EVALUATION OF NUTRIENT EXTRACTION ABILITY OF COMMONLY EMPLOYED PROCEDURES IN NUTRIENT SORPTION STUDIES

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1 Indian J. Agric. Res., () : -, 7 EVALUATION OF NUTRIENT EXTRACTION ABILITY OF COMMONLY EMPLOYED PROCEDURES IN NUTRIENT SORPTION STUDIES M.R. Latha and V. Murugappan Office of Dean (Agriculture), Tamil Nadu Agricultural University, Coimbatore-6 3, India ABSTRACT Nutrient sorption studies were conducted in two benchmark soils belonging to Kalathur and Irugur series by two methods, viz., Agro Services International (ASI) and conventional methods in order to quantitatively assess the variations in their nutrient extracting ability. The results indicated that the two methods differed very much in their nutrient extracting ability among soils of different characteristics and exhibited specificity with some nutrients. Thus, enough caution must be exercised while using such data of nutrient sorption studies in defining fertilizer optima in any fertilization programme for different soil types. INTRODUCTION The sorption of nutrients in soil controls their availability to plants. This is of particular interest in a rice soil because of its reduced state. Bansal and Sekhon (99) have observed differences in crop response due to differences in sorption and desorption of P in soil. Hunter (9) optimized the nutrients required for better crop growth by means of nutrient sorption and greenhouse nutrient survey studies based on the fundamental principles of missing element test. Shinde (999) and Latha and Murugappan () evolved fertilizer optima, respectively, for wheat and rice by employing the same procedure. However, these optima are specific to method of extraction of nutrients in the sorption studies and therefore, one should be cautious enough to ensure validity to the calculated optima for developing a sound fertilization programme. In the present study, an attempt was made to quantitatively assess the variations among different methods of extraction employed to extract nutrients in nutrient sorption studies for different soil types. MATERIAL AND METHODS Nutrient sorption studies were conducted in two soils belonging to Kalathur and Irugur series. The former soil constitutes one of the benchmark soils in major rice growing Cauvery delta zone and the latter in Lower Bhavani Ayacut of Tamil Nadu. The characteristics of these soils are given in Table. The soil reaction was near neutral and Electrical conductivity of the soils was within safe limits. The kalathur series soil was calcareous in nature. The nutrient levels were moderate in Kalathur series and low in Irugur series. Regarding micronutrients, both the soils were deficient in zinc.the procedure by which the sorption studies were performed in these soils is described below. Preparation of nutrient solutions for the sorption studies Solution A: 7. g of MnCl. H O,.73 g of CuCl. H O and. g of ZnCl were dissolved in separate beakers with ml of water. These three solutions were quantitatively transferred into a ml volumetric flask and the final volume was made up with distilled water. The final concentration of nutrients in this solution was mg l - of copper, mg l - of manganese and mg l - of zinc. Solution B: 3. g of KH PO was dissolved in about ml water in a ml volumetric flask. ml of solution A was added to this and volume was made up with distilled water. The final concentration of elements in solution B was mg l - of P, mg l - of Cu, mg l - of Mn, mg l - of Zn and.3 me ml - of K. Solution C:.76 g of K SO and. g of Na B O 7. H O were dissolved in ml of distilled water in a ml volumetric flask and the volume was made up to litre with distilled water. This solution contained mg l - of S and mg l - of B. Centre for Soil and Crop Management Studies, TNAU, Coimbatore-6 3, India

2 Vol., No., 7 3 TABLE : Characteristics of the experimental soils Measured value Parameter Kalathur series Irugur series Method of measurement ph Jackson (973) EC (ds m - ).66.9 Jackson (973) Organic carbon (Per cent).6.3 Walkley and Black(93) Free CaCO 3 (Per cent)..9 Piper (966) CEC C mol (p + ) kg -.. Schollenberger and Dreibelbis (93) KMnO -N (kg ha - ) 37 Subbiah and Asija (96) Olsen- P (kg ha - ).. Olsen et al. (9) NH OAc- K (kg ha - ) 3. Hanway and Heidal (9) CaCl -S (mg kg - ) 67.. Williams and Steinbergs (99) DTPA-Zn (m g kg - ) 3.3. Lindsay and Norvell (97) DTPA-Cu (m g kg - ) do - DTPA-Mn (mg kg - ) do - DTPA-Fe (mg kg - ) do - Hot water soluble B (mg kg - ).. Berger and Troug (939) Solution D: ml of solution C was added to a ml volumetric flask and the volume was made up to one liter with distilled water. This solution D contained mg l - of S and mg l - of B. Treatments for the sorption studies From each of solution B and D, five sorption treatments were made as indicated in Tables and 3. Sorption studies were conducted by two methods as described below. ASI method The Agro Services International (ASI) method was described by Hunter (9) which is briefly presented below with respect to two groups of nutrients. P, K, Cu, Mn and Zn sorption: By this method,. ml of soil (bulk density based weight of.9 g in case of Kalathur series and 3.7 g in case of Irugur series) was added to each beaker.. ml of each of the treatment solutions ( to ) prepared from solution B (Table ) was added to the corresponding numbered beakers, i.e., to in both replications. To each of the beakers numbered 6 in both replications, which constituted the check treatment,. ml of water was added. The samples were allowed to incubate under air-dry condition for 6 days. S and B sorption: S and B sorption study was conducted separately by following the same procedure adopted in P, K, Cu, Mn and Zn sorption study except that ml of soil (bulk density based weight of.9 g in the case of Kalathur series and 6. g in the case of Irugur series) instead of. ml and ml of sorption treatment solution ( to ) prepared from solution D (Table 3) instead of. ml were used. Also, to each of the beakers numbered 6 in both replications, ml of water was added which constituted the check treatment in each replication. The samples were allowed to incubate under air-dry condition for 6 days.

3 INDIAN JOURNAL OF AGRICULTURAL RESEARCH TABLE : Details of sorption treatments from solution B Sorption treatment number ml of solution B diluted to ml Concentration of nutrients in sorption treatments (mg l - ) P Cu Mn Zn K * * Concentration in me ml - TABLE 3: Details of sorption treatments from solution D Sorption treatment number ml of solution D diluted to ml Concentration of nutrients in sorption treatments (mg l - ) S B Conventional method Nutrient sorption studies were also conducted for both soils by following the conventional methods. There were sets of ml polythene beakers one each for P, K, S, B and micronutrients (Zn, Cu, Mn). For P, K and S sorption study, g of soil was weighed into each beaker. For P and K sorption, nutrient sorption treatments were imposed as specified in Table whereas for S, as given in Table 3. For B and micro nutrients (Zn, Cu, Mn) sorption study, g soil was weighed into each beaker. For B sorption study, treatments were imposed as given in Table 3 and for micronutrients (Zn, Cu, Mn) as specified in Table. The samples were allowed to incubate under air-dry condition for 6 days. Nutrient extraction and estimation from incubated samples Nutrients in the incubated samples in the respective methods were extracted and quantified as given below. ASI method P, K, Cu, Zn and Mn sorption: g of superfloc 7 was weighed into a one litre volumetric flask. ml of methanol was added to this and the volume was made up to litre with distilled water. This solution was allowed to stand for hours and stored by closing the flask. g of NaHCO 3, 3.7 g of di-sodium EDTA and.37 g of NH F were dissolved in a ml beaker and quantitatively transferred to a one litre volumetric flask. ml of superfloc 7 solution was added to this and the volume was made up to liter with distilled water. ml of the solution was added to each beaker containing the incubated sample. The contents of the beaker were stirred for minutes and filtered using Whatman No. filter paper. In this filtrate, P was determined by colorimetry, K by Flame photometry and micronutrients by atomic absorption spectrophotometry as given by Hunter (9). S and B sorption:. g of Ca (H PO ). H O was dissolved in distilled water containing one ml of concentrated HCl in a one liter volumetric flask. ml of superfloc 7 solution was added to this and the volume was made up to one liter. ml of this solution was added to each beaker containing the incubated samples. The contents of the beaker were stirred for minutes and filtered using Whatman No. filter paper. In this filtrate, S and B were estimated by turbidimetry

4 Vol., No., 7 TABLE : Results of nutrient sorption studies by ASI method in Kalathur series Amount of nutrient added (mg l - ) Amount of nutrient extracted (mg l - ) * Concentration in me ml - and colometry respectively, as specified by Hunter (9). Conventional method The extraction and quantification were done for P by employing the procedure of Olsen et al. (9), K by Hanway and Heidal (9), Zn, Cu and Mn by Lindsay and Norvell (97), S by Williams and Steinbergs (99) and B by Berger and Troug (939). Using the data of sorption studies, sorption curves were drawn for each nutrient by plotting the amount of nutrient extracted (Y axis) against the amount of nutrient added (X axis). RESULTS AND DISCUSSION The results of the nutrient sorption studies have indicated that the two methods viz., ASI and conventional, employed to extract the nutrients from the incubated samples differed very much in their nutrient extracting ability among soils and exhibited specificity with some nutrients. For example, in Kalathur series soil the amount of P extracted at all range of concentrations of added P was lesser with conventional method as compared to ASI method (Tables and ). But, in case of Irugur series soil, the extracted amounts of P at lower concentrations of added P were higher and at higher concentration it was lower with the conventional method as compared to the ASI method. (Tables 6 and 7). The ASI method contained three reagents, viz.,. N NaHCO 3,. M EDTA and. N NH F whereas in conventional method, only. M NaHCO 3 (ph.) was used. Therefore, the extracting power of the ASI method was over a wider range of P compounds as compared to conventional method of extraction (Williams and Steinbergs, 96). This fact was evidently proved in the present study where comparatively the P extracting efficiency of conventional method was lesser than that of the ASI method. Also, the phosphorus level in Irugur series soil was low. So response to added P was quite naturally higher at lower concentrations of added P. In case of K extraction both ASI and conventional methods exhibited differential behaviour in the two experimental soils (Tables -7). The amount of K extracted by conventional method in Kalathur series soil was marginally lesser, whereas in Irugur series soil this method extracted marginally higher amounts of K as compared to the ASI method at all concentrations of added K. The presence of : expanding type of clay in predominant amounts in Kalathur series soil as compared to Irugur series soil, where the dominant clay is of : type, has enabled high level of added K to move into fixed positions, which the neutral N NH OAc used with conventional method could not extract. The initial K level in Irugur series soil was less resulting in good response to the added concentrations of K.

5 6 INDIAN JOURNAL OF AGRICULTURAL RESEARCH TABLE : Results of nutrient sorption studies by conventional method in Kalathur series Amount of nutrient added (mg kg - ) Amount of nutrient extracted (mg kg - ) * Concentration in me g The two methods of extraction also showed variations in their efficiency of extraction of Zn, Cu and Mn. Mostly the conventional method extracted lesser amounts of these micronutrients in both soils as compared to ASI method throughout the range of their added levels (Tables -7). One exception to this observation was the extraction of Mn in Kalathur series soil where the conventional method extracted higher amounts of Mn as compared to the ASI method. The theoretical basis considered by Lindsay and Norvell (97) for choosing. M DTPA, which was used in the conventional method in the present study, was that it offered the most favourable combination of stability constants for the simultaneous complexing of Mn, Zn and Cu. Therefore, the results obtained with conventional method in the simultaneous extraction of Zn, Cu and Mn would be more valid as compared to those with ASI method which used. M EDTA as a component in the extracting solution to complex these micronutrients. With respect to S and B extraction, mono-calcium phosphate [Ca (H PO ) ] was the extractant in the ASI method to extract both of them, whereas in case of conventional method.% CaCl was used to extract S and hot water to extract B. These reagents also differed in their extracting efficiency (Tables -7). For example, in case of S extraction,.% CaCl used in the conventional method extracted higher amount of S in Kalathur series soil and this was also found true at higher concentration of added S in case of Irugur series soil. Contrary to this, Williams and Steinbergs (96) had found that mono-calcium phosphate, which was used in the ASI method in the present study, extracted more SO - -S from soils as compared to that of CaCl. The amount of B extracted by hot water in the conventional method was lower at low concentrations in Kalathur series soil and at all the range of concentrations of added B in Irugur series soil as compared to the ASI method in which mono-calcium phosphate was used for extracting B. Thus, the results of the present study indicate that the two methods differ very much in their nutrient extracting ability among soils of different characteristics and exhibit specificity with some nutrients. Thus, enough caution must be exercised while using such data of nutrient sorption studies in defining fertilizer optima in any fertilization programme for different soil types.

6 Vol., No., 7 7 TABLE 6: Results of nutrient sorption studies by ASI method in Irugur series Amount of nutrient added (mg l - ) Amount of nutrient extracted (mg l - ) * Concentration in me ml - TABLE 7: Results of nutrient sorption studies by conventional method in Irugur series Amount of nutrient added (mg kg - ) Amount of nutrient extracted (mg kg - ) * Concentration in me g - ACKNOWLEDGEMENT The authors wish to acknowledge the financial support provided by the Potash Phosphate Institute of Canada - India Programme (PPIC-IP) for the investigation. REFERENCES Bansal, S.K. and Sekhon, G.S. (99). Fertil. News. 39(9): 3-7. Berger, K. C., and Troug, E. (939). Ind. Eng. Chem. Anal. Ed. : -. Hanway, J.J. and Heidal, H. (9). IOWA State College Agric. Bull., 7. pp.-3. Hunter, A.H. (9). Laberatory and Green house Techniques for Nutrent Survey Studis to determine the Soil amendments required for optimum plant growth Agro Services International Inc., Orange city, Florida, USA. Hunter, A.H. (9). ASI Soil Analysis Methods for P,Kcu, Mn, Zn, B, S Using ASI Extracting Solution. Agro Services International Inc., Orange City, Florida, and USA. Jackson, M.L. (973). Soil Chemical Analysis. Prentice Hall of India Private Limited, New Delhi. Latha, M.R. and V. Murugappan. (). Madras Agric. J., (-6): 9-9. Lindsay, W.L., and Norvell, W. A. (97). Soil Sci. Soc. Am. J., : -.

7 INDIAN JOURNAL OF AGRICULTURAL RESEARCH Olsen, S.R., et. al. (9). U.S.D.A Circ., 939. U.S.Govt. Printing Office, Washington DC. Piper, C.S. (966). Soil and Plant Analysis, Hans Publishers, Bombay. Schollenberger, C. J. and Dreibelbis, F. R. (93). Soil Sci., 3: Shinde, P.B. (999). Proceedings of Meeting of Scientists Involved in PPIC Sponsored Project held at New Delhi, June -, 999. Subbiah, B.V. and Asija, G.L. (96). Curr. Sci., : 9-6. Walkley, A. and Black, C.A. (93). Soil Sci., 37: 93-. Williams, C. H. and Steinbergs, A. (96). Pl. Soil. : -6. Williams, C.H. and Steinbergs, A. (99).Aust. J. Agric. Res., : 3-3.

Stoichiometry ( ) ( )

Stoichiometry ( ) ( ) Stoichiometry Outline 1. Molar Calculations 2. Limiting Reactants 3. Empirical and Molecular Formula Calculations Review 1. Molar Calculations ( ) ( ) ( ) 6.02 x 10 23 particles (atoms or molecules) /