Agriculture & soil science.

Aim - Determination of chloride from irrigation water simple.  Principle - Mohr's titration method (argentrometric) is most commonly used for chlorides determination.  It Depend upon formation of sparingly soluble greek silver chromate (AgcrO4) precipitated at the end point.  When sample is titrated against the standard Silver Nitrate (AgNo3) solution in presence of potassium chromate (k2crO4) as colour indicator. Reagents - 1) potassium chromate indicator 5% solution - Dissolved 5gm potassium chromate in about 75 distilled water and add saturated solution of silver nitrate. Dropwise until a slite permanent red precipitated is formed. Filter and dilute 100ml with distilled water . 2) standard silver nitrate (0.02 normality AgNo3) - Dissolved 3.40 gram silver nitrate in distilled water and volume made up to 1 litre and stored in Amber colour bottle away from light.  Procedure - Take 10 ml of water sample in hundred ml conical flask and dilute to 25 ml with distil...

Aim -  Determination of carbonates and bicarbonates from irrigation water sample.  In irrigation water important ions namely chloride, sulphates, nitrates, carbonates and bicarbonates are present . some of the carbonates and bicarbonates ions constituted the total alkalinity of water. Principle - The Carbonate  and Bicarbonate ions in the sample can be determined by titrating it against standard sulphuric acid using phenolphthalein and methyl orange indicator respectively . addition of phenolphthalein gives pink red colour in presence of carbonates and titration with H2So4 converts this carbonates into bicarbonates and decolourise the pink red colour of the solution.  In colourless solution methyl orange is added with gives yellow colour to the solution further titration against H2 s o4 neutralization of all bicarbonates and colour of solution changes from yellow to red orange.  Reagents - 1 ) standard sulphuric acid (0.01 normality) -  Take 0.28 ml H2 s o...

Title. - Determination of PH and electrical conductivity from irrigation water sample Determination of PH.- The pH value is the negative normal logarithmic of the hydrogen ion activity.  As a result of presence of strong bases increase PH value and presence of strong acid cause decrease in pH value.  The pH value of neutral water usually lie between 6.5 to 7.5 . lower value of PH results of free carbonates #decalcification in surface water can increase PH value upto 9.5  Apparatus .  -  PH metre with glass calomel electrode assembly. Regent. Buffer solution of PH 4, 7, 9.2 Procedure.- Take 50 ml water sample in hundred ml beaker . Determine pH of water. Before measurement of pH of sample standardise the pH metre using standard buffer solution.   Result -------  PH ratings - <6.5.              Acidic  6.5 to 7.5.     Neutral  >7.5.              Basic /al...

 Common sampling tools and accessories  Clean Plastic or glass bottle of 500 ml capacity . cotton or nylon thread . water table recorder. Glass marking pencil . labels and tags Sample collection procedure. The container must be thoroughly clean before the use. Bottle  should be rinsed 3 to 4 time with water from which the sample is drawn . care should be taken to collect sample only after continuous discharge of the source for 10 to 20 minute . if the source of irrigation water is tank channel or river  the sample should be drawn either away from the sides or from the mid stream.  the tubewell and hand pump are to be Run for about 10 to 20 minut prior to the sampling and for open well several buckets of water have to be thrown out first . About half litre of the sample is quite sufficient.  the water sample after labelling must be send laboratory immediately for testing in order to avoid any change or deterioration in its quality due to the chemical microbi...

TITLE  - Determination of available boron in given soil. Method - 1) Azomethine H 2) Hot water extraction method. Scientists - burger and truog (1939)  Reagents - Azomethine H - Dissolved 0.45 gram Azomethine H and one gram ascorbic acid in hundred ml distilled water Buffer solutions - Dissolved  250 gram ammonium acetate and 15 gram EDTA (disodium salt) in 400ml distilled water then add 125/8 Glacial acetic acid slowly. Calcium carbonate solutions - 0.01 M Dissolved 1.11 gram calcium chloride in 900ml distilled water and make the volume of one litre.                                                                                                  PROCEDURE - Extraction   - take 20 grams soil sample in conical f...

 TITLE  -  Determination of available Phosphorus in soil.   Method  -  Acid soil - Bray's method.  Alkaline soil - olsen method.  Regents .- 1) 0.5 ml NaHco3 (PH = 8.5 ) - Dissolved 21 gram sodium bicarbonate in 450 ml water adjust the pH 8.5 and make up the volume up to 500 ml . 2) Activated charcoal  3) solution 'A' - a) Dissolved 12 gram ammonium molybdate in 250 - 300 ml distilled water . b ) Dissolved 0.291 gram antimony potassium tartrate in 100 ml distilled water.  c) 5 normality - H2 s o4  Dissolved 140 ML concentrated H2 S o4 in 1000 ml water  . Solution 'A'- Add cool ammonium molybate in normal H2 s o4 solution followed by cool antimony potassium tartrate and volume is made up upto 2 litre  . Solution 'B'- Dissolve 1.056 gram ascorbic acid in 200 ml of solution 'A'. solution B should be prepared fresh.  0.25% - 2.4 paranitrophenol. -  Dissolved 0.25 gram 2.4 para-nitrophenol in hundred gram distilled wa...

TITLE - Detemination of available potassium from soil.  REAGENTS  -  1) Neutral ammonium acetate - Dissolved 77.1 gram ammonium acetate 900 ml water & adjust the pH to 7 by Acetic Acid or Ammonium hydroxide dilute to 1 litre. 2) preparation of standad solution.- Dissolved 1.908 gram KCL in distal water. And makeup the final volume one litre. this solution called as stock solution. 3)  Preparation working solution. - Take 10 ml solution from stock solution and makeup volume 100 ml. 4) Preparation of standard series - Prepare 0 2 4 6 8 10 ml of working solution **** PROCEDURES  - 1) Take 5 gram of soil in conical flask. 2) Add 25 ml of neutral normal            ammonium acetate.  3) Shake for 5 minut. 4) Filter the content.  5) Take reading on flame photometer. GRAPH FACTOR Graph factor reading            Flame Concentration.                  ...

TITLE  - Determination of available nitrogen  in the soil. METHOD - Alkaline permagnate. Scientists : Subbiah and asijo 1956. Principle - the organic matter in the soil is oxidized by Kmno4 in presence of NaoH. The ammonia released during oxidation is absorbed in boric acid to convert the ammonia to ammonia borate. The ammonia borate formed is titrated with standard H2So4 from the volume of standard H2So4 required for reaction with ammonium borate.The Nitrogen is calculated.   REAGENTS   -  1) Potassium   permagnate Kmno4 (0.32%).- Dissolve 3.2 gram potassium permagnet in one litre of distilled water with the intermittent shaking till it completely dissolved. store in umbrella colour bottle and keep it in the dark.  2)Sodium hydroxide solution NaoH (2.5%)- Dissolve 25gm of pure sodium hydroxide in 1 litre of distilled water. 3) Boric acid H3Bo3 (2%)  Dissolve 20 gram of boric acid AR grade in 800ml distil water by heating to content cool...

TITLE :- Determination of organic carbon in soil by walkley & black method.  Principle -   The organic carbon in organic matter is oxidised by known excess of chromic acid .(K2 cr2 O7 + H2 s o4). The excess acid chromic acid not reduced by organic matter is determined by Black titration which standard feso4 solution (redox titration) using ferroin indicator. the organic in soil calculated from the chromic acid utilised (reduced by it) Reagent  Potassium dichromate solutions,  Dissolve 49.04gm of dried reagents grade potassium dichromate, K2cr2O7 in distilled water & dilute it to one liter.  Ferrous sulphate solutions 0.5N Dissolve 139gm of reagent grade ferrous sulphate feso4. 7H2o in distilled  water and add 15ml of concentrated H2so4 cool and dilute to one litters or dissolve 196.19gm ferrous  ammonium sulphate feso4(NH4)so4.6H2o and making up-to one litters standardized the solution against potassium add 20 ml concentrated H2so4, before...

TITLE-  DETERMINATION OF CALCIUM CARBONATE (Caco3) of soil.  Principle  The soil is titrate  with known extended of standards hydrochloric acid to neutralize all carbonate and excess Hcl acid is back titrate with NaoH using phenolphthalein indicator . The calcium carbonate equivalent is calculate by the volume of standard Hcl required for neutralization. RAPID TITRATION METHOD -  REAGENT  0.5 N Hcl :dissolve 44.5ml Hcl in 1L of water.  0.25 N NaoH:dissolved 10gm NaoH in 1 L of water.  Phenolphthalein indicator.  PROCEDURE  Take 5gm soil in 250 ml conical flask.  Add 100 ml 0.5 N Hcl. Stir & keep for 1 hours.  Allow it to settle  & filter.  Take 10 ml filtrate into another conical flask.  Add 3 to 5 drops of phenolphthalein Indicators.  Titrate it against of 0.25 N NaoH still the color changes to pink. (A) note reading.  Run the blank. (B) note reading.  OBSERVATION  B - blank sample re...

TITLE DETERMINATION OF ELECTRICAL CONDUCTIVITY OF SOIL. Summary Equipments of soil EC Reagents  Procedure Result Equipment  Electrical conductivity meter.  Reagent - Potassium chloride, kcl- 0.001N Dissolve 0.7456gm kcl in distilled water and add water and make up volume to 1L at 25 degrees Celsius. It has an electrical conductivity of 1.412ms cm^-1 or dsm^-1. Procedure  Take 20 GM of soil sample in beaker.  Add 50ml of distilled water.  Stir for 15 minutes . Stand for half hour.  take the reading. Results -  Reading Is electrical conductivity of soil sample. Unit of E. C. Is dsm-¹.

TITLE - Determination of PH of soil DEFINITION -  PH is defined a minus the decimal logarithmic of the hydrogen ion activity is a solution by virtue of its logarithmic nature.  PH is dimensions less quantity.  EQUIPMENTS FOR SOIL PH-  PH meter -  It consist of two electrodes.  A)  - glass electrodes  and B)  - calomel electrodes (reference      electrodes)  REAGENTS -   1) Standard buffer solutions PH 4.00- Prepare stock solutions of 0.3m potassium hydrogen phthalate by dissolving 15.3gm of the analytical grade salt in about 225ml of hot water. cooling the solution and diluting at 250ml. Add Drop of **** to discharge growth  of micro organisms. For standard buffer pH 4.0 mix 100ml of the stock solutions with 500ml water.  Prepare the fresh solutions every week 2) Standard buffer solutions PH 9.2- Dissolve 3.81gm sodium tetraborate(AR) in water and dilute to 1000ml.  3) 1 N potassium chloride solutions (...

Sampling Equipments-   Spade, screw auger (depth wise) or post-hole auger (for moist soil), khudali (pick axe), khurpi, trowel, steel spatula clean plastic bucket, plastic container, cloth bag, information sheet, scale for measuring pit depth marking pencil.  How to collect the soil sample  Remove or scrap the upper portion  or surface of the soil and remove the crop residues and litters which is on the soil surface. Take pick axe (khudali) and spad with spatula and dig out near about 15-20 cm deep soil width khudali or picking axe. The shape should be V shaped. Remove and reject first digged surface soil. Then collect the soil in the plastic paper or container from selected spots in the field.  Mix all the soil which is taken from different spots in the plastic paper or container.  Avoid soil sampling where  fertilizer and manure applied recently. After mixing the soil sample divide it in four part. Then reject two part form quarter and  take rem...