Characterization and classification of soil resources derived from chlorite schist in northern transition zone of Karnataka

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1 Karnataka J. Agric. Sci.,27 (1): (14-21) 2014 Characterization and classification of soil resources derived from chlorite schist in northern transition zone of Karnataka H. B. P. PULAKESHI, P. L. PATIL AND G. S. DASOG Department of Soil Science and Agricultural Chemistry University of Agricultural Sciences, Dharwad , Karnataka, India plpatiluasd@gmail.com (Received: July, 2010 ; Accepted: February, 2014) Abstract: A study was undertaken to characterize, and classify the soil resources of Mantagani village in northern transitional agro-climatic zone (zone-8) of Karnataka. Fourteen profiles were studied for the morphological, physical and chemical properties. Eight representative pedons covering all the soil types were selected and their properties and classification is discussed in this paper. Soils under the study were silty clay in texture, alkaline reaction with low salt content. Calcium and magnesium were the dominent cations follwed by sodium and potassium. Soils studied were classified up to family level according to revisions in Soil Taxonomy using morphological, physical and chemical properties. Major proportion of the soils in the village belonged to the order Vertisols (pedons 4 to 11) and others Alfisols (pedon 12), Inceptisols (pedon 13) and Entisols (pedons 1, 2, 3 and 14). Seven series were identified in the study area. Keywords: Soil resources, Soil survey, Soil characterization, Soil classification Introduction Soil is a vital natural resource on whose proper use depends the life supporting systems of a country and the socio-economic development of its people. Soils provide food, fodder and fuel for meeting the basic human and animal needs. With the increase in human and animal population, nutrient depletion of soils for more food production is on the increase. However, the capacity of a soil to produce is limited and the limits to production are set by intrinsic characteristics, agro-ecological settings, use and management. This demands systematic appraisal of our soil resources with respect to their extent, distribution, characteristics, behaviour and use potential, which is very important for developing an effective land use system for augmenting agricultural production on a sustainable basis. Material and methods Mantagani village in Savanur taluka of Haveri District (Fig 1.) was selected as a study site which is located between 14º " and " N latitude and 75º " and 75º " E longitude with an average elevation of 750 m above Mean Sea Level (MSL). The climate is tropical with mean annual maximum temperature of 31.7ºC and mean annual minimum temperature of 20.1ºC. The area receives a mean annual rainfall of 528 mm and having undulating to rolling topography with frequent mount like features. Vegetation of the area is moist deciduous. Chlorite schist is the parent rock in the study area. The area has relief on both west and south directions. It is drained by a stream in the west and by Varada river in the south. Soils on the rolling topography are severelly affected by erosion. The area is under Ustic moisture regime and Isohyperthermic temperature regime. Soil survey was carried out in Mantagani village during April 2010 using IRS P6 LISS-III data, survey of India toposheet and cadastral map of the village. After intensive traversing, 14 pedons were studied depending upon soil heterogeneity. Morphological characters like colour, structure, consistency and physico-chemical properties like bulk density, water holding capacity, ph, electrical conductivity, organic carbon, cation exchange capacity, etc. were studied for the profile samples. The soils were classified at family level according to revisions in soil taxonomy (Soil Survey Staff, 1999). After correlating for the above referred properties of pedons, eight representative pedons were selected and presented in the paper. Karnataka Mantagani Village Results and discussion Savanur Taluka Brief morphological features of the pedons are presented in Table 1. The soils were dark grayish brown (10 YR 4/2) to very dark grayish brown (10 YR 3/2) in pedons 1, 3, 4 and 8, whereas in pedons 12, 13 and 14 light reddish brown (2.5 YR 6/4) to reddish brown (5 YR 4/4). There was not much variation in the soil colour with depth in all the pedons except in pedon 1 and 12. All the black soil pedons exhibited hue of 10 YR throughout the profile and the dominant colour was dark grayish brown to very dark grayish brown due to the clay-humus complex in the presence of lime. The dark matrix colour was due to presence of high organic matter content in the surface horizons (Tripathi et al., 2006). In red soil pedons, hue was yellowish * Part of M. Sc. thesis submitted by the first author to the University of Agricultural Sciences, Dharwad , India 14

2 Karnataka J. Agric. Sci.,27 (1): 2014 Table 1. Soil morphological characteristics of representative pedons in Mantagani village Horizon Depth (cm) Colour Texture Structure Consistency Root Boundary Special features Dry Moist Dry Moist Wet Ap YR 5/6 10 YR 4/4 sil 1f sbk sh fi ss & sp mf ds Slight effervescesnce A YR 5/6 10 YR 4/4 sil 2 m sbk sh fi ss & sp ff ds with HCl & animal AC YR 3/2 10 YR 3/2 sil 1 f sbk sh fi ss & sp ff ds activities are observed AC YR 4/2 10 YR 3/2 sil 1 f sbk sh fri ss & vp fm ds AC YR 4/2 10 YR 3/2 sil 2 m sbk s fi ss & vp - ds AC YR 4/2 10 YR 4/2 sil 2 m sbk sh fi ss & sp - ds A YR 4/2 10 YR 3/2 sil 2 m sbk sh fri ss & sp mf cs Slight effervescence with A YR 4/2 10 YR 4/4 sil 1 m sbk sh fri ss & sp mf cs HCl, common CaCO3 AC YR 4/2 10 YR 3/2 sil 1 m sbk sh fi ss & sp ff cs are prominent brown Ab1ss YR 4/2 10 YR 4/4 sil 2 m sbk sh fi ss & sp ff cs mottles were observed ACb YR 4/2 10 YR 3/2 sil 2f sbk sh fri ss & sp ff cs between 40 to 125cm Ab2ss YR 4/2 10 YR 3/2 sil 2f abk sh fri ss & sp - cs depth. Prominent slicken Ab3ss YR 4/2 10 YR 3/2 sil 1f abk sh fri ss & sp - cs sides were obsereved Ab YR 4/4 10 YR 4/4 sil 1f abk sh fi ss & sp - cs at cm and cm depth Ap YR 4/2 10 YR 3/2 c 1 f sbk h fri vs & vp mf cs Prominent slicken slides A YR 3/2 10 YR 3/2 c 2 m sbk sh fr vs & vp mf cs were observed from Bss 1 k YR 4/2 10 YR 4/2 c 2 m sbk sh fr vs & vp ff cs cm. Strong k YR 4/2 10 YR 3/2 c 1 f sbk sh fi vs & vp - cs effervescence with HCl, BCssk YR 3/2 10 YR 3/2 c 2 m sbk h fi vs & vp - cs many prominent CaCO3 was observed from cm. Ap YR 4/2 10 YR 3/2 c 3 m sbk h fr vs & vp fc cs Prominent slicken slides A YR 5/2 10 YR 4/2 c 1 f sbk sh fr vs & vp ff cs were observed from Bss YR 4/2 10 YR 4/2 c 1f sbk sh fr vs & vp ff cs cm. Slight Bss YR 4/2 10 YR 3/2 c 3 m sbk sh fi vs & vp ff cs effervescence with HCl, Bss YR 4/2 10 YR 3/2 c 2 m sbk h fi vs & vp - cs few to common CaCO3 was observed from cm Ap YR 4/4 5 YR 3/4 c 2 m sbk sh fri ss & sp fm cs Clay skins on peds Bt YR 3/4 5 YR 3/4 c 1 m sbk sh fri ss & sp ff cs were observed at Bt YR 3/4 2.5 YR 3/4 c 1 m sbk sh fri ss & mp - cs cm depth BC YR 5/4 2.5 YR 5/4 sl 2 m sbk h fri ss & sp - cs BC YR 6/4 2.5 YR 6/4 sl 1 m sbk sh fri ss & sp - cs Ap YR 5/4 10 YR 4/3 sicl 2 m sbk sh fri ss & sp fm cs Weathered rock was A YR 6/6 10 YR 6/6 sicl 2 m sbk sh fri ss & sp ff cs observed from 80 cm Bw YR 5/4 7.5 YR 4/6 sicl 1 f sbk sh fri ss & sp - cs to below 150 cm depth Bw YR 5/4 10 YR 4/3 sicl 2 m sbk sh fi ss & sp - cs BC YR 4/3 10 YR 3/3 sicl 2 m sbk sh fi ss & sp - cs Ap YR 3/3 7.5 YR 4/8 sicl 1 f sbk sh fi ss & sp fc cs Weathered rock was Bw YR 4/4 2.5 YR 4/4 sicl 1 f sbk sh fi ss & sp - cs observed from 40 cm Bw YR 5/4 5 YR 4/8 sicl 1 f sbk h fri ss & p - cs to below 20 cm depth BC YR 5/8 7.5 YR 4/8 cl 2 f sbk h fri ss & sp - cs (5 YR). The soils exhibited sub-angular blocky structure in the surface horizons of all the pedons. The structure designates the mode of arrangement of the particles and their aggregation, therefore the structural variation in soils were useful to differentiate the horizon. Structure in black soil pedons was 15 predominantly angular to strong medium sub-angular blocky in the surface horizons. The dry consistency of surface horizon ranged from slightly hard to hard in all pedons. Moist consistency was firm to friable in all the pedons. Slightly sticky to slightly plastic consistency

3 Characterization and classification... Table 2. Particle size distribution in representative pedons of Mantagani village Horizon Depth (cm) Coarse Coarse sand Fine sand Total sand Silt Clay (<0.002 mm) fragments ( mm) ( mm) ( mm) ( mm) (>2 mm) % Ap A AC AC AC AC A A AC Ab1ss ACb Ab1ss Ab3ss Ab Ap A Bssk k BCssk Ap A Bss Bss Bss Ap Bt Bt BC BC Ap A Bw Bw BC Ap Bw Bw BC was also observed in all the pedons except in Ap horizons. All the horizons of pedon 8 were found to be very sticky and very plastic in consistency (wet). Increase in stickyness and plasticity may be due to high clay content. Similar observations were made by Sarkar et al. (2001) in soils of lower outer of Chhotanagapur plateau. were clay, silt loam and silt clay loam in texture and clay content was high in the sub-soil. Cracks were 16 noticed in all the pedons. In red soil pedons, soils were clay, clay loam and silt clay in texture. This variation in texture was mainly because of deposition of finer fractions. Few to many roots were observed in all pedons. Prominent slickensides were observed in AB horizon to Bss C horizon in black soil pedons. They were prominent in pedon 3. Abundant accumulation of calcium carbonate nodules was observed in pedons 4 and 8 at Bssk1 and Bssk2 horizons.

4 Karnataka J. Agric. Sci.,27 (1): 2014 Table 3. Bulk density and moisture retention in representative pedons of Mantagani village Horizon Depth (cm) Bulk density Water holding Field capacity Permanent Available Water content (Mg/m 3 ) capacity (%) ( %) wilting point (%) (%) Ap A ` AC AC AC AC A A AC Ab1ss ACb Ab1ss Ab3ss Ab Ap A Bssk k BCssk Ap A Bss Bss Bss Ap Bt Bt BC BC Ap A Bw Bw BC Ap Bw Bw BC Physical characteristics of the soil are presented in Table 2 and 3. A perusal of the data on particle size distribution in soils revealed that, all the soil pedons are clay in texture according to the USDA textural triangle. However pedon 1 and 3 were dominated by silt as they were formed under the influence of river. The clay and silt content varied with depth in most of the soils. In black soil pedons, the increase in clay content through the soil depth observed in the study could be attributed to several processes like illuviation of the finer fraction to the 17 lower depth. Generally, sand content was low as compared to silt in all the pedons. High clay and silt content in some of the pedons of study area may be due to their formation on the transported parent material. In red soil pedons, the clay content increased with depth but stabilizes at second or third horizon. Whereas, sub-surface horizons exhibited higher clay content as compared to surface horizons due to the illuviation process occurring during soil development. Similarly, the illuvation process also affected the vertical distribution of silt and sand

5 Characterization and classification... Table 4. Soil ph, electrical conductivity, organic carbon and calcium carbonate content in representative pedons of Mantagani village Horizon Depth (cm) ph (1:2.5) Electrical Organic carbon (g/kg) Calcium carbonate (%) conductivity (ds/m) Ap A AC AC AC AC A A AC Ab1ss ACb Ab1ss Ab3ss Ab Ap A Bssk k BCssk Ap A Bss Bss Bss Ap Bt Bt BC BC Ap A Bw Bw BC Ap Bw Bw BC content. Similar observations were also made by Sharma et al. (2004). Water holding capacity of soils in the transported pedons was comparatively lower than that in the black soils as they were predominated by silt content. In black soil pedons, the maximum water holding capacity (WHC) of the soils ranged between 51.1 to 74.2 per cent. In general, the water holding capacity of the upper solum was more than the lower solum. This low WHC may be due to increase in calcium carbonate in 18 the lower layers. In red soil pedons, the WHC of the soils ranged between to per cent. These differences were due to the variation in the depth, clay, silt and organic carbon content of the pedons. These results are in line with those of Thangaswamy et al. (2005) in soils of Sivagiri village in Chittoor district of Andhra Pradesh. Bulk density varied from 1.1 to Mg per m 3 in transported soil pedons, where as in black and red soil pedons, the bulk density varied from 1.16 to 1.55 Mg per m 3 and 1.24 and 1.56 Mg

6 Karnataka J. Agric. Sci.,27 (1) : 2014 Table 5. Exchangeable cations and CEC in representative pedons of Mantagani village Horizon Depth (cm) Ca Mg Na K CEC ESP BS CEA* Cmol (p+)/kg - % - Ap A AC AC AC AC A A AC Ab1ss ACb Ab1ss Ab3ss Ab Ap A Bssk k BCssk Ap A Bss Bss Bss Ap Bt Bt BC BC Ap A Bw Bw BC Ap Bw Bw BC *CEA = Cation exchange activity per M 3, respectively. In general, the bulk density of the lower solum was more than the upper solum. This could be attributed to clogging of pores by dispersed clays in sub-soil layers and reduction of organic carbon with depth. In transported and black soil pedons, ph ranged from neutral to strongly alkaline and acidic to neutral in red pedons. High ph in black soil pedons was due to their calcareous nature and the accumulation of bases in the solum as they were poorly leached. Increase in soil ph with depth was evident in some of the pedons, 19 which may be ascribed to increasing content of exchangeable and soluble sodium and calcium. The ph was high at surface and then showed decreasing trend with depths in some other pedons. This may be attributed to high base status of these horizons resulting from the recycling of bases through the addition of crop residues. In red soil pedons, large amount of bases have been leached out of the solum leaving behind iron and aluminium oxides and hence the ph in red soil pedons was low compared to their black soil counterparts. ph increased

7 Characterization and classification... Table 6. Classification of soils of Mantagani village Pedon No. Soil type Soil classification at Family level Series (& 2) Alluvial soils Fine loamy, mixed, isohyperthermic, Typic Ustifluvents MTN1 Fine loamy, mixed, isohyperthermic, Vertic Ustifluvents. MTN2 (5, 6 & 7) Black soils Very fine, smectitic, isohyperthermic, Typic Calciusterts. MTN3 (9, 10 & 11) Very fine, smectitic, isohyperthermic, Chromic Haplusterts MTN4 Red soils Very fine, mixed, isohyerpthermic, Inceptic Haplustalfs MTN5 Loamy skeletal, mixed isohyperthermic, Fluventic Haplusteps MTN6 Loamy skeletal, mixed, isohyperthermic, Typic Ustorthents MTN7 Note: Data is not presented for the pedons indicated in the parentheses as they are correlated with depth in both black and red soil pedons as the bases increased with depth. This increase in soil reaction down the slope could be due to leaching of bases from higher topography and getting deposited at lower elevations (Sitanggang et al., 2006). Whereas, C horizon had higher ph and attributed to the accumulation of bases. Similar type of results are reported by Thangaswamy et al. (2005). Electrical conductivity was higher in transported pedons and in black soil pedons compared to red soil pedons, indicating that the black soil pedons were less leached compared to associated red soil pedons. In black soil pedons and red soil pedons, the EC values of the soils ranged from 0.12 to 1.53 and 0.09 to 0.74 ds per m respectively. In the soils studied, the electrical conductivity generally increased with depths. The upper solum was relatively low in salts than in the lower solum. This might be due to leaching of salts from the soil surface to lower depths due to irrigation and their accumulation in lower depths. Even at the time when irrigation was introduced the distribution of salts showed a concentration of salts in the lower solum in Malaprabha project area of Karnataka. The free calcium carbonates in black and red soils ranged from 10.7 to 19.9 and 5.2 to 7.9 per cent, respectively. Organic carbon followed irregular distribution in pedon 3 reflecting its transported nature. Organic carbon content in black and red soil pedons ranged from 1.8 to 6.7 g/kg and 1.0 to 6.6 g/kg, respectively, which in general accumulated in surface layers. The lower contents of organic carbon apparently resulted because of high temperature which might have induced its rapid oxidation. Observations in the line with the present findings have been reported by Basavaraju et al. (2005) for soils of Chandragiri Mandal of Chittoor district of Andhra Pradesh. The organic carbon content of surface soil was greater than the subsurface soils in most of the pedons due to high amount of litter and the crop residues at the surface. Organic carbon content of the soils followed by decreasing trend with depth in all the pedons. It reflects the rapid rate of organic matter mineralization in these soils. Similar findings were reported by Shadaksharappa et al. (1995) for Malaprabha command area soils. The dominant cations on the clay complex were calcium followed by magnesium, sodium and potassium in black soil pedons. The exchangeable calcium plus magnesium dominated over the exchangeable sodium and potassium and was in the range of to and to mol (p+) per kg, respectively. The exchangeable calcium decreased and that of magnesium increased with depth. The content of exchangeable sodium in black and red soil pedons ( and cmol (p+)/kg) varied with 20 profile depth. The soils under investigation contained exchangeable potassium in quantities less than 1 cmol (p+) per kg except few depths and the values exhibited a decreasing trend with depth in few pedons and increased with depth in pedons 8 and 12 and varied from 0.35 to 1.36 and 0.50 to 0.91 cmol (p+) per kg, respectively. In both black and red soil pedons, Ca +2 shows the strongest relationship with all the species, comparing these ions (Ca +2, Mg +2, K + and Na + ), it was clear that Mg +2 was present in low amount than Ca +2 because of its mobility. The low value of exchangeable monovalents compared to divalents due to preferential leaching of monovalents than divalent. These findings are in accordance with Thangaswamy et al. (2005). The values of cation exchange capacity increased with profile depths and followed the trend of clay. This is due to accumulation of clay and may be due to presence of smectic group of clay minerals (Das, 1999). Similar findings have been reported by Shadaksharappa et al. (1995) in Malaprabha Command soils. The exchangeable sodium percent in both black and red soil pedons ranged from 5.85 to per cent and 6.42 to per cent respectively, indicated initiation of the process of sodification in a downward direction. A measure of relative amounts of exchangeable sodium in comparison with the total cations in the soil are dependent on factors such as type of minerals, concentration of electrolytes and status of soluble cations. The findings are in accordance with the works of Thangaswamy et al. (2005) Soils were classified according to the revision in Soil Taxonomy (Soil Survey Staff, 1999). The pedons, 1, 2, 3 and 14 were classified as Entiosols, because there was little or no evidence of development of pedogenic horizons. Pedons 4, 5, 6, 7, 8, 9, 10 and 11 were classified as Vertisols at order level as these pedons did not have lithic or paralithic contact within 50 cm of soil surface and had a weighted average of >30 per cent clay in all the horizons down to a depth of 1 m and had a cracks that open and close periodically. These pedons have a layer of 25 cm or more thick, with an upper boundary within 100 cm of mineral soil surface that has slickensides. Red soil pedon (pedon 12) has surface texture of clay with clay content more than 40 per cent. The Bt horizon (35-60 cm) had a thickness of more than 7.5 cm and clay content increase of more than 8 per cent and presence of oriented clay bridging around sand grains and clay films on the ped surfaces, hence the pedon qualifies for the order Alfisol. Cambic horizon was identified in pedon 13 at a depth of cm and has the properties that do not meet the

8 Karnataka J. Agric. Sci.,27 (1) : 2014 requirements of anthropic, histic, folistic, mollic, plaggen or umbric epipedon, duripan or fragipan or argillic, calcic, gypsic, oxic, patrocalcic, petrogypsic, placic or spodic horizon and not part of Ap horizon. All these properties qualified pedon 13 for the order Inceptisol. All the soils under study had isohyperthermic temperature regime, since, the mean summer and winter temperatures differ by less than 6 0 C and mean annual temperature exceeds 22 0 C (Eswaran et al., 1990). The cation exchange activity class of pedons under study was super active, where CEC to clay content ratio exceeds 0.60 (Soil Survey Staff, 1999). At family and series level, the pedons under study are classified and presented in table 6. Soils studied were silty clay, clay, silt clay loam and the clay content increased with depth. The ph was alkaline and EC increased with depth ( ds/m). Organic carbon decreased and calcium carbonate content increased with depth. Calcium and magnesium were the dominant exchangeable cations followed by sodium and potassium. According to revisions in Soil Taxonomy, soils of Mantagani village belonged to the order Vertisols (pedon 4, 5, 6,7, 8, 9, 10 and 11), Entisols (pedon 1, 2, 3 and 14), Alfisols (pedon 12) and Inceptisols (). References Basavaraju, D., Naidu, M. V. S., Ramavatharam, N., Venkaiah, K., Rama Rao, G. and Reddy, K. S., 2005, Characterization, classification and evaluation of soils in Chandragiri mandal of Chittoor district, Andhra Pradesh. Agropedology, 15: Das, D. K., 1999, Role of soil information systems in sustainable use of land resources. J. Indian Soc. Soil Sci., 47: Sarkar, D., Gangopadhyay, S. K. and Velayutham, M., 2001, Soil toposequence relationship and classification in lower outlier of Chhotanagpur plateau. Agropedology, 11: Shadaksharappa, G. S. and Patil, C. V. and Hebsur, N. S., 1995, Irrigation induced changes in soil properties of Malaprabha Command Area. J. Maharashtra Agril. Univ., 20: Sharma, V. K., Sharma, P. D., Sharma, S. P., Acharya, C. L. and Sood, R. K., 2004, Characterization of cultivated soils of Neogal watershed in North-West Himalayas and their suitability for major crops. J. Indian Soc. Soil Sci., 52: Sitanggang, M., Rao, Y. S., Nayan Ahmed and Mahapatra, S. K., 2006, Characterization and classification of soils in watershed area of Shikohpur, Gurgaon district, Haryana. J. Indian Soc. Soil Sci., 54: Soil Survey Staff, 1999, Soil taxonomy A basic system of soil classification for making and interpreting soil surveys (Second edition). Agricultural Handbook No. 436, United States, Department of Agriculture, Washington DC, USA. Thangasamy, A., Naidu, M. V. S., Ramavatharam, N. and Raghava Reddy, C., 2005, Characterization, classification and evaluation of soil resources in Sivagiri micro-watershed of Chittoor district in Andhra Pradesh for sustainable land use planning. J. Indian Soc. Soil Sci., 53: Tripathi, D., Verma, J. R., Patial, K. S. and Karan Singh, 2006, Characteristics, classification and suitability of soils for major crops of Kiar-Nagali micro-watershed in North-West Himalayas. J. Indian Soc. Soil Sci., 54: