TEMPERATURE, MOISTURE AND COMPACTION AND THEIR EFFECTS ON THE DIFFUSION OF ETHYLENE DIBROMIDE IN THREE ONTARIO SOILS

1980 ◽  
Vol 60 (2) ◽  
pp. 177-184 ◽  
Author(s):  
J. L. TOWNSHEND ◽  
V. A. DIRKS ◽  
C. F. MARKS

Three southwestern Ontario soils differing in texture were studied for penetration of the nematicide ethylene dibromide. A 3 × 2 × 2 factorial experiment was used that permitted evaluation of the effects of temperature, bulk density and moisture level in all combinations on response to the fumigant. The coursest soil (Fox loamy sand) showed the most rapid penetration, with moisture level, temperature and their interactions having the greatest effect on fumigant movement. On a medium-textured soil (Vineland silt loam) the degree of penetration was dependent on moisture, temperature and bulk density, with relatively small interaction effects, suggesting that effective fumigation depends upon careful soil management and timeliness of application. On the fine-textured soil (Lincoln clay) the fumigant did not move in the soil, regardless of edaphic factors, thereby explaining the difficulty of using fumigation to control nematodes on clay. The development of factorial methods and statistical techniques to study several variables concurrently should lead to more specific and effective methods of soil fumigation.

1996 ◽  
Vol 25 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Charles L.A. Asadu

An comparison of soilmanagement techniques In the different irrigation zones of Lower Anambra Irrigation Project (LAIP) In eastern Nigeria showed that heavy use of machinery led to Increases In bulk density and decreases In field water Infiltration rate. The relative proportion of clay In the irrigated fields Increased as a result of Irrigation, suggesting that mobilized clay from uncemented main and distribution canals Is carried and deposited In the rice fields. Both Irrigation and the use of machinery have had substantial negative effects on soli nutrient levels, and there is a danger of this process continuing. Soli management for sustainable production in the area should centre on applying organic matter in combination with inorganic fertilizers, monitoring the soli properties on yearly basis before the cropping season for fertilizer and lime recommendations, and varying the depth of tillage to Increase or maintain the effective soli depth.


2021 ◽  
Author(s):  
Martin Zanutel ◽  
Sarah Garré ◽  
Charles Bielders

<p>In the context of global soil degradation, biochar is being promoted as a potential solution to improve soil quality, besides its carbon sequestration potential. Burying biochar in soils is known to effect soil physical quality in the short-term (<5 years), and the intensity of these effects depends on soil texture. However, the long-term effects of biochar remain largely unknown yet and are important to quantify given biochar’s persistency in soils. The objective of this study was therefore to assess the long-term effect of biochar on soil physical properties as a function of soil texture and biochar concentration.  For this purpose, soil physical properties (particle density, bulk density, porosity, water retention and hydraulic conductivity curves) were measured in the topsoil of three fields with former kiln sites containing charcoal more than 150 years old in Wallonia (southern Belgium).  The fields had a silt loam, loam and sandy loam texture.  Samples were collected along 3 transects in each field, from the center of the kiln sites outwards. </p><p>Particle density and bulk density slightly decreased as a function of charcoal content. Because particle density and bulk density were affected to a similar extent by charcoal content, total porosity was not affected by the presence of century-old charcoal. Regarding the soil water retention curve, charcoal affected mostly water content in the mesopore range. This effect was strongest for the sandy loam. On the other hand, the presence of century-old charcoal increased significantly the hydraulic conductivity at pF between 1.5 and 2 for the silt loam, while no effect of charcoal was observed for the loamy soil.  The study highlights a limited effect of century-old charcoal on the pore size distribution (at constant porosity) and on the resulting soil physical properties for the range of soils and charcoal concentrations investigated here.  Further research may be needed to confirm the observed trends over a wider range of soil types. </p>


Weed Science ◽  
1975 ◽  
Vol 23 (3) ◽  
pp. 191-194 ◽  
Author(s):  
A. G. Ogg

Three years of field experiments showed that Canada thistle. [Cirsium arvense (L.) Scop.] could be controlled with deeply injected soil fumigants without covering the soil with a tarpaulin. The degree of control depended on the kind of fumigant, the rate of application, and the depth of injection. Weed control with fumigants usually improved as the rate of application and depth of injection increased. The most effective treatment was 1,3-dichloropropene at 560 kg/ha injected to a depth of 46 cm. Good to excellent control of Canada thistle was also obtained with 1,3-dichloropropene at 280 kg/ha injected either 23 or 46 cm and ethylene dibromide at 160 kg/ha and chloropicrin + ethylene dibromide at 20 + 55 kg/ha injected at 46 cm. Results with ethylene dibromide and chloropicrin + ethylene dibromide were more erratic than with 1,3-dichloropropene. Increasing the percentage of chloropicrin in the combination reduced the control of Canada thistle.


1992 ◽  
Vol 9 (4) ◽  
pp. 138-141 ◽  
Author(s):  
Thomas W. Reisinger ◽  
Phillip E. Pope ◽  
Sheldon C. Hammond

Abstract Recovery of soils compacted from conventional ground-based logging operations was assessed on six upland oak-hickory timber sales in south central Indiana. Two areas were selectively harvested in each of the years 1984, 1986, and 1988. Mean bulk density of undisturbed forest soils ranged from 0.93 to 1.02 mg/m3 for the silt loam soils found on all six study areas. Even though soil disturbance averaged 18% of the total sale area immediately after harvesting, the visible amount of soil disturbance decreased to 2.0 and 2.5% for the areas sampled 2 and 4 years after logging, respectively. Compacted soils on secondary skid trails (i.e., 1.08 mg/m3) recovered to preharvest bulk density in 2 to 4 years, but primary skid trails and landings with higher bulk density values (i.e., 1.19 to 1.28 and 1.35 mg/m3) will require somewhat longer than 4 years to recover. North. J. Appl. For. 9(4):138-141.


2001 ◽  
Vol 36 (12) ◽  
pp. 1539-1545 ◽  
Author(s):  
Maria Alexandra Reis Valpassos ◽  
Eloiza Gomes Silva Cavalcante ◽  
Ana Maria Rodrigues Cassiolato ◽  
Marlene Cristina Alves

The objective of this experiment was to study the effects of soil management systems on the bulk density, chemical soil properties, and on the soil microbial activity on a Latossolo Vermelho distrófico (Oxisol). Soil samples were collected from plots under the following management conditions: a) natural dense "cerrado" vegetation (savanna); b) degraded Brachiaria decumbens pasture, 20 years old; c) no-tillage treatment with annual crop sequence (bean, corn, soybean and dark-oat in continuous rotation), 8 years old; d) conventional tillage treatment with crop residues added to the soil, and annual crop sequence, 10 years old. The continuous use of no-tillage system resulted in an increase in microbial biomass and decrease in soil basal respiration, therefore displaying evident long-term effects on the increase of soil C content. The no-tillage system also provided an improvement in bulk density and chemical properties of the soil. Hence, the no-tillage management system could be an alternative for the conservation and maintenance of physical and chemical conditions and the productive potential of "cerrado" soils.


Sign in / Sign up

Export Citation Format

Share Document