soil potassium dynamics under intensive rice cropping in...

An Asian Journal of Soil ScienceVolume 8 | Issue 2 | December, 2013 | 319-324

Soil potassium dynamics under intensive ricecropping in TBP command area of north Karnataka

K. NARAYANA RAO, N.A. YELEDHALLI AND H.T. CHANNAL

HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE

MEMBERS OF RESEARCH FORUM :

Received : 16.08.2013;Revised :25.09.2013; Accepted : 03.10.2013

SummaryDistribution of different forms of potassium was studied in surface and subsurface soils samples of paddy-paddy cropping sequence in TBP command area. The water soluble K ranged from 0.04 to 0.18 per cent, and0.04 to 0.23 per cent, exchangeable K 1.03 to 3.26 per cent and 1.30 to 3.40 per cent, non exchangeable K4.10 to 11.13 per cent and 4.11 to 10.92 per cent and lattice K 85.79 to 96.60 per cent and 85.97 to 94.31per cent in surface and subsurface layers of total potassium, respectively. All the forms of soil potassium werecorrelated with each other indicating the existence of dynamic equilibrium among them.

Key words : Correlations, Cropping sequence, Dynamic equilibrium, Forms of potassium, Paddy

How to cite this article : Rao, K. Narayana, Yeledhalli, N.A. and Channal, H.T. (2013). Soil potassium dynamics underintensive rice cropping in TBP command area of north Karnataka. Asian J. Soil Sci., 8(2): 319-324.

Research Article

Corresponding author :K. NARAYANA RAO, Department ofSoil Science and AgriculturalChemistry, University ofAgricultural Sciences, RAICHUR(KARNATAKA) INDIAEmail: [email protected]

Co-authors :N.A. YELEDHALLI AND H.T.CHANNAL, Department of SoilScience and Agricultural Chemistry,University of Agricultural Sciences,DHARWAD (KARNATAKA) INDIA

IntroductionThe importance of K in Indian agriculture is increasing

with the passage of time. The response of crops to Kapplication is frequent and pronounced. The soil potassiumgets depleted with the use of high yielding crop varieties,increase in cropping intensity and intensive use of nitrogenand phosphatic fertilizers. The results of long term fertilizerexperiments in India revealed that by growing crops withoutK for longer periods, the available K status of soils decreasesand needs immediate replenishment. Paddy-paddy is thedominant cropping sequnce of the region-2 (North EasternDry Zone) of Karnataka which is followed in dominant blacksoils under irrigated condition. Paddy is grown in an area of0.44 m ha with a production of 2.07 mt and productivity of5347 kg ha-1 (Anonymous, 2009). Despite enormous growthof this cropping systems in this region, there are reports ofstagnation in the productivity of paddy crop with possibledecline in production which have raised doubts onsustainability of this cropping system in future. The farmersof the region lacks the proper knowledge of balancednutrition, assuming that these soils are rich in potassium.

They are applying heavy doses of nitrogen (200% more thanthe recommended), phosphorus as per recommended doseand little (about 25% of‘recommended dose) application ofpotassium for paddy under irrigated condition. Thisimbalanced nutrition has resulted decline in soil fertility status,over mining of nutrients from soil, decrease in response tonutrients application, build up of pests and diseases anddecline in yields of the crops. Hegde and Sudhakar babu (2001)reported a negative balance for potassium in all agro-climaticzones of Karnataka with a net negative balance of 0.39 mt.Potassium, being an essential element for plant growth, existsin four forms in soils viz., water soluble, which is taken up byplant directly, exchangeable K, held by negatively charged onclay particles and available to plants, fixed K, which is trappedbetween layers of expanding lattice clays and lattice K anintegral part of primary K bearing mineral. For practicalappraisal of K supplying power of these soils, it is essential tohave the knowledge of all four forms of K and their status.Although, the attempts have been made earlier to studypotassium status and its dynamics in different soils ofKarnataka but, the information on status of potassium and

HIND AGRICULTURAL RESEARCH AND TRAINING INSTITUTE 320 Asian J. Soil Sci., (Dec., 2013) 8 (2) :

its dynamics in dominant black soils of the region underpaddy-paddy cropping systems is lacking.

Resource and Research MethodsSeventy five surface and subsurface soil samples of

dominant soil series of Raichur (Typic haplustert) werecollected from different villages of Raichur, Manvi andSindhnur taluks of Raichur District and the details of soilscollected are presented in Table A. The samples wereanalyzed for pH, (Jackson 1973), electrical Conductivity,EC (Jackson ,1973), particle size distribution (Piper, 1966),organic carbon, O.C. (Jackson 1973), calcium carbonate,CaCO

3 (Piper, 1966) and cation excgange capacity, CEC

(Black 1965). The different forms of potassium like watersoluble potassium in 1:2 soil water suspension (MacLean,1961), exchangeable potassium (Knudsen et al., 1982), nonexchangeable potassium by boiling nitric acid extractionmethod (Knudsen et al., 1982) and total potassium contentby digesting the soil samples with hydrofluoric acid (Limand Jackson, 1982) were determined. The potassium in theextracts was estimated by using flame photometer. The latticepotassium was calculated by deducting the sum of watersoluble, exchangeable, non exchangeable from total K. Thecorrelations studies were carriedout with the help ofstatistical package for social sciences (SPSS) software andthe results are discussed accordingly (Table A).

Research Findings and DiscussionThe findings of the present study as well as relevant

discussion have been presented under following heads :

Forms and distribution of K :The water soluble potassium content of surface and

subsurface layers ranged between 4 to 14 and 1 to 10 mg kg-1

respectively and decreased with soil depth. The water solubleK contributed least to the total potassium, i.e. 0.04 to 0.23 percent in surface and 0.04 to 0.13 per cent in subsurface layers.(Table 1). A similar trend was reported by Kadrekar (1976)and Hebsur (1997). The higher amount of water soluble K inthe surface layer could be attributed to more exposure of Kbearing minerals to weathering and or upward translocationof K from sub surface layers by capillary rise or due toaddition of K through plant residues, manures and fertilizers.

The fraction of exchangeable potassium content variedfrom 88 to 238 mg kg-1 and 103 to 265 mg kg-1 for surface andsubsurface layers, respectively (Table 1). Similar results werereported by Patel et al. (1986) and Venkatesh andSathyanarayana (1994) for medium black calcareous soils ofwestern Gujarat and some black soils of North Karnataka. Theper cent contribution of exchangeable K to the total K variedfrom 1.03 to 3.26 and 1.30 to 3.40 per cent from surface andsubsurface layers, respectively. The content of exchangeableK increased with depth. The higher amount of K in thesubsurface layer might be due to higher amount of claycontent with higher surface area and more adsorption onexchange sites (Table 1).

The non exchangeable potassium content in surface andsubsurface layers varied between 342 to 602 mg kg-1 and 374to 631 mg kg-1, respectively (Table 1). These values are incomparison with the results reported by Venkatesh andSathyanarayana (1994) for black soils of North Karnataka.The contribution of non-exchangeable K to total K variedfrom 4.10 to 11.13 per cent in surface and 4.11 to 10.92 per centin subsurface layers, respectively. The non exchangeable Kcontent of soils increased with depth.

The lattice K fraction followed a definite pattern withrespect to depth wise distribution of potassium. The content

Table A : Details of the soil samples collected for study under paddy-paddy cropping sequenceSr. No. Name of the village Taluk District Soil type Geology Soil Classification Rainfed/ Irrigated

1. Kasbe camp Raichur Raichur Black Gneiss Typic haplustert Irrigated

2. Vijayanagar camp Raichur Raichur Black Gneiss Typic haplustert Irrigated

3. Kalmala Raichur Raichur Black Gneiss Typic hapluetert Irrigated

4. Ganjalli Raichur Raichur Mixed red and black Gneiss Typic pallustert Irrigated

5. Devasugur Raichur Raichur Mixed red and black Gneiss Typic palluetert Irrigated

6. Sirwar Manvi Raichur Black Gneiss Typic haplustert Irrigated

7. Harvi Manvi Raichur Black Gneiss Typic haplustert Irrigated

8. Neermanvi Manvi Raichur Black Gneiss Typic haplustert Irrigated

9. Amarewara camp Manvi Raichur Black Gneiss Typic haplustert Irrigated

10. Potnal Manvi Raichur Black Gneiss Typic haplustert Irrigated

11. Jawalgera Sindhanur Raichur Black Gneiss Typic haplustert Irrigated

12. Raithanagar camp Sindhanur Raichur Black Gneiss Typic haplustert Irrigated

13. Araginamara camp Sindhanur Raichur Black Gneiss Typic haplustert Irrigated

14. Gorebal camp Sindhanur Raichur Black Gneiss Typic haplustert Irrigated

15. Hanchinal camp Sindhanur Raichur Black Gneiss Typic haplustert Irrigated


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SOIL POTASSIUM DYNAMICS UNDER INTENSIVE RICE CROPPING IN TBP COMMAND AREA OF NORTH KARNATAKA

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of lattice K in surface and subsurface layers varied from 2.90to 9.88 g kg-1 and 3.25 to 10.28 g kg-1, respectively (Table1). These values are in accordance with the findings ofPharande and Sonar (1996) for soils of Maharashtra andVenkatesh and Sathyanrayana (1994) for black soils of NorthKarnataka. The lattice K accounted for major portion of thetotal K exceeding 85 per cent. The lowest and highestcontribution of lattice K to total K was 85.79 and 96.60 percent and 85.97 and 94.31 per cent in surface and subsurfacelayers of the both the cropping sequence, respectively. Thecontent of lattice K increased with soil depth.

The total K content ranged from 3.38 to 10.6 g kg-1 and3.89 to 11.0 g kg-1 and increased with depth (Table 1). Thesevalues are comparable with the values obtained by Raskarand Pharande (1997) for vertisols of Western Maharashtra.The high content of total K in these soils might be attributedto the dominance of K bearing primary minerals such as micain clay fraction (Ranganathan and Sathynarayana, 1980).

The correlation studies indicated that the water solubleK is negatively but non significantly correlated withexchangeable K (Table 2). Similar observation was made byAmiri and Dorudi (1997) in paddy soils of Northern Iran,indicating its non replenishment from other forms of K.Exchangeable K was positively and significantly correlatedwith non exchangeable K, lattice K and total K indicatingdynamic equilibrium among all these forms of K (Table 3). Thenon exchangeable, lattice and total K is correlated with all theforms of K.

The correlation among different forms of K and soilproperties indicated that the all the forms of K were positivelyand significantly correlated with clay but negatively correlatedwith sand and silt fractions (Table 2). This might be due thedominance of mica in the finer fraction of soils. The

observations are in conformity with findings of Singh et al.(1985) and Gali (1998), suggesting that available K status ofthe soil is largely governed by clay fraction. All the forms of Kwere positively and significantly correlated with CaCO

3 and

CEC and negatively with organic carbon (Table 2). It is quiteevident that an increase in CEC means increased adsorptionof potassium. Patil and Sonar (1993), observed similarcorrelations of exchangeable K with CEC and CaCO

3.

Conclusion :The availability of potassium mainly depends on the

status and the forms of K present in the soils. Among theforms, the exchangeable and non exchangeable K play a majorrole in availability of K to plants.

Literature CitedAmiri, R. and Dordoi, M.S. (1997). Potassium forms and claymineralogy of some paddy soils in Northern Iran. J. Pot. Res., 13(1):1-11.

Anonymous (2009). Statistical Abstract of Karnataka, Directorateof Economics and Statistics, BANGALORE (KARNATAKA) INDIA.

Black, C. A. (1965). Methods of soil analysis. Part II Chemical andmicrobiological properties. American Soc. Agron., Inc. Madison,USA.

Hebsur, N.S. (1997). Studies on chemistry of potassium insugarcane soils of North Karnataka. Ph.D. Thesis, University ofAgricultural Sciences, DHARWAD, KARNATAKA (INDIA).

Hegde, D.M. and Sudhakar Babu, S.N. (2001). Nutrient mining inagroclimatic zones of Karnataka. Fert. News, 46(7) : 55-72.

Gali, S.K. (1998). Studies on potassium dynamics in rice soils ofdifferent agro climatic zones of Karnataka. Ph.D. Thesis, Universityof Agricultural Sciences, DHARWAD, KARNATAKA (INDIA).

Table 2 : Simple correlation co-efficients between selective soil properties and different K forms of surface soil samples under paddy-paddycropping sequence

Parameters WS-K (mg kg-1) Exch.-K (mg kg-1) Non Exch.-K (mg kg-1) Lattice-K (g kg-1) Total-K (g kg-1)

Coarse sand (%) 0.196* 0.012 -0.043 0.216* 0.210*

Fine sand (%) -0.239 -0.098 -0.312 -0.334 -0.337

Silt (%) -0.211 -0.279 -0.248 -0.386 -0.391

Clay (%) 0.254* 0.282* 0.463* 0.458* 0.467*

OC (g kg-1) -0.093 -0.072 -0.239 -0.346 -0.346

CaCO3 (%) 0.421* 0.170* 0.421* 0.478* 0.483*

CEC (c mol(p+) kg-1) 0.046 0.381* 0.411* 0.474* 0.482*

Simple correlation co-efficients between different K forms of surface soil samples under Paddy-Paddy cropping sequence

WS-K (mg kg-1) 1.000

Exch-K (mg kg-1) -0.124 1.000

Non Exch-K (mg kg-1) 0.159* 0.448* 1.000

Lattice-K (g kg-1) 0.316* 0.457* 0.507* 1.000

Total-K (g kg-1) 0.310* 0.480* 0.536* 0.999* 1.000n = 150* and ** indicates significance of value at P=0.05 and 0.01, respectively.

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Jackson, M.L. (1973). Soil chemical analysis. Prentice Hall (India)Pvt. Ltd., NEW DELHI (INDIA).

Kadrekar, S.B. (1976). Soils of Maharashtra State with referenceto the forms and behavior of potassium. Bull. Indian Soc. Soil Sci.,10 : 33-37.

Knudsen, D. Peterson, G.J., and Pratt, P.F. (1982). Lithium, sodiumand potassium. In: Method of soil analysis part II. Chemical andmicrobiological properties. Ed. Page, A.L., American Society ofAgronomy, Inc., Soil Science Society of America. Inc., Madison,Wiscosin, USA.

Lim, C.H. and Jackson, M.L. (1982). Dissolution for total chemicalanalysis In: Method of soil analysis part II Chemical andmicrobiological properties. Ed. Page, A.L., American Society ofAgronomy, Inc., Soil Sci. Soc. Am. Inc Madison, USA.

Mac Lean, A.J. (1961). Potassium supplying power of someCanadian soils. Canadian J. Soil Sci., 41 : 196-197.

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Patel, M.S., Patil, R.G. and Sutaria, G.S. (1986). Potassium

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Pharande, A.L. and Sonar, K.R. (1996). Depth wise distribution ofdifferent forms of potassium in important vertisol soil series ofMaharashtra. J. Indian Soc. Soil Sci., 12(2): 127-134.

Piper, C.S. (1966). Soil and plant analysis. Hans Publishers Bombay.

Ranganathan, A. and Sathynarayana, T. (1980). Studies onpotassium ststus of soils of Karnataka. J. Indian Soc. Soil Sci., 28:148-153.

Raskar, B.N. and Pharande, A.L. (1997). Different forms ofpotassium and their distribution in some important soil series ofVertisol and Alfisol of western Maharashtra. J. Pot. Res., 13(1): 21-30.

Singh, Y.P., Singh, M. and Singh, R. (1985). Forms of soil potassiumin western part of Haryana. J. Indian Soc. Soil Sci., 33 : 284-291.

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