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Soil is an oligotrophic medium for fungal growth. Fungi are important component in soil
microbiota. Depending on soil depth and nutrient conditions, the fungal biomass exceeds that of
bacteria in almost every soil except rhizosphere soil which is dominated by bacteria. Filamentous
fungi in soil degrade organic matter and help in soil aggregation. Some produce substances similar
to humic substances and some are capable of forming ectotrophic associations on the root system of
forest trees and help in mobilisation of soil phosphorus and nitrogen into plants. Many fungi are
biological control agents for plant pathogens and insect pests. In Uttarakhand especially in
Dehradun District very scanty information is available regarding soil inhabiting microfungi of
Agricultural fields. Therefore some agricultural lands growing Brassica crop were selected to study
the composition, dominance and diversity of microfungi and physico-chemical properties of the soil
inhabited by these fungi.
Five agricultural lands viz. Rajawala (RAJ), Bahadarpur(BAH), Bhauwala (BHAU), Telpura (TLP)
and Sudhowala (SUDH) were selected. Each land was surveyed repeatedly to collect soil samples.
Soil samples were collected from different depths viz. 0-5 cm, 5-10 cm, 10-15 cm, 15-20 cm. and 20-
25 cm and composite samples were made for each agricultural land.
For all soil samples examined, pH varied from 6.42±1.24 to 7.84±1.56; moisture content varied
from8.42±1.68 to 10.84±2.16; organic contents varied from 1.55 to 3.00 and texture varied from
sandy to sandy loam. Micronutrients were very high in all the soil samples. A total of 383 colonies of
microfungi belonging to 11 genera and 26 species were isolated. Anamorphic fungi (Deuteromycota)
were dominant and represented by 9 genera and 22 species followed by Zygomycota represented by
2 genera and 4 species. Fungal populations were always highest in surface soil and decreased along
with soil-depth. Maximum fungal species were isolated from BAH at the depth of 0-10 cm followed
by RAZ, whereas the minimum fungal species were isolated from BHAU, TPR and SUDH at the
depth of 15-20 cm. Of the total 26 species recorded, 8 species were of common occurrence, 9 species
of frequent, 8 species of moderate and 1 species of rare occurrence respectively.
Shanon- Wiever index of species diversity was highest (2.734) in BAH followed by RAZ (2.686), TLP
(2.583) and SUDH (2.553) while it was lowest for BHAU (2.540). Simpson index of diversity also
showed identical trends. Highest similarity (84.2%) was observed between RAJ and BAH and lowest
(55.6%) between RAJ and TLP.
The present investigation will be helpful in documentation and conservation as well as in controlling
soil borne pathogens. Further, it certainly opens up a new horizon for the researchers in this
interesting and challenging field of soil microfungal biodiversity.
Key words: Diversity, Soil mycoflora, Brassica, Agriculture, Dehradun District