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LIBRANZA, Alexander Ken

2 BS ABE

July 7, 2012

CRSC 10

SOIL SAMPLING and ANALYSIS

SOIL SAMPLING is the process of taking a representative/sample from the field toidentify the area in question. Soils are sampled to determine physical conditions, fertility

(nutrient) status, and chemical properties that affect their suitability as plant growing media.Through a combination of field and greenhouse research, analytical methods have been

developed which provide quantitative estimates of plant-available nutrients. Field research

determines the optimum soil test levels for various nutrients for specific soil and crop

combinations. Optimum fertilizer practices can be determined by knowing the optimum test levelof each nutrient for a specific crop and soil, and by knowing how much fertilizer is required to

change soil test values.

Soil testing is comprised of four steps: (1) Collection of a representative soil sample, (2)

 Laboratory analyses of the soil sample, (3) Interpretation of analytical results, and, (4)

 Management recommendations based on interpreted analytical results.

The first and most critical step in soil testing is collecting a soil sample. A soil analysis

can only be as good as the sample sent to the laboratory. Therefore, it is vital that the soil samplebe representative of the entire field.

Two layers of the soils are analyzed: the top soils and the subsoil. Top soil refers to the top layer

of soil that has a mix of vegetative matter and soil in it. It is usually a darker color than thedeeper subsoil because of its higher organic content. Because of this relative organic richness, it

is generally easier to handle than subsoil. It cultivates better, is less sticky or likely to cake.

Subsoil is usually lighter in color, stickier, less fertile and more difficult to handle. Generally, thetop soil is darker because of the amount of decomposed plant matter in it - and the subsoil is

lighter because it is mostly the mineral content: silt, clay, and sand.

In the process, we are first introduced to the Do’s and Don’ts of soil sampling.

   No soil samples from road cuts/ road sides/ landfills

   A difference in soil topography is very important. (Soil sample from sloping areais different from the soil sample on the flat area)

  Visual observation on the area. (Through physical appearance of the plants –  

color of leaves, size of the stems, fruit-bearing – we could easily identify nutrientlosses and absent on that certain area in question.)

   Hidden hunger of the plants (Some plants may appear healthy, but through

research and observation, we could easily identify the actual condition of the

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plant) – this would also help identify the maximum potential of the plant to

provide to the farmer.

  Optimum condition of the soil  –  not too wet and not too dry

   In case of rain, Soil samples should be collected at least 3 days after the rain. 

  SMOKING is highly discouraged while taking soil sample since it can affect/ 

alter the chemical properties of the plants.  Testers are required to wear cloves to prevent alteration of the soil properties

because of the chemicals that are present in their hands.  

Using a soil auger, we take soil samples from the field. First is that we have to remove all

vegetation from the area in question. In the process, you need to dig 0-6 inches to get a sampleof the topsoil, and 6-12 inches for the subsoil. Twenty holes are the minimum number of 

sampling sites to cover the whole hectare, however,  the more samples we collect,  the more

efficient our sample will become. Holes/ sampling sites are made in zigzag or W- pattern to

efficiently represent our area. From those holes, we collect soil samples and place them in cleanplastic bags or any clean container free from chemicals that might damage our sample.

Soil samples are commonly at least a kilo  –  500 grams of topsoil and 500 grams of subsoil. These samples are collected randomly from the different holes made. Samples from

different holes are collected and mixed to create one composite soil sample. Then, the collected

sample is taken to the laboratory to be  air dried  in  room temperature. Air drying is done byscattered properly in a week or more depending on the need of the soil. Then, the sample will besieved. Half of the sample will be sent to the laboratories for analysis and the other half will be

kept for future purposes or failure in the first sample.

SOIL SAMPLING can be done annually but the most common soil sampling is done

every 3-5 years because this is the span of time that changes in the soil properties occur. Also, in

doing soil sampling, we do not only look at the physical and chemical properties of the soil, wealso take into account the history of the area  – What were the plants planted there? Was there ashift of crops? Are there any animals inhabiting the area? - These information will give us

historical evidence of the area in question.

To prevent failure we need to observe the Dos and  Don’ts of soil sampling that are stated

above. Alterations, changes and failure sample are most commonly due to errors done before,

during, and after the process. A vigilant mind is needed on the whole span of the activity.

______________________________

  http://wiki.answers.com/Q/What_are_the_differences_between_top_soil_and_sub_soil#ixzz1zvat02bF 

  Soil Sampling and Analysis,  J.L. Walworth, University of Arizona,  College of Agriculture and Life Sciences, “AZ142.pdf ” 

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LEAF SAMPLING and ANALYSIS

After examining what the soil has to offer to our plant, we now precede on what

 nutrients have the plant been taking from the soil or what the soil has been providing to the

plant for its growth and development.

Leaf analysis provides information about the nutritional status of a crop and can be used

to identify nutrient imbalances, deficiencies and toxicities. In applying fertilizers, the bestmethod of determining the kind and amount of fertilizer to apply to fruit trees is by leaf analyses.

It effectively measures macro and micronutrients and indicates the need for changes in fertilizer

programs. Leaf analyses integrate all the factors that might influence nutrient availability anduptake. It shows the balance between nutrients.

We start the sampling by identifying the different leaf number  – such as:

   Leaf #9  – the leaf holding the spith (bungol), biggest inflorescence

   Leaf #14  – leaf holding the fist-sized coconut

   Leaf #19  – leaf holding the adult coconut (butong)

Secondly, we identify/ learned that coconuts have handedness. Facing the coconut, the

direction where the leaf number 14 is pointing, is the handedness of the coconut. The specificcoconut that we observed is Left-handed .

Sample leaflets are taken from the  Leaf #14 since it has the  optimum level of leaf  nutrients which is neither too old or too young. We gather a minimum of  five leaflets from the

middle of the leaf #14. Then those leaflets would be detached from the stick (removing them

from its midrib), and then again cut and will only make use of the middle of the leaflet. The

sample should be composed of 5 leaflets randomly taken from 20 trees in the area in question.

The collection would then make up one composite leaf sample.

The appropriate time for leaf sampling in the day is  between 9am to 2pm. In case of rain, leaf samples should be collected at least 3 days after the rain. In collecting leaf samples, we

should always keep it safe from chemicals that might damage our sample. In cleaning the leaf,

we need to use  tap distilled water to prevent chemical alteration, and changes due totemperature.

When we collected enough leaf samples, we send the leaf samples to the laboratory tobe oven dried at 80°C for 24 hours.

When the samples are ready, we then label it with the following:  sample code,  areawhere it is taken,  treatments used , leaf rank,  other relative information needed , and who prepared the sample.

_______________________

  http://cottassist.cottoncrc.org.au/NutriLOGIC/  

   LEAF SAMPLING & ANALYSES, Duncan Weir1 Ian Rochester, Agri-scienceQueensland, CSIRO. 2009, “  Leaf_Sand_A2_pg2011.pdf ”  

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QUESTIONS TO PONDER:

1.  What is meant by essential elements?

Essential elements are those numbers of mineral nutrients that are absolutely essential to

plant life. They are essential because a plant deprived of any“one

”of these elements wouldcease to exist. Plants will use essential elements only in proportion to each other, and the

element that is in shortest supply — in proportion to the rest — will determine how well the

plant uses the other nutrient elements

The 'beneficial elements' are those that can compensate for toxic effects of other elements, or

may replace mineral nutrients in some other less specific functions such as the maintenanceof osmotic pressure.

There are 16 nutrient elements required to grow crops. Three essential nutrients — carbon

(C), hydrogen (H) and oxygen (O2) — are taken up from atmospheric carbon dioxide and

water. The other 13 nutrients are taken up from the soil and are usually grouped as primarynutrients, secondary nutrients and micronutrients.

Knowing the nutrients required to grow plants is only one aspect of successful crop

production. Optimum yield also requires knowing the rate to apply, the method and time of 

application, the source of nutrients to use, and how the elements are influenced by soil andclimatic conditions.

 2.  What is meant by microelements?

 Microelements/ Micronutrients are those nutrients that are demanded only in trace

amounts. This includes iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu),

molybdenum (Mo), chloride (Cl), sodium (Na), nickel (Ni), silicon (Si), cobalt (Co) and

selenium (Se).

The importance of micro-elements in plant nutrition is high and they should not be

neglected although they are needed in minor quantities.  Any deficiency of a nutrient, no

 matter how small the amount needed, it will hold back plant development.

 3.   After a farmer has received the result of soil or leaf analysis, what could be his/her next

 move?

The last step I presented in the soil analysis includes Management recommendations

 based on interpreted analytical results. The farmer after receiving the result should properlyinterpret the soil-leaf analysis values, and then develop a fertilizer management program for

his/her crops. However, fertilizer programs are  crop specific and sometimes dependent on

additional soil and climatic properties, and are beyond the scope of this document. With theuse of this analysis, farmers could produce better yield and would at least lessen crop failure.

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  “  cals.arizona.edu/pubs/crops/az1412.pdf,”  James L. Walworth, State Soil Specialist,

The University of Arizona Cooperative Extension, The University of Arizona, College of 

 Agriculture and Life Sciences, Tucson, Arizona 85721

  “  MICRO-ELEMENTS in Agriculture,

” Practical Hydroponics & Greenhouses .July/August . 2007

  “  Essential Plant Nutrients: their presence in North Carolina soils and role in plant nutrition,”   M. Ray Tucker, Agronomist, NCDA & CS Agronomic Divisions, October 

1999.