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Decrease of take‐all by a transmissible factor in take‐all decline soils
Author(s) -
POPE A. M. S.,
HORNBY D.
Publication year - 1975
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1975.tb00531.x
Subject(s) - soil water , seedling , sowing , biology , soil type , agronomy , ecology
SUMMARY Irrespective of type and cropping history, soils with take‐all decline (D soils) contained a take‐all‐decreasing factor that could be transmitted to cereal soils in which take‐all had not declined (U soils). As little as 0.001 % by weight of D soil decreased take‐all by 50 % in some seedling assays, but in a longer, outdoor test the decrease proved to be temporary and within 10 wk disease increased to equal that in unamended U soil. In two tests in which D soil was amended with U soil there was an unexpected increase in disease in seedling assays. Particulate fractions (0.2‐2.0 μm) from leachates of D soils, but not the coarse fractions (> 1 mm, dry sieved; > 150μm, wet sieved) of these soils, decreased disease in assays. Although moved downwards by water, the transmissible factor in D soil did not spread laterally into adjacent unamended U soil and D soil amendments of U soil were most effective as top dressings and least effective when initially placed below assay seedlings. D soil was slightly less effective when added 14 days after planting wheat in U soil, but incubating soil mixtures for up to 4 wk before planting gave variable results, although there was always some decrease in take‐all. The transmissible factor could be eliminated by heating moist soil for 30 min at 70 o C (but not 60 o C). The evidence suggests that the factor is biological, but is insufficient to suggest that it is the cause of take‐all decline.