Soil Tech Midterm 2

51問 • 2年前

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Essential steps in soil chemical test

Collection and preparation of soil samples for analysis, The actual analysis, Interpretation of results and formulation of fertilizer recommendations, Implementation and making adjustments

These tests require small quantities of soil to quantify availability of nutrients

Greenhouse Tests

Fertilizer trials in the researcher’s or farmer's fields are conducted to assess the effect of fertilizers

Field Fertilizer Tests

This is the process that results in the accumulation of soluble salt in the soil, mainly sulfates and chlorides of calcium, magnesium, sodium and potassium.

Salinization

Refers to the total concentration of salts in the soil. It is usually measured by electrical conductivity (EC) of a saturated soil extract.

Salinity

Soils which have an exchangeable sodium percentage (ESP) of more than 15.

Sodic soils

Soils with an an electrical conductivity of the saturation soil extract of more than 4 dS/m at 25°C.

Saline soils

Soils that have both detrimental levels of neutral soluble salts (ECe > than 4 dS/m and a high proportion of sodium ions (ESP > than 15 or SAR > than 13.

Saline-Sodic Soils

This refers to the concentration of sodium.

Sodicity

Soils containing sufficient soluble salts to adversely affect the growth of most plants.

Saline soils

Meaning of SAR

Sodium Adsorption Ratio

An expression that tells how much sodium is adsorbed compared to two of the most common cations in the soil.

Sodium Adsorption Ratio

Effects of high concentration of salt on plant growth

Osmotic effect, Specific ion effect, Destruction of soil structure

The high concentration of salts outside the roots forces the water to move outside of the cells

Osmotic effect

How to test for salinity

Electric Conductivity Meter

What is the meaning of ASS

Acid Sulfate Soils

The meaning of PASS

Potential Acid Sulfate Soils

Essential Ingredients for Pyrite Formation

Sulfate, Iron, Metabolized organic matter, Sulfate-reducing bacteria, Anaerobic condition alternated with limited aeration

A natural or artificial substance containing the chemical elements that improve growth and productiveness of plants.

Fertilizer

Classification of Fertilizers

Organic, Inorganic

are those fertilizer which are the products of plant or animals.

Organic fertilizer

Sometimes called artificial fertilizer, are minerals that have been mined or produced in a factory.

Inorganic fertilizer

Indicates the proportion of N, P O and K O contained in 252

Fertilizer ratio

Are primarily used in the small fruit and nursery industries.

Special Purpose Fertilizers

Are used primarily in the turf, sod and ornamental nursery industries.

Slow-release Fertilizers

The most important fertilizer properties

Hygroscopicity, Caking, Particle shape and size distribution, Particle strength and mechanical resistance, Tendency to generate dust and fines, Bulk density, Compatibility (chemical and physical)

Air contains moisture as water vapour and therefore exerts a water vapour pressure (p H2O) that is determined by humidity and temperature

Hygroscopity

Arises due to the formation of strong crystal bridges and adhesive forces between granules.

Caking

volume weight (kg/m3) differs between fertilizer types.

Bulk Density

Methods of Fertilizer Application

Frequency of Fertilizer and Lime Applications, Timing of Fertilizer and Lime Applications, Different Application Methods

Different Fertilizer Application Methods

Broadcasting, Banding, Sidedressing, Fertigation, Foliar Feeding

is the application method generally used for large field areas

Broadcasting

This term generally refers to those fertilizer materials applied to the soil, (after the crop is up), during the early to mid-growth period of the crop.

Sidedressing

This method is primarily used to apply small amounts of fertilizer as a plant starter.

Banding

nutrients are absorbed and used by the plant quite rapidly.

Foliar Feeding

Nitrogen and potassium are sometimes sidedressed by applica- tion in the irrigation water that is applied to crop production systems at intervals during the growing season.

Fertigation

The practical goal is to determine how much nutrient material to add.

Economics of Fertilizer

solid fertilizer materials blended together in small blending plants delivered to the farm in bulk

Bulk blended fertilizer

fertilizers that are present in the form of rather stable granules of uniform size

Granulated fertilizer

fluid fertilizers that contain essential elements in liquid forms either as soluble nutrients or as liquid suspension or both

Liquid fertilizer

two or more fertilizer materials mixed together, maybe as dry powders, granules, pellets, bulk blends or liquids

Mixed fertilizer

Materials that contain the three major plant-nutrient elements - nitrogen, phosphorus and potassium

Complete fertilizer

the guaranteed minimum analysis, in percent, of the major plant nutrient elements contained in a fertilizer material or in a mixed fertilizer

Fertilizer grade

refers to the relative percentage of N, P₂Os and K2O

Fertilizer ratio

An expression of the quantity and analysis of the material in a mixed fertilizer

Fertilizer formula

One capable of increasing the acidity of the soil, which is derived principally from the nitrification of ammonium salts by bacteria.

Acid-forming fertilizer

one capable of decreasing the acidity of the soil.

Basic fertilizer

one that is guaranteed to leave neither an acidic nor basic residue in the soil

Neutral fertilizer

the quantity of certain plant nutrient elements needed

Fertilizer requirement

The acidity developed in the soil by the fertilizer

Equivalent acidity/Residual acidity

The basic residues left in the soil by the fertilizer, expressed as equivalent calcium carbonate

Equivalent Basicity

Soil Tech Midterm 1

Mutated Lemon · 100問 · 2年前

Soil Tech Midterm 1