OCCURRENCE OF BACILLUS POLYMYXA (PRAZ.) MIG. IN ALBERTA SOILS WITH SPECIAL REFERENCE TO ITS PATHOGENICITY ON POTATO TUBERS

1946 ◽  
Vol 24c (2) ◽  
pp. 39-46 ◽  
Author(s):  
A. W. Jackson ◽  
A. W. Henry
Keyword(s):  
Special Reference ◽  
Soil Surface ◽  
Bacillus Polymyxa ◽  
Potato Tubers ◽  
Pure Cultures ◽  
Soil Temperatures ◽  
Bacterium Bacillus ◽  
Storage Temperatures ◽  
Potato Slices

The spore-forming bacterium, Bacillus polymyxa, was found to occur widely in Alberta soils. All isolates obtained from the soil, together with several from other sources, proved capable of rotting potato tubers when introduced through wounds under conditions of abundant moisture and high temperature.In these studies pure cultures of Bacillus polymyxa rotted potato slices at temperatures from 20 °C. to 45 °C. and whole tubers at temperatures from 30 °C. to 45 °C. but caused no damage below the minimum temperatures mentioned.Though potato tubers and other vegetables that are formed in the soil probably often come in contact with Bacillus polymyxa, they are not likely to be rotted by it except when temperature and other factors are favourable. In general, soil temperatures in the field in Alberta are not conducive to the decay of potatoes by this organism, but those near the soil surface may on occasion reach favourable levels. The fact that B. polymyxa can be isolated quite frequently from rotted stored potatoes indicates that it is of some importance as a cause of decay in harvested potatoes. If, however, recommended storage temperatures are maintained in the storage quarters no damage from this organism should occur there.

scholarly journals Crop residues on short-term CO2 emissions in sugarcane production areas

2013 ◽  
Vol 33 (4) ◽  
pp. 699-708 ◽  
Author(s):  
Mariana M. Corradi ◽  
Alan R. Panosso ◽  
Marcílio V. Martins Filho ◽  
Newton La Scala Junior
Keyword(s):  
Co2 Emissions ◽  
Field Experiments ◽  
Crop Residues ◽  
Soil Surface ◽  
Dry Mass ◽  
Agricultural Crop ◽  
Short Term ◽  
Sugarcane Production ◽  
Soil Temperatures ◽  
Production Areas

The proper management of agricultural crop residues could produce benefits in a warmer, more drought-prone world. Field experiments were conducted in sugarcane production areas in the Southern Brazil to assess the influence of crop residues on the soil surface in short-term CO2 emissions. The study was carried out over a period of 50 days after establishing 6 plots with and without crop residues applied to the soil surface. The effects of sugarcane residues on CO2 emissions were immediate; the emissions from residue-covered plots with equivalent densities of 3 (D50) and 6 (D100) t ha-1 (dry mass) were less than those from non-covered plots (D0). Additionally, the covered fields had lower soil temperatures and higher soil moisture for most of the studied days, especially during the periods of drought. Total emissions were as high as 553.62 ± 47.20 g CO2 m-2, and as low as 384.69 ± 31.69 g CO2 m-2 in non-covered (D0) and covered plot with an equivalent density of 3 t ha-1 (D50), respectively. Our results indicate a significant reduction in CO2 emissions, indicating conservation of soil carbon over the short-term period following the application of sugarcane residues to the soil surface.

scholarly journals Seasonal emergence of selected summer annual weed species in dependence on soil temperature

2010 ◽  
Vol 56 (No. 9) ◽  
pp. 444-450 ◽  
Author(s):  
M. Jursík ◽  
J. Holec ◽  
J. Soukup ◽  
V. Venclová
Keyword(s):  
Chenopodium Album ◽  
Soil Surface ◽  
Main Field ◽  
Weed Species ◽  
Soil Temperatures ◽  
Field Emergence ◽  
The Relationship ◽  
Galinsoga Ciliata ◽  
Surface Layer Temperature ◽  
Mass Field

This study aimed to describe emergence cycles of selected weed species under Central European conditions in relation to cumulative soil temperatures from the start of the vegetation season. Emergence of Chenopodium album, Echinochloa crus-galli, Galinsoga ciliata, and Abutilon theophrasti was observed from March to October during the period 2001–2006 at two locations. The beginning of main field emergence was determined as the day when the sum of effective hour temperatures was achieved, and was detected from the second decade of April to early May for C. album, in the second decade of May for E. crus-galli, from late April to the beginning of May for G. ciliata, and from the end of April to mid-May for A. theophrasti. The relationship between cumulative soil surface layer temperature and weed mass field emergence at the beginning of the growing season is very direct (differences ±7 days) – but only when soil moisture is sufficient. In a drier spring, the beginning of mass field emergence occurs with 1–4 weeks of delay and field emergence is usually slower and protracted.

Effects of depth and time of sowing on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth

1993 ◽  
Vol 44 (6) ◽  
pp. 1311 ◽  
Author(s):  
GM Lodge ◽  
AJ Schipp
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Maximum Temperature ◽  
Sowing Time ◽  
Sand Mixture ◽  
South Wales ◽  
Seed Field ◽  
Dry Conditions ◽  
Soil Temperatures

Two experiments examined the effects of sowing time and depth (surface and 10, 25, 50 mm) on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth. Experiment 1 was conducted from January to December 1990 on a loam/sand mixture in boxes. Emergence was highest in both species for seeds sown onto the soil surface in summer and autumn (P < 0.05). Sowing at any depth at any time of the year, or surface sowing in winter and spring, markedly reduced emergence. Experiment 2 was conducted in the field at Tamworth, northern New South Wales from September 1991 to August 1992, on a red brown earth and a black earth. This study confirmed that emergence in both species was highest from surface sown seed. Field emergence was lowest in winter, but in contrast to experiment 1, it was higher in spring, particularly on the black earth. Seedling emergence appeared to be related to mean maximum temperature, decreasing in winter as it declined below 20�C, and increasing in spring when it was greater than 23�C. Differences in seed weight were reflected in emergence of D. richardsonii and D. linkii in experiment 1. Similar emergence was recorded for the loamlsand mixture and sand, indicating that there was little effect of texture. Phalaris aquatica L. cv. Sirosa surface sown in December had lower emergence ( P < 0.05) than both Danthonia spp., but emergence of this larger seeded cultivar was higher at depths of 10 and 25 mm. Laboratory studies to determine reasons for the low emergence of D. richardsonii and D. linkii from depth, indicated that neither had an obligate light requirement for germination. Depth, however, reduced germination (P < 0.05) compared with surface sowing of seed. Seedlings at depth also were observed to have slower rates of shoot and root elongation. In the field, the most successful establishments of D. richardsonii and D. linkii seedlings are likely to occur from surface sowings in April and May. Sowing in spring may also be possible if mean maximum soil temperatures exceed 23�C, and seedlings can establish before the onset of hot, dry conditions in summer.

Temperature affects the dormancy and germination of sympatric annual (Oryza meridionalis) and perennial (O. rufipogon) native Australian rices (Poaceae) and influences their emergence in introduced para grass (Urochloa mutica) swards

2015 ◽  
Vol 63 (8) ◽  
pp. 687 ◽  
Author(s):  
Sean M. Bellairs ◽  
Penelope A. S. Wurm ◽  
Beckie Kernich
Keyword(s):  
Soil Surface ◽  
Field Studies ◽  
Oryza Rufipogon ◽  
Oryza Species ◽  
Northern Australia ◽  
Seed Biology ◽  
Oryza Meridionalis ◽  
Native Grasslands ◽  
Wild Rice Species ◽  
Soil Temperatures

The seed biology of two ecologically and genetically important sympatric wild rice species from northern Australia was compared – perennial Oryza rufipogon Griff. and annual Oryza meridionalis N.Q.Ng. The aim was to determine mechanisms of dormancy exhibited at seed shed and to identify factors that trigger or inhibit germination. This information was used to investigate the ecology of in situ Oryza populations in introduced para grass swards (Urochloa mutica (Forssk.) T.Q. Nguyen) and to understand interactions between the two sympatric Oryza species. Primary dormancy in the two species is similar, namely, non-deep physiological dormancy, determined by external maternal structures and broken by warm temperature treatments equivalent to dry season soil temperatures. Light quality, smoke water, gibberellic acid and nitric acid treatments had minor influences on germination. Changes to the soil profile and aboveground biomass structure due to swards of U. mutica significantly affected emergence of O. meridionalis. Thus the influence of soil temperature explains the results of previous field studies in which biomass or litter on the soil surface prevented germination. This has implications for biodiversity management on monsoonal floodplains of northern Australia, where introduced pasture species produce greater biomass than native grasslands, reduce soil temperatures and are displacing native rices. There were differences between the Oryza species – dormancy was more quickly broken in annual O. meridionalis, reflecting the reduced need for investment in seed bank persistence for annual species in annually inundated and climatically reliable wetlands.

Soil temperatures in Egypt

1928 ◽  
Vol 18 (1) ◽  
pp. 90-122 ◽  
Author(s):  
E. McKenzie Taylor
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Soil Surface ◽  
Temperature Wave ◽  
Maximum Temperature ◽  
Straight Line ◽  
Temperature Waves ◽  
Soil Temperatures ◽  
The Times ◽  
Maximum Air Temperature

1. The soil temperatures in Egypt at a number of depths have been recorded by means of continuous recording thermometers. In general, the records show that the amplitude of the temperature wave at the surface of the soil is considerably greater than the air temperature wave. There is, however, a considerable damping of the wave with depth, no daily variation in temperature being observed at a depth of 100 cm.2. No definite relation between the air and soil temperatures could be traced. The maximum air temperature was recorded in May and the maximum soil temperature in July.3. The amplitude of the temperature wave decreases with increase in depth. The decrease in amplitude of the soil temperature wave is not regular owing to variations in the physical properties of the soil layers. Between any two depths, the ratio of the amplitudes of the temperature waves is constant throughout the year. The amplitude of the soil temperature wave bears no relation to the amplitude of the air temperature wave.4. The time of maximum temperature at the soil surface is constant throughout the year at 1 p.m. The times of maximum temperature at depths below the surface lag behind the time of surface maximum, but they are constant throughout the year. When plotted against depth, the times of maximum at the various soil depths lie on a straight line.

scholarly journals Specifics of soil temperature under winter wheat canopy

2013 ◽  
Vol 43 (3) ◽  
pp. 209-223 ◽  
Author(s):  
Jana Krčmáŕová ◽  
Hana Stredová ◽  
Radovan Pokorný ◽  
Tomáš Stdŕeda
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Soil Temperature ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Soil Surface ◽  
Regression Equations ◽  
Experimental Plot ◽  
Near Surface ◽  
Soil Temperatures

Abstract The aim of this study was to evaluate the course of soil temperature under the winter wheat canopy and to determine relationships between soil temperature, air temperature and partly soil moisture. In addition, the aim was to describe the dependence by means of regression equations usable for phytopathological prediction models, crop development, and yield models. The measurement of soil temperatures was performed at the experimental field station ˇZabˇcice (Europe, the Czech Republic, South Moravia). The soil in the first experimental plot is Gleyic Fluvisol with 49-58% of the content particles measuring < 0.01 mm, in the second experimental plot, the soil is Haplic Chernozem with 31-32% of the content particles measuring < 0.01 mm. The course of soil temperature and its specifics were determined under winter wheat canopy during the main growth season in the course of three years. Automatic soil temperature sensors were positioned at three depths (0.05, 0.10 and 0.20 m under soil surface), air temperature sensor in 0.05 m above soil surface. Results of the correlation analysis showed that the best interrelationships between these two variables were achieved after a 3-hour delay for the soil temperature at 0.05 m, 5-hour delay for 0.10 m, and 8-hour delay for 0.20 m. After the time correction, the determination coefficient reached values from 0.75 to 0.89 for the depth of 0.05 m, 0.61 to 0.82 for the depth of 0.10 m, and 0.33 to 0.70 for the depth of 0.20 m. When using multiple regression with quadratic spacing (modeling hourly soil temperature based on the hourly near surface air temperature and hourly soil moisture in the 0.10-0.40 m profile), the difference between the measured and the model soil temperatures at 0.05 m was −2.16 to 2.37 ◦ C. The regression equation paired with alternative agrometeorological instruments enables relatively accurate modeling of soil temperatures (R2 = 0.93).

scholarly journals Time Series Analysis of Soil Freeze and Thaw Processes in Indiana

2008 ◽  
Vol 9 (5) ◽  
pp. 936-950 ◽  
Author(s):  
Tushar Sinha ◽  
Keith A. Cherkauer
Keyword(s):  
Air Temperature ◽  
Water Cycle ◽  
Soil Surface ◽  
Bare Soil ◽  
Cold Season ◽  
Freezing And Thawing ◽  
Soil Frost ◽  
Significance Level ◽  
Freeze Thaw ◽  
Soil Temperatures

Abstract Seasonal cycles of freezing and thawing influence surface energy and water cycle fluxes. Specifically, soil frost can lead to the reduction in infiltration and an increase in runoff response, resulting in a greater potential for soil erosion. An increase in the number of soil freeze–thaw cycles may reduce soil compaction, which could affect various hydrologic processes. In this study, the authors test for the presence of significant trends in soil freeze–thaw cycles and soil temperatures at several depths and compare these with other climatic variables including air temperature, snowfall, snow cover, and precipitation. Data for the study were obtained for three research stations located in northern, central, and southern Indiana that have collected soil temperature observations since 1966. After screening for significant autocorrelations, testing for trends is conducted at a significance level of 5% using Mann–Kendall’s test. Observations from 1967 to 2006 indicate that air temperatures during the cold season are increasing at all three locations, but there is no significant change in seasonal and annual average precipitation. At the central and southern Indiana sites, soil temperatures are generally warming under a bare soil surface, with significant reductions in the number of days with soil frost and freeze–thaw cycles for some depths. Meanwhile, 5-cm soils at the northernmost site are experiencing significant decreases in cold season temperatures, as an observed decrease in annual snowfall at the site is counteracting the increase in air temperature. Seasonal mean maximum soil temperatures under grass cover are increasing at the southernmost site; however, at the central site, it appears that seasonal minimum soil temperatures are decreasing and the number of freeze–thaw cycles is increasing.

Sign in / Sign up

Export Citation Format

Share Document