Soil and productivity

Soil Fertility and Productivity

Dr. Mohinder SinghAssistant Professor (Agronomy)Faculty of Agricultural Sciences

SGT University,Gurgoan, 9466310014

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Importance of Soil• Soil: The layer of material that covers the land

– Where plants anchor and grow– Made of weathered rock, decomposing plant and

animal matter– Has spaces for air and water movement– Soils differ in organic content which effects the

ability to support plant life.

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Layers of composition• 3 major types of soil

– Horizon A: Topsoil– Horizon B: Subsoil– Horizon C: Parent Rock– Horizon D: Bedrock

• Each layer has different characteristics depending on where it is found.

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Soil productivity: The capability of soil to produce specified crop yield under well defined and specified systems of management of inputs and environmental conditions.

Soil Fertility:Factors Governing• Parent material: Fertility of a soil depends on the chemical composition of parent material from

which it derived.

• Topography: Soils on the upper slope are less fertile than the soils on lower slope because high leaching and erosion on upper slope.

• Climate In tropical climate decomposition of organic matter is faster than temperate climate. Thus soils of tropical regions are less fertile when compared to temperate region.

• Depth of Soil Profile: Deep soils are more fertile than the shallow soils and the roots are spread well enough in deep soils than the shallow soils.

• Physical Condition of Soil: The soil texture and soil structure influence the soil fertility.

• Artificial Factors:I. Water loggingii. Cropping systemiii. Toxic chemicals and pesticides in the soil.

Soil Fertility

Chemical

Physical BiologicalBacteria

(Living) plant roots

Fungi,actinomycetesOther organisms

Agronomic/ Cultural practices

Improved soil fertility and productivity

Sustainable agriculture

Rhizosphere

Soil Fertility

Chemical

Physical Biological

Importance of soil fertility

Biological soil fertility: The capacity of organisms living in soil to contribute to the nutritional requirements of plants and foraging animals for productivity, reproduction and quality while maintaining biological processes that contribute positively to the physical and chemical state of the soil.

Chemical soil fertility: The capacity of soil to provide a suitable chemical and nutritional environment for the plants and foraging animals for productivity, reproduction and quality in a way that supports beneficial soil physical and biological processes, including those involved in nutrient cycling.

Physical soil fertility: The capacity of soil to provide physical conditions that support plant productivity, reproduction and quality without leading to loss of soil structure or erosion and supporting soil biological and chemical processes.


Components of soil fertility

Soil depth (determining the volume of soil accessible to the root system). Most arable crops prefer about one metre without any obstructing layer.

Soil structure (based on size distribution and aggregation of particles). This determines the distribution of pore sizes which is decisive for the supply of air and water to the roots.

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Content of nutrients with different degrees of availability. Storage capacity for soluble nutrients from the soil and fertilizers.

Soil pH/ reaction (an indicator and regulator of chemical processes

and equilibrium).


Picture shows the availability of nutrients at different soil pH



Nutrient gain as a result of N fixation from the air. It influences promotion or retardation of growth through growth hormones.

Soil Organic Matter (SOM)It promotes soil structure improvement by plant residues and humic substances leading to higher WHC, better soil aeration and protection of soil against erosion. Helps in keeping the nutrients in

available forms and protecting them against losses.Nutrient mobilization from

decomposed organic nutrient sources and mineral reserves: N, P, S, Zn, etc.


A highly productive soils with high fertility:

mobilize soil nutrients from the reserves;

transform fertilizer nutrients into easily available forms;

store water-soluble nutrients in easily available forms, thus preventing leaching;

offer the plants a balanced nutrient supply due to its self-regulating system;

store and supply sufficient water;

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A highly productive soils with high fertility:

maintain good soil aeration for the oxygen requirements of roots;

not 'fix' nutrients, i.e. convert them into available form;

Improve crop use efficiency of nutrients and resources such as water and light; and

Provide nutrients throughout the growing season and especially during critical peak periods of plant development

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• Difference between Soil Fertility and Productivity:Soil Fertility Soil • 1. It is an index of available nutrient to plants• 2. Influenced by the physical, chemical and biological factors of

the soil.• 3. It is the function of available nutrients of the soil.• 4. All fertile soils are not productive.• 5. It is an inherent property of the soil.Soil Productivity• 1. It is used to indicate crop yields• 2. Depends upon fertility and location. • 3. It is the function of soil fertility, management and climate. 4.

All productive soils are fertile. • 5. It is not the inherent property of the soil.

Productivity of Ecosystems

• Ecosystems have different productivities, based on light availability, soil types, precipitation, temperature, nutrients.

• Productivity: the quantity of biomass of plants produced each year on a given area (g/m2)

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Soil and productivity

Environment

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