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Isolation and selection of K-solubilizing Bacteria from overburdens of Indian k-Mines

KrishiKosh

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Title Isolation and selection of K-solubilizing Bacteria from overburdens of Indian k-Mines
 
Creator Bahadur, Indra
 
Contributor Maurya, Prof. B.R.
 
Subject null
 
Description Abstract
ISOLATION AND SELECTION OF EFFICIENT K-SOLUBILIZING BACTERIA FROM OVERBURDENS OF INDIAN K-MINES
Potassium is third most important essential element for plant growth after nitrogen and phosphorous. It is the seventh most abundant element in earth’s crust. Potassium plays an important role in plant growth, performs many functions in plants like water movement, electrical balance, regulation of hormones, opening and closing of stomata, resistance against biotic and abiotic stresses. In soil, K exists mainly in four different pools: mineral, non-exchangeable, exchangeable and solution K. The concentration of soluble K in soils is meagre and its major portion (98%) exists as insoluble minerals. For optimum crop production, soil solution and exchangeable K need to be replenished continually with non-exchangeable K through weathering of K bearing minerals such as waste micas or by addition of K fertilizers. Plants can take potassium only from the soil solution. Its availability is dependent upon the K dynamics as well as on total K content of soil.
Microorganisms play a key role in conversion of unavailable form of K, i.e. mineral form of potassium (muscovite, biotite, feldspar, orthoclase and illite) to available form i.e. solution form of potassium. These transformations have been a subject of study for a long time and still a matter of curiosity. Soil microorganisms and their enzymatic activities are the potential bio-indicator to assess the soil health so the use of these in existing situation can sustain the system a long run.
Keeping these point in mind the present investigation entitled “Isolation and Selection of Efficient K-Solubilizing Bacteria from Overburdens of Indian K-mines” involved an in-vitro studies in Soil Biology laboratory and an in-vivo experiment in net house of the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi. With the following objectives:
1. Isolation & screening of K solubilizing bacteria from Soils and Overburdens of Indian K-mines.
2. To study the morphological, physiological and biochemical characteristics of screened K-solubilizing bacterial isolates.
3. To study the periodical K-release capacity of promising K-solubilizing bacterial isolates from different K-minerals.
4. To study the effect of some efficient K-solubilizing bacterial isolates on germination, growth and yield of Maize.
To fulfil the objectives of the research programme, 70 soil samples were collected from rhizosphere and overburdens of Indian K mines of Andhra Pradesh, Rajasthan, Jharkhand and Bihar. From each sample one bacterial K-isolate was developed. Isolated bacterial K-isolates were primarily screened on basis of their K-solubilizing capacity in biotite supplemented Aleksandrov broth. Twenty four efficient isolates having higher K-solubilization capacity were selected for their detail study. Morphological characteristics such as colony characteristics, zone of solubilization, slime production, shape, margin and gram reaction; production of plant growth promoting substances (IAA, GA3, HCN, NH3 and siderophore); biochemical characteristic (Starch hydrolysis, H2S & acid production, urease, catalase, methyl red and citrate utilization test) and physiological characteristics such as their growth in different pH, salt concentration and temperature of 24 isolates were studied. Quantitative estimation of K-released and pH dynamics of Aleksandrov broth supplemented with biotite, muscovite and feldspar were studied. Five virulent KSB isolates emerged out from the various tests were used as seed inoculants with maize in Kharif as a test crop under pot culture experiment in net house. Height of plant, number of leaves, SPAD value (chlorophyll) were recorded at various growth periods. For enzymatic activity rhizospheric soil samples were collected at 30 & 60 days of sowing and at harvest. Yield attributes such as cob length (cm), grain cob-1, test weight (g) and grain yield plant-1 were recorded. Data obtained from various parameters were statistically analysed to draw the valid conclusion. Experimental findings are summarized here under:
5.1 Isolation and screening of bacterial K-isolates
• Seventy rhizospheric and overburden soil samples were collected from K-mines of Jharkhand, Bihar, Rajasthan and Andhra Pradesh during July, 2014 to February, 2015 and from that 70 purified isolates were developed.
• K-solubilization capacity of all of isolates in Aleksandrov broth were determined which ranged from 4.45 to 17.25 µg K mL-1. Out of these 70 isolates tested for K solubilization capacity, 23% isolates gave more than 10 µg K mL-1, 17 % isolates showed < 6 µg K mL-1, 37% isolates caused 6 to 8 µg K mL-1 and 23% isolates solubilized 8 to 10 µg K mL-1.
• Based on greater K-solubilization capacity, 24 K-isolates were selected and characterized for their morphological, physiological, biochemical, growth substances production and periodic minerals K-solubilization.
5.2 Characterization of bacterial K-isolates
• Zone of solubilization formed by the bacterial K-isolates ranged from 6.69 mm to 8.17 mm. Among the isolate, JHK2 caused highest 8.17 mm zone of solubilization which was significantly superior to other isolates.
• Out of 24 bacterial K-isolates 21 % (5 isolates) caused >7.5mm zone of solubilization and 37% (9 isolates) showed BRG6>JHG11>RJJ4>APN7. With 245 grains per cob, JHK2 showed significant superiority over rest of the isolates.
• The highest grain yield (62.24 g pot-1) was obtained with JHK2 followed by RJJ4 (59.85 g pot-1). Inoculation of JHK2 resulted 18.30% higher grain yield as compared to un-inoculated control.
• Grain yield of maize influenced by various bacterial K-isolates followed the order as JHK2>RJJ4>BRG6>58.90>JHG11.
• KSB isolates JHK2 followed by BRG6 showed higher available K in soil at harvest of the maize and uptake of potassium by maize crop compared to other KSB isolates.
• JHK2 followed by RJJ4 showed maximum and significantly higher population of KSB compared to un-inoculated control.
Conclusion:
Screened isolates were gram positive, slime producer, forming zone of solubilization, acid and siderophore producers. Both acidophile & Alkaliphile KSB isolates were found. During the study BRG6 was found to be achidophile and RJJ4 was efficient alkaliphile. They signifies their use in acid and in alkali soils, respectively. KSB isolates efficiently increased the release of K from biotite, muscovite and feldspar. Application of bacterial K-isolates and mineral K significantly influenced the yield of maize crop and availability of K as compared to un-inoculated control. These efficient bacterial K-isolates may be used as K inoculants for saving the input of K- fertilizers in agricultural crops. But prior to recommendation, thier authentication through multilocation field trials are necessary.




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Date 2018-05-30T06:08:54Z
2018-05-30T06:08:54Z
2017-08
 
Type Thesis
 
Identifier k-Mines
http://krishikosh.egranth.ac.in/handle/1/5810048162
 
Language en
 
Format application/pdf
 
Publisher Department of Soil Science and Agricultural Chemistry , Institute of agricultural Science, BHU. Varanasi