Tips for soil and water sampling

Out line

SamplingFactors Influence SamplingErrors in SamplingTools for sampling

Why Sample?

Get information about large populations

Lower costMore accuracy of resultsHigh speed of data collectionAvailability of Population elements.Less field timeWhen it’s impossible to study the whole population

FACTORS INFLUENCE SAMPLING…….

3 factors that influence sample representative-nessSampling procedureSample sizeParticipation (response)

When might you sample the entire population?When your population is very smallWhen you have extensive resourcesWhen you don’t expect a very high response

The sample must be: representative of the population; appropriately sized (the larger the better); unbiased;random (selections occur by chance);

What is Good Sample?

Merits of SamplingSize of populationFund required for the studyFacilitiesTime

Types of Sampling

Sampling Techniques

Probability Non-Probability

Errors in Sampling

Non-Observation Errors:-Sampling error: naturally occursCoverage error: people sampled do not match the population of interest

Non-response: won’t or can’t participate

Errors of Observation

Respondent error: respondents have difficult time answering the question

Measurement error: inaccurate responses when person doesn’t understand question or poorly worded question

Errors in data collection

The top layer of the earth's surface in which plants can grow, consisting of rock and mineral particles mixed with decayed organic matter and having the capability of retaining water.

SOIL

Soil profile horizon

It is the vertical section of the soil from the ground surface downwards to where the soil meets the underlying rock.They are the layers of the different types of soil found at different depths in the soil profile.

soil sampling

Main purpose is to evaluate the fertility status of the soil

It provide a basis for fertilizer, lime and gypsum recommendation

Take sample from ,

15 cm depth- ordinary crop

25 cm depth- perennial crop

5 cm depth-pasture and Lawn

In line sown crop, take sample between the line

Soil Sampling Tools 1.Soil sampling probe (tube) A soil probe works best in well cultivated soils without rocks but is difficult to use in rocky, very dry or very wet soil,Soil probe provides a continuous soil core with minimal disturbance to the soil

2.AugerAn auger is better for less well cultivated or

rocky soils.Commonly used for obtaining disturbed soil

samples at or near the surface.

3. ShovelIf the soil texture is very coarse or there are many coarse fragments, a shovel can be used instead of a soil sampling tube or auger.

Procedure for sampling

Scrape the litter from the surface of the soilThen dig a ‘V’ shaped cut to the required

depth(15-20cm)Cut a thin slice(1 inch) from one side of the holeCollect the soil and put it in a clean bucketCollect atleast 10 samples like this

Break all bumps and mix well in the container

reduce the size of the sample by successive quartering to about 500g

Dry the sample in shade for 1-2 hours by spreading over a paper or a polythene sheet

Use polythene bags for bagging the sample

Then put it in a cloth bag

Fine a paper tag for identification

Fill the information sheet and send it along with soil sample to the soil testing laboratory

Information sheet contain following details1. Name of the person, address2. Village, district, survey number3. Wet/dry/garden land4. Area of the field5. Depth of sampling6. Processed crop or variety7. existing crop or variety8. Cropping history of the field for 3 years9. Signature of farmer

General Rules for Water Sampling

Do Not: Contaminate the bottle by touching the inside of the

bottle. Contaminate the bottle lid by touching the inside rim. Put the bottle lid on the ground while sampling. Rinse the bottle. Transport aquatic facility water samples with other

water samples, e.g. effluent or drinking water.

Always: Collect microbiological samples before

collecting other samples. Label the bottle before sampling. Discard damaged or contaminated bottles. If

in doubt throw it out and take sample in a new bottle.

Wash your hands thoroughly before and collecting samples.

Take extra care to avoid contaminating the sample container and water sample.

Sampling Bottle Labeling

Sampling Methods

There are two methods of water sampling

Static systemDynamic system

A static system is one which does not change much with time. It must be sampled so that the sample reflects all the inhomogeneity of the system

A dynamic system is one whose content changes with time. When a river or a waste effluent stream is to be characterized, its concentration will probably change over a period of minutes, days, or hours.

Important Water Analysis Equipment

Total Organic Carbon Analyzer (TOC)A total organic carbon analyzer determines the amount of carbon in a water sample. There are two types of analyzers. One uses combustion and the other chemical oxidation.

pH AnalyzerWater pH testers and analyzers help analyze pH levels and detect faults in systems with electronic pH meters.