Unit 4: Watering Crops

Unit 4: Watering Crops

• This unit covers the significance of soil moisture, measuring soil moisture, and performing irrigation.

Objectives

• Students should be able to describe the significance of soil moisture.
• Students should be able to measure soil moisture.
• Students should be able to perform irrigation.

Lesson 1: Determining Soil Moisture - Introduction

• Water is crucial for crop survival and growth.
• Various factors affect crop water needs, including climate, crop type, and soil type.
• This lesson focuses on understanding soil moisture content for better crop management.

Topic 1: Measuring Soil Moisture

• Soil moisture is the amount of water in the soil.
• Soil moisture content varies based on conditions like rain, irrigation, and evaporation.
• Factors influencing soil moisture include climate, soil type, topography, and soil cover.
• Farm activities like crop residue burning, tillage, and drainage can reduce soil moisture content.

Topic 2: Standardized Soil Moisture Index

• Soil moisture content can be expressed as millimeters of water per meter (mm/m).
• For example, 200 mm/m indicates 200 mm of water in a one-meter depth of soil.
• Soil moisture content can also be expressed as a percentage of volume.
• For instance, 1 cubic meter of soil containing 0.2 cubic meters of water is 20% by volume.

Field Crops (Consumptive Use)

• Data provided includes crop types, root zone depth, growing period, and consumptive use in centimeters.

Vegetable Crops (Consumptive Use)

• Data provided includes vegetable types, root zone depth, growing period and consumptive use in centimeters.

Lesson 2: Irrigation Systems

• Irrigation is the artificial application of water to supply moisture needed for plant survival and growth.
• Irrigation provides crop insurance against drought, cools the soil, and washes out salinity.
• Irrigation enhances the functioning of microorganisms and improves fertilizer application.

Why Irrigation Is Important

• It increases crop yield.
• It enables production of special crops.
• It provides employment during the dry season.
• It boosts national economies through exports.
• It increases farmer income.
• It intensifies land use.

Topic 1: Drip Irrigation

• Drip irrigation applies water slowly to the plant root zone.
• This system uses pipes and drippers to provide water and fertilizer directly to plants.
• Drip irrigation is an efficient water-delivery system, transferring water directly to the roots.

Topic 2: Sprinkler Irrigation

• Sprinkler systems spray water into the air, allowing it to fall on the ground.
• Sprinkler irrigation is also called spray irrigation.
• Common sprinkler systems include large-scale spray, center-pivot, and sprinkler types.
• This method can be inefficient due to water loss from evaporation and wind.

A. Center Pivot Irrigation System

• A center pivot system uses a large-diameter pipe that rotates around a central pivot point.
• It delivers low/medium-pressure water to the field.
• Commonly used for large-scale farms.

B. Lateral Move Irrigation System

• A lateral move system uses pipes with wheels connected at the midpoint.
• Water is supplied to the system via a large hose.
• Sprinklers are moved across the field until sufficient water is applied.
• This method can have lower efficiency, and higher labor costs than center-pivot systems.

Topic 3: Surface Irrigation

• Surface irrigation uses gravity to spread water across the field.
• This system is typically the least expensive to install but may require considerable effort to build.

Furrow or Flood Irrigation

• This involves channels (furrows) in the soil
• Water runs through the furrows to irrigate the crops.
• Row crops (like corn, sunflower, sugarcane) are best suited.

Basin Irrigation

• Water is applied to a level area enclosed by borders (dikes).
• Suitable for paddy rice, pastures, citrus, and banana trees.
• Crops that cannot tolerate prolonged wet conditions should not be used.

Ditch Irrigation

• Ditch Irrigation, also known as border strip irrigation, involves steps or leveled land areas across sloping dimensions.
• Used for narrow-row crops (cereals and grasses).
• Compared to other furrow methods this may be more productive and uniform.

Topic 4: Manual Watering

• Manual watering is a common method for small-scale farms and backyards.
• It uses basic gardening tools like cans or hoses to deliver water.
• Allows for control over water use, minimizing loss.

References

• Various websites and publications (sources are listed in the original document) are cited.