Soil Placement Research Articles

Spatial patterns of microbial denitrification genes change in response to poultry litter placement and cover crop species in an agricultural soil

Subsurface-banding manure and winter cover cropping are farming techniques designed to reduce N loss. Little is known, however, about the effects of these management tools on denitrifying microbial communities and the greenhouse gases they produce. Abundances of bacterial (16S), fungal (ITS), and denitrification genes (nirK, nirS, nosZ-I, and nosZ-II) were measured in soil samples collected from a field experiment testing the combination of cereal rye and hairy vetch cover cropping with either surface-broadcasted or subsurface-banded poultry litter. The spatial distribution of genes was mapped to identify potential denitrifier hotspots. Spatial distribution maps showed increased 16S rRNA genes around the manure band, but no denitrifier hotspots. Soil depth and nitrate concentration were the strongest drivers of gene abundance, but bacterial gene abundance also differed by gene, soil characteristics, and management methods. Gene copy number of nirK was higher under cereal rye than hairy vetch and positively associated with soil moisture, while nirS gene copies did not differ between cover crop species. The nirS gene copies increased when manure was surface broadcasted compared to subsurface banded and was positively associated with pH. Soil moisture and pH were positively correlated to nosZ-II but not to nosZ-I gene copy numbers. We observed stronger correlations between nosZ-I and nirS, and nosZ-II and nirK gene copies compared to the reverse pairings. Agricultural management practices differentially affect spatial distributions of genes coding for denitrification enzymes, leading to changes in the composition of the denitrifying community.

Effect of inorganic fertilizer dose and vermicompost on growth and yield of Guava (Psidium guajava L.) cv. Lalit

The experiment was conducted on two years old guava at Research Field, Department of Horticulture, SHUATS, Allahabad, during the year 2016-2017. It was laid out in Randomized Block Design (R.B.D) with 4 replications and 11 treatments. The treatments included different levels of inorganic fertilizer and vermicompost. The maximum increase in plant height (155.71 cm), number of branches (25.23), canopy spread E-W direction (101.88 cm) and N-S direction (104.88 cm), was obtained with the application of T10 [50% RDN through chemical fertilizer +50% RDN through vermicompost (100:50:50 g NPK+1kg vermicompost)]. Maximum number of flowers/plant (18.25), fruit set (48.42%), fruit length (7.57 cm), fruit diameter (7.78 cm), volume of fruit (118cm3) and specific gravity (1.14 g/ml), were recorded with the application of T10 (50% RDN through chemical fertilizer +50% RDN through vermicompost), which was superior as compared to other treatments taken under present study. The maximum average fruit weight (128g) and number of fruits per plant (8.53) as well as significant highest yield per plant (959.14g) were obtained with the application of 50% RDN through chemical fertilizer+50% RDN through vermicompost (T10). The maximum total soluble solids (12.040Brix), ascorbic acid (180.89mg/100 g pulp) and minimum titratable acidity (0.51%) were recorded with the soil placement of 50% RDN through chemical fertilizer +50% RDN through vermicompost (T10), which was superior and economically viable as compare to other treatments with a maximum cost benefit (C:B) ratio of (1: 1.04).

Optimization of Quality Control of Gravel-Pebble Soil Placement During Dam Construction

Recommendations are given for determining the maximum density of the investigated soil when calculating their compaction coefficient in the dam body.

Sub-watershed prioritization based on sediment yield using game theory

The proper placement of soil and water conservation measures cannot be designated due to lack of appropriate technical prioritization of different areas of a watershed. Therefore, quantifying soil erosion hazard and spatial prioritization of sub-watersheds would aid in better watershed management planning. Although, many approaches have been applied to prioritize sub-watersheds, but still the efficient techniques like game theory have not been practically applied to prioritize sub-watersheds. The present study therefore has used the game theory to prioritize sub-watersheds in Gorganroud and Qareh Sou watersheds in Golestan Province, northern Iran. Towards this goal, 38 independent factors were classified in seven components using Principal Component Analysis (PCA) method with one representative variable in each component. The Condorcet method used for prioritization of effective variables indicated that the percent of forestry lands (52 scores) and discharge with 10 years of return period (32 scores) were respectively the most and the least effective variables on sediment yield. The Fallback bargaining and the Borda Scoring algorithms were also selected to prioritize study sub-watersheds based on weighted grades of total score for each variable. Accordingly, the aforesaid algorithms classified sub-watersheds in three categories. Comparison of results similarly introduced Galikesh, Qazaqli, Gonbad, Siyah Ab and Tamar as first ranked sub-watersheds with the worth condition, Tangrah and Naharkhoran as second priority and eventually Pole Ordougah as sub-watershed with the lowest priority.

Effect of geomembrane colour and cover soil on solar-driven down-slope bentonite erosion from a GCL

The surface temperature of an exposed composite liner consisting of a geosynthetic clay liner (GCL) covered by a black geomembrane (GMB) can routinely exceed 60°C during summer solar exposure before falling to ambient air temperature at night. Observations at the Queen's University Environmental Liner Test Site (QUELTS) have recently shown that the evaporation and cooling of the air space at the GMB–GCL interface causes condensed water to form underneath the GMB. These water drops flow down-slope until they are released onto the top surface of the GCL at points of contact, seams, or changes in geomembrane curvature. An unforeseen consequence of this solar-driven generation and release of distilled water onto the GCL was discovered to be down-slope erosion of bentonite from the GCL. The objective of the current study was to repeat the QUELTS field exposure experiment to confirm whether the immediate covering of the GMB will supress the mechanism of down-slope bentonite erosion through the elimination of the air gap at the GMB–GCL interface and a reduction in thermal cycling. Further, this study examined whether the use of a white-coloured GMB can reduce the time to onset of erosion if immediate cover is not possible. Results confirm that no erosion occurred on the composite liner test section covered by 0.3 m of gravel after the 15 month duration of the study. In contrast, erosion was observed to occur on the exposed white GMB section, but at a slower rate than that observed on the exposed black GMB section. The timely placement of cover soil on the composite liner as per manufacturers' recommendations is therefore the most effective strategy to avoid the issue of down-slope bentonite erosion.

Perpetuation of <i>Alternaria solani</i> of Potato under Temperate Kashmir Valley Conditions

The present study on perpetuation of Alternaria solani , causing early blight of potato in Kashmir valley was conducted during 2009 and 2010. The perpetuation of the fungus A. solani was studied on diseased leaves by placing the leaves on ground surface and at 20 cm depth, as well as on diseased potatoes kept in ambient store. The pathogen perpetuated as mycelium and conidia throughout winter on diseased leaves left on the ground surface and on diseased potatoes kept in ambient store. The number of spores cm -2 leaf area and the viability of spores decreased with increase in depth of placement in soil. Maximum spores production on over wintered leaves was observed during first fortnight of June during the year 2009 and 2010, with maximum number of 294 and 323 spores, respectively. However, by the first fortnight of July, the number gradually declined to 160 and 220 spores, respectively. The highest spore viability of 44.3 and 49.3 per cent in leaves on ground surface was recorded in the first fortnight of June, 2009 and 2010, respectively. In potatoes kept in ambient store the average number of spores increased upto first fortnight of June, both in 2009 and 2010, with a maximum number of 430 and 508 spores, respectively. The number then gradually declined to 216 and 263 spores, respectively, till last observation recorded in the second fortnight of July.

Responses of an ancient woodland field layer to soil translocation: methods and timing

AbstractQuestionsDo woodland field layer communities reassemble effectively after being translocated from a donor to a receptor site? Does the method of soil handling (turfing or loose‐tipping) or the season of transfer determine the outcome?LocationA deciduous ancient coppice woodland in Kent, southeast England.MethodsTwo methods of soil translocation were compared: loose‐tipping, involving stripping a layer of topsoil and re‐spreading it at a receptor site; and soil placement, in which soil turves were cut and laid intact. The operation also provided an opportunity to observe the effects of seasonal translocation, respectively, in autumn and spring. Soil compaction, texture and chemistry were assessed after translocation, while vegetation cover changes were followed over a 10‐yr period.ResultsImmediately after soil transfer, the vegetation community reverted to an earlier successional stage, with bare ground rapidly colonized by annuals and biennials, many germinating from the soil seed bank. By the third year after translocation, a perennial vegetation cover had developed comprising grasses and woodland‐edge opportunists as well as most of the original woodland species. After 10 yr, bramble (Rubus fruticosus agg.) dominated the receptor sites, along with the woodland geophyte bluebell (Hyacinthoides non‐scripta), while some woodland species became less abundant. Localized soil compaction radically altered species composition. Autumn translocation promoted better immediate recovery of forest species than spring translocation, while soil placement caused less initial damage than loose‐tipping. Convergence in vegetation composition in all soil handling treatments was observed towards canopy closure.ConclusionsResults illustrate the importance of conducting translocation operations in the autumn when the vegetation is dormant and soil moisture is low, and point to the need for sensitive soil handling. After 10 yr the field layer at the receptor site still resembled that of the donor, but with differences in abundance of some individual species.

Design of self-sustainable land surface against soil erosion at rehabilitation areas in open-cut mines in tropical regions

Soil erosion is one of the major environmental problems in open-cut mines in tropical regions. It causes negative impacts including the removal of nutrient rich topsoil and subsequent reduction of agricultural productivity in the rehabilitation process. Therefore, it is important to predict soil erosion in advance and establish the proper process to minimise the phenomenon for the success of rehabilitation in the disturbed land. Field investigation to understand soil characteristics in rehabilitation areas and artificial rainfall experiment in laboratory scales were used to assess soil erosion. From a series of investigations, the soil characteristics that spread to the rehabilitation areas were uneven due to mixing overburden as contamination; moreover, it can increase the risk of soil erosion when the soil has high soil erodibility. Another study finding shows the importance of selective placement of erosion-resistant soil in an area which has a high potential for soil erosion to occur, such as slope with an establishment of rapid growing cover crop species on the surface. This paper describes soil erosion under the various soil characteristics and effective countermeasures in situ, and discusses the design of the self-sustainable land surface against soil erosion.

Forest floor protection during drilling pad construction promotes resprouting of aspen

Drilling pads that are used to explore petroleum reserves in the boreal forest are often only used for a short time. We studied the vegetative regeneration potential of aspen (Populus tremuloides) through root suckers as a means to rapidly recover forest vegetation in these disturbed sites. We compared protecting the original forest floor under a layer of subsoil during the leveling of drilling pads, with the current practice of stripping off the forest floor and topsoil and placing it back on the site (Rollback) in the re-contouring of the reclamation phase. We also tested three techniques of delineating the forest floor so that it can be effectively uncovered during the reclamation phase. After re-contouring and top soil placement on the sites, we assessed the extent of surface disturbance, soil temperature, soil bulk density, and the density and height of aspen regeneration. Aspen suckers were tallest, had the highest density and had better survival when the forest floor was protected compared to the standard Rollback treatment. When protecting the forest floor, delineating the original forest floor from the subsoil cover resulted only in small differences in the aspen regeneration among delineation treatments with little impact on soil compaction and only moderate effects on soil surface disturbance. The study indicates that protection and the careful uncovering of the forest floor with or without using a delineation layer should be a preferred strategy for temporary drilling pad construction and their subsequent reclamation in aspen-dominated boreal forests.

Injection of Dicyandiamide-Treated Pig Slurry Reduced Ammonia Volatilization without Enhancing Soil Nitrous Oxide Emissions from No-Till Corn in Southern Brazil.

There is a lack of information on how placement in soil and nitrification inhibitors affects nitrous oxide (NO) and ammonia (NH) emissions from pig slurry (PS) applied under no-till (NT) conditions. Our objective was to determine the impact of injecting PS and treating it with the nitrification inhibitor dicyandiamide (DCD) on NH and NO emissions from soils under NT in subtropical southern Brazil. The emissions of these gases were compared for shallow (∼ 10 cm) injection and surface broadcasting of PS with and without DCD (8.1-10.0 kg ha; 6.5-8.4% of applied NH-N). Measurements were made at two sites during two summer growing seasons under NT corn crops. Injection reduced NH volatilization by 70% but increased NO emissions 2.4-fold (from 2628 to 6198 g NO N ha) compared with surface broadcast application. Adding DCD to PS inhibited nitrification and reduced NO emissions by an average of 28% (730 g NO-N ha) for surface broadcast and 66% (4105 g NO-N ha) for injection but did not increase NH volatilization. Consequently, NO emission factors were much higher for injection (3.6%) than for surface broadcast (1.3%) application and were reduced (0.9%) when DCD was added to injected PS. In conclusion, the injection of DCD-treated slurry is a recommendable practice for reducing NH and NO emissions when applying PS on NT corn in southern Brazil.

Fusarium rot in cucumber greenhouses of Jiroft region

The present work was done to identify Fusarium species that cause Fusarium rot in greenhouse cucumber crop in Jiroft region (Kerman, Iran), in 2006–2007. During these years, a vast sampling was done from several greenhouses of Jiroft. The plants with rot symptoms as well as the soil samples of greenhouse were transferred to lab. The isolates of plants and soil samples were detached by direct isolation of the infected tissue and soil suspension methods, respectively. Totally 120 isolates were obtained, which were classified into the following six species according to their morphological and physiological characteristics: Fusarium oxysporum, Fusarium solani, Fusarium culmorum, Fusarium monoliforme, Fusarium sambucinum, Fusarium subglutinans. It is the first time that three of these taxons, i.e. F. culmorum, F. monoliforme and F. subglutinan are reported in cucumber of Iran. Pathogenesis studies of the isolates were done by mycelium placement and spore suspension injection methods in sterile soil under greenhouse conditions. Then the disease symptoms were investigated.

Recovery of Fertilizer Nitrogen by Maize Grown with Nutriseed Pack and Soil Nitrogen Retention Using 15N Tracer

In a cropped land plant and soil utilizes nitrogen (N) mainly from fertilizer. Deep placement of fertilizer N enhances added N use efficiency. Nutriseed Pack technique is a way of deep placing fertilizer in the root zone simultaneously when sowing the seed. A Green house experiment with 15 N tracer technique was conducted during 2009 at open premises of green house in the Department of Soil Science and Agricultural Chemistry, TNAU, Coimbatore to evaluate the effect of application of fertilizers in maize by surface broadcast and Nutriseed Pack. Each Nutriseed Pack was assembled by stacking of seed, manure and fertilizer pellets and then wound in newspaper as a roll. On placement in soil, supply of nutrients is expected from Nutriseed pack throughout the crop period. Column study on 15 N recovery of added fertilizer by maize resulted in high recovery (NUE) for horizontal placement of Nutriseed Pack (36.17%) followed by placement of vertical Nutriseed Pack with Furadan (33.62%), and moderate recovery for surface broadcast (30.45%). The applied labelled N retained in surface layer was high in horizontal placement of Nutriseed Pack which ranged from 8.0 to 18.1 per cent in surface layer (0-15 cm), 4.9 to 10.8 per cent in sub-surface layer (15-30 cm), and 2.8 to 6.0 per cent the lower layer (30-45cm) respectively. In case of surface application of fertilizers, N retained was 5.5 per cent in surface layer (0-15 cm), 3.2 per cent in sub-surface layer (15-30 cm), and 11.1 per cent in lower layer (30-45 cm) respectively.

Laboratory-based nitrogen mineralization and biogeochemistry of two soils used in oil sands reclamation

MacKenzie, M. D. and Quideau, S. A. 2012. Laboratory-based nitrogen mineralization and biogeochemistry of two soils used in oil sands reclamation. Can. J. Soil Sci. 92: 131–142. In the Athabasca oil sands region of Alberta, Canada, peat mineral and upland forest floor mineral soils are salvaged and stockpiled for reclamation. Previous work showed that sites reclaimed with forest floor mineral soil had better understory regeneration and nitrogen dynamics more similar to naturally disturbed ecosystems. Both soils and a mixture of the two were compared in laboratory incubations by examining nitrogen mineralization (over 45 wk) and factorial fertility additions (4 wk trial with NPK) on microbial community structure and nutrient availability. Nitrogen mineralization indicated forest floor mineral soil had lower release rates and a higher estimated labile nitrogen pool than peat mineral soil. Nitrogen mineralization in mixed soil started like peat mineral soil and finished like forest floor mineral soil. Fertility additions influenced microbial community structure less than soil type. Multi-response permutation procedure indicated the forest floor mineral soil microbial community was significantly different from peat mineral and mixed soil communities. Control nutrient profiles differed from those with added NPK. Forest floor mineral soil retained nitrogen as ammonium, while peat mineral and mixed soils were nitrate dominated. Reclamation will require all soil types to be used and these data will help determine soil placement prescriptions.

Categorization and numerical assessment of wireworm mobility over time following exposure to bifenthrin

We discuss the effect of the pyrethroid insecticide bifenthrin incorporated into soil at 100, 200, and 300 g AI/ha on late-instar larvae of the dusky wireworm, Agriotes obscurus (Coleoptera: Elateridae), and present a method of assessing wireworm health and mobility over time. Wireworms became moribund within 1 h of placement in soil amended with bifenthrin at all rates. After 2 weeks of morbidity in amended soils, wireworms recovered within 7 days of being placed in clean soil. A considerable proportion (0.13–0.93) of wireworms placed in amended soil moved to the soil surface and remained there for 2 weeks or more in a moribund state; wireworms transferred to clean soil no longer moved to the soil surface. Eight distinct mobility categories were observed and are described, and a new method for assessing wireworm health and mobility over time is discussed.

Examining restoration methods in brackish marshes on the Gulf of Mexico coast

Introduction Compensatory habitat restoration is a useful tool for oil spill mitigation, but different restoration methods may vary in ecological success. Restoration construction designs vary in terms of soil placement and elevation gradients. These designs may alter features such as erosion and accretion rates and connectivity between habitat types, and may subsequently influence the development of plant and animal communities. Habitat restoration success is often gauged by assessing a few prominent plant canopy characteristics However recovery of Results

Densification of granular soil by dynamic compaction

Land reclamation often involves the placement of loose granular soil by means of hydraulic filling. Sand fill formed by hydraulic filling generally does not allow densification by surface compaction methods because of their limited depth of influence. Loose granular soil is susceptible to liquefaction upon the impact of dynamic forces. Even under static conditions, loose granular soil may be subjected to bearing capacity failure and large settlements, because of its low shearing resistance and high compressibility. Various densification methods are used for improving such soils to increase the friction angle and elastic modulus. Several methods of deep compaction are available for such applications; among these, dynamic compaction is one of the most effective ways of densifying granular soils to a significant depth. However, the success of dynamic compaction is affected by many factors, several of which are not yet fully understood. This paper deals with the dynamic compaction densification method utilised at the Changi East reclamation site in Singapore for the improvement of reclaimed sand fill. Field data collected are used as a basis to investigate the effectiveness of the densification method and the effect of various influencing factors critical to the success of dynamic compaction treatment.

In‐Furrow Inoculation and Selection for Higher Motility Enhances the Efficacy of Bradyrhizobium japonicum Nodulation

The issue of competition for nodulation has received much attention in studies on soybean [Glycine max (L.) Merr.] crops because native soil rhizobia often preclude nodulation of inoculated high‐quality strains. In this work, soil placement and enhanced motility of Bradyrhizobium japonicum were investigated as strategies to improve the competitiveness of soybean inoculants applied in the presence of large populations of native (or indigenous) soybean‐nodulating rhizobia. The first strategy might allow for the enhanced distribution of inoculant rhizobia in the surface soil, compared with inoculant that is directly applied to soybean seed, while the second strategy is expected to enhance root colonization. The effects of soil placement and enhanced bacterial motility on percentage nodule occupation, grain yield, and grain N contents were examined during the 2004–2005 soybean season at three locations in Argentina, comprising soils classified as entic hapludol, argillic pelludert, and typical argiudol. The experimental design was a randomized complete block design, and main effects and interactions were also analyzed with a factorial design. Strain LP 3008, previously selected for increased motility, was more effective than the commonly inoculated strain E 109. While E 109 occupied, on average, 13.2% of nodules with seed inoculation, LP 3008 occupied 28.2%. In comparison, in‐furrow inoculation yielded 24.2 and 37.2% average nodule occupancies for E 109 and LP 3008, respectively. However, these gains in nodulation efficacy lead to a modest, nonsignificant yield increase, and grain N content was unaffected.

Manure placement depth impacts on crop yields and N retained in soil

The objective of this study was to determine the impact of manure placement depth on crop yield and N retention in soil. Experimental treatments were deep manure injection (45 cm), shallow manure injection (15 cm), and conventional fertilizer-based management with at least three replications per site. Water infiltration, and changes in soil N and P amounts were measured for up to 30 months and crop yield monitored for three seasons following initial treatment. Deep and shallow manure injections differed in soil inorganic N distributions. For example, in the manure slot the spring following application, NO3-N in the surface 60 cm was higher (p < .01) when injected 15 cm (21.4 μ g/g) into the soil than 45 cm (11.7 μ g/g), whereas NH4-N had opposite results with shallow injection having less (p = 0.045) NH4-N (102 μ g/g) than deep (133 μ g/g) injection. In the fall one year after the manure was applied, NO3-N and NH4-N were lower (p = 0.001) in the shallow injection than the deep injection. The net impact of manure placement on total N was that deep injection had 31, 59, and 44 more kg N ha− 1 than the shallow injection treatment 12, 18, and 30 months after application, respectively. Deep manure injection did not impact soybean (Glycine max L.) yield, however corn (Zea mays L.) yield increased if N was limiting. The higher corn yield in the deep injected treatment was attributed to increased N use efficiency. Higher inorganic N amounts in the deep injection treatment were attributed to reduced N losses through ammonia volatilization, leaching, or denitrification. Results suggest that deep manure placement in glacial till soil may be considered a technique to increase energy, N use efficiency, and maintain surface and ground water quality. However, this technique may not work in glacial outwash soils due to the inability to inject into a rocky subsurface.

Reinforcement design for construction of cover soil over soft sludge

This paper presents a design procedure for selecting the reinforcement tensile strength and strain that are required for the construction of cover soils over soft low-permeability sludge using the ‘finger fill soil placement technique’, which consists in placing a high-strength reinforcement over the soft, low-permeability sludge and building parallel narrow berms over the reinforcement. The design procedure described in this paper: (1) considers the proposed construction sequence; (2) takes advantage of the ability of the high-strength reinforcement to withstand tensile stresses; and (3) considers the large vertical displacement due to the applied load. The proposed design procedure allows the design engineer to select the reinforcement characteristics as well as the initial berm thickness and spacing.

English

Paracatu is located in northwest Minas Gerais State, 230 kilometers from Brasilia, the capital of Brazil, and for the last two centuries has been an important gold mining site. With more of 600 ha of acid-sulfate soils across the open cut mine to be revegetated, the company is working to develop a method to reliably establish sustainable vegetation and minimize acid drainage. With this goal, we established a field experiment to evaluate five soil placement combinations to isolate (saddle) and/or cover the acid substrate. We also evaluated five plant species and three combinations to revegetate the materials. The five cover treatments were composed of three layers to: 1) isolate/saddle the substrate; 2) break capillarity and, 3) form a suitable surface material for plant growth. Ore (from mining zone B1) or clay was used as the saddle layer and sand, lime gravel, and sand plus oxalic acid were tested as capillary barriers. Then KCl and NaCl were also added to induce jarosite formation (geochemical barrier) to reduce availability of Fe and As in the drainage. As a cover layer, we tested B1 and local B horizon clay. Each (3) experimental block was comprised of five plots (to test the layers materials) with eight split sub-plots to evaluate the species and combinations. Ten months after establishment, we took samples of the layers to evaluate density and porosity, and the revegetation species were sown. Preliminary results showed that the saddle layer with clay resulted in higher density/less porosity. Non-compacted clay, when used to form the third layer, had higher water retention than B1 ore. This characteristic is very important to reduce water movement into underlying acid-sulfate materials. Among the evaluated species, Crotalaria juncea performed best followed by Melinis minutiflora. For most tested plant species and mixtures, the use of clay as the first and third layer coupled with sand plus KCl and NaCl as the capillary barrier resulted in optimal biomass production.