Maharashtra Board Class 11 Agriculture Science and Technology Chapter 7 Irrigation Management PDF Download

Irrigation Management

For successful crop production water must be supplied to plant as required by them through irrigation. Plant receives water required for their growth from soil moisture. The soil moisture can be replenished whenever it gets depleted. Irrigation helps to maintain soil water balance during stress period.

What is the main source of irrigation in India?

What efforts are made to distribute water uniformly?

7.1 Definition of Irrigation

The artificial application of water for supplying moisture essential to plant growth is known as irrigation.

It is the artificial provision of water to supplement rainfall for crop production. Irrigation provides favorable environment for higher crop growth and yield. Effective irrigation is the controlled and uniform application of water to crop land in the required amount at the required time, with minimum cost to produce optimum yields without wastage of water and any adverse effect.

7.2 Advantages and Adverse Effects of Irrigation

7.2.1 Advantages of Irrigation

Irrigation provides insurance against short duration drought during crop season.

Yield of crop is increased and it maintains soil temperature.

It maintains soil water balance completely and plant water balance partly.

Irrigation is necessary for raising winter and summer season crops.

It improves the ground water storage.

Water supplies two essential elements, hydrogen and oxygen to the crops.

It is necessary for the absorption of mineral nutrients by the plants from the soil.

It brings biological equilibrium and enrichment of soil.

Irrigation ensures choice of efficient valuable crop and increases efficiency of inputs.

Teacher's Note

Irrigation helps farms get water when rain does not come. In villages of Maharashtra, farmers use tube wells to irrigate their fields.

Exam Trick

Remember: Irrigation = adding water to fields. Just like we drink water when thirsty, plants need water to grow. In exams, always remember irrigation provides water when rain is less.

Points to Remember

Irrigation is the artificial supply of water to crops.
Water gives hydrogen and oxygen to plants.
Irrigation keeps soil wet and helps crops grow better.
Farmers can grow winter crops with irrigation help.
Good irrigation increases crop production and yield.

7.2.2 Adverse Effects of Irrigation

The indiscriminate use of water leads to the problem of waterlogging and salt imbalance making the agricultural land unproductive.

The root growth is restricted in irrigated soil and therefore nutrients that leach downward are not extracted by the crops.

Irrigated soil become more compact on drying and thus tillage requirements are high.

Erosion of soil and loss of plant nutrients and wastage of water in sloppy land.

In deep clay soils a huge quantity of water is lost in filling up cracks before it reaches at saturation level.

Preparation of boundary bunds, plot bunds, channels for irrigation and drainage reduce effective sowing area.

The requirements of costly inputs such as fertilizer and tillage are considerable in irrigated agriculture.

Irrigation water is often acidic or alkaline and contains injurious salts, impurities and weed seeds that affect crop production.

Incidence of insects, pest, pathogens, parasite and weed are high in irrigated areas.

Teacher's Note

Too much water is bad for soil and crops. When fields have too much water, the land becomes useless for farming.

Exam Trick

Remember: Bad irrigation = waterlogging, salt problems, and pests. Too much water kills crops like too much salt in food ruins taste.

Points to Remember

Too much irrigation causes waterlogging.
Excess water reduces crop roots growth.
Soil becomes hard and compact when too wet.
Salty water harms plants and soil.
Pests and weeds increase in wet fields.

7.3 Systems of Irrigation

Different systems are used to apply irrigation water to the crop depending upon topography (present condition of land), soil type, crop water resources, climatic condition, and cost.

These systems are as follows:

7.3.1 Surface Irrigation System

In this system water is applied and distributed over the soil surface by gravity. It is often referred as flood irrigation in which applied water moves over the land surface freely and also infiltrate in to the soil.

The various methods of surface irrigation systems are flooding.

Flooding includes (a) Wild flooding and (b) Controlled flooding.

(a) Wild Flooding: In this method water from channel is allowed to flood in the entire field in an uncontrolled way. This practice is followed where water is abundant and inexpensive. It is followed on smooth lands like wet land of rice and close growing crops like leafy vegetables and fodder crops.

Teacher's Note

Wild flooding wastes lots of water. In dry areas like Rajasthan, farmers use controlled methods to save water.

Exam Trick

Remember: Wild flooding = no control, lots of water waste. Like opening a tap fully with no care - water goes everywhere.

Points to Remember

Wild flooding is cheap but wastes water.
No special planning needed for wild flooding.
Some fields stay dry and some get too wet.
Best for rice fields and vegetables.
Poor results with this method.

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