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Our analyses revealed the spatial variability of the vertical distribution of fallout radiocesium measured in small cylindrical soil cores taken in a non-disturbed paddy field contaminated by the F...

A long-term experiment was conducted in soils across a decreasing pH gradient (7.0, 6.3, 5.7, 4.9 and 4.3). Intact soil cores across the pH gradient were sampled and incubation experiments were use...

Cement soil mixing piles are an effective treatment method for marine soft clay. To investigate the static and dynamic characteristics of the composite soil with cemented soil core, a serie...

Soil nitrogen (N) mineralization rates from different agricultural regions in California were determined and related to soil properties. Undisturbed soil cores were sampled in spring from 57 fields...

In this study, we conducted an incubation experiment on a frozen soil core collected from a black spruce forest in Interior Alaska, in order to investigate potential changes in greenhouse gaseous (...

Swiss needle cast (SNC) is a disease specific to Douglas-fir (Pseudotsuga menziesii) caused by the ascomycete Phaeocryptopus gaeumannii. Here we examine characteristics of the EM fungus community that are potentially useful in predictive models that would monitor forest health. We found that mean EM density (number of colonized root tips/soil core) varied nearly 10-fold among sites of varying levels of SNC, while mean EM fungus species richness (number of species/soil core) varied by about 2.5 times. Strong relationships were found between EM and SNC parameters: EM species richness was positively correlated with both Douglas-fir needle retention (R(2) = 0.93) and EM density (R(2) = 0.65); EM density also was significantly correlated with Douglas-fir needle retention (R(2) = 0.70). These simple characteristics of the EM fungus community could be used to monitor forest health and generate predictive models of site suitability for Douglas-fir. Based on previous findings that normally common EM types were reduced in frequency on sites with severe SNC, we also hypothesized that some EM fungi would be stress tolerant-dominant species. Instead, we found that various fungi were able to form EM with the stressed trees, but none were consistently dominant across samples in the severely diseased areas.

Soil population densities and spatial patterns of sclerotia produced by Sclerotinia sclerotiorum were determined in six commercial lettuce production fields with varying histories of lettuce drop in Yuma County, AZ. Each field was divided into eight approximate equal sections and in each section, a plot (10 × 20 m) was randomly selected for soil sampling. Soil cores were collected along both diagonals at 2 m intervals in each plot and sclerotia populations were determined by wet sieving. The average soil sclerotia population per plot ranged from 0.0 to 5.8/100 g soil. The highest and the lowest percent of individual soil samples with ≥ 1 sclerotia/100 g soil per plot were 63% and 7%, respectively. Three indices of dispersions - variance/mean, Morisita's index and Lloyd's index - calculated for each of the six fields indicated that sclerotia distributions were aggregated. However, in none of the fields could the sclerotia distributions be adequately described by the Poisson, negative binomial or Neyman type A distributions.

Ion exchange resin / soil cores are a common in situ approach to estimating soil nitrogen (N) mineralization rates. However, no studies compare the two common methods of core preparation (disturbed and undisturbed). The objective of our study was to compare N mineralized and soil temperature in disturbed versus undisturbed cores of manured agricultural soils. Undisturbed cores were prepared by driving aluminum tubes (25 cm long with 10 cm inner diameter) into soil, removing the tubes, and then inserting an ion-exchange resin bag beneath the soil at the bottom of the tube. Disturbed cores were prepared with the same materials, but soil was excavated, mixed, and then filled into tubes fitted with ion-exchange resin bags at the bottom. Soil from six agricultural fields (five of which had more than 10 years of regular dairy manure application) was incubated over four time periods during summer and winter. A total of 13 soil / incubation-period combinations were tested. Disturbed cores tended to have more N mi...

It was previously hypothesised that reduction in the soil will set in at 70% water saturation (S0.7). This study aimed to determine the effect of different degrees and durations of water saturation on reduction in soil. Reduction was measured as a decrease in soil oxidisability (pe) and an increase in soluble iron (Fe2+). A yellow brown apedal B horizon from profile 234 in the Weatherley catchment was used in this study. Soil cores were packed to a bulk density of 1.6 Mg m−3 and saturated to S0.6 (60% of the pores saturated with water), S0.7 (70% of the pores saturated with water), S0.8 (80% of the pores saturated with water), and S0.9 (90% of the pores saturated with water). Analyses started three days after water saturation. Samples were analysed every 3.5 days for the first three months and then once a week for another month. The experiment was terminated after 121 days. There was a good correlation between an increase in degree of water saturation and pe (R2=0.95), Mn2+ (R2=0.99) and Fe2+ (R2=0.99) co...

Site 22LI504 is a predominantly Archaic period site in Lincoln County, Mississippi. One of its primary elements of interest is a single conical mound from which small-diameter cores revealed evidence of advanced pedogenesis. A radiocarbon sample from one soil core produced a date suggesting that the mound was Archaic in age (Fulmer 2001); however, it was unclear whether the sample came from within the mound or an underlying midden. In the spring of 2006, we excavated a 1-x-1-m unit in the mound to investigate this question. Diagnostic lithic artifacts, an advanced state of soil horizonation, and a lack of ceramics indicate that the mound is of Archaic period construction, with as many as five construction stages and artifact-rich features. We describe the soil profiles, features, and artifacts recovered from the mound, with comparisons to excavation units in an adjacent Archaic midden to show that there is no clear evidence for the mound being a functionally specific locus. We also present radioca...

This study determined rates of in situ fine root decomposition and changes in trace metals concentration during decomposition at sites in Sudbury, ON, and Rouyn-Noranda, QU, with elevated or background concentrations of Cu, Ni, Pb, and/or Zn in the soil, and correlated the depth gradients of Cu, Ni, Pb, and Zn for soils and roots at the same sites. Fine roots were extracted from soil cores within root traps several times over 12 months; biomass and metal concentrations were measured. Live roots were collected from 30-cm soil cores, separated into three depths. Elevated soil metal concentrations did not necessarily reduce fine root decomposition, and effects on decomposition were similar to those previously reported for surface foliar litter at the same sites. Decomposing roots at only the high metal sites demonstrated increased metal concentrations with time. Root tissue concentrations of Cu, Ni, and Zn, but not Pb, at lower soil depths were generally higher than expected from soil metal concentr...

Forest soils are sensitive to compaction by forest machinery. Forest operations such as harvesting and skidding have a high potential for soil compaction. This study was carried out in the Hyrcanian hardwood forests of Iran to measure the changes in bulk density (ρb) in the top 10 cm of soil following machine and animal skidding. The density change or compaction was induced by (i) a rubber-tired skidder in three skid trails: flat skid trail (STF), skid trail with transversal slope (STTS), and skid trail with longitudinal gradient (STLG) and (ii) a mule in two animal trails: flat animal trail (ATF) and animal trail with transversal slope (ATTS). Soil cores were collected pre- and post-skidding at random locations along the upslope and downslope tracks of each skid trail to determine bulk density and moisture content of the soil. Average soil bulk density in the tracks of machine skid trails was significantly greater than the soil density outside the tracks, but the increase in bulk density was not significant on the animal trails. An increase in soil density was considered significant if p < 0.05. A highly significant increase in soil bulk density (p < 0.01) occurred with machine skidding after the first 12 skidding cycles on the STF before stabilizing. In comparison, on STLG and STTS the increase of bulk density was greatest after the first six skidding cycles. Additional cycles did not cause a significant increase in soil density. While the number of skidding cycles to reach the steady compaction state varied between flat trails and those with a slope, the severity of compaction was the same between them. Concentrating machine operations will minimize the areal extent of compaction and the use of mules could further reduce the impact of the extraction of short logs.

The turnover of fine roots in northern coniferous forests has conventionally been assumed to be rapid, in line with results from sequential coring in the late 1970s in a Swedish Scots pine stand (SWECON project) where a rate of 7.4 year−1 was estimated. New quantifications of the root respiration in other stands motivated a recalculation of the SWECON data; an indirect estimation of the turnover rate was much slower, about 2.1 year−1. As a consequence, fine-root production is considered to be much lower than in previous estimates. Furthermore, direct observations of Norway spruce fine roots (

SummaryRoot distribution was determined for apple trees [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. ‘Fuji’/’M.26’ (syn. M. domestica Borkh. non Poir.)] 1, 2 and 3 years after planting in trellised orchards in central Texas. Using a soil-coring method, measurable differences were detected in root-length density (RLD; root length per unit volume of soil) by tree age, soil depth, radial distance from the tree, and spatial bearing within and across rows (P ≤ 0.05). For fine roots (root diameters < 1 mm), mean RLD values were 0.1028, 0.1139 and 0.2911 cm cm–3 for 1, 2 and 3 year-old plantings, respectively. For coarse roots (root diameters 1–5 mm), mean RLD values were 0.0006, 0.0009 and 0.0015 cm cm–3 for 1, 2 and 3 year-old plantings, respectively. Mean RLD values declined for both fine and coarse roots of all ages with increasing soil depth and radial distance from the trunk (P ≤ 0.05). Similar patterns were observed for the number of soil cores containing measurable roots. The percentage of...

Pisolithus is restricted in New Zealand to geothermal areas where it associates with Kunzea ericoides var. microflora (prostrate kanuka) and occasionally Leptospermum scoparium. Here we describe for the first time the ectomycorrhizal morphotypes of three New Zealand Pisolithus species and report the frequency and abundance of these morphotypes against other mycorrhizal fungi associated with these hosts in New Zealand geothermal areas. The three Pisolithus species form typical ectomycorrhizal associations with Kunzea ericoides var. microflora, and one also was observed forming typical ectomycorrhizal associations with Leptospermum scoparium. Although the morphotypes from the three Pisolithus species share many morphological and anatomical characteristics, they vary with regard to the abundance of rhizomorphs. The common occurrence of Pisolithus fruiting bodies at the geothermal sites was matched by frequent and abundant Pisolithus ectomycorrhizas. Pisolithus ectomycorrhizas were frequent (100% of soil cores) and abundant (between 55 and 88% of ectomycorrhizal tips) associates of prostrate kanuka in hot (50 C at 8 cm depth), highly acidic and N depleted soils. The levels of arbuscular mycorrhizal colonization of prostrate kanuka were lower than on K. ericoides and L. scoparium on cooler soils. The stressful conditions where prostrate kanuka dominates probably favor Pisolithus over the mycorrhizal fungi occurring in cooler geothermal areas. Questions about how several genetically similar Pisolithus species co-occur on prostrate kanuka in geothermal areas without mutual competitive exclusion are discussed.

We estimated fine root biomass in a Japanese cedar (Cryptomeria japonica) plantation using a minirhizotron technique. Since data obtained from minirhizotrons are limited to the length and diameter of fine roots observed on minirhizotron tubes, data conversion is necessary to determine the fine root biomass per unit soil volume or unit stand area. We first examined the regression between diameter squared and weight per unit length of fine roots in soil core samples, and calculated the fine root biomass on minirhizotron tubes from their length and diameter. Then we determined conversion factors based on the ratio of the fine root biomass in soil core samples to that on minirhizotron tubes. We examined calculation methods, using a single conversion factor for total fine root biomass in the soil for depths of 0–40 cm (Cal1), or using four conversion factors for fine roots in the soil at 10-cm intervals (Cal2). Cal1 overestimated fine root biomass in the lower soil or underestimated that in the upper soil, while fine root biomass calculated using Cal2 better matched that in soil core samples. These results suggest that minirhizotron data should be converted separately for different soil depths to better estimate fine root biomass.

Decisions about the tolerable loading of sodium during land application of dairy factory effluent (DFE) are often based on the risk of exceeding a “critical” exchangeable sodium percentage (ESP) in the soil. The concept of a “critical” ESP value is based on overseas research that investigated the effects of saline irrigation water on soil structure, rather than on experimental evidence based on research using DFE. The problem is that sodium may degrade the structural stability of the soil and eventually cause surface ponding and effluent run‐off. The aim of this investigation was to determine the effects of land treatment of DFE on key soil physical properties and to establish if a single “critical” ESP value is appropriate for these situations. Intact soil cores (200 mm diameter × 200 mm deep) were collected from three sites at the Clandeboye dairy factory in Canterbury covering two periods of application (4, 10 years) of land treatment of DFE, plus an adjacent control site that had not received...

Soil cores (35 cm long, 7 cm diameter) from the Macaulay Land Use Research Institute's Sourhope Research Station in the Scottish Borders were kept and monitored at constant temperature (18± 1°C) for gas production using a 1.6 mm diameter stainless steel probe fitted with a membrane inlet and connected to a quadrupole mass spectrometer. This provided a novel method for on-line, real time monitoring of soil gas dynamics. In closed-system headspace experiments, O2 and CO2 (measured at m/z values 32 and 44, respectively) showed anti-phase diurnal fluctuations in low-intensity simulated daylight and under a light-dark (LD, 12:12 h) regime. O2 increased during periods of illumination and decreased in the dark. The inverse was true for CO2 production. Ar (m/z = 40) concentration and temperature (°C) remained constant throughout the experiments. The same phase-related oscillations, in CO2 and O2 concentrations, were observed at 2 and 5 cm depth in soil cores. The O2 concentration did not oscillate diurnally at 10...

Inorganic soil profile nitrogen (N) levels can increase with application rates greater than those necessary for maximum cereal grain yields. Forage systems are different than grain production systems in that harvest is generally prior to anthesis and gaseous plant N loss is not allowed to occur. This promotes removal of more total N from the system and results in higher nitrogen use efficiencies (NUE).Nitrogen rates representing increased profile N accumulation as well as those below this threshold were evaluated from a long-term rye–wheat–ryegrass production experiment. Nitrogen rates from 1979–1993 were 0, 56, 84, 112, 168, and 224 kg N ha−1.Rates were doubled in 1994 in an effort to add N at a rate above which no increase in forage production would be expected.Wheat was eliminated from the winter seeding mix in 1994, as it was an extremely small portion of the total harvested forage. Deep soil cores (0–366 cm) were taken during the early summer of 1996 from plots with a history of continuous f...

Cultivation systems with mulching have been successfully tested in spring cereals for several years in Sweden. The water conserving effect of the mulch was considered to be important in these field experiments. Three experiments with lysimeters were conducted in this study to investigate the effect on evaporation of a) different amounts of mulch, b) different types of mulch and c) different frequencies of rain in combination with mulching. The lysimeters contained undisturbed soil cores from a heavy clay soil. The protection against evaporation was largest at the beginning of soil drying. It increased with increasing amounts of mulch, but there were no differences in protection between the various kinds of mulch tested. Accumulated evaporation was 12, 14 and 30% lower in the mulched compared to bare soil after 28 days with no rain, infrequent rain and frequent rain respectively. The implications for designing a cultivation system with mulching are discussed as well as its potential in different weathers.

A procedure for examining water and solute transport in large undisturbed soil cores is described and tested. The procedure involves three main steps: (1) collecting soil cores using a “pushing method”, (2) attaching a tension drainage system once soil cores are transported to the laboratory, and (3) inserting tensiometers and thetaprobes for continuous monitoring of soil water tension and soil water content before, during and after, water and solute application. This procedure allows accurate recording of the soil hydraulic properties over the entire experiment, and provides valuable information for developing and running mathematical simulation models. Application of the outlined procedure to solute leaching is demonstrated for a well-structured Oxisol. Results from the laboratory leaching study are compared with theoretical predictions using a simple analytical model for weakly-sorbed ions. Contrasting behaviour between the model predictions and the experimental data is attributed to ion adsorption by ...

Experiments were conducted from 1994 through 1996 at the Dixon Springs Agricultural Center of the University of Illinois and the Belleville Research Center of Southern Illinois University to evaluate potassium rates (56, 112, and 168 kg K ha‐1 as liquid KCl formulations) and placement methods in a com (Zea mays L.) and soybean (Glycine max L.) rotation using chisel tillage (CT) and no‐tillage (NT) practices. Four placement methods were used: surface broadcast, surface band (25 cm wide band over each row), surface dribble (15 cm from each row), and banding 28 kg K ha‐1 (as a starter) 5 cm to the side and 5 cm below the planted seed (remainder of the K rate was surface broadcast). In April of 1997, at the Belleville Research Center only, soil cores in incremental depths of 0–5, 5–10, and 10–20 cm were collected in a 5‐cm spaced transect across and perpendicular to the two center rows of plots of each placement method that received 112 kg K ha‐1. Four transects were taken from each plot with the soi...

The biomass and the spatial distribution of fine and small roots were studied in two Japanese black pine (Pinus thunbergii Parl.) stands growing on a sandy soil. More biomass of fine and small roots was found in the 17-year-old than in the 40-year-old stand. There were 62 g m−2 of fine roots and 56 g m−2 of small roots in the older stand, which represented mean values of 608 g for fine and 552 g for small roots per tree, respectively. In the younger stand, a total of 85 g m−2 of fine roots and 66 g m−2 of small roots were determined, representing a mean of 238 g for fine and 186 g for small roots per tree, respectively. Fine and small root biomasses decreased linearly with a soil depth of 0–50 cm in the older stand. In the younger stand, the fine and small roots developed only up to a depth of 30 cm. Horizontal distributions (with regard to distance from a tree) of both root groups were homogeneous. A positive correlation in the amount of biomass of fine and small roots per m2 relative to tree size was fo...

We investigated the potential of soil pollen analysis to provide information about recent land use and vegetation history in the lowland humid tropics. Our initial work at the La Selva Biological Station in Costa Rica revealed that pollen was surprisingly well preserved in mineral soil, with pollen concentrations in the upper 10 cm of our soil cores as high as values for some lake sediment samples. Pollen percentages in our initial core samples showed down‐core variations that appeared to relate to what we knew about past episodes of forest clearance, pasture establishment, and secondary succession at our sampling sites. We carried out further tests of soil pollen analysis by collecting and analyzing additional soil cores from the La Selva Biological Station. Based on these new results, we conclude that soil pollen analysis in the lowland humid tropics does not hold the promise suggested by our initial work. Most pollen in our soil cores may be only a few decades old, and rapid downwash and/ or b...

The Tesponse of ambient nitrous oxide (N2O) emissions to four levels of simulated rainfall (5, 10, 20, and 40 mm) was assessed using large‐diameter cores of undisturbed soil in a greenhouse. The soil cores were taken from the two dominant soil‐landform groups present in the study area: Mollic Albaqualfs in footslope complexes and Typic Haploborolls in shoulder complexes. The footslope complexes had higher ambient N2O emission than the shoulder complexes at all rainfall levels which was attributed to the differences in inherent characteristics of the soils occurring at these landscape positions. This demonstrates the importance of a spatially‐based investigative approach to account for landscape‐scale differences in soil characteristics when investigating N2O emission at a large scale. Rainfall level strongly influenced the aeration status of the soil which, in turn, affected N2O emission. Rainfall showed to be a potential suitable parameter in a predictive model for N2O emissions (R2 = 0.73∗∗ and...

Roots control the uptake of water and nutrients by plants, and hence their dry matter production. One of the greatest constraints to our understanding of root dynamics has been the laborious tedium associated with accurate measurements of various root parameters. A technique is presented for the fast and accurate measurement of the length and diameter of all fragments of corn (Zea mays L.) roots contained in most 0.04 by 0.15 m soil cores by analyzing a single NIH‐Image of those roots. These parameters are determined by measuring the perimeter and area of each root fragment utilizing NIH‐Image analyses contained in a public domain software (NIH‐Image). When length and diameter are coupled with nutrient uptake data, we will have a better understanding of where plants extract nutrients and water in space and time.

Intact and partial soil cores from a small catchment (Dargall Lane) of the Galloway Hills of southwest Scotland were treated in the laboratory with simulated precipitation using double‐distilled, deionized water (DDDW) as a “control rain”, and artificial rain of composition similar to local bulk atmospheric deposition. The leachate chemistry shows that periods of drying and re‐wetting of the acidic, organic‐rich soils of this typical moorland catchment, may produce large flushes of cations (including Al) and anions. This means that increased element mobility can be caused by processes other than external hydrogen loadings.

This paper reports some results on natural and artificial radionuclide distribution in snow samples collected at the Priestly Neve—Plateau (inland, 1998 m a.s.l.) and the Vegetation Island (near the coast, 200 m a.s.l.) stations, and in a soil sample from Wood Bay station, both near the Italian Base at Terranova Bay in Antarctica. Data on Pb-210 and Cs-137 in snow samples from an 80 cm deep trench and in granulometric fractions of a soil core are discussed.

Factors such as small plot size, restricted access, and remote sites can often limit adequate sampling of belowground components in field research. Thus, the objective of this study was to design and construct a simple, inexpensive, portable soil coring system for rapid deployment under field conditions which eliminated some or all of the above mentioned limitations. Components of the system included a manual driver of adjustable weight, a manual core extractor, and steel core tubes with clear plastic (butyrate) liners which encase the soil core for retrieval and transport. This system proved to be reliable and efficient in repeated field trials, causing minimal plot disturbance. The use of Styrofoam plugs to separate multiple core samples within the plastic liner drastically reduced the time spent on handling individual samples. Continuous soil cores measuring up to 1 m long can also be collected with this system. The use of plastic liners also greatly facilitated the transport and storage of sa...

A description is offered of the equipment needed to determine herbicide mobility in natural soil columns. The devices were developed to extract intact soil cores from the field and to remove the soil cores from the stainless steel tubes. The method was applied to the mobility of metamitron in two soils. Herbicide distribution along the column was determined by bioassay. The results show that pH and other physical soil parameters are related to the mobility of this herbicide.

The controlled environment soil‐core microcosm unit (CESMU) methods embody a collection of techniques that began with soil sampling in the field and continued throughout the laboratory investigation of chemical fate, migration, and transformation in site‐specific soils; it was a cost‐effective investigative methodology that could be used to screen chemical materials before initiating high‐cost environmental field studies. Intact soil cores were collected in the field using a hydraulically controlled probe, delivering intact soil‐cores with minimal disturbance directly into high‐density polyethylene pipe (10.3‐cm ID). The inert polyethylene pipe was an effective hydrophobic barrier that remained an integral part of the soil‐core column, obviating subsequent transfers of soil. In the laboratory, each soil column was fitted with a porous ceramic plate and a polyethylene endcap containing fittings for teflon tubing, so that a tension could be applied at the bottom of each soil column (30–35 kPa) to m...

Vertical leaching of Na+ and Br‐ in a yellow podzolic soil has been studied in the field following an application of 370 kg ha‐1 NaBr. Soil cores to a depth of SO cm were collected on three occasions. Each core was divided into 2.5‐cm segments, and solution and exchangeable ions (Na+, Ca2+, Mg2+, K+, Br‐and Cl‐) were extracted from each segment using a centrifuge technique. The extraction technique was easy to use, and provided valuable information on the mechanisms influencing cation and anion distributions in the solution and exchange phases as a function of depth. The resulting distribution of exchangeable Na+ with depth was satisfactorily predicted using a simple mathematical model.

Soil cores were collected in and around an injection slit in each of two field plots on a coarse sandy soil. The plots received either raw or anaerobically digested liquid cattle manure at a rate of 240 kg NH4 +-N ha−1. During the three week period of the experiment, concentrations of dissolved organic carbon and NH4 + and the moisture content of cores from the injection slit were consistently above the background level in the soil. Denitrification activity was only registered in soil cores sampled in the injection slit. A dramatic increase occurred between Day 14 and Day 21, when the denitrification rate reached 3.5 kg N ha−1day−1 in cores from the plot treated with raw manure, while the rate was 20-fold lower in the plot treated with digested manure. Nitrate accumulated between Day 7 and Day 21, suggesting a coupling between nitrification and denitrification.

Methods of determining saturated hydraulic conductivity of soil in the absence of a high water table and difficulties inherent in their use are discussed. A new tool for determining saturated hydraulic conductivity, the Velocity Permeameter, is described. The accuracy of the device is shown through the use of undisturbed soil core comparisons. The application of the Velocity Permeameter to the selection of septic disposal sites, especially for decisions involving expected borderline soil hydraulic conductivities is presented.

Following an application of dairy cow urine to intact cores of four contrasting soil types, the redistribution of urine potassium (K) as a result of leaching, plant uptake, and soil adsorption was investigated. In climatic conditions that simulated those of August/September in the Manawatu region, 5–39% of the applied urine K immediately moved by macropore flow to beyond the 15cm depth of soil. Leaching losses of K from 90 mm of simulated rain events, which followed the urine application, were smaller than K losses immediately following the urine application and accounted for only 2–6% of the applied urine K. The urine K adsorbed by the soil was retained mainly in the 0–7.5 cm depth of soil in an exchangeable form. During the 30-day period of the experiment less than 10% of the urine K was recovered in the herbage. Overall these results suggest that, irrespective of soil type, a major loss of K occurs as a result of macropore flow of the urine following a urination event. The concentration of K i...

Acetylene reduction (AR) assays of N2 fixation in clover-ryegrass pasture were made on bulked samples of 2.54 cm diameter by 7.5 cm deep soil cores. The assays gave a reasonable reflection of N2 fixation as indicated by their relationship to assays on pasture turfs and by their responses to seasonal conditions and imposed treatments. However, variability in the assay was large (25% coefficient of variation on a 12-core sample) apparently because of irregular spatial distribution of N2 fixation in pasture, and AR activity was subject to sharp short-term fluctuations presumably reflecting climatic conditions before the assay. Consequently, quantitative interpretation of the assay in terms of N2 fixed was considered liable to substantial error. There was also some indication that the AR potential of pastures was not fully expressed by the assay method used. The experiments suggest that the AR assay using small soil cores could be a useful index of N2 fixation in making between-treatment comparisons ...

The design, materials and dimensions for constructing a coring device for sampling soil fauna and flora at different depths is described.

Construction details and operational features are given for a variety of unpatented devices used at Grasslands Division, DSIR, Lincoln. These arc: a pelleting press for dry powders dosed to animals; vacuum tweezers for handling small objects such as grass seeds; a soil corer with readily replaceable components in the event of frequent damage; a soil core divider; a windlass method for straining netting fence; an auger for planting materials grown in small peat pots; and a scarifier for small samples of legume seed.

A field trial carried out in North Otago was designed to determine the most beneficial time (April or June) and rate of application (1 or 2 kg a.i./ha) of lindane granules to pasture to control striped chafer (Odontria striata White) and alleviate pasture damage in spring. Only the 2 kg a.i./ha rate of lindane applied in April reduced larval density in the field (48%) compared with control plots when sampled in September. However, all lindane treatments gave good control of the next generation (85 – 92%) when sampled in February in the following year. Soil cores taken from the field trial plots in May and September were used in laboratory bioassays to investigate the effect of lindane on adult striped chafers. The bioassays showed that lindane caused adult mortality in winter (77 – 84%) and spring (92 – 100%) with no difference between the rates or times of application. Striped chafer larval density was low in the field trial area (31/m2 before treatment) and no differences in pasture production ...

(1983). Denitrification Measurements in Intact Soil Cores. Acta Agriculturae Scandinavica: Vol. 33, No. 2, pp. 145-151.

Eggs of the black field cricket, Teleogryllus commodus Walker (Orthoptera: Gryllidae), were sampled from clay soils in Northland. Soil cores were taken at regular intervals from February to May, and occasionally over the winter and early spring, from 1979 to 1982. Eggs were extracted from the soil by wet-sieving, elutriation, and floatation. Adult crickets were present in February, March, and April, but numbers declined rapidly after mid April as a result of senescence. Numbers of eggs stored in female crickets' oviducts were low in February, rapidly increased to a maximum in March (60 – 140 eggs per female), then gradually declined to low levels in May. The main oviposition period began in March with peaks occurring in March and April following high rainfall and culminating in a maximum density in April or May. The average number of non-damaged eggs recovered was 360 eggs per female with a range of 60 – 1000 eggs per female. Egg densities declined following the autumn peak at a rate of 9 (range ...

Delimiting and testing deeply stratified archaeological sites in frozen ground is facilitated by drilling and analyzing soil cores. After a test grid of the proposed area has been surveyed, a lightweight, portable diamond drill is used to sample those subareas selected through the use of (1) surface clues, (2) test-pit data, and (3) knowledge of standard site patterns of the cultures represented. Gross core analysis demonstrates soil profile continuities and discontinuities throughout the site. Munsell colours, thicknesses and gross inclusions of soil levels are recorded before thawing of the cores. Most cultural and human chemical residues are studied following thawing and dissection of the cores. The locations of bone, lithics, and human waste in frozen arctic and alpine soils and possibly in augured southern soils aid in vertical and horizontal site delimitation. Small samples of archaeologically important trace chemicals such as bone apatite and phosphorous can be taken for field analysis. Re...

Water content, wet and dry bulk density, plastic limit, liquid limit, clay content, total P, K-supplying power (Kc), cation exchange capacity (CEC), and exchangeable K, Ca, and Mg determinations were carried out on soil core samples from three 0.1-ha sampling sites on the Dannevirke silt loam, Kiwitea silt loam, and Marton silt loam soil types. The variation in the results obtained was then examined, using two-way analyses of variance, to determine core and depth effects and coefficients of variation (CV). Estimates were also made of the sample numbers required to be 95% certain that the population mean was within ± 10% of the sample mean thus obtained. Exchangeable K, Ca, and Mg were the most variable, CVs ranging from 5% to 60%. The remaining parameters had CVs ranging from 2% to 12%, wet and dry bulk density, clay content, liquid limit, and plastic limit generally being less variable than CEC, Kc, and total P. When results were expressed on a weight basis it was found that all three soil types...

Retentivity data for 409 South African soils were obtained from several sources. Water retained at matric potential values of 0, −1, −3, −10, −30, −100, −500 and −1500 kPa was determined from the retentivity curve for each soil core. Retentivity at each matric potential value was related to clay, silt, (or clay plus silt), fine sand and bulk density using multiple regression analysis. For the combined data, R2 values ranged from 0,59 at −3 kPa to 0,86 at −1500 kPa. Using data from a single source, R2 values ranged from 0,55 at −1 kPa to 0,93 at - 50 kPa.

A simple apparatus for obtaining unbroken soil cores from a variety of soil types is described. The equipment is light to carry and can be assembled or dismantled in the field. Samples of 30 cm depth have been obtained without difficulty and, with slight modification, the apparatus can be used to obtain longer cores. The depth of soil cores obtained can be pre‐determined, or gauged simply in the field by means of graduations on the external surface of the apparatus. For maximal ease of sampler operation some disturbance is caused to surrounding soil, but this disturbance can be reduced to a minimum where necessary. The presence of plant roots does not greatly impede progress of the sampler. Soil cores obtained are retained in plastic tubes, but can be removed if required.

Introduction Recent investigations in soil science have shown that physical properties of paddy soils are of great importance to rice-production. There is extensive literature on the chemical property of paddy soils, but little information on the physical property of paddy soils, especially under waterlogged condition. For studying the physical property of flooded paddy soils, it is necessary to collect the soil cores under an undisturbed condition.

SUMMARY A description is given of a technique for assaying the mycorrhizas found in a forest soil using a wet sieving method with two B.S.S. standard sieves of mesh size 0.066 and 0.0197 inches. Sampling is restricted to the top six inches of soil, from which the samples are collected with a corer. After extraction from the soil cores, the mycorrhizas are counted on a 10-inch square grid subdivided into numbered, one-inch squares that are further subdivided into 0.1-inch squares. A travelling stereo-zoom binocular microscope is used to examine and count the mycorrhizas on randomly-sampled 1-inch squares. It is estimated that there are about 580kg/acre of mycorrhizas in the top six inches of a good quality radiata (P. radiata D. Don) forest soil, and that approximately 55.2 per cent of them are living. A proposal is made that the results of future mycorrhiza assays include an ‘attrition ratio’, (ratio of inactive mycorrhizas to the total number seen in the sample). Examples are given of the use of this exp...

Acetylene reduction assays of nitrogen fixation were carried out on intact white clover (Trifolium repens L.) plants, and soil cores from a white clover sward using acetylene gas from three sources. Commercial grade acetylene gave significantly lower ethylene production than instrument grade acetylene or scrubbed commercial grade acetylene.

Data from periodic N fixation assays of soil cores from rotationally grazed pasture showed, over 2 years, marked similarity in seasonal pattern. The pattern was characterised by two distinct peaks in activity: the first in early spring, the second in early summer. While the N fixation patterns were similar in both years, clover growth rate curves were dissimilar.