Fungal Diversity and Physico-chemical Parameters of Rhizospheric Soil from Banana Plantation Sites at Nagaland, India

Soil microbial population plays a key role in soil health. It determines the soil fertility, regulates plant growth and actively partakes in decomposition, mineralization, biochemical transformation and soil aggregation (Sinha et al., 2018; Chandrashekar et al., 2014) Soil microbes further improves the plants adaptation to a variety of extreme stresses (Yang et al., 2018). Such Microbial communities aid vital processes that ultimately offer stability and greater yield in agro-ecosystems (Singh, 2015). It has also been reported that fungi are a significant component of soil microbiota (Sinha et al., 2018) and are present in larger quantity as compared to bacteria (Gnanasekaran et al., 2015). With just 5-10% of the total 1.5 million fungal species being described formally (Chandrashekar et al., 2014) proper inventorying and monitoring of the Soil Fungal diversity is essential to maintain soil Health. Improvements of soil health can certainly promote crop yields (Foley et al., 2011; Delgado and Follett, 2002).With regards to yield, Banana is a vital cash crop in India with an average production of about 29, 779.91 thousand tons, it is the second most important cash crop in India (Gnanasekaran et al., 2015). The interactions of these fungi with the plants is certainly the rule and not the exception (Fitter et al., 2005). keeping in view the importance and the role of soil fungal population, the present work was carried out to determine the Soil fungal diverisity and to estimate the physico-chemical paramters of the soils collected from the banana plantation sites.

Soil sampling
 
Soil samples were collected from two Banana plantation sites i.e. Mokokchung district (Site MK) located at Latitude 26°13¢38²N and Longitude 94°32'24"E, 1024 m above msl and Zunhebuto district (Site ZB) located at Latitude 26°16'18" N and Longitude 94°28'31"E, 1192 above msl, respectively under Nagaland State, India during the month of October 2019.
 
Physico-chemical parameters of soil sample
 
Five random soil samples were collected from both the sites (0-15 cm deep) and were combined to form a composite sample. Soil temperatures was recorded during sampling with a soil thermometer. pH was measured using digital systronic pH meter 361. Soil moisture was recorded via oven-dried method (Anderson and Ingram, 1993). Soil organic carbon was determined following the wet digestion method (Walkey and Black, 1934). Available Nitrogen (N) was determined using KEL PLUS Nitrogen analyser. Reagent preparations and experimental setup were done following manufactures manual. All test were performed in triplicates.
 
Isolation and identification of Fungi
 
Fungi were isolated in Potato dextrose agar (PDA) and Rose bengal agar (RBA) plates following serial dilution method. (Plate 1) Plates were incubated at 25±1°C for 5-7 days. Fungal colonies were observed and transferred to appropriate identification media and identified with the help of literature (Afzal et al., 2013; Webster and Weber, 2007; Nagmani et al., 2006; Gillman, 1957).
 

Soil physico-chemical paramters
 
Soil Temperature was observed to be 26°C (Site MK) and 24°C (Site ZB) respectively (Table 1). Soil temperature effects organic matter mineralization (Arevaloc et al., 2012).  Soil pH was mildly acidic in both the sites and was found to be 5.29±0.17 (Site MK) and 5.16±0.11 (Site ZB) respectively (Table 1). Soil pH affects the biology, chemistry and physical properties of soil (Brady and Weil, 2002). Soil Moisture values have immense effect on microbial activity (Liu et al., 2009) and was recorded as 21.86±0.30% (Site MK) and 14.93±1.11% (Site ZB) respectively (Table 1). Soil organic carbon impacts soil fertility (Tiessen et al., 1994) and its values were recorded as 2.57±0.26% (Site MK) and 1.54±0.05% (Site ZB) (Table 1). Available Nitrogen varied from 379.37±13.01 Kg/ha (Site MK) and 290.73±7.58 Kg/ha (Site ZB) respectively (Table 1).
 

 
Fungal diversity
 
A total of 19 fungal species were identified from the two sites (Plate 2). Aspergillus candidus, Aspergillus flavus, Aspergillus fumigatus, Aspergillus lentulus, Aspergillus niger, Aspergillus versicolor, Chaetomium sp, Cladosporium chaldosporiodes, Geotrichum candidum, Humicola sp, Mortierlla sp, Mucor circinelloides, Penecillium sp.1, Penecillum sp.2, Penicillium chrysogenum, Rhizopus sp, Trichoderma harzianum, Trichoderma viride and Trychophyton sp were the total fungal diversity found at both the sites during the month of October 2019. Site MK had a total of 15 fungal population (Table 2) while Site ZB had a total of 10 fungal isolates (Table 2).
 

 

In the present study, a total of 19 fungal isolates were recorded. It was observed that the Genus Aspergillus was dominant in both the sites which may be attributed to better speculating features of the Genus. The study of the fungal diversity in the rhizospheric region highlights the diversity of the fungus and their importance in soil health. Further monitoring and inventorying is recommended to comprehend the diversity present in the state.

JRF-Fellowship, File no. 16-6 (Dec 2018)/2019(NET/CSIR) provided by the CSIR-UGC, Government of India, Nationality Eligibility Test (NET) is acknowledged for supporting the work financially. The Head, Department of Botany, Nagaland University is duly acknowlegded for providing necessary laboratory facilities for conducting the experiments.