Principles and Management of Soil Fertility

Soil Fertility

quality that enables the soil to provide the proper compounds in the proper amounts and in the proper proportion, for the power growth of specifice kind of plants when all factors are favorable for growth

Soil Productivity

Capability of the soil to produce a specific plant under a specified system of management

A productive soil is always fertile soil

True

A fertile soil is always productive soil

False

Factors affecting soil fertility

• Favourable Physical Properties

• Good aeration and drainage

Nutrients

Chemical elements or compounds required by plants for normal growth an development

Leibig’s Law of Minimum

• Growth of plants is limited by the plant nutrient element present in limiting amounts

• growth is a function of several factors

• G=f(x1,x2, …xn), isolating the influence of a single factor on growth can be represented by linear relationship

• G=Ax+B

  • where:

  A and B are constants

  X= growth factor

  An increasein the quantity of the limiting growth factor will result to a proportional increase in plant growth

Liebig’s Law of the Minimum 1840

Unless the soil is in perfect balanse, the Yield/Quality potential of a crop is like a barrel with staves of unequal lenght. The crop will be limited by the shortest stave of the barrel

Pottasium

Can regulates water/Avoid plants from water stresses

Calcium

Calcium pectate is part of cell wall ; exists in oxalate form in plants; high in meristem

Calcium

Can regulate salinity

Magnesium

Part of chlorophyll; aid in translocation of Phosporus and enzyme activation

Boron

Cell wall Stability/Cellulos fiber Stability

Copper and Zinc

Plant growth promoting hormone

Molybdenum

Co-factor of enzyme nitrate reductase

Passive uptake

Root interception

Active Uptake

• Mass Flow

• Diffusison

Factor affecting Water And Ion Uptake

• Intensity factor

• Capacity Factor

• Rate of change Factor

Soil Fertility Diagnostic Procedures

1. Nutrient Deficiency Symptos in Plants

2. Plant Analysis

3. Soil Testing

4. Fertilizer trials

Nitrogen Deficiency Chlorosis

Occur in older Leaves of plants

Phosporus Deficiency symptoms

Pigmented or Purplish

Pottasium Deficiency

Side of a leaves will yellowish

Magnesium Deficiency

Older leaves have yellow dicoloration between veins-finally reddish purple from edge inward

Zinc Deficiency

Pronounced Interval Chlorosis and bronzing leaves

Soil testing

Air dry

Fertilizer And Soil fertility Management

• Fertilizer

• Fertilizer Grade

• Fertilizer Ratio

• Filler

• Fertilizer requirement

4Rs of Proper Fertilizer Use

1. Right Source

2. Right Amount for the particular soil,crop, and environmental condition

3. Right time

4. Right Method/Technique

Types of Fertilizer

1. Single or Straight Fertilizer

   • Carries only 1 primary nutrient (either N, or P2O5 or K2O)

2. Compound Fertilizer

   • It carries 2 Elements

3. Complete Fertilizer

   • Contain all the three basic (primary) elements. N,P,K

4. Mixed Fertilizer

   • Contains several elements and the source of elements cannot be identified. A chemical o mechanical combination of two (2) or more fertilizers

Classification Of fertilizer

1. Mineral (Inorganic) Fertilizer

2. Organic and Bio0Organic Fertilizer

Putting Organic to the Field

1 month before Planting

Immobile

It need sidedressed application or band application (e.g. Phosphorus, Potassium)

Mobile

Nitrogen is okay to be broadcast

Fertilizer Placement

For Solid:

1. Broadcast

2. Band

3. Topdressed or Sidedressed

4. Row application

5. Spot Application

6. Ring Application

7. Hole

   For Liquid:

   1. Foliar Application

   2. Soil Injection

   3. Fertigation

Factors affecting the rate and Placement of Fertilizers

1. Soil Factors

2. Crop Factors

3. Climatic Factors

Nutrient Loss

1. Bacterial Denitrification

2. Leaching of NO3-

3. Erosoin Losses

4. Volatilization