CHEMICAL PROPERTIES OF SOIL AS AFFECTED BY A SINGLE BURN OF ALFALFA STUBBLE TO CONTROL INSECTS

1985 ◽  
Vol 65 (2) ◽  
pp. 357-361 ◽  
Author(s):  
J. F. DORMAAR ◽  
B. D. SCHABER

Southern Alberta growers often burn fields of seed alfalfa (Medicago sp.) prior to initiation of growth in the spring as apart of an Integrated Pest Management Program. The present study examined the effect of a single burn of the standing dead growth and debris of a 4-yr-old alfalfa crop in early spring, late spring, or autumn on various chemical properties of the upper 50 mm of soil. Burning led to small but significant increases in organic matter, NO3-N, NH4-N, available P, extractable K, EC, and pH levels immediately after the fire. The only measurable impact 1 year later was slightly higher (P < 0.05) organic matter, but after 2 years there were no differences in these levels. Even though this study portrayed a single burn event, thereby precluding predictions of the long-term effects of different fire regimes, the changes observed were only measurable for less than 1 year. If the burning of the alfalfa stubble is done every third year it is unlikely that this practice would be detrimental to the soil characteristics examined. Key words: Fire, pest management, organic matter, prescribed burning

1992 ◽  
Vol 72 (2) ◽  
pp. 169-175 ◽  
Author(s):  
J. F. Dormaar ◽  
B. D. Schaber

Southern Alberta growers often burn fields of seed alfalfa (Medicago sp.) prior to initiation of growth in the spring as a part of an Integrated Pest Management Programme. An 8-yr study compared the effects of (a) fall-burned every year, (b) spring-burned, prior to growth, every year, (c) spring-burned, prior to growth, every other year, and (d) zero burned, on various chemical properties of the upper 50 mm of soil. Burning led to highly significant increases in carbohydrates, total N, NO3-N, and extractable K over the 8 yr. Increases were also highly significant for NH4-N under the fall-burned every year regime. Spring-burning, prior to growth, every other year, led to the least accumulations of measured parameters. Although pest insects were controlled and pedigreed alfalfa seed production was increased under the various burn treatments examined within the conditions of the experiment, changes in certain soil chemical properties identified the need to monitor subsequent crop behavior once the alfalfa fields have been ploughed. Key words: Fire, prescribed burning, pest management, seed alfalfa


2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.


1985 ◽  
Vol 117 (9) ◽  
pp. 1159-1161 ◽  
Author(s):  
B.D. Schaber

A search is being conducted to determine the indigenous parasites and predators of the alfalfa weevil, Hypera postica (Gyll.), in Alberta (Schaber 1981). A clearer understanding of the biology of the predator Odynerus dilectus Saussure will augment control of the alfalfa weevil in an integrated pest management program.Odynerus dilectus has been recorded in the United States (Bohart et al. 1982) and in Alberta, Canada (Strickland 1947). In California, Linsley and Michener (1942) reported that females stocked their nests with small caterpillars, but Bohart et al. (1982) reported that in Utah females of O. dilectus provisioned their nests with larvae of the alfalfa weevil. This paper summarizes data about the nesting and prey-provisioning behavior of O. dilectus in southern Alberta.


Author(s):  
J. R. Adams ◽  
G. J Tompkins ◽  
A. M. Heimpel ◽  
E. Dougherty

As part of a continual search for potential pathogens of insects for use in biological control or on an integrated pest management program, two bacilliform virus-like particles (VLP) of similar morphology have been found in the Mexican bean beetle Epilachna varivestis Mulsant and the house cricket, Acheta domesticus (L. ).Tissues of diseased larvae and adults of E. varivestis and all developmental stages of A. domesticus were fixed according to procedures previously described. While the bean beetles displayed no external symptoms, the diseased crickets displayed a twitching and shaking of the metathoracic legs and a lowered rate of activity.Examinations of larvae and adult Mexican bean beetles collected in the field in 1976 and 1977 in Maryland and field collected specimens brought into the lab in the fall and reared through several generations revealed that specimens from each collection contained vesicles in the cytoplasm of the midgut filled with hundreds of these VLP's which were enveloped and measured approximately 16-25 nm x 55-110 nm, the shorter VLP's generally having the greater width (Fig. 1).


Author(s):  
Amita M Watkar ◽  

Soil, itself means Soul of Infinite Life. Soil is the naturally occurring unconsolidated or loose covering on the earth’s surface. Physical properties depend upon the amount, size, shape, arrangement, and mineral composition of soil particles. It also depends on the organic matter content and pore spaces. Chemical properties depend on the Inorganic and organic matter present in the soil. Soils are the essential components of the environment and foundation resources for nearly all types of land use, besides being the most important component of sustainable agriculture. Therefore, assessment of soil quality and its direction of change with time is an ideal and primary indicator of sustainable agricultural land management. Soil quality indicators refer to measurable soil attributes that influence the capacity of a soil to function, within the limits imposed by the ecosystem, to preserve biological productivity and environmental quality and promote plant, animal and human health. The present study is to assess these soil attributes such as physical and chemical properties season-wise.


1997 ◽  
Vol 42 (4) ◽  
pp. 229-240 ◽  
Author(s):  
Francis J. Larney ◽  
Eric Bremer ◽  
H.Henry Janzen ◽  
Adrian M. Johnston ◽  
C.Wayne Lindwall

2016 ◽  
Vol 25 (11) ◽  
pp. 1117 ◽  
Author(s):  
Marie-Pierre Rogeau ◽  
Mike D. Flannigan ◽  
Brad C. Hawkes ◽  
Marc-André Parisien ◽  
Rick Arthur

Like many fire-adapted ecosystems, decades of fire exclusion policy in the Rocky Mountains and Foothills natural regions of southern Alberta, Canada are raising concern over the loss of ecological integrity. Departure from historical conditions is evaluated using median fire return intervals (MdFRI) based on fire history data from the Subalpine (SUB), Montane (MT) and Upper Foothills (UF) natural subregions. Fire severity, seasonality and cause are also documented. Pre-1948 MdFRI ranged between 65 and 85 years in SUB, between 26 and 35 years in MT and was 39 years in UF. The fire exclusion era resulted in a critical departure of 197–223% in MT (MdFRI = 84–104 years). The departure in UF was 170% (MdFRI = 104 years), while regions of continuous fuels in SUB were departed by 129% (MdFRI = 149 years). The most rugged region of SUB is within its historical range of variation with a departure of 42% (MdFRI = 121 years). More mixed-severity burning took place in MT and UF. SUB and MT are in a lightning shadow pointing to a predominance of anthropogenic burning. A summer fire season prevails in SUB, but occurs from spring to fall elsewhere. These findings will assist in developing fire and forest management policies and adaptive strategies in the future.


Soil Research ◽  
1989 ◽  
Vol 27 (1) ◽  
pp. 45 ◽  
Author(s):  
IR Willett

In a laboratory experiment, samples of 18 soils, which are known to be flooded in the field, were flooded for up to 32 days. Both untreated and phosphate-treated (50 mg P kg-1) soils were studied. It was attempted to identify which chemical properties measured on the dry untreated soils, and the changes in pH, Eh and extractable Fe and Mn over the flooding periods, controlled the changes in sodium acetate buffer (pH 3.0) extractable phosphorus during flooding. It was shown that the reduction of iron(III) oxides was the dominant source of the P released during flooding. However, the amount of P released was strongly inhibited by re-sorption. Direct measurement of the amount of iron(III) reduced during flooding and measurement of phosphate sorption were required to predict the amount of P released during flooding. Organic matter contributed toward the P released during flooding. Its contribution appeared to be by mineralization, rather than by accelerating FeIII reduction. The reduction of MnIII and MnIII was a minor source of P in the untreated soils. Changes in soil pH during flooding were responsible for desorption of freshly applied P, but did not appear to affect P release in the untreated soils. The Vertisols and some of the Alfisols showed very little, or no release of P during flooding.


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