MICROORGANISMS IN THE ROOT ZONE IN RELATION TO SOIL MOISTURE

1965 ◽  
Vol 11 (3) ◽  
pp. 483-489 ◽  
Author(s):  
E. A. Peterson ◽  
J. W. Rouatt ◽  
H. Katznelson
Keyword(s):  
Soil Moisture ◽  
Soil Moisture Content ◽  
Root Colonization ◽  
Microbial Population ◽  
Root Zone ◽  
Root Surface ◽  
High Soil Moisture ◽  
High Soil ◽  
High Level ◽  
Taxonomic Studies

The influence of soil moisture on the microbial population of rhizosphere soil and of the root surface (rhizoplane) of wheat was studied under controlled conditions. Fertile soil adjusted to 30%, 60%, and 90% of its moisture-holding capacity was used. Bacterial counts and numbers of specific "physiological groups" of bacteria all increased in the rhizosphere and the rhizoplane as soil moisture decreased. Taxonomic studies of the bacteria isolated from the rhizoplane showed a marked preponderance of species of Pseudomonas under conditions of low and intermediate soil moisture content. On the other hand species of Arthrobacter, Bacillus, and Cytophaga dominated the population at high soil moisture. Although the distribution of fungi on the roots was very similar for the low and intermediate moisture levels, there was some restriction of colonization at the high level. Species of Mortierella, Rhizopus, Chaetomium, Curvularia, and Helminthosporium were not represented among isolates from roots at high soil moisture and the relative incidence of species of Fusarium and Phoma decreased. However, high soil moisture favored root colonization by species of Rhizoctonia and sterile dark fungi.

scholarly journals White Root Rot of Raspberries

1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade
Keyword(s):  
Soil Moisture ◽  
Root Rot ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Causal Organism ◽  
White Root Rot ◽  
High Soil Moisture ◽  
High Soil ◽  
Soil Temperatures ◽  
Dry Soil

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.

scholarly journals Impact of slurry application method on phosphorus loss in runoff from grassland soils during periods of high soil moisture content

2016 ◽  
Vol 55 (1) ◽  
pp. 36-46
Author(s):  
D.A. McConnell ◽  
D.G. Doody ◽  
C.T. Elliott ◽  
D.I. Matthews ◽  
C.P. Ferris
Keyword(s):  
Soil Moisture ◽  
Dairy Cow ◽  
Soil Moisture Content ◽  
Agricultural Soils ◽  
P Fractions ◽  
Application Technique ◽  
P Loss ◽  
High Soil Moisture ◽  
High Soil ◽  
Cow Slurry

Abstract Previous studies have reported that the trailing shoe application technique reduces phosphorus (P) in the runoff postslurry application when compared to the traditional splash-plate application technique. However, the effectiveness of the trailing-shoe technique as a means of reducing P losses has not been evaluated when slurry is applied during periods of high soil moisture levels and lower herbage covers. To address this issue, three treatments were examined in a 3 × 4 factorial design split-plot experiment, with treatments comprising three slurry treatments: control (no slurry), splashplate and trailing-shoe, and four slurry application dates: 7 December, 18 January, 1 March and 10 April. Dairy cow slurry was applied at a rate of 20 m3/ha, while simulated runoff was generated 2, 9 and 16 days later and analysed for a range of P fractions. Dissolved reactive P concentrations in runoff at day two was 41% lower when slurry was applied using the trailing-shoe technique, compared to the splash-plate technique (P < 0.05). In addition, P concentrations in runoff were higher (P < 0.05) from slurry applied in December and March compared to slurry applied in January or April, coinciding with periods of higher soil moisture contents. While the latter highlights that ‘calendar’-based non-spreading periods might not always achieve the desired consequences, the study demonstrated that further field-scale investigations into the trailing shoe as a mitigation measure to reduced P loss from agricultural soils is warranted.

Studies on field establishment of monogerm sugar beet

1973 ◽  
Vol 81 (2) ◽  
pp. 245-252 ◽  
Author(s):  
D. A. Perry
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Sugar Beet ◽  
Soil Compaction ◽  
Field Experiments ◽  
Soil Moisture Content ◽  
Rank Order ◽  
Soil Conditions ◽  
High Soil Moisture ◽  
High Soil

SummaryThe percentage emergence from monogerm sugar-beet seed in field experiments was reduced by high soil moisture content and soil compaction, but was unaffected by soil temperature. Seed lots were differentially influenced when the soil conditions were very adverse. Pelleted seed emerged a little better in good soil conditions and was not more sensitive to high soil moisture content than raw seed.The relation between laboratory germination and the number of emerged seedlings was variable and followed no obvious trends, and there was no consistent rank order in the emergence ability of four commercial cultivars.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

Factors influencing the development of bacterial blight of peas.

1954 ◽  
Vol 5 (3) ◽  
pp. 365 ◽  
Author(s):  
DC Wark
Keyword(s):  
Soil Moisture ◽  
Low Temperature ◽  
Moisture Content ◽  
Bacterial Blight ◽  
Soil Moisture Content ◽  
Atmospheric Humidity ◽  
Disease Symptoms ◽  
High Soil Moisture ◽  
Factors Influencing ◽  
Number Of Bacteria

Garden peas commonly carry a nucleus of plants with bacterial blight (Pseudomonas pisi Sackett) in a masked form. When such plants were exposed to low temperature, either by natural frosting or by dipping the tops of the plants in cold liquids, the number of bacteria in the tissues increased rapidly and typical symptoms of the disease occurred in a few days. Soil type and soil moisture content also influenced the development of the disease, which was more marked in peas grown on a red loam from the Dickson Experiment Station than in peas grown on a prepared potting soil. Disease symptoms developed more rapidly a t high soil moisture content than at lower soil moisture content, following exposure to high atmospheric humidity.

Environment and Chlorsulfuron Phytotoxicity

Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 395-399 ◽  
Author(s):  
John D. Nalewaja ◽  
Zenon Woznica
Keyword(s):  
Soil Moisture ◽  
Soil Nitrogen ◽  
Setaria Viridis ◽  
Kochia Scoparia ◽  
Humidity Effects ◽  
High Soil Moisture ◽  
High Soil ◽  
Green Foxtail ◽  
Temperature And Humidity ◽  
Reduced Toxicity

Glasshouse and growth chamber experiments were conducted to determine chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} phytotoxicity to kochia [Kochia scoparia(L.) Schrad. ♯ KCHSC] and green foxtail [Setaria viridis(L.) Beauv. ♯ SETVI] as influenced by temperature and humidity for 1 week after treatment, and by soil moisture and nitrogen. Chlorsulfuron was more phytotoxic to both kochia and green foxtail at 95 to 100% than at 45 to 50% relative humidity for 1 week after treatment whether at 10, 20, or 30 C. Chlorsulfuron phytotoxicity was similar with all posttreatment temperatures at each humidity, except that phytotoxicity was lower at 30 C than at 10 or 20 C at 90 to 100% humidity. Surfactant added to chlorsulfuron exhanced control of kochia more than that of green foxtail and overcame temperature and humidity effects on chlorsulfuron phytotoxicity. A simulated rainfall of 2 mm after chlorsulfuron application reduced toxicity of chlorsulfuron to green foxtail more than to kochia. Chlorsulfuron was more phytotoxic to green foxtail growing with a high than a low soil nitrogen level. High soil moisture following chlorsulfuron application enhanced phytotoxicity to kochia and green foxtail compared to high soil moisture before treatment.

A GREENHOUSE EVALUATION OF THE EFFECTS OF SOIL MOISTURE, RELATIVE HUMIDITY, AND HELMINTHOSPORIUM SATIVUM INFECTION ON BRITTLENESS OF BARLEY AWNS

1964 ◽  
Vol 44 (2) ◽  
pp. 157-160
Author(s):  
R. B. MacLaren ◽  
J. D. E. Sterling
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Cell Structure ◽  
Ash Content ◽  
High Relative Humidity ◽  
High Soil Moisture ◽  
High Soil ◽  
Greenhouse Evaluation ◽  
Helminthosporium Sativum

High soil moisture and high relative humidity gave a higher incidence of brittle awns on barley than did restricted soil moisture and low relative humidity. Ash content of awns was highest when soil moisture and relative humidity were maintained at high levels. Helminthosporium sativum (P, K and B) infection reduced awn brittleness of one variety and had no effect on the others.No differences in cell structure of the awns were attributed to treatment.

Sign in / Sign up

Export Citation Format

Share Document