The use of zymogram and anastomosis techniques to follow the expansion and demise of two coalescing bare patches caused by Rhizoctonia solani AG-8

1993 ◽  
Vol 44 (6) ◽  
pp. 1161 ◽  
Author(s):  
GC MacNish ◽  
CK McLernon ◽  
DA Wood
Keyword(s):  
Rhizoctonia Solani ◽  
Growing Season ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Wheat Seedlings ◽  
Bare Patch ◽  
Apparent Death ◽  
Low Levels ◽  
Undisturbed Soil Cores

Pectic zymogram characterization and anastomosis techniques were used to study the distribution of strains of R. solani AG-8 in a large rhizoctonia bare patch. Undisturbed soil cores were removed on nine occasions during the period 1988 to 1992. Identification of the isolates of R. solani from wheat seedlings grown in the cores demonstrated that the patch was a coalescence of two patches, each colonized by isolates of R. solani AG-8 representing different zymogram groups (ZG1-1 and ZG1-5). The demarcation between the two patches remained unchanged while both patches were active. Between the 1989 and 1990 seasons, the pathogen in half of the ZG1-5 patch died, or was reduced to such low levels that it was difficult to detect. In the remainder of the ZG1-5 patch, the pathogen died or was reduced to undetectable levels between the 1990-91 seasons. The ZG1-1 patch was evident at the beginning of the 1991 growing season and the pathogen could be isolated; however, by the end of the season the pathogen could not be isolated. In all these instances the demise of the patch was associated with the disappearance of field symptoms and an inability to isolate the pathogen and therefore the apparent death of the fungus in the soil.

Evidence that each Rhizoctonia bare patch is dominated by an individual zymogram group (ZG) of Rhizoctonia solani AG-8

1993 ◽  
Vol 44 (6) ◽  
pp. 1175 ◽  
Author(s):  
GC MacNish ◽  
MW Sweetingham
Keyword(s):  
Rhizoctonia Solani ◽  
Western Australia ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Wheat Seedlings ◽  
Bare Patch ◽  
Infection Focus ◽  
Undisturbed Soil Cores

Studies of rhizoctonia bare patches in the southern part of the cereal belt of Western Australia indicate that each patch is dominated by an individual pectic zymogram group (ZG) of R. solani AG-8. R. solani was isolated from plants sampled from patches or from wheat seedlings grown in undisturbed soil cores removed from patches. The Rhizoctonia spp. isolated were characterized using electrophoresis in pectin-acrylamide gels. Four patch-forming zymogram groups (ZG1-1, ZG1-2. ZG1-4 and ZG1-5) were isolated. Of 121 patches examined, only five yielded more than one ZG. Two of these were due to the coalescing of two patches dominated by different zymogram groups. For the remaining three, there was only an occasional isolation of a ZG different from the dominant ZG. This may indicate a new infection focus endeavouring to establish in soil that another ZG occupies. Occasionally, patch-forming ZG1-1, ZG1-2, ZG1-4 and ZG1-5 were isolated from non-patch sites.

scholarly journals Bioassay of Undisturbed Soil Cores for the Presence of Gaeumannomyces Graminis Var. Tritici

1973 ◽  
Vol 26 (6) ◽  
pp. 1267 ◽  
Author(s):  
GC Mac Nish ◽  
RL Dodman ◽  
NT Flentje
Keyword(s):  
Main Parameter ◽  
Gaeumannomyces Graminis ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Wheat Seedlings ◽  
The Core ◽  
Plant Remains ◽  
Undisturbed Soil Cores ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

The presence of viable G. graminis var. tritici in field soil was detected by a bioassay. Wheat seedlings were grown in undisturbed soil cores maintained under standard conditions for 4 weeks. The percentage of roots infected per core was the main parameter chosen to give an estimate of the level of G. graminis var. tritici inoculum in the core. Some variability between cores from the same site was observed, but this could be reduced by taking cores over plant remains within take-all patches. In this way, high and reasonably uniform levels of inoculum could be obtained to study the effect of various treatments on the incidence of G. graminis var. trifici.

Isoproturon movement and dissipation in undisturbed soil cores from a grassed buffer strip

Agronomie ◽  
2000 ◽  
Vol 20 (3) ◽  
pp. 297-307 ◽  
Author(s):  
Pierre Benoit ◽  
Enrique Barriuso ◽  
Philippe Vidon ◽  
Benoit Réal
Keyword(s):  
Soil Cores ◽  
Undisturbed Soil ◽  
Buffer Strip ◽  
Undisturbed Soil Cores

Relationship Between Soil Properties and Nitrogen Mineralization in Undisturbed Soil Cores from California Agroecosystems

2018 ◽  
Vol 50 (1) ◽  
pp. 77-92 ◽  
Author(s):  
Kenneth Miller ◽  
Brenna J. Aegerter ◽  
Nicholas E. Clark ◽  
Michelle Leinfelder-Miles ◽  
Eugene M. Miyao ◽  
...  
Keyword(s):  
Soil Properties ◽  
Nitrogen Mineralization ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Undisturbed Soil Cores

Three-Dimensional Quantification of Macropore Networks in Undisturbed Soil Cores

1999 ◽  
Vol 63 (6) ◽  
pp. 1530-1543 ◽  
Author(s):  
Johan Perret ◽  
S. O. Prasher ◽  
A. Kantzas ◽  
C. Langford
Keyword(s):  
Three Dimensional ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Undisturbed Soil Cores

scholarly journals Estimating the van Genuchten retention curve parameters of undisturbed soil from a single upward infiltration measurement

Soil Research ◽  
2017 ◽  
Vol 55 (7) ◽  
pp. 682 ◽  
Author(s):  
D. Moret-Fernández ◽  
C. Peña-Sancho ◽  
B. Latorre ◽  
Y. Pueyo ◽  
M. V. López
Keyword(s):  
Water Retention ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Water Retention Curve ◽  
Internal Diameter ◽  
Soil Cores ◽  
Undisturbed Soil ◽  
Retention Curve ◽  
Loam Soil ◽  
Undisturbed Soil Cores

Estimation of the soil–water retention curve, θ(h), on undisturbed soil samples is of paramount importance to characterise the hydraulic behaviour of soils. Although a method of determining parameters of the water retention curve (α, a scale parameter inversely proportional to mean pore diameter and n, a measure of pore size distribution) from saturated hydraulic conductivity (Ks), sorptivity (S) and the β parameter, using S and β calculated from the inverse analysis of upward infiltration (UI) has been satisfactorily applied to sieved soil samples, its applicability to undisturbed soils has not been tested. The aim of the present study was to show that the method can be applied to undisturbed soil cores representing a range of textures and structures. Undisturbed soil cores were collected using stainless steel cylinders (5cm internal diameter×5cm high) from structured soils located in two different places: (1) an agricultural loam soil under conventional, reduced and no tillage systems; and (2) a loam soil under grazed and ungrazed natural shrubland. The α and n values estimated for the different soils using the UI method were compared with those calculated using time domain reflectometry (TDR) pressure cells (PC) for pressure heads of –0.5, –1.5, –3, –5, –10 and –50kPa. To compare the two methods, α values measured with UI were calculated to the drying branch of θ(h). For each treatment, three replicates of UI and PC calculations were performed. The results showed that the 5-cm high cylinders used in all experiments provided accurate estimates of S and β. Overall, the α and n values estimated with UI were larger than those measured with PC. These differences could be attributed, in part, to limitations of the PC method. On average, the n values calculated from the optimised S and β data were 5% larger than those obtained with PC. A relationship with a slope close to 1 fitted the n values estimated using both methods (nPC=0.73 nUI+0.49; R2=0.78, P<0.05). The results show that the UI method is a promising technique to estimate the hydraulic properties of undisturbed soil samples.

Colloid and Phosphorus Leaching From Undisturbed Soil Cores Sampled Along a Natural Clay Gradient

Soil Science ◽  
2011 ◽  
Vol 176 (8) ◽  
pp. 399-406 ◽  
Author(s):  
Anders Lindblad Vendelboe ◽  
Per Moldrup ◽  
Goswin Heckrath ◽  
Yan Jin ◽  
Lis Wollesen de Jonge
Keyword(s):  
Phosphorus Leaching ◽  
Soil Cores ◽  
Natural Clay ◽  
Undisturbed Soil ◽  
Undisturbed Soil Cores
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