MATERIAL AND METHODS. The present investigation entitled Integrated Nutrient Management Studies on

Transcription

1 Chapter-III MATERIAL AND METHODS The present investigation entitled Integrated Nutrient Management Studies on Yield and Quality of Turmeric (Curcuma longa L.) in an Acid Alfisol was conducted in Department of Soil Science, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya, Palampur, Himachal Pradesh (India). The description of methodology followed and the material used in this study is documented under the following heads: 3.1 Experimental site 3.2 Experimental details 3.3 Field observations 3.4 Laboratory studies 3.5 Statistical analysis 3.6 Economic analysis 3.1 Experimental site The experimental farm of Department of Soil Science, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur is located at 32 6 N Latitude and E Longitude at an elevation of 1290 meters above Mean Sea Level. The area comes under high rainfall mid-hill wet temperate zone Climate and weather conditions The region is characterized by wet- temperate climate with severe winter and mild summer with annual temperature ranging from around C in December to C during May and June. The place receives annual rainfall in the range of mm, with an average value of 2500 mm of which 80 per cent is received during

2 the period of June to September. The mean humidity varies from per cent, minimum being in April and maximum in rainy season i.e. July and August (Fig. 3.1 and 3.2) Soils The soils of experimental area fall in the subgroup of Typic Hapludalf (Verma, 1979). These soils owe their origin to parent material such as slates, phyllites, quartzite, schists and gneiss. The soils are acidic in reaction, medium in organic carbon, and low to medium in available phosphorus. These soils have high P-fixing capacity and are rich in active forms of aluminium and iron. Some of the important physical, chemical and physico-chemical properties of the soil under the study at the initiation of the experiment are given in Table 3.2. Table 3.1 Basic physical, chemical and physico-chemical properties of the experimental soil Soil property Average value Mechanical composition Sand (%) 27.4 Silt (%) 41.6 Clay (%) 30.1 Textural class Silty clay loam ph 5.6 Organic carbon (g kg -1 ) 11.8 Available N (kg ha -1) 264 Contd Available P (kg ha -1 ) 16

3 Available K (kg ha -1 ) 204 Available S (kg ha -1 ) 12 CEC [cmol (p + ) kg -1 ] 9.5 Exchangeable acidity [cmol (p + ) kg -1 ] 0.28 ph dependent acidity [cmol (p + ) kg -1 ] 6.74 Total acidity [cmol (p + ) kg -1 ] 6.80 Forms of Aluminium (mg kg -1 ) a) Exchangeable 12.4 b) Extractable 54 c) Amorphous 438 d) Crystalline 1459 e) Total Forms of Iron (mg kg -1 ) a) Exchangeable 22.0 b) Extractable 63.0 c) Amorphous 2150 d) Crystalline 1759 e) Total Experimental details The field experiments were conducted during Kharif 2004 and Kharif 2005 at the experimental farm of Department of Soil Science, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur. The experiment was laid out in randomized block design

4 (RBD) with eleven treatments, each replicated three times with a plot size of 5 m 2. The layout of the experiment is shown in Fig Treatments Serial No. The treatment detail for the experiment on turmeric (variety T-12) is given below: Treatment T 1 T 2 Control 20 t FYM ha -1 (soil incorporation)* T 3 20 t FYM ha -1 (soil mulch) ** T 4 T 5 100% NPK 100% NPKS T 6 100% NPKS+ 10 t FYM ha -1 * T 7 100% NPKS+ 15 t FYM ha -1 * T 8 100% NPKS+ 20 t FYM ha -1 * T 9 100% NPKS+ 10 t FYM ha -1 ** T % NPKS+ 15 t FYM ha -1 ** T % NPKS+ 20 t FYM ha -1 ** * Soil incorporation (applied at the time of field preparation). ** Soil mulch (applied on the plot surface at the time of sowing and incorporated into soil at the time of first earthing up operation) Sources of fertilizer Urea 46 % N Di-ammonium phosphate 18% N and 46 % P 2 O 5 Muriate of Potash (MOP) Single Super Phosphate (SSP) Elemental Sulphur 60 % K 2 O 16 % P 2 O 5 and 12 % S 85 % S FYM compositions

5 (Moisture = 70 %, N = 0.56 %, P = 0.22 %, K = 0.50 % and S = 0.30 %) Recomended fertilizer doses (100 % NPKS) N 30 kg ha -1 P 2 O 5 30 kg ha -1 K 2 O 60 kg ha -1 S 30 kg ha -1 The first crop of turmeric was taken during kharif Before sowing of the crop, field layout and preparation was done. The turmeric variety T-12 was sown on 27 th May 2004 with a seed rate of 20 q ha -1 and spacing of 30 cm x 20 cm. One-third of nitrogen along with full doses of P 2 O 5, K 2 O and S were applied at the time of sowing. Remaining two-third of N was applied equally in two splits at an interval of one month. All other agronomic practices like weeding (manual), earthing up etc. were followed during the crop growth. The crop was harvested on 2 nd December, 2004 (Plate 3.1). Similarly, during second year (2005), turmeric crop was sown on 2 nd June and harvested on 5 th December. Soil and crop management were same as practiced during the first year. 3.3 Field Observations Germination percentage was recorded 45 to 50 days at sowing by counting the total germinated plants per plot in comparison to number of rhizomes sown. The plant height was also recorded at the time of maximum growth (last week of October). Data like plant height was taken from ground level to tip of top most leaf. Number of fingers per rhizome per plant were calculated by average 5 plant per plot, number of

6 rhizomes per plant and rhizome yield were recorded at the time of harvesting of the crop Soil sampling Initial soil sampling Composite soil samples ( m depth) were collected before initiation of the experiments and plot wise at the harvest of the crop in each year. The initial soil samples were analyzed for different physical, chemical and physio-chemical properties listed in the table 3.2. The plot wise soil samples at the harvest were processed and kept for analytic work. 3.4 Laboratory studies Preparation and analysis of soil samples All the soil samples collected were air-dried, ground, passed through 2 mm sieve and finally stored in polythene bags for further analytical work. The methods used for analysis are given in (Table 3.2, 3.3 and 3.4). Table 3.2: Methods used for determination of different soil properties

7 S. No. Soil Property Method Followed 1 Mechanical analysis International Pipette Method (Piper, 1966) 2 ph (1:2.5 soil water ratio) (Jackson, 1967) 3 Organic Carbon Rapid Titration Method (Walkley and Black, 1934) 4 Available Nitrogen Alkaline Permanganate Method (Subbiah and Asija, 1956) 5 Available Phosphorus 0.5 M NaHCO 3, ph 8.5 (Olsen et al., 1954) 6 Available Potassium Neutral Normal Ammonium Acetate Method (Black, 1965) 7 Available Sulphur 0.15 per cent CaCl 2 extractable S Method (Williams and Steinbergs, 1959) Table 3.3: Methods used for determination of different forms of acidities S. No. Determination Method Followed 1 Exchangeable acidity: Soil was leached with 1N unbuffered KCl solution and leachate was titrated with 0.01 N NaOH using phenolphthalein indicator 2 ph dependent/ non-exchangeable acidity: 1N KCl pre-leached soil was extracted with BaCl 2 -TEA (ph 8.2) and the extract was titrated with 0.2 N HCl using mixed indicator 3 Total Acidity: Soil extracted by BaCl 2 - TEA (ph 8.2) and extract was titrated with 0.2 N HCl using mixed indicator Determination of different forms of Al and Fe Yuan s Method (1959) and improved by Amedee and Peech (1962) Coleman et al. (1959) Mehlich s Method (1948) and improved by Peech et al. (1962) The detailed procedure as proposed by Ballard and Fiskell (1974) for the determination of different forms of Al and Fe is described as under: Table 3.4: Methodology for determination of different forms of Al and Fe

8 S. No. Extractant ph Soil solution ratio Shaking time Forms of Al and Fe 1 1 N KCl 7.0 1:10 1 hour Exchangeable Al 2 1 N NH 4 OAc 4.8 1:5 30 minutes Exchangeable Al and Fe M Ammonium Oxalate 4 Citrate Dithionite Bi-carbonate 5 Conc. HCl (11.3 N) Pre-treatments of extracts 3.2 1:50 1 hour (in dark) 8.2 1:50 Kept for 15 minutes on water bath at 80 C - 1:125 4 hours reflux on hot plate Amorphous and extractable Al and Fe Amorphous and Crystalline Al and Fe Total Al and Fe A pre-treatment of 10 ml mixture of HNO 3 : H 2 SO 4 (10:3) was given to a known amount of citrate-dithionite-bicarbonate extract in silica crucible. The crucibles were kept on a sand bath until the residue attained brownish colour. Later, the residue in the silica crucibles was kept in the muffle furnace at 550 C to get rid of citrate dithionite, which interferes during the determination of Al. The oxalate extract was treated with 5 ml of HNO 3 and 2 ml of HClO 4 acid and were digested on hot sand bath till the residue attained white colour, so as to remove the interference of oxalate during the determinations of Al and Fe. Determination After the pretreatments to citrate dithionite- bicarbonate and oxalate extracts, a known amount of each was taken in 0.5 N HCl and volume was made to 50 ml. Aluminium was determined by the method of aluminon as proposed by Herwitz (1975), whereas iron was determined in atomic absorption spectrophotometer.

9 Computation of different forms of Al and Fe Different forms of Al and Fe were calculated as described below: Amorphous Al Crystalline Al Amorphous Fe Crystalline Fe = Oxalate Al - KCl Al = Citrate-dithionite-bicarbonate-Al - Oxalate Al = Oxalate Fe - 1 N NH 4 OAc Fe = Citrate-dithionite-bicarbonate Fe - Oxalate Fe Plant sample preparation and analysis Plant samples collected at the harvest of crop were dried in oven at 60 0 C for 3-4 days, ground and stored for further analysis. a) Total nitrogen content Leaf/ straw as well as rhizome samples were digested with concentrated H 2 SO 4 using digestion mixture and total nitrogen was determined by Micro- Kjeldahl s method (Jackson, 1967). b) Total phosphorus content Both the leaf and rhizome samples were digested with di-acid mixture of HNO 3 and HClO 4 acid (4:1 ratio) and extract was made to a definite volume. Total phosphorus content was determined by vando-molybdate phosphoric yellow colour method at 430 nm wavelength (Jackson, 1967). c) Total potassium content The extract obtained by digestion with di-acid mixture was determined by flame photometer (Chapman and Brown, 1950). d) Total sulphur content

10 The extract obtained by digestion with di-acid mixture was used for sulphur determination by turbidimetric method at 340 nm wavelength (Chesin and Yien, 1950). e) Nutrients uptake The concentration of nitrogen, phosphorus, potassium and sulphur were determined in rhizome and straw (leaf) and uptake was calculated as follows: Uptake (kg ha -1 ) = concentration of nutrient (%) x yield of crop (q ha -1 ) f) Curcumin content in rhizomes Finely ground turmeric powder samples (1 g) were extracted by refluxing over a water-cooled condenser with 100 ml of distilled alcohol (methanol) for 2 ½ hours. The extract was transferred to a 100 ml volumetric flask and volume was made to 100 ml with alcohol (methanol). It was then filtered and an aliquot of 2 ml was transferred to a 25 ml volumetric flask and made to 25 ml volume, mixed well and the absorbance of this solution was measured at 425 nm wavelength against blank made of alcohol. Preparation of standard curve Primary curcumin standard (1000 ppm): 100 mg curcumin was dissolved in some amount of methanol, mixed well and the final volume was made to 100 ml. Secondary curcumin standard: For preparing 25 ppm curcumin standard, 2.5 ml of 1000 ppm (primary standard) was diluted to 100 ml. Then 0.5, 1, 2, 2.5, 3, 4 and 5 ppm curcumin solutions were also prepared. A standard curve was prepared

11 by taking graded amounts of standard curcumin solution including blank (methanol). The concentration was plotted on X-axis and readings on Y-axis. Curcumin concentration was calculated from the standard curve as follows: Reading from standard curve = y ppm Curcumin content (% by weight) = X X The above procedure was given by Manjunath et al. (1991). g) Starch content in rhizomes Turmeric powder sample (0.5 g) was added in hot 80 per cent ethanol to remove sugars, centrifuged and the residue was retained. The residue was then washed repeatedly with hot 80 per cent ethanol until the washings did not give colour with anthrone reagent. The residue was dried well over a water bath. Then 5 ml of water and 6.5 ml of 52 per cent perchloric acid were added to the residue and extracted at 0 0 C for 20 minutes. Again centrifugation was done and the supernatant was saved. The extraction was repeated using fresh perchloric acid and then centrifuged. The supernatant was cooled and volume made to 100 ml. thereafter, the supernatant was pipetted out (0.1 or 0.2 ml) and the volume was made up to 1 ml with distilled water. Primary standard of glucose (1000 ppm): 100 mg glucose was dissolved in 100 ml water. Working standard of glucose: 10 ml of primary standard was diluted to 100 ml with distilled water. The standard was prepared by taking 0.2, 0.4, 0.6, 0.8 and 1.0

12 ml of working standards and the volume was made to 1 ml in test tube with distilled water. To each tube of sample and standard, 4 ml of anthrone reagent was added, then heated for 8 minutes in a boiling water bath and cooled rapidly. The intensity of green colour was read at 630 nm wavelength. Calculation The glucose content in sample was determined using standard graph and multiply the value by factor 0.9 to arrive at the starch content. The above method was given by Sadasiram and Manickam (1996). h) Curing percentage Mother and finger rhizomes were cured after harvesting. The curing process consisted of boiling the rhizomes in water until frothing occurred with emission of characteristic odour and fingers becoming soft. The cured material was sun-dried for days until the rhizomes produced metallic sound. The curing percentage was calculated as below: Cured turmeric yield Curing percentage = X 100 Raw turmeric yield i) Essential oil content The essential oil content from rhizome was extracted by water distillation with the help of Coking and Middleton apparatus using petroleum ether. j) Protein content in rhizomes

13 Protein content in rhizomes was estimated by multiplying the nitrogen content with 6.25 factor. 3.5 Statistical analysis The data generated from field and laboratory analysis were statistically analyzed using technique of analysis of variance for randomized block design for the interpretation of results as described by Gomez and Gomez (1984). Simple correlations were worked out between yield nutrients status in the soil with quality, different forms of acidity with different forms of aluminium, iron and yield with different nutrients status in soil. 3.6 Economic Analysis a) Net returns = Total value of produce Total value of the inputs used b) Benefit cost ratio (B: C) was calculated as: B: C ratio = Gross returns Total expenditure 1) Fertilizer price (Rs kg -1 ) = FYM N P 2 O 5 K 2 O S ) Turmeric price (Rs kg -1 ) = 7.0