Irrigation Systems

Rainwater

Most farmers in the world depend solely on seasonal rains to water their crops

Rainwater

Advantages: No labor required Free No technology or equipment required

Disadvantages: Not suitable for all crops in all climates A dry year can severely lessen yields or loose

an entire crop Bad droughts and lead to little or no income

and/or famine

Hand Watering

Watering individual plants by hand

Usually involved hauling buckets, watering cans or a hose

Hand Watering

Advantages: Minimal and low-tech equipment needed Very cheap Water applied directly to plants

Disadvantages: Labor intensive Inefficient for watering a large amount of

land Slow

Surface or Flood Irrigation

Water moves over and across the land by simple gravity flow

This has been the most common method of irrigating agricultural land

Surface or Flood Irrigation

Advantages: Relatively small investment on low-tech

equipment Simple to understand

Disadvantages: Labor intensive High maintenance Can lead to water-logging and soil salinity if

there is not adequate drainage Won’t work well on uneven surfaces

Sprinkler

Water is piped in and distributed by overhead high-pressure sprinklers or guns from a central location in the field or from sprinklers on moving platforms

Sprinkler

Advantages: Even distribution of water Unaffected by uneven land surfaces Ability to apply fertilizers and herbicides through

the system Less labor required

Disadvantages: Can cause crusting of soil surface Strongly affected by windy conditions High maintenance requirements Initial investments can be high Wet foliage is susceptible to disease Up t0 50% of water can be lost to evaporation

before plants absorb it

Center Pivot

Water is distributed by a system of sprinklers that move on wheeled towers in a circular pattern

This system is common in flat areas of the United States

Center Pivot

Advantages: Even distribution of water Ability to apply fertilizers and herbicides through the

system Covers a large area with less sprinkler heads Low labor

Disadvantages: Can cause crusting of soil surface and soil erosion Strongly affected by windy conditions High maintenance requirements Expensive to setup and fix Technical knowledge of system required

Lateral Move Irrigation

Water is distributed from a main hose through a series of pipes, each with a wheel and a set of sprinklers

After an area has been sufficiently watered the system is moved across the field either by hand mechanically

Lateral Move Irrigation

Advantages:Similar to center pivot irrigationLower input costs than center pivot

Disadvantages:Also similar to center pivot

irrigationHigher labor requirements than

center pivot

Drip Irrigation

also known as trickle irrigation

Water is delivered near the plants roots, drop by drop

Drip Irrigation

Advantages:Ability to irrigate irregularly shaped

fieldsMinimal soil erosionHighly efficient and conserves waterReduced risk of disease from wet

foliage Waters only root zone of plants Less soil crusting and weedsLess water lost to evaporation

Drip Irrigation

Disadvantages:Very expensive investmentInitial setup is labor and time intensivePost-season cleanup requiredUses lots of plasticCan result in seed germination

problemsRequires sediment-free water

Drip Irrigation

Used since ancient times when buried clay pots were filled with water, which would gradually seep into the grass

Modern drip irrigation began its development in Afghanistan in 1886 with clay pipes

The advent of modern plastic allowed for vast improvements in tubing

Plastic emitters and modern drip irrigation was developed in Israel by Simcha Blass

Drip Irrigation

Drip irrigation is a sustainable solution in many, BUT not all agricultural applications.

Ideal for watering landscapes, vegetable crops, orchards and vineyards.

Not ideal for large field crop production such as alfalfa or soybeans.

Greatly reduces the overall amount of water used by supplying water only where the plants can use it

What is the Best?

Irrigation method used depends on :Crop being grownTopographyRegionClimateWater availabilityAvailable money and labor

Sustainable Water

Practices

Don’t Lose to Evaporation

When crops are irrigated by overhead sprinklers nearly 50% of the water is lost to evaporation before it is absorbed by the plants.

Even when watered with drip irrigation water evaporates faster than it is absorbed.

Evaporation is caused by the sun hitting and heating water molecules.

Watering plants in the early mornings or late afternoon/evening when the sun is not shining will greatly reduce water lost to evaporation

Mulch Magic

Mulch is a protective cover placed over soil to help retain moisture…as well as reduce erosion and suppress weeds.

Mulching provides a more natural environment for plants by mimicking leaves that pile up on the forest floor.

Materials: Organic mulches include yard clippings,

leaves, straw, shredded tree bark, sawdust and compost

Synthetic mulches such as rubber from recycled tires and plastic sheeting

Mulch Magic

Swales

A Swale is a ditch on the contour of a hillside.

It does not direct water, but rather holds it and allows it to gradually infiltrate the soil down-slope of it. Soil and water run-off are caught in the swale, which becomes a fertile area. Gradual infiltration of water and nutrients in the swale slowly improve soil structure down-slope.

Swales

How a swale works: Swale Plume

Example of what can be accomplished with swales: Greening the Desert