The influence of the microflora on the physical properties of soils. II. Field studies on water repellent sands

Soil Research ◽  
1964 ◽  
Vol 2 (1) ◽  
pp. 123 ◽  
Author(s):  
RD Bond
Keyword(s):  
Management Practices ◽  
Plant Cover ◽  
South Australia ◽  
Field Studies ◽  
Water Repellent ◽  
Mosaic Pattern ◽  
Narrow Channels ◽  
Upper South ◽  
Water Repellence ◽  
Contact Angle Of Wetting

The water repellence of sandy soils has been investigated at sites in the upper south-east of South Australia by observation of infiltration patterns and measurement of contact angle of wetting. Water penetrated into repellent sands through narrow channels, the intervening soil remaining dry. Such dry areas persisted through the winter months and were responsible for a mosaic pattern of bare and grassed areas in severely affected paddocks. The intensity of water repellence has been found to vary with species of plant cover, age of pasture, and also management practices.

The effect of plant top material on the water repellence of fired sands and water repellent soils

1981 ◽  
Vol 32 (4) ◽  
pp. 609 ◽  
Author(s):  
DA McGhie ◽  
AM Posner
Keyword(s):  
Organic Matter ◽  
Native Species ◽  
Plant Cover ◽  
Subterranean Clover ◽  
Infiltration Rate ◽  
Contact Angles ◽  
Water Infiltration ◽  
Cereal Crops ◽  
Water Repellent ◽  
Water Repellence

Large differences in the water repellence were conferred on fired sand by adding the ground tops of a range of plant species. Contact angles of 75� to 90� were caused at 2% of most pasture and native species and at 5 % many gave contact angles > 95� The cereal crops gave contact angles of about 60� (2%) and 83�(5 %) and were more wettable than pasture and native species. The addition of ground Geraldton subterranean clover (Trifolium subteraneum cv. Geraldton) or brown mallet (Eucalyptus astrigens (Maiden)) to water-repellent sands increased the water repellence. Addition of clover to a water-repellent mallet-hill soil increased the water infiltration rate while the mallet did not change the slow rate. Wheat (Triticum aestivm), when added to water-repellent soils, always reduced the water repellence. Attention is drawn to the importance of the relative wettability of the soil and added organic matter, and therefore the type of plant cover. Soils sampled from beneath wheat/clover rotations of various lengths showed that water repellence increased in the pasture phase and was reduced during the cropping phase. The importance of the type, as well as the amount, of organic matter in the rotations is demonstrated.

Delving of sandy surfaced soils reduces frost damage in wheat crops

2007 ◽  
Vol 58 (2) ◽  
pp. 105 ◽  
Author(s):  
M. Rebbeck ◽  
C. Lynch ◽  
P. T. Hayman ◽  
V. O. Sadras
Keyword(s):  
Management Practices ◽  
Field Experiments ◽  
Wheat Yield ◽  
South Australia ◽  
Frost Damage ◽  
Canopy Height ◽  
Water Repellent ◽  
Substantial Part ◽  
Yield Gain ◽  
The Many

Delving is a farming practice involving the mixing of a deep clayey subsoil layer with a sandy topsoil. One of the many effects of this practice is to reduce soil albedo and increase water-holding capacity of the topsoil, thus increasing the potential for storage and release of heat and potential attenuation of the effects of radiative frost. At Keith, a frost-prone location of South Australia, we investigated the effect of management practices with putative capacity to reduce frost damage, with emphasis on delving. Three field experiments were established on Brown Sodosols with a water-repellent sand topsoil. In relation to crops in untreated control soil, delving increased wheat yield from 1.9 to 3.1 t/ha in 2003, and from 0.5 to 1.5 t/ha in 2004. This large delving effect contrasted with the minor effects of other treatments including soil rolling, sowing rate, row spacing, and cultivar mixture. Lack of significant interactions between treatments indicated a robust response to delving across a range of management practices. Topsoil and canopy-height minimum temperatures were consistently higher in the delved treatment. The average difference in canopy-height minimum temperature between delved and control treatments was 0.3–0.4°C, with a maximum of 1.6°C in 2003 and 1.2°C in 2004. A single, robust relationship between yield and frost damage fitted the data pooled across treatments and seasons. This, together with the temperature differential between treatments, and significant relationships between minimum canopy-height temperature around flowering and frost damage supported the conclusion that a substantial part of the yield gain attributable to delving was related to reduced frost damage.

scholarly journals Prediction of leaching and groundwater contamination by pesticides

2006 ◽  
Vol 78 (5) ◽  
pp. 1081-1090 ◽  
Author(s):  
Werner Kördel ◽  
Michael Klein
Keyword(s):  
Maximum Concentration ◽  
Management Practices ◽  
Preferential Flow ◽  
Soil Depth ◽  
Sandy Soils ◽  
Field Studies ◽  
Macropore Flow ◽  
Eu Directive ◽  
Present Information ◽  
Silty Soils

Herein, we describe how pesticide leaching is assessed in Europe in order to fulfill EU Directive 91/414. The assessment schemes were developed to protect groundwater from unacceptable effects caused by pesticide use. They presently focus on chromatographic flow processes, which are dominant in sandy soils. Nevertheless, important regions in Europe are characterized by structured soils where transport through macropores is most relevant.Comparison of parallel field studies with isoproturon performed in sandy and silty soils showed that maximum concentration in the structured soil at a soil depth of 1 m may exceed respective concentrations in sandy soils by a factor of 60. Similar results were obtained by lysimeter studies using silty soil cores with maximum concentration of 40 μg/l at the soil bottom. These results demonstrate that preferential flow is more the rule than the exception in well-structured fine-textured soils, and pesticide losses via macropore flow may exceed losses via matrix transport considerably. All present information available for macropore flow suggest the need for greater regional assessments. Other recommendations include analysis of the influence of different soil management practices on the formation of macropores.

The Initial Response of a Chenopod Shrubland Plant and Invertebrate Community to Two Pulses of Intensive Cattle Grazing.

1999 ◽  
Vol 21 (2) ◽  
pp. 169 ◽  
Author(s):  
JL Read
Keyword(s):  
Water Distribution ◽  
Marked Effect ◽  
Plant Cover ◽  
South Australia ◽  
Initial Response ◽  
Plant Species Richness ◽  
Cattle Grazing ◽  
Invertebrate Community ◽  
Distribution Features ◽  
One Year

The initial effect of two pulses of heavy cattle grazing on chenopod shrubland plants and invertebrates in northern South Australia was assessed in a two year trial. Both plant and invertebrate communities were structured by subhabitats which were defined by edaphic and water-distribution features. The cover of grasses and the dominant shrubs, Atriplex vesicaria and Maireana astrotricha, declined significantly following grazing but only total vegetation cover was significantly lower than controls one year after grazing. Plant species richness was not affected by the grazing pulses. Abundance of ants increased, but the responses of other invertebrates were inconsistent following grazing. Rainfall had a marked effect upon both plant cover and invertebrate abundance. Key words: chenopod shrublands, pulsed cattle grazing, Atriplex vesicaria, invertebrates, bioindicators

The Influence of Weed Management in Wheat (Triticum aestivum) Stubble on Weed Control in Corn (Zea mays)

1998 ◽  
Vol 12 (3) ◽  
pp. 522-526 ◽  
Author(s):  
Theodore M. Webster ◽  
John Cardina ◽  
Mark M. Loux
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Practices ◽  
Field Studies ◽  
Giant Foxtail ◽  
Giant Ragweed ◽  
Herbicide Treatments ◽  
Postharvest Treatment ◽  
Full Rate ◽  
Wheat Stubble

The objectives of this study were to determine how the timing of weed management treatments in winter wheat stubble affects weed control the following season and to determine if spring herbicide rates in corn can be reduced with appropriately timed stubble management practices. Field studies were conducted at two sites in Ohio between 1993 and 1995. Wheat stubble treatments consisted of glyphosate (0.84 kg ae/ha) plus 2,4-D (0.48 kg ae/ha) applied in July, August, or September, or at all three timings, and a nontreated control. In the following season, spring herbicide treatments consisted of a full rate of atrazine (1.7 kg ai/ha) plus alachlor (2.8 kg ai/ha) preemergence, a half rate of these herbicides, or no spring herbicide treatment. Across all locations, a postharvest treatment of glyphosate plus 2,4-D followed by alachlor plus atrazine at half or full rates in the spring controlled all broadleaf weeds, except giant ragweed, at least 88%. Giant foxtail control at three locations was at least 83% when a postharvest glyphosate plus 2,4-D treatment was followed by spring applications of alachlor plus atrazine at half or full rates. Weed control in treatments without alachlor plus atrazine was variable, although broadleaf control from July and August glyphosate plus 2,4-D applications was greater than from September applications. Where alachlor and atrazine were not applied, August was generally the best timing of herbicide applications to wheat stubble for reducing weed populations the following season.

scholarly journals Mushrooms of Grand Teton National Park

1983 ◽  
Vol 7 ◽  
pp. 59-71
Author(s):  
Kent McKnight ◽  
Kimball Harper ◽  
Karl McKnight
Keyword(s):  
National Parks ◽  
Vascular Plants ◽  
National Park ◽  
Annual Report ◽  
Plant Cover ◽  
Field Studies ◽  
Soil Samples ◽  
Site Quality ◽  
Soil Parameters ◽  
Quantitative Estimates

The primary overall objective of inventorying the macrofungi growing in and around Grand Teton and Yellowstone National Parks was partially achieved with the published checklist (McKnight 1982) and additions from the 1982 Research Center Annual Report (McKnight, Harper, & McKnight 1984). The intensive collecting of the 1982 fruiting season including a 12-week phenological study at 11 selected sites left many species unidentified and numerous others observed but not collected, or with inadequately annotated collections made. Litter and soil moisture data for the 11 study stands are also given in the 1982 annual report cited above, as well as data on 15 overstory and understory vegetation and soil parameters. Field studies in the Parks during the summer of 1983 concentrated on (1) identification of chlorophyllous and vascular plants at the 11 sites selected for concentrated study in 1982; (2) quantitative estimates of chlorophyllous plant cover and height; (3) estimates of site quality; (4) collections of composite soil samples; and (5) additional records of macrofungi for the Parks with supporting data in the form of photographs, drawings, and annotations.

scholarly journals Soil Properties and Plant Community Changes along a Goat Grazing Intensity Gradient in an Open Canopy Oak Forest

2013 ◽  
Vol 41 (2) ◽  
pp. 567 ◽  
Author(s):  
Aimilia LEMPESI ◽  
Apostolos P. KYRIAZOPOULOS ◽  
Michail ORFANOUDAKIS ◽  
Georgios KORAKIS
Keyword(s):  
Soil Properties ◽  
Plant Community ◽  
Management Practices ◽  
Plant Cover ◽  
Grazing Intensity ◽  
Oak Forest ◽  
Goat Grazing ◽  
Open Canopy ◽  
Grazing Intensities ◽  
Soil Measurements

Understanding how the management practices of silvopastoral systems affect the long-term sustainability of oak ecosystems and what their influence is on nutrient cycling and plant community, is of great interest. The aim of this study was to examine the effects of relative grazing intensity on soil properties and on vegetation characteristics in an open canopy oak forest dominated by Quercus frainetto. The research was conducted in the area of Pentalofos, which is located in Evros region, north-eastern Greece and is grazed by goats. The distance from a goat corral was used to represent relative grazing intensity. In June 2011, soil and vegetation samples were collected along transects placed at 50, 150, 300, 600 and 1200 m from the goat corral, running perpendicular to three replicates. Soil measurements included pH, phosphorous (P) and nitrogen (N) concentrations while vegetation measurements included plant cover, species composition and diversity. Plant cover was not significantly different among grazing intensities. Species diversity, especially of the woody vegetation layer, was significantly higher in the light grazing intensity in comparison to both the heavy and the very light grazing. Heavy grazing reduced soil organic matter while it increased total nitrogen. Grazing intensity did not affect available P and soil pH. Light to moderate goat grazing could ameliorate floristic diversity and increase sustainability of oak forests in the Mediterranean region.

Water repellence in sandy soils of South-Western Australia. II. Some chemical characteristics of the hydrophobic skins

Soil Research ◽  
1972 ◽  
Vol 10 (1) ◽  
pp. 35 ◽  
Author(s):  
FJ Roberts ◽  
BA Carbon
Keyword(s):  
Organic Matter ◽  
Diethyl Ether ◽  
Cold Water ◽  
Sandy Soils ◽  
Prolonged Treatment ◽  
Water Repellent ◽  
Chemical Characteristics ◽  
Produce Water ◽  
Water Repellence ◽  
Humic Fraction

The hydrophobic organic skins on sand grains were resistant to removal by solvents such as cold water, concentrated acid, diethyl ether, ethanol, benzene, chloroform, and acetone. Prolonged treatment with hot diethyl ether, ethanol, and benzene removed part of the coating. Treatment with dilute solutions of alkali removed the skin as suspended particles. Compounds within the very stable humic fraction of the soil organic matter appeared to be mainly responsible for water repellence in soils. Deposits of fresh organic materials could also produce water repellent properties.

THE 3-C ACOUSTIC PROCESS—A NEW APPROACH TO PREDICTING ACOUSTIC WAVE PERFORMANCE IN SEDIMENTS

2000 ◽  
Vol 40 (1) ◽  
pp. 367
Author(s):  
M.J. Wiltshire ◽  
L.M. Huggard
Keyword(s):  
Acoustic Wave ◽  
Management Practices ◽  
Wave Theory ◽  
Field Studies ◽  
Acoustic Properties ◽  
P Wave ◽  
Performance Modelling ◽  
Seismic Attribute ◽  
Log Data

Acoustic wave performance modelling is of considerable interest to seismic interpreters. Conventional interpretative models employ continuous density log data to compute theoretical acoustic data. Their dependence on high quality density log data limits the application of these techniques to areas where good logs have been acquired. Such techniques are therefore commonly used in field studies, but are generally not used in exploration.This paper details a newly developed method of predicting acoustic compression wave performance, based on sequence compaction theory, elastic wave theory and established petrophysical relationships. This allows extension of the existing density log based p-wave velocity prediction methods into areas where log data are minimal and log quality is marginal.Applications of the technique include:improvements to the quality of acquired sonic data;improved velocity control, resulting in better quality synthetic seismograms and more precise control of time-depth conversion; andimproved seismic attribute mapping, offering possibilities of better drilling target selection.With application of the technique, many wells can now be used in which poor log data quality or absence of key logs previously prevented their use as well-to-seismic control points in basin modelling. The technique can be allied to MWD resistivity logging technology to allow continuous computation of acoustic properties and realtime correlation of drilling data to seismic. This results in better location of casing and logging points, and the design of more efficient logging programs, with benefits to both drilling safety and economics.The technique allows improvement in the quality of acquired data and acquisition economics, better utilisation of old data, and better engineering and geologic management practices in current exploration drilling. It has considerable potential for overcoming sonic log acquisition problems associated with poorly compacted rocks, and has application in many areas of sequence and basin studies.

Influence of chemical properties on nitrogen mineralization and nitrification in podzolized sands. Implications for forest management

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 981 ◽  
Author(s):  
JC Carlyle ◽  
JR Lowther ◽  
PJ Smethurst ◽  
EKS Nambiar
Keyword(s):  
Forest Management ◽  
Total Nitrogen ◽  
Nitrogen Mineralization ◽  
Management Practices ◽  
Organic Phosphorus ◽  
Chemical Properties ◽  
South Australia ◽  
Major Effect ◽  
Correct Classification ◽  
Loss On Ignition

The relationship between selected chemical properties and nitrogen mineralization and nitrification was examined in soils collected from 39 sites of varying history. All sites were on podzolized sands; such soils represent more than 95% of the P. radiata growing area in south-east of South Australia/western Victoria. Given their uniformity in texture and similarity in pedogenesis, the organic matter concentrations of the sampled soils were highly variable (loss-on-ignition 0.8-10.2%). Total nitrogen was highly correlated with loss-on-ignition (r2 = 0.95, P<0.001). Nitrogen mineralization was correlated neither with total nitrogen nor loss-on-ignitition (i.e. P > 0.05), but was correlated with organic phosphorus (r2 = 0 70, P < 0.001), suggesting a major effect of phosphorus on nitrogen mineralization in these soils. On the basis of nitrate production during a 56-day aerobic incubation of disturbed soil, 18 soils were classed as strongly nitrifying (having a high potential to nitrify) and 18 as weakly nitrifying (having a low potential to nitrify). This separation reflected differences in other soil properties, with discriminant analysis giving a 91.7% correct classification into the two groups using only pH and Bray (II) extractable phosphorus for discrimination. Strongly and weakly nitrifying groups could also be discriminated on the basis of their value/chroma rating (after ignition), with a 94.4% probability of correct classification. Within each classification, nitrogen mineralization was correlated with total nitrogen (r2 =0.59 and 0.65, P< 0.001, for strongly and weakly nitrifying soils, respectively) but with a different relationship in each case. The significance of this difference in nitrogen dynamics is discussed in relation to site-specific forest management practices.

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