CASE STUDY 1: A STUDY ON BIODIVERSITY OF SOIL FUNGI OF BHADRACHALAM FOREST , KHAMMAM District, Andhra Pradesh, India
The biodiversity of soil fungi have been studied at Bhadrachalam forest which is located in Khammam district, Andhra Pradesh state, India. The Bhadrachalam forest study area lies on left bank of river Godavari in Bhadrachalam revenue division. The area is located between east 80021’ - 81009’ longitudes and 17036’ - 18038’ North latitudes. The total geographic area of the division is 1, 96,800 Ha with 1, 44,603 Ha under forests. For the present study, soil samples were collected from North zone of Bhadrachalam forest on 5th of every month starting with March-2009 to Febrauary-2010.The collections were made by taking composite samples up to a depth of 10cm after scrapping off 3cm of surface soil with a sterile trowel. The samples were systematically analyzed for physico-chemical parameters such as seasonal variation, moisture content, pH, soil temperature, soil organic carbon content which affects fungal population. The soil exhibit dynamic nature with everlasting interaction between abiotic and biotic factors. Fungi is an important component of the terrestrial ecosystem as it plays an vital role on recycling of organic wastes, nature conservation,agriculture.The present work has been initiated to determine the effect of the key abiotic factors on soil fungi. It is observed that soil fungus of the study area is affected due to abiotic factors and it should be properly mitigated to continue the natural benefits of the soil fungi and its role in sustaining fertility to the forest ecosystem. As a part of present study an attempt has been made to study the ecology and dynamics of soil fungi associated with Bhadrachalam forest.
Key words: Forest ecosystem, Physico-chemical parameters, Soil fungi, Bhadrachalam forest, Khammam District, A.P
Bhadrachalam forest division is one of among the territorial divisions of Khammam circle and one wildlife division. The North division of the Bhadracham forest is the part of the Godavari upper division and was formed on 1st July 1964, by bifurcating upper Godavari division into Bhadrachalam and V.R.Puram divisions with head quarters at Bhadrachalam. The terrain shows great variation in the altitude with undulations constituting high ranges of hills on the north and numerous scattered groups of hills intercepted by the river Taliperu and streams. The terrain falls in to two well defined zones namely eastern zone comprising east of Taliperu river and Nugur zone comprising charla, venkatapuram and wazeedu mandals.The important rivers which drain the study area are the Godavari and Taliperu. The Forests of the tract can be divided into the two Physio-graphic zones namely Eastern zone lying east of Taliperu river and Nugur zone. The eastern zone lies between the river Taliperu and Nandigama vagu along the left bank of river Godavari. Its length along the Godavari is 74.835 Km with an area of about 24501.305 Ha. It is bounded by the politically defined cut line of Chhattisgarh State on the North, by Nandigama Vagu on the East, by river Godavari on the South and river Taliperu on the West. There are many reserves in this zone containing occasional isolated hills. The whole terrain is either plain or gently undulating. This contains both a plateau with a general elevation of 305 m to 425 m and a narrow alluvial flat country with a general elevation of about 92 m. Towards the South and the West near Tippapuram and Venkatapuram, the plateau rises abruptly from the plains with a precipitous wall of 152m to 213m high. Further towards North near Krishnapuram, the rise is gentler then again at the North Eastern edge of the plateau, the ground rises abruptly with perpendicular rocky sides to an elevation varying between 610m to 975m. To the South-East of this plateau, the Charla Reserved Forests, there is a Range of hills about 12 Km long and 6 Km broad. The general terrain of this plateau is undulating and is well drained by many streams that have cut deep ravines into the plateau.
The Bhadrachalam Forest Division forms a part of Pranahita-Godavari valley region.The Pranahita-Godavari valley has not yet been fully surveyed geologically; only small portions of the field where the coal bearing Barakar Strata found were once explored by Mr.W.T.Blandford, and later by Mr.W.King (Records of the Geological Survey of India, Volume XVIII-Part-3, 1881). Inspite of the presence of Coal bearing Barakar Strata, this area has not been taken up for systematic geological mapping so far. The area to the North of River Godavari and West of Sabari river is of a complicated nature, but in general the area represents a Graben (rift valley). A view from Pavanoor village in Nugur R.F. of Venkatapuram Range will give an idea of this rift valley. In many places the earth has folded itself, resulting in the sudden lowering of a part of rocks (rifts). Thus abrupt occurrence of precipitous, perpendicular rocky sides (walls) has resulted. These rifts later formed the sources of mountain streams, which are conspicuously many in this Division due to these rifts. These numerous mountain streams, used to drain their water and silt into the river Godavari ultimately, were tamed by constructing a dam across Taliperu near Charla, creating immense irrigation facilities for the adjacent lands. The rocks do not generally show any folding or any tectonic symptoms. But near Baster, the Archeans show the effects of folding. The Godavari valley is flanked on either side by extensive tracts of ancient archeans gneiss, with superincumbent later formations covering portions of the middle area from end to end of the field. The recent formations in the middle of the graben near about Dummugudem are denuded away.
The study area in the part of Khammam District of Andhra Pradesh is in between east 80021’ - 81009’ longitudes and 17036’ - 18038’ North latitudes and falls in the Survey of India toposheet no. 55 G/2, 5. It is on left bank of river Godavari.
Soil samples were collected from North Zone of Bhadrachalam forest on the 5th of every month starting with march, 2009 to February, 2010. Each month at 50 x 50 m area was selected. Collections were made by taking composite samples up to a depth of 10cm, after scraping off 3cm of surface soil with a sterile trowel. A pit was dug with the trowel which was sterilized with 70% alcohol and the root zone soil was collected in fresh polyethene bags along with root bits. The soil temperature was measured with help of soil thermometer. The soils were brought to the laboratory immediately and composite soil samples of each plant species were thoroughly mixed and kept in one big polythene bag in refrigerator at 50C until further study. Soils were taken from the root zone soils, supporting two Angiospermic plants, Hardwikia bipinata (Caesalpiniaceae) for determining number of soil fungi and VAM fungal propagules after removing stones and vegetable debris present. Root bits of each species were fixed separately every month in 1:3 acetic alcohols. Soil samples for chemical analysis were air dried and passed through 2 mm sieve.
The soil reaction and moisture content were determined immediately after getting the samples to the laboratory. The pH of each soil was determined using digital electronics, pH meter. The moisture content, mechanical analysis, water holding capacity, quantity of organic carbon, chlorides, available nitrogen, available phosphorus, exchangeable potassium, iron, copper, zinc and manganese were determined by the methods recommended by piper (1944). The microelement content of iron, copper, zinc and manganese (in ppm) was measured using Perkin Elmer model 373 atomic absorption spectrophotometer. Available nitrogen was estimated by Kjeldahl’s method. Exchangeable potassium was measured by the intensity method with the help of Elico flame photometer. Olsen’s method as modified by Betramson (1942) was employed in estimating available phosphorous using Elico colorimeter.
The moisture content of the soil was determined as follows:
10 g of 2 mm sieved soil was taken in a known weight of card board paper boat. The same is kept in hot air oven, adjusted at 1050C, for 11 hours. Next day, the weight of the boat including dry soil was taken, when it was cool. The moisture content in % was determined as follows:
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Likewise, the moisture content (in %) of the rhizoshpere soil supporting the two angiospermic plants under study was determined individually each month.
The quantity of organic carbon of the soil was estimated by the modified method of Walkley and Black (Piper, 1944).To one gram of 0.5 mm sieved soil, 10 ml of 1NK2Cr2O7 and 2 ml of conc. H2SO4 were added. The contents were allowed to cool for 30 min. and then added 3 g of sodium fluoride. The solution was titrated against 1N ferrous sulphate solution using diphenyl amine indicator. The turbid blue colour was changed to brilliant green. A blank titration was carried at the beginning. The organic carbon content (in %) of the soil was calculated as follows:
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1 1N K2Cr2O7 solution; dissolve 49.04 g of K2Cr2O7 in distilled water and dilute of 1 liter.
2 1N FeSO4 solution; Dissolve 280g of FeSO4 in 40ml of Conc. H2SO4 ,cool and dilute of 1 liter with distilled water.
The soil temperature was recorded while collecting the soil samples with the help of a soil thermograph at a depth of approximately 10 cm in the top horizon.
Results and discussion:
Quantitative data in relation to Physico-chemical factors:
The results of the quantitative data in relation to physico-chemical factors were analyzed and represented in table 1 through 5.The following statistical parameters which include minimum, maximum, median, standard deviation, skewness and kurtosis were studied. The analysis was carried out keeping view of the importance of the soil quality and a fungal component in it. The pH values of the soil ranges from 6.5 to 7.9 for soil-1 and 6.56 to 8.39 for soil-2.The other key parameters were also carefully studied and represented in tabulated form.
The main objective of the present study was to understand and analyze the quality of soil in northern part of Bhadrachalam, Khammam district, Andhra Pradesh, India. The present work was designed to statistically represent the physico chemical parameters involved with fungi of the study area. The physico-chemical characteristics of the soil samples reveal that the soils in this region require attention.
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Table 1: Result of chemical and statistical analysis of fungal numbers and seasonal variations of soil samples collected from the study area.
Fungal Numbers and Seasonal Variation:
Distribution of Fungal numbers (per g) in two soils
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Soil-1: Dalbergia Paniculata
Soil-2: Hardwickia bipinata