Friesia X, 4-5

- 304 -
Fig. 2. The soil borer used for colleeting soil samples.
JOHS. JØRGENSEN phat.
The interest for the ecological demands of C. geophilum and for
the significance of various factors for the mycorrhiza-formation has
implicated several growth tests on artificial substratum (MELIN &
NYMAN 1940, LIHNELL 1942, MELIN & NORKRANS 1942, MELIN &
MIKOLA 1948, MIKOLA 1948a, HACSKAYLO 1961, SANTORO & CASIDA
1962, HACSKAYLO et al. 1965 , TRAPPE 1969).
MATERlALS AND METHODS
Collection of samples, separation and determination of sclerotia
During the period 1/8 - 3/9 1964 soil samples were collected from
57 fields on Funen and particularly in Jutland (cf. Fig. 1) for
examination of the seed content. Twenty fields were grown with root
crops (cf. Fig. 1, Nos. 1-20) and 37 with cereals (Fig. 1, Nos. 21-57).
Within an area of 40-50 m 2 30 soil samples were taken with a borer
(cf. Fig. 2), which removed a circular soil column of 9.9 cm- X 20 cm.
The soil samples were air-dried, mixed and divided into six portions.
One portion was washed at a Fenwick washing apparatus, where the
fine sieve retained particles larger than 0.14 mm. These particles were
then examined for content of seed (cf. JENSEN 1969).