Commercial Lab

 The commercial laboratory is section within the department services offered which aimed at serving customers from defferent area in a commercial basis


  • Soil testing for agricutural purposes.
  • Water analysis for Irrigation purposes.
  • Plant tissue analysis.
  • Fertlizer testing for Quality (These are done mostly for elemental basicaly impurities).
  • Manure nutrients analysis.
  • Sampling ( under request)




Soil testing is an important diagnostic tool for determining the nutrient needs of plants and for environmental assessments. Some soils are inherently deficient in plant nutrients. Other soils had sufficient levels of nutrients in the past, but removal with crop harvest has depleted the reserves. Thus, soil testing is widely accepted and used in most advanced crop-production areas of the world to determine fertilization needs for crops. Soil testing can also be used to identify application rates of waste materials containing nutrients or other elements that could harm the environment. Waste materials such as animal manures and industry by-products may provide various plant nutrients. However, high application rates to soils designed to dispose of the material at a low cost may result in nutrient loads that are harmful to plant, animal, or human health. Nutrient management regulations are being developed to address land application of waste materials. Soil testing is required in many regulations and management guidelines to assess environmentally harmful levels of certain elements and to determine limits to application rates.

Soils are tested routinely for the primary nutrients phosphorus (P), potassium (K), and nitrogen (N). In some regions, soils are also routinely tested for other primary nutrients such as calcium (Ca), magnesium (Mg), and sulfur (S), and for other nutrients required in very small amounts by crops such as boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn). Soils receiving waste materials are also tested for elements such as arsenic (As), cadmium (Cd), nickel (Ni), lead (Pb), mercury (Hg), and selenium (Se) among others.

Two of the primary plant nutrients, N and P, may have harmful effects on the environment when applied to soils in excessive amounts. Excessive N and P applications to agricultural fields and ineffective nutrient, soil, and water conservation practices are increasing nutrient pollution in many regions of the world. However, the basic concepts of soil testing also apply to other elements. Phosphorus is included with the group of elements with relatively low mobility in soils (Ca, Cd, Cu, Fe, Mg, Mn, Mo, Ni, Pb, and Zn among others). N, especially in the nitrate form, is included with the group of elements with greater mobility (which include B, Cl, S, and others). Important concepts include the meaning of a soil-test value, soil-testing quality, use of soil testing to determine economically optimum nutrient application rates, and use of soil testing for environmental assessments.

Soil Electrical Conductivity (SEC)

 The preferred index to assess soil salinity is electrical conductivity. Electrical conductivity measurements are reliable, inexpensive to do, and quick. Thus, EC is routinely measured in many soil testing laboratories. The EC is based on the concept that the electrical current carried by a salt solution under standard conditions increases as the salt concentration of the solution increases. A sample solution is placed between two electrodes of known geometry; an electrical potential is applied across the electrodes, and the resistance (R) of the solution between the electrodes is measured in ohms. Electrical conductivity is expressed in micromhos per centimeter µmho cm−1) or in millimhos per centimeter (mmho cm−1). In SI units the reciprocal of the ohm is the siemen (S) and EC is given as S m−1 or as decisiemens per meter (dS m−1). One dS m−1 is one mmho cm−1.

The electrical conductivity of the extract of a saturated paste of a soil sample (ECe) is a very common way to measure soil salinity. In this method, a saturated soil paste is prepared by adding distilled water to a 10- to 50-g sample of air-dry soil and stirring. The mixture should then stand for several hours so that the water and soil react and the readily soluble salts dissolve. This is necessary so that a uniformly saturated and equilibrated soil paste results.



General considerations to take into account when making lab test of irrigation water are listed below:

– Usually 1L of sample is sufficient

– All samples should be labelled to indicate date, location, time and other pertinent data.

– Take seasonal samples for representative data due to variation of water quality by climate conditions

– Take samples before and after the treatment plant for recycled water and other representative samples when appropriate such as after the storage tank, etc.


There are four basic criteria for evaluating water quality for irrigation purposes:

  • Total content of soluble salts (salinity hazard)

  • Relative proportion of sodium (Na+) to calcium (Ca2+) and magnesium (Mg2+) ions  sodium adsorption ratio (sodium hazard)

  • Residual sodium carbonates (RSC)  bicarbonate (HCO3) and carbonate (CO32−) anions concentration, as it relates to Ca 2+ plus Mg2+ ions.

  • Excessive concentrations of elements that cause an ionic imbalance in plants or plant toxicity.


Soil fertility evaluation does not rely on soil testing alone. Visual diagnosis of plant nutrient deficiencies, in-field measurements of plant nutrient status, laboratory analysis of tissue nutrient concentrations, and remote sensing of plants can all be valuable tools in identifying plant nutrient deficiencies, so that they can be corrected or prevented. Soil testing can be used before planting or in season to guide nutrient applications. Plant tissue analysis can be used in season to identify or confirm visually observed nutrient deficiencies. When combined with a soil testing program, plant tissue sampling and testing or analysis can be very useful in determining the cause of visual deficiency symptoms. There are many tools available for in-field plant analysis, including the leaf chlorophyll meter that measures light absorption at specific wavelengths and handheld or equipment-mounted photometers that measure light reflectance. These tools are often used to calculate various vegetative indexes based on the ratio of light reflectance at different wavelengths to estimate sufficiency or predict nutrient need through more advanced algorithms. However, these types of diagnostic tools are beyond the scope of this article, which is limited to traditional visual diagnosis and plant tissue analysis.

It is important to take a holistic approach to soil fertility management and interpret tissue test results in the context of soil test results, field conditions, plant health, and other potential plant stresses. Many factors can influence relative nutrient availability or the ability of a plant to take up available nutrients, causing a nutrient deficiency to be expressed visually or in tissue nutrient concentrations. For example, a grower may visually identify P deficiency in a corn field due to the presence of stunted, purple-colored plants. If only a tissue sample was collected and it showed P deficiency, the grower may then conclude that additional P is required. However, a soil sample may reveal that there was adequate P in the soil, but that the pH was low, limiting P availability, evaluation of the whole plant could reveal that a root disease, such as Pythium root rot, induced the above-ground P deficiency symptoms. In either case P fertilizer was not truly required, even though a tissue test alone would have indicated that it was. There are many examples where soil nutrient concentration is not the culprit of a deficiency identified visually or through tissue analysis, so caution should be applied when interpreting plant tissue concentrations. A valuable application of tissue testing is to confirm nutrient deficiencies within problem areas observed in a field. For example, many nutrient deficiencies result in plants exhibiting interveinal chlorosis. If the symptom is exhibited sporadically across the field, tissue samples can be collected from within the affected regions and compared with results from samples collected from unaffected regions. This comparison along with soil test results from both areas can be used to narrow which specific nutrient might be causing the symptoms. However, it is important to remember that it is not enough to identify a nutrient deficiency, the cause must also be determined before corrective action can be taken. It does no good to apply a nutrient that is deficient if soil compaction, pH, root disease, or other problems are limiting uptake of that nutrient by the crop.

The results of tissue analysis are highly dependent on how and when the sample was collected. Some of the essential elements are considered mobile nutrients within plants because they can be translocated from mature plant parts to the areas of the plant that are actively growing (meristem), so that deficiencies will occur initially in the older parts of the plant. Conversely, immobile nutrients cannot translocate and therefore deficiency symptoms are typically exhibited initially in the youngest part of the plant.


DSGS laboratory offer a broad range of analytical services to the fertilizer industry