Agriculture Form 3 – SOIL AND ITS AGRICULTURAL UTILIZATION

SOIL AND ITS AGRICULTURAL UTILIZATION

 
 

PHYSICAL PROPERTIES OF SOIL

SOIL TEXTURE: This refers to the relative proportion of various soil separates in soils.

SOIL SEPARATE: This is an individual particle occurring or aggregate e.g. Sand, silt, day, etc

 
 

Particle size analysis

This is the process of determining the amount of the individual particles fraction done in the laboratory to get individual fractions sand, silt and gravel.

         The quantity of each group determines the % volume or weight of each group as calculated on the basis of the original sample.

         The % of clay sand, silt is then used to determine the soil texture using Textural Triangle.

Procedure of using the triangle

 
 

 
 

 

 
 

 
 

 
 

 
 

 

 
 

 
 

         The percentage of the silt and clay are located on silt and clay side respectively.

         Lines are then projected in wards.

         From the silt side, the line should pass in wards and parallel to clay side.

         From the clay side, the line should run in wards and parallel to sand side.

         From the clay side, the line should run in wards and parallel to sand side.

         The area within which these lines meet gives the texture of the soil in question.

         Normally, If the soil contains a lot of sand, It is cause textured and it is said to be sand. Since they easily mark able (i.e. cultivated) and soils are sand to be light.

         Silt soil with fine texture consists of larger day and silt. They are plastics, sticky and difficult to cultivate heavy soil.

Importance of soil texture as related to production

         Soil texture gently affected the rate of productivity of the soil for agricultural uses, coarse textured soil such as sand and loam sand cannot hold sufficient water and nutrients to produce top yield every year, and they require irrigation and frequent use of fertilizer.

o   Fine textured soils such as clay and silt clay, may hold water and nutrients very tightly that may becomes un available to plant growth, difficult to till, become very poor water percolation hence reliable to water logging.

o   Silt soils and silt loam give few agriculture problem of/ as they provide high agriculture production. They have good drainage and they can support a wide range of crops, root penetration, water infiltration and management.

Texture Classes: Sand, sandy loam, loam, silt loam, sand clay loam, day loam, silt clay, silt clay loam, clay and sand clay

1.       SAND:

         The grains are roughed or irregular in shape, can be felt and seen by naked eyes.

         Consist of mainly original minerals.

         It exposes little surface and chemically inactive.

         Sand grains, primary farm the frame work of the skeleton of the soil.

         Poor water holding capacity but well orated.

         Contain more than 70% particles size nglish-swahili/distribution” target=”_blank”>distribution.

2.       SILT

         The separate include mainly original mineral fragments which are diverse in shape rarely smooth or flat. When dominant gives a soapy feel

3.       CLAY

         This fraction gives the finest particles in the soil.

         These are secondary product of chemical weather.

         They are active and have influence most of physical-chemical properties of soil.

         They have ultra-microscopic structure and expose a large surface area.

         Exhibit such properties as swelling, shrinking, plasticity and cohesion under various moisture conditions.

         Particles are usually plate like in shape.

         Permit greater absorption and water retaination.

         Contain more than 35% particle size nglish-swahili/distribution” target=”_blank”>distribution.

4.       LOAMS

         Soils containing sand and silt in almost equal proportion (usually 40% sand, 40%silt and 20%clay). The most important soils as they are ideate for the majority of agronomic crops.

SOIL PLANTS NUTRIENTS

Classification of soil plant nutrient

i.e. Macro nutrients-needed in large quantities, Micro nutrients- needed in small quantities.

NB: Both are termed as ESSENTIAL NUTRIENTS meaning that nutrients needed by plants for different function.

There are 17elements needed for plant growth

a)      Those needed in high amount- Macro elements

b)      Those needed in small amount- Micro elements

MACRO ELEMENTS: Nitrogen, Sulphur, Phosphorus, Potassium, Magnesium, Calcium, Hydrogen.

MICRO/ TRACE ELEMENTS: Carbon, Chloride, Manganese, Copper, Water, Oxygen, Zinc, Boron, Molyberium.

NB: If they are in excess become toxic to plants.

Occurrence of nutrients in the soil – found when

a)      Combined with other elements in minerals e.g. K, AL, Silicate (KALSi3O5)

b)      Dissolved in water as icons.

c)       On the surface of organic nitrogen, sulphur.

FUNCTION OF PLANT NUTRIENTS

NITROGEN: Occurrence: In form of nitrate, Ammonia or organic matter. Functions:

         The quantities taken are larger than any other nutrients

         Formation of protein and Amino acids (green pigment)

         Facilitate carbohydrate utilization and uptake of phosphorus and calcium and increase vegetative growth.

 
 

Deficiency:

         Lack in sufficient N2 results to

         Carbohydrates deposition in the vegetative cell causing thickening of the cells.

         Poor photosynthesis

         Stunted growth and low yield.

Symptoms:

         Loss of green pigments i.e. yellowing of leaves.

         Firing of tips and margin of a leaf.

         Stunted growth. Correction:

         Use organic and in organic manure

         Crop rotation with legume inclusive

         Early planting to utilize early nitrogen

PHOSPHORUS:

Occurrence: In form of phosphorus ions e.g. H2PO4. Availability is low in acidic soils.

Functions:

It promotes the formation of lateral and fibrous roots increasing water nutrients absorption.

         Increase tell ring of cereals and straw strength

         Increase plants resistance to diseases and hastens crop maturity.

         Improve seed formation and fruiting.

Deficiency:

         Stunted growth

         Deficiency symptom zed by purplish colorization on the leaves.

         Poor root formation

         Delayed maturity

POTASSIUM:

Occurrence: In ionic form

Functions:

         2nd element needed by plant in large quantity.

         Increases plant resisting to diseases and adverse weather.

         Increases efficiency of leaves to manufacture sugar and starch.

         It helps in better utilization of elements.

Deficiency:

         Weakness of plant

         Slow plant growth

         Shriveled seeds and fruits.

         Burning effect starting with older leaves.

         Low resistance to rust and other diseases.

 
 

Correction:-Use of organic manure and inorganic manure e.g. Murrieta of potash (MODI Potassium

Sulphate)

CARBON, HYDROGEN AND OXYGEN: It is used to make carbohydrates.

CALCIUM:

         Promote the growth of root tips

         Increase stiffness of the straws

         Promote good seed production.

MAGNESIUM

         Essential in chlorophyll formation

         Increase efficiency of phosphorus intake

         Regulate good seed production

SULPHUR:-Essential in the formation of protein

         Stimulate root growth, seed setting and nodule formation. IRON:-Essential catalyst in the formation of chlorophyll

         Deficiency is symptom zed by chlorosis

LUXURY CONSUMPTION OF PLANT NUTRIENTS

Is the habit of some plant taking more potassium element than that their requirement for normal growth.

Effects:

         Increased synthesis of complex carbohydrate, protein and nucleic acids.

         Reduction the synthesis of sugar, amino acids and nuclei tides.

Correction:

         Increase La, K ratio in the solution by over limiting which reduce uptake of K and thus prevent it living consumption by plants.