Tillage, compaction and wetting effects on NO3, N2O and N2 losses

Soil Research ◽  
2019 ◽  
Vol 57 (6) ◽  
pp. 670 ◽  
Author(s):  
Stephen M. Thomas ◽  
Patricia M. Fraser ◽  
Wei Hu ◽  
Timothy J. Clough ◽  
Gina van der Klei ◽  
...  
Keyword(s):  
Soil Surface ◽  
Field Capacity ◽  
Gas Diffusion ◽  
Soil Drainage ◽  
Forage Crops ◽  
Compacted Soils ◽  
Air Content ◽  
Irrigation Drainage ◽  
Intact Soil ◽  
Weekly Application

Denitrification is sensitive to changes in soil physical properties that affect solute transport, air content and gas diffusion. Using lysimeters, containing intact soil from intensively tilled (IT) and no-tilled (NT) soil used to grow forage crops, we examined how simulated animal treading at different moisture contents (above and below field capacity; >FC and <FC respectively) affected losses of nitrous oxide (N2O), dinitrogen (N2) and nitrate (NO3). We applied 15N-labelled NO3 (250kg N ha–1) to the soil surface after treading (applied at 220 kPa to 40% of the soil surface), or to untrodden soil. Drainage occurred following weekly application of water over the experiment (two pore volumes over 84 days). Treading at >FC greatly increased denitrification, especially from IT soil and produced the greatest amount of N2 (64kg N ha–1), N2O (8.2kg N ha–1), as well as the lowest N2O to N2O+N2 ratio (0.08) and NO3 leaching (136kg N ha–1 below 30cm). In both the uncompacted or compacted soils <FC, emissions of N2O were greater (1.5–2.7% of N applied) and the N2O to N2O+N2 ratios were closer to 0.2 compared to compaction at >FC. Treading at <FC had minimal or no effect on denitrification compared to untrodden soil. Fluxes of N2 and N2O were strongly influenced by the weekly irrigation–drainage cycle. The N2 production and reduction in NO3 leaching were best correlated with increases in microporosity and reduced saturated hydraulic conductivity following treading. Although recovery of 15N was high (84.3%), the remainder of the balance was likely lost as either N2 or, of greater concern, as N2O. Practically, animal trampling on wet soils, especially when recently cultivated, should be avoided.

scholarly journals The influence of soil structure and air content on gas diffusion in soils.

1970 ◽  
Vol 18 (1) ◽  
pp. 37-48
Author(s):  
J.W. Bakker ◽  
A.P. Hidding
Keyword(s):  
Diffusion Coefficient ◽  
Soil Structure ◽  
Soil Surface ◽  
Ambient Air ◽  
Gas Diffusion ◽  
Undisturbed Soil ◽  
Air Content ◽  
Temperature And Pressure ◽  
Storage Term ◽  
Puddled Soil

A method is described of determining the diffusion coefficient of O2 in undisturbed soil samples. Calculations were made of errors involved when neglecting the storage term, temperature and pressure variations, O2 consumption and resistance of ambient air. The diffusion coefficient (Ds) is a function of air porosity (eg) and soil structure. At values of eg below 0.2, the effect of a puddled soil surface becomes evident. In puddled soils values of Ds at equal eg are far below those in non-puddled soils and the differences increase with decreasing eg. A wet soil crust can severely limit gas exchange by diffusion. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Characterization and Evaluation of Aerobic Rice Genotypes under Transplanted Condition

2016 ◽  
Vol 20 (1) ◽  
pp. 45-50
Author(s):  
S Akter ◽  
S Pervin ◽  
KM Iftekharuddaula ◽  
A Akter ◽  
R Yasmeen
Keyword(s):  
Irrigation Water ◽  
Block Design ◽  
Soil Surface ◽  
Field Capacity ◽  
Underground Water ◽  
Yield Reduction ◽  
Aerobic Rice ◽  
Moisture Condition ◽  
Aerobic Culture ◽  
Moisture Regimes

Due to over sinking of underground water, scarcity of irrigation water is becoming a threat to the sustainability of irrigated rice production and the concept of aerobic culture appeared prominently. Aerobic rice has the ability to grow under minimum irrigation water and minimum yield reduction occurs when grown under aerobic culture with less water. This experiment aimed to evaluate two advanced aerobic rice lines under transplanted condition in net house. Two advanced lines, IR83140-B-36-B-B and IR83142-B-71-B-B and two check varieties BRRI dhan28 and BRRI dhan29 were grown in three moisture regimes. The moisture regimes included a) continuous standing water (CSW) b) saturated moisture condition (SMC) and c) moisture content at field capacity (FCM). The experimental units, drum containing 110 kg soil, were arranged in randomized complete block design (RCBD) with five replications. Three to four seedlings of forty days were transplanted at the soil surface of each drum. Seedlings were thinned to one plant per genotypes one week after transplanting. Genotype × water interaction showed significant variation in total dry matter production, panicle length, panicle exertion rate, sterility percentage and yield contributing characters. Irrespective of the genotypes, CSW conditions favored to produce maximum number of tiller and panicle. Although BRRI dhan29 gave the highest yield at both CSW and SMC, IR83142-B-71-B-B produced the highest yield at FCM. However, BRRI dhan28 gave similar yield to that of IR83142-B-71-B-B in FCM treated drums.Bangladesh Rice j. 2016, 20(1): 45-50

Volatility and Photodecomposition of Trifluralin, Benefin, and Nitralin

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 469-473 ◽  
Author(s):  
J. V. Parochetti ◽  
E. R. Hein
Keyword(s):  
Soil Moisture ◽  
Flow Rate ◽  
Air Flow ◽  
Soil Surface ◽  
Field Capacity ◽  
Loamy Sand ◽  
Spray Application ◽  
Air Flow Rate ◽  
Laboratory Conditions ◽  
Spray Applications

Vapor losses of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-p-toluidine), and nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] were studied under controlled laboratory conditions using a Florisil vapor trap. No nitralin vapor losses were detected at 50 C from a Lakeland loamy sand at field capacity with an air flow rate of 0.04 m3/hr for 3 hr; whereas, 24.5% and 12.5% of trifluralin and benefin, respectively, were lost as vapors. Volatility of trifluralin and benefin increased with increasing temperatures of 30, 40, and 50 C and increasing soil moisture from air dryness to field capacity. Vapor losses from granular benefin were similar to the spray applications at 30 and 40 C. Volatilization of granular trifluralin was reduced when compared to the spray application at 40 C and 30 C but was similar for both formulations for benefin. No significant losses from photodecomposition were noted for trifluralin, benefin, or nitralin when comparing radiated and unradiated soil surface treated samples.

scholarly journals Liming in Agricultural Production Models with and Without the Adoption of Crop-Livestock Integration

2015 ◽  
Vol 39 (5) ◽  
pp. 1463-1472 ◽  
Author(s):  
Francisco Carlos Mainardes da Silva ◽  
Luís Guilherme Sachs ◽  
Inês Cristina Batista Fonseca and ◽  
João Tavares Filho
Keyword(s):  
Agricultural Production ◽  
Chemical Properties ◽  
Soil Surface ◽  
Forage Crops ◽  
Long Period ◽  
Production Models ◽  
Dry Spells ◽  
Tillage System ◽  
Rate Of Decline ◽  
Harmful Effects

ABSTRACT Perennial forage crops used in crop-livestock integration (CLI) are able to accumulate large amounts of straw on the soil surface in no-tillage system (NTS). In addition, they can potentially produce large amounts of soluble organic compounds that help improving the efficiency of liming in the subsurface, which favors root growth, thus reducing the risks of loss in yield during dry spells and the harmful effects of “overliming”. The aim of this study was to test the effects of liming on two models of agricultural production, with and without crop-livestock integration, for 2 years. Thus, an experiment was conducted in a Latossolo Vermelho (Oxisol) with a very clayey texture located in an agricultural area under the NTS in Bandeirantes, PR, Brazil. Liming was performed to increase base saturation (V) to 65, 75, and 90 % while one plot per block was maintained without the application of lime (control). A randomized block experimental design was adopted arranged in split-plots and four plots/block, with four replications. The soil properties evaluated were: pH in CaCl2, soil organic matter (SOM), Ca, Mg, K, Al, and P. The effects of liming were observed to a greater depth and for a long period through mobilization of ions in the soil, leading to a reduction in SOM and Al concentration and an increase in pH and the levels of Ca and Mg. In the first crop year, adoption of CLI led to an increase in the levels of K and Mg and a reduction in the levels of SOM; however, in the second crop year, the rate of decline of SOM decreased compared to the decline observed in the first crop year, and the level of K increased, whereas that of P decreased. The extent of the effects of liming in terms of depth and improvement in the root environment from the treatments were observed only partially from the changes observed in the chemical properties studied.

scholarly journals Underestimation of denitrification rates from field application of the <sup>15</sup>N gas flux method and its correction by gas diffusion modelling

2019 ◽  
Vol 16 (10) ◽  
pp. 2233-2246 ◽  
Author(s):  
Reinhard Well ◽  
Martin Maier ◽  
Dominika Lewicka-Szczebak ◽  
Jan-Reent Köster ◽  
Nicolas Ruoss
Keyword(s):  
Field Experiments ◽  
Pore Space ◽  
Soil Surface ◽  
Gas Diffusion ◽  
Surface Fluxes ◽  
Soil Gas ◽  
Total Production ◽  
Concentration Gradients ◽  
Flux Method ◽  
Gas Flux

Abstract. Common methods for measuring soil denitrification in situ include monitoring the accumulation of 15N-labelled N2 and N2O evolved from 15N-labelled soil nitrate pool in closed chambers that are placed on the soil surface. Gas diffusion is considered to be the main transport process in the soil. Because accumulation of gases within the chamber decreases concentration gradients between soil and the chamber over time, the surface efflux of gases decreases as well, and gas production rates are underestimated if calculated from chamber concentrations without consideration of this mechanism. Moreover, concentration gradients to the non-labelled subsoil exist, inevitably causing downward diffusion of 15N-labelled denitrification products. A numerical 3-D model for simulating gas diffusion in soil was used in order to determine the significance of this source of error. Results show that subsoil diffusion of 15N-labelled N2 and N2O – and thus potential underestimation of denitrification derived from chamber fluxes – increases with chamber deployment time as well as with increasing soil gas diffusivity. Simulations based on the range of typical soil gas diffusivities of unsaturated soils showed that the fraction of N2 and N2O evolved from 15N-labelled NO3- that is not emitted at the soil surface during 1 h chamber closing is always significant, with values up to >50 % of total production. This is due to accumulation in the pore space of the 15N-labelled soil and diffusive flux to the unlabelled subsoil. Empirical coefficients to calculate denitrification from surface fluxes were derived by modelling multiple scenarios with varying soil water content. Modelling several theoretical experimental set-ups showed that the fraction of produced gases that are retained in soil can be lowered by lowering the depth of 15N labelling and/or increasing the length of the confining cylinder. Field experiments with arable silt loam soil for measuring denitrification with the 15N gas flux method were conducted to obtain direct evidence for the incomplete surface emission of gaseous denitrification products. We compared surface fluxes of 15N2 and 15N2O from 15N-labelled micro-plots confined by cylinders using the closed-chamber method with cylinders open or closed at the bottom, finding 37 % higher surface fluxes with the bottom closed. Modelling fluxes of this experiment confirmed this effect, however with a higher increase in surface flux of 89 %. From our model and experimental results we conclude that field surface fluxes of 15N-labelled N2 and N2O severely underestimate denitrification rates if calculated from chamber accumulation only. The extent of this underestimation increases with closure time. Underestimation also occurs during laboratory incubations in closed systems due to pore space accumulation of 15N-labelled N2 and N2O. Due to this bias in past denitrification measurements, denitrification in soils might be more relevant than assumed to date. Corrected denitrification rates can be obtained by estimating subsurface flux and storage with our model. The observed deviation between experimental and modelled subsurface flux revealed the need for refined model evaluation, which must include assessment of the spatial variability in diffusivity and production and the spatial dimension of the chamber.

Effects of Starch Encapsulation on Clomazone and Atrazine Movement in Soil and Clomazone Volatilization

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 445-453 ◽  
Author(s):  
Todd L. Mervosh ◽  
Edward W. Stoller ◽  
F. William Simmons ◽  
Timothy R. Ellsworth ◽  
Gerald K. Sims
Keyword(s):  
Unsaturated Flow ◽  
Soil Surface ◽  
Silty Clay ◽  
Silt Loam ◽  
Starch Granules ◽  
Soil Cores ◽  
Silty Clay Loam ◽  
Intact Soil Cores ◽  
Water Tension ◽  
Intact Soil

The effects of formulation on clomazone volatilization and transport through soil were studied. After 22 days of leaching under unsaturated flow in 49-cm long intact soil cores, greater clomazone movement was observed in Plainfield sand than in Cisne silt loam or Drummer silty clay loam soils. Soil clomazone concentrations resulting in injury to oats occurred throughout Plainfield soil cores but were restricted to the upper 14 cm of Cisne and Drummer soils. In addition, clomazone was detected in the leachate from Plainfield soil only. In a similar study with Plainfield sand cores, clomazone was less mobile than atrazine; encapsulation of the herbicides in starch granules did not affect clomazone movement but greatly decreased atrazine movement from the soil surface. Similarly, starch encapsulation did not affect bioavailability of clomazone but did reduce bioavailability of atrazine. In a laboratory study with continual air flow, volatilization of clomazone applied to the soil surface was reduced by encapsulation in starch and starch/clay granules. Clomazone volatilization was not affected by soil water content within a range of 33 to 1500 kPa water tension. Following soil saturation with water, clomazone volatilization from both liquid and granular formulations increased. Granule size appeared to have a greater impact than granule composition on clomazone volatilization.

Evaluation of the magnetite as a magnetic tracer of eroded sediment from ephemeral gullies: conditioning factors of magnetic susceptibility

2020 ◽  
Author(s):  
Elena Zubieta ◽  
Juan Larrasoaña ◽  
Rafael Giménez ◽  
Alaitz Aldaz ◽  
Javier Casalí
Keyword(s):  
Magnetic Susceptibility ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Surface ◽  
Field Capacity ◽  
Field Studies ◽  
Silty Clay ◽  
Magnetic Signal ◽  
Conditioning Factors ◽  
Detection Depth

&lt;p&gt;In gully erosion, the soil detached by the action of the erosive flow can be transported over long distances along the drainage network of the watershed. In this long way, the eroded material can be redistributed and/or deposited on the soil surface, and then eventually buried by eroded material from subsequent erosion events. Likewise, the variability of the soil (i.e., in texture and moisture content) over which this material moves can be considerable. The presence of the eroded material could be detected through magnetic tracers attached/mixed with the eroded soil. In this experiment, the degree to which the magnetic signal of the magnetite is conditioned by (i) the burying tracer depth, (ii) the texture and moisture content of the soil covering the tracer and (iii) the tracer concentration was evaluated.&lt;/p&gt;&lt;p&gt;The study was carried out in the lab in different containers (0.5 x 0.5 x 0.3 m&lt;sup&gt;3&lt;/sup&gt;). Each container was filled with a given soil. In the filling process, a 0.5-cm layer of a soil-magnetite mixture of a certain concentration was interspersed in the soil profile at a certain depth. Overall, 3 different soil:tracer concentrations (1000:1, 200:1, 100:1), 4 tracer burying depths (0 cm, 3 cm, 5 cm and 10 cm from soil surface), and &amp;#160;2 contrasting soils (silty clay and sandy clay loam) were used. In each case, the magnetic susceptibility was measured with a magnetometer (MS3 by Bartington Instruments). Experiments were repeated with different soil moisture contents (from field capacity to dry soil).&lt;/p&gt;&lt;p&gt;If the tracer is located under the soil surface a minimum soil:tracer concentration of 200:1 is required for its correct &amp;#160;detection from the surface using a magnetometer. The intensity of the magnetic signal decreases dramatically with the vertical distance &amp;#160;of the tracer from the soil&amp;#160; surface (burying depth). The maximum detection depth of the tracer magnetic signal is strongly dependent on the natural magnetic susceptibility of the soil which hides the own tracer signal. Variation in soil moisture content does not significantly affect the magnetic signal. For extensive field studies the soil-tracer volume to be handled would be very high. Therefore, it is necessary to explore new tracer application techniques.&lt;/p&gt;

scholarly journals Monitoring Soil Surface Mineralogy at Different Moisture Conditions Using Visible Near-Infrared Spectroscopy Data

2019 ◽  
Vol 11 (21) ◽  
pp. 2526
Author(s):  
Irena Ymeti ◽  
Dhruba Pikha Shrestha ◽  
Freek van der Meer
Keyword(s):  
Organic Matter ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Imaging Spectroscopy ◽  
Soil Surface ◽  
Field Capacity ◽  
Spectroscopy Data ◽  
Silty Loam ◽  
Surface Mineralogy ◽  
Moisture Conditions

The soil minerals determine essential soil properties such as the cation exchange capacity, texture, structure, and their capacity to form bonds with organic matter. Any alteration of these organo-mineral interactions due to the soil moisture variations needs attention. Visible near-infrared imaging spectroscopy is capable of assessing spectral soil constituents that are responsible for the organo-mineral interactions. In this study, we hypothesized that the alterations of the surface soil mineralogy occur due to the moisture variations. For eight weeks, under laboratory conditions, imaging spectroscopy data were collected on a 72 h basis for three Silty Loam soils varying in the organic matter (no, low and high) placed at the drying-field capacity, field capacity and waterlogging-field capacity treatments. Using the Spectral Information Divergence image classifier, the image area occupied by the Mg-clinochlore, goethite, quartz coated 50% by goethite, hematite dimorphous with maghemite was detected and quantified (percentage). Our results showed these minerals behaved differently, depending on the soil type and soil treatment. While for the soils with organic matter, the mineralogical alterations were evident at the field capacity state, for the one with no organic matter, these changes were insignificant. Using imaging spectroscopy data on the Silty Loam soil, we showed that the surface mineralogy changes over time due to the moisture conditions.

The effect of preferential flow of dairy cow urine and simulated rainfall on movement of potassium through undisturbed topsoil cores

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 857 ◽  
Author(s):  
PH Williams ◽  
MJ Hedley ◽  
PEH Gregg
Keyword(s):  
Dairy Cow ◽  
Preferential Flow ◽  
Structural Characteristics ◽  
Near Field ◽  
Tritiated Water ◽  
Soil Surface ◽  
Field Capacity ◽  
Direct Consequence ◽  
Cow Urine ◽  
Rain Events

Cores of undisturbed topsoil (15 cm in depth and diameter) were taken from a range of soil types to a controlled climate chamber. Urine from dairy cows was spiked with tritiated water (3H2O) and then applied to these cores which had moisture contents near field capacity. Liquid draining from these cores, as a direct consequence of urine application, contained up to 72% of the tritiated water, 74% of the potassium (K), 62% of the nitrogen (N) and 80% of the chloride (Cl) applied in the urine, indicating that urine could flow preferentially beyond the 15 cm depth in these soils. The activity of tritium and the concentrations of K, N and Cl in the effluent indicated that this preferential movement of urine occurred too quickly for sorption reactions to occur between the soil surface and the majority of solutes in the urine. After preferential flow had ceased, the amounts of K leached by subsequent simulated rain events were much smaller than losses immediately following the urine application. Leaching losses were particularly small (accounting for 3-15% of the applied urine K) when the majority of the rain water moved preferentially through the soil cores, thus bypassing the urine K which was in soil micropores or which had been sorbed by the soil. Overall, these results suggest that substantial movement of K (and N) through the topsoil of grazed pastures may occur following a urination event due to preferential flow of dairy cow urine through the soil profile, at least when soils are near field capacity at the time of urine deposition. The extent of this movement through topsoil will be more dependent upon soil structural characteristics rather than soil chemical characteristics.

An experiment to assess the influence of urban pavements on biocide leaching from facades into urban soil and groundwater

2020 ◽  
Author(s):  
Felicia Linke ◽  
Jens Lange
Keyword(s):  
Solute Transport ◽  
Urban Environment ◽  
Soil Layer ◽  
Soil Surface ◽  
Urban Groundwater ◽  
Field Capacity ◽  
Transformation Products ◽  
Small Scale ◽  
Rain Event ◽  
Building Facades

&lt;p&gt;Biocides added to facade renders and paints prevent algae and fungi growing at conventional buildings. During rain events biocides leach from facades into the urban environment and its compartments i.e. soil, surface water and groundwater. In many cases polluted fa&amp;#231;ade runoff reaches partly sealed pavements and a major part infiltrates. Transport and transformation processes of biocides below these pavements are largely unknown. It may be hypothesized that concentrated infiltration in joints surrounding paving stones may enhance water percolation and accelerate solute transport. This would mean that partly sealed pavements beneath building facades are hotspots for the entry of biocides into groundwater. This study aims at testing this hypothesis using an experimental mass balance approach.&lt;/p&gt;&lt;p&gt;&lt;br&gt;Five weighable lysimeters in freestanding boxes represent a small-scale section of an urban environment. Three lysimeter have a sealed or partly sealed plaster surface (concrete stones, granite stones with sand joints, and grass paver). The other two lysimeter represent unsealed surfaces, one of them contains a 10cm soil layer with grass cover. The fifth lysimeter acts as a control and has a 40cm layer of filter gravel. Below all surface layers there is 20cm of crushed sand and 10cm of filter gravel. This setup follows typical guidelines of urban construction.&lt;/p&gt;&lt;p&gt;&lt;br&gt;A hose with holes represents the linear leachate of a fa&amp;#231;ade during a rain event. In pre-tests isotopically depleted (collected snowmelt) and enriched (spiked with a heavy standard) water serves to illustrate differences between areal and linear infiltration. Then Terbutryn dissolved in water acts as the main contaminant. It is a biocidal ingredient of a variety of paints and renders. Additional tracers such as bromide, uranine and sulforhodamine B help to illustrate the solute transport inside the lysimeters. Brilliant blue is used to visualize infiltration patterns.&lt;/p&gt;&lt;p&gt;&lt;br&gt;For the experiment the boxes are saturated to field capacity. Pulses of the Terbutryn and tracer solution are poured on the gutter to represent a series of rainfall events with fa&amp;#231;ade leaching. The entire percolate is collected at the bottom of the lysimeter and water samples are taken at regular intervals. After the experiment, the lysimeter matrices are sampled for Terbutryn, three prominent transformation products and for the different tracers. In parallel, physico-chemical soil properties are assessed. This experiment will provide new insights into processes that promote biocide leaching from building facades into urban groundwater.&lt;/p&gt;

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