Reasons for decline in soil fertility

 Reasons for decline in soil fertility

Introduction

Soil fertility is a component of overall

soil productivity that deals with its

available nutrient status, and its ability

to provide nutrients out of its own

reserves and through external

applications for crop production.

Increasing pressure on limited agricultural land in Indiahas resulted in overuse of chemical fertilisers, excessive tillage, and lack of appropriate crop rotation.

This has resulted in soil degradation and loss of fertility,which are emerging as major challenges for the Indianfarmers.

Clearly, the pressures of constantly increasing productionhave in turn resulted in a persistent decline in soilfertility– a major challenge that Indian agriculture iscurrently facing.

With rising population, limited availability of agriculturalland, small land holdings and declining soil fertility, Indiais under serious threat of losing its food surplus status inthe near future.

According to estimates, the demand for food grains isexpected to increase from 192 million tonnes in 2000 to 355 million tonnes in 2030.

Causes of decline in soil fertility

1. Loss of top soil by erosion

2. Nutrient mining

3. Physical degradation of soil (poor structure, compaction,

crusting and waterlogging etc.

4. Decrease in organic matter content and soil bioactivity

5. Loss of nutrients through various routes

6. Soil acidification, salinization and alkalization

7. Inefficient soil management

8. Soil pollution

1. Loss of top soil by erosion

The top soil is rich in nutrients and organic

matter. Loss of the fertile topsoil components

through erosion by water and wind results in

decreased fertility.

Soil erosion is very common in many parts of

the country.

The basic causes of soil erosion are the result

of human activities such as deforestation,

overgrazing and poor soil management.

2. Nutrient mining

• Removal of more nutrients by crops than

added through manures or fertilizers is

called as nutrient mining or depletion.

•  At present, nutrient mining is a

major threat to productive

sustainable farming. It is a widespread problem in

low- and medium input

agriculture. Nutrient mining is accelerated by

imbalanced fertilization.