This presentation discusses soil fertility and nutrient cycles. It defines soil fertility as the soil's inherent capacity to supply available nutrients to plants. There are two types of soil fertility: inherent/natural fertility that comes from nutrients originally in the soil, and acquired fertility developed through practices like applying manures, fertilizers, tillage, and irrigation. The presentation outlines the importance of soil fertility for crop production. It also discusses ways to improve soil fertility, such as using organic matter, green manuring, mulching, and crop rotation. Finally, it provides an overview of the nitrogen, carbon, oxygen, and phosphorus cycles that are essential for recycling nutrients in an ecosystem.

1. Presentation on Principles and Practices of
Organic Farming (AGRON-513)
Topic : Soil fertility and Nutrient cycle
Submitted to : Dr. Sunil Kumar Submitted by : Hasandeep Singh
Class : M.Sc. Agronomy II
Roll no. : 9603

2. Historical developments of soil fertility :
• A number of Roman authors (e.g., Xenophan,
Cato, Columella, Pliny the Elder) wrote detailed
textbooks on agricultural that described the use
of animal manures, green manures and crop
rotations to improve soil productivity.
• Egypt is big example of improved soil fertility
because Egyptian shows lots of agricultural
practices i.e. tillage, planting, irrigation and
harvesting but no fertilization.

3. Definition :
• The inherent capacity of the soil to supply
available nutrients to plants in an adequate
amount and in suitable proportion to maintain
growth and development.
• It is an index of available nutrient to plants.
• All fertile soils are not productive.
• It contains sufficient mineral, soil organic
matter, good soil structure and soil moisture
retention.

4. Types Soil Fertility
Inherent or Acquired fertility
Natural fertility

5. 1. Inherent or Natural fertility :
(a) Nature contains some nutrient
(b) Among plant nutrients nitrogen, phosphorus
and potassium is essential for normal growth
and yield of crop.
(c) It is limiting factor so, fertility is not decreased.
2. Acquired fertility :
(a) Developed by application of manures and
fertilizers, tillage, irrigation, etc.
(b) It is also limiting factor. The yield is increased
by additional quantities of water.

6. Natural Artificial
Factor Factor
(influence the (climate and vegetation,
Soil formation & topography, inherent
Proper use of land) capacity of soil to supply
nutrients, micro-organisms,
soil erosion, cropping
system, organic matter.
Factor
affecting
soil
fertility

7. Importance :
• Increase crop production.
• Sufficient soil depth for adequate root growth and
water retention.
• Good internal drainage, allowing sufficient
aeration for optimal root growth.
• Top soil with sufficient organic matter for healthy
soil structure and soil moisture retention.
• Soil ph range 5.5 to 7.0.
• Adequate concentrations of essential plant
nutrient in plant- available forms.
• Presence of range of micro-organisms that
support plant growth.

8. Ways to improve soil fertility :
• Organic matter
• Green manuring
• Mulching
• Mixed cropping
• Crop rotation
• Use of fertilizers.

10. Nutrient cycle :
• It is an essential process in an ecosystem. In the
nutrient cycle, the usage of the nutrients in the
environment, their movement and the processes
their recycling are described.
• Important nutrients include carbon, oxygen,
hydrogen, phosphorus and nitrogen are required to
be recycled for the existence of organisms.
• They also involved biological, geological and
chemical processes and thus, these nutrient circuits
are also known as biogeochemical cycles.

11. Diagram of Nutrient Cycle :

12. Types of nutrient cycle
Nitrogen Carbon Oxygen Phosphorus
Cycle Cycle Cycle Cycle

13. Nitrogen Cycle :
• 79 % N in air
• Plant absorbed ammonium NH4
+ or nitrate NO3
-

14. Carbon Cycle :
• It contain proteins, carbohydrates and organic molecules.
• Carbon being fixed by plants from the atmosphere.

15. Oxygen Cycle :
• It is an element that is essential to biological organisms.

16. Phosphorus Cycle :
• It is a component of biological molecules such as RNA,
DNA, phospholipids and adenosine triphosphate (ATP).
• Form used PO4
3-

18. THANK
YOU