50 km by 75 km region and five of the six 25 km by 25 km EASE-Grids demonstrated time stable characteristics. Time stability analysis and statistical tests demonstrated the in situ stations had a small dry bias as compared to the SMEX03 GA measurements. These results indicate that the in situ network will be a good resource for long-term calibration of remotely sensed soil moisture and provide a new and unique source for future satellite product validation.

Evaluation of the Relationship between Volumetric Soil Water Content and Readings From a Portable Tensiometer in Sandy South Georgia Soils

Soil Survey HorizonsVolume 45, Issue 3 p. 103-108 Article Evaluation of the Relationship between Volumetric Soil Water Content and Readings From a Portable Tensiometer in Sandy South Georgia Soils M. T. Caverzasi, M. T. Caverzasi Atlantic Geoscience, Inc., 1300 S. Rossiter Terrace, Watkinsville, GA, 30677Search for more papers by this authorEric C. Brevik, Corresponding Author Eric C. Brevik ecbrevik@valdosta.edu Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, GA, 31698-0055Search for more papers by this authorJudith L. Grable, Judith L. Grable Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, GA, 31698-0055Search for more papers by this author M. T. Caverzasi, M. T. Caverzasi Atlantic Geoscience, Inc., 1300 S. Rossiter Terrace, Watkinsville, GA, 30677Search for more papers by this authorEric C. Brevik, Corresponding Author Eric C. Brevik ecbrevik@valdosta.edu Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, GA, 31698-0055Search for more papers by this authorJudith L. Grable, Judith L. Grable Department of Physics, Astronomy, and Geosciences, Valdosta State University, Valdosta, GA, 31698-0055Search for more papers by this author First published: 04 August 2015 https://doi.org/10.2136/sh2004.3.0103Citations: 2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume45, Issue3Fall 2004Pages 103-108 RelatedInformation

Morphological Properties of Surface Seals in Georgia Soils

AbstractThe morphology of surface seals has not been extensively described for acid, sandy and loamy soils common in the U.S. Southeast. The objectives of this study were to: (i) evaluate evolution of seal morphological properties for seven soils in Georgia during the course of a rainfall event, and (ii) relate seal morphology and development to soil properties. Columns were packed with Ap horizons from seven soils in Georgia and subjected to simulated rainfall at 50 mm h−1 for intervals from 10 to 60 min. Seal morphological properties along with thickness and porosity were evaluated from thin sections. The most common feature of seals formed in all of the soils was a disruptional layer with 30 to 50% fewer pores &gt;0.02‐mm diam. than unaffected soil. In readily sealed soils with sandy loam textures, low Fe contents, and high amounts of water‐dispersible clay, this layer formed within the first 10 min of rainfall, and thickness and porosity were constant at longer rainfall durations. In other soils, longer rainfall durations were required to form a disruptional layer. In addition to the disruptional layer, other morphological features observed in the seals included a thin layer of micromass concentration that occurred at the soil surface (skin seal). At intermediate rainfall durations in readily sealed soils, this layer was overlain by a layer of micromass‐depleted grains, which was removed by erosion at longer rainfall durations. Grain size and initial development in microtopographic lows suggest that the micromass‐depleted layer formed by transport and redisposition rather than in‐place disjunction of micromass.

Hydraulic Properties of Surface Seals in Georgia Soils

AbstractTo predict infiltration in a sealing soil, the seal hydraulic conductivity as a function of time or cumulative rainfall must be known. Few studies have reported measured seal hydraulic conductivities in soils from the southeast USA. Seven Georgia soils packed in columns were subjected to simulated rainfall at an intensity of 50 mm h−1. The sandy loam soils were easily disrupted by rainfall. The calculated seal hydraulic conductivities (Kc) dropped sharply in 10 min of rain and were less than 10% of the initial saturated hydraulic conductivity (Ki) after 45 min. The sandy loam soil with low aggregate stability and Fe content was especially prone to sealing in that Kc dropped to 4% of Ki after 10 min. The well‐structured soil with a clay texture declined in Kc gradually with time, indicating a high resistance to rainfall energy. The sandiest soil showed intermediate resistance to raindrop impact, and Kc leveled off at a high value after 20 min due to the low clay content. The loamy soil with smectitic clay had the lowest Ki and showed little change in Kc with time. Relative seal hydraulic conductivity after 10 or 60 min of rain were good indices differentiating the relative resistance of these soils to surface sealing. A soil stability factor, used to characterize the decrease of Kc in an exponential decay equation, was significantly correlated with water‐dispersible clay on a soil basis.

Microbial Degradation of Flurtamone in Three Georgia Soils

Degradation of flurtamone in a Greenville sandy clay loam, a Cecil loam, and a Dothan loamy sand with 0, 1, or 2 yr of previous flurtamone field use was evaluated under controlled conditions. Soil sterilization by autoclaving significantly reduced flurtamone dissipation rate in all soils. Enhanced degradation of flurtamone was observed in a Greenville sandy clay loam after 1 yr of previous flurtamone field use and in a Cecil loam after 2 yr of previous flurtamone field use. No enhancement of flurtamone degradation was observed in a Dothan loamy sand. Flurtamone degradation kinetics in these studies was described as a first-order process. Microbial populations in each soil showed no major changes in total bacterial numbers due to preexposure to flurtamone in the field.

Flurtamone Adsorption and Mobility in Three Georgia Soils

Flurtamone and atrazine adsorption to soil was examined using a batch equilibrium method. Flurtamone mobility in packed soil columns under saturated flow conditions was also evaluated. Adsorption was greater for flurtamone than atrazine in the three soils, and the order of adsorption to soil for both herbicides was Greenville sandy clay loam &gt; Cecil loam &gt; Dothan loamy sand. Greater adsorption of each herbicide corresponded to soils with greater organic matter and clay content. The14C–flurtamone movement under saturated flow conditions in 28–cm soil–packed columns was limited to 16 cm, with no flurtamone leaching from any soil column after the addition of two pore volumes of water. Seventy–five percent of the applied14C–flurtamone remained in the 0– to 4–cm soil depth in the Greenville sandy clay loam, with less than 5 percent moving to a depth &gt; 4 cm. Flurtamone movement was greater in the Cecil loam and the Dothan loamy sand, with movement in each soil to a depth of 16 and 12 cm, respectively.

Dissipation of Flurtamone in Three Georgia Soils

The dissipation of flurtamone was determined in three Georgia soils in 1987 to 1989. Flurtamone dissipation in soil was initially rapid but gradually slowed throughout the sampling interval. Dissipation was not affected by rate (0.8 or 1.7 kg ai ha-1) or application method (PPI or PRE). Dissipation rates were slightly more rapid in the Greenville and Dothan soils than in the Cecil soil, with calculated initial half-lives for each respective soil being 6 to 7, 8 to 10, and 9 to 23 days. There was no effect of previous flurtamone exposure on the dissipation rate in soil at any location.

Paecilomyces Lilacinus, a Colonist of Aspergillus Flavus Sclerotia Buried in Soil in Illinois and Georgia

(1990). Paecilomyces Lilacinus, a Colonist of Aspergillus Flavus Sclerotia Buried in Soil in Illinois and Georgia. Mycologia: Vol. 82, No. 3, pp. 393-395.

DIFFERENCES IN CLAY MINERALOGY AND OXIDIC RATIO OF SELECTED LAC SOILS IN TEMPERATE AND TROPICAL REGIONS

We studied clay mineralogy and differences in oxidic ratio and CEC of selected low-activity clay soils in temperate and tropical regions. Samples were collected from six Ultisols in Georgia (Bradson, Cecil, Davidson, Decatur, Greenville, and Madison soils). Two Oxisols (Cibinong and Sitiung) and four Ultisols (Ciomas, Jasinga, Jonggol, and Kedunghalang soils) were sampled in Indonesia. The samples from A, Bt, and B horizons were analyzed for CEC by the NH4OAc and NH4Cl methods, effective CEC (ECEC), and oxidic ratio ((extractable Fe2O3% + gibbsite%)/ clay%). Clay mineralogy was studied by x-ray diffraction (XRD), and gibbsite concentrations were measured by differential thermal analysis (DTA). Iron oxide was extracted from the soils by the dithionitecitrate-bicarbonate (DCB) procedure, and the concentration was determined in the extract by atomic absorption spectroscopy. The results indicated that the Bt horizons of the soils in Georgia had values for CEC(NH4OAc) and ECEC ranging from 14.7 to 28.9 and 8.1 to 11.9 cmol(+)kg-1 clay, respectively. With the exception of the Decatur soil, the oxidic ratio of the Bt horizons of the Georgia soils was >0.20, which could qualify them for placement in the oxidic mineralogy class, provided their quartz content would support it. The Davidson soil, especially, exhibited CEC and ECEC values within the requirement limits for both kandic and oxic horizons. These chemical properties were related closely to the clay mineralogy, which was composed of large amounts of kaolinite and especially gibbsite. Some hydroxy-A1-interlayered clays were also detected. In comparison, the Bt and B horizons of the soils in Indonesia, with oxidic ratios <0.20, were less oxidic in nature. On a soil basis, the Indonesia soils were generally higher in CEC values than the six Georgia soils. These differences in chemical characteristics were attributed to a variation in soil mineralogy, indicating the absence of quartz and considerably lower amounts of sesquioxides, but larger kaolinite contents, in the Indonesian than in the Georgian soils.

Movement of an Aqueous Spray of Beauveria bassiana into the Profile of Four Georgia Soils

Vertical movement of commercially formulated conidia of Beauveria bassiana (Balsamo) Vuillimen was measured by recovery of colony-forming units (CFUs) at selected depths in four soil series after application of an aqueous suspension of conidia to soil surfaces. In greenhouse studies with soil blocks (40 by 20 by 20 cm) removed from field plots with a coring device, the number of CFUs recovered 72 h after application from depths below the surfaces was correlated ( P = 0.0001) with water infiltration values of the respective soils. However, 95% of the total number of CFUs recovered in core samples of the Townley (29% sand, 32% clay, 39% silt), Greenville (64% sand, 28% clay, 8% silt), and Cecil series (59% sand, 22% clay, 19% silt) soils remained at the surfaces. In the Tifton series soil (87% sand, 5% clay, 8% silt), 87% of the total CFUs were recovered from the surface with an additional 9% recovered 4 cm below the surface. Core samples taken 2 h after application of an aqueous suspension of conidia to field plots also indicated that the four soils restricted vertical movement of the conidia. Greater than 94% of the total number of CFUs recovered in the cores were from the upper 5 cm of the profile of each soil series. At the 5–10 cm depth, 0.7, 1.8, 3.3, and 4.4% of the total CFUs were recovered from the Cecil, Greenville, Tifton, and Townley series soils, respectively. Only small percentages of total CFUs were recovered from the 10–15 cm profile of each soil. Retention of conidia in the upper profile of these soils appears to be caused by mechanical filtration within the soil structure.