msu-ceco/aec_v1 · Datasets at Hugging Face

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This is done to provide more uniform water distribution around the edges of the field.
Figure 1.
Schematic of a portable hand-move aluminum pipe irrigation system.
Laterals and sprinklers are typically moved twice per day which requires 4.5 days to irrigate the 30-acre field shown in Figure 1.
Each setup and movement of the pipe is referred to as a "set".
Approximately 22.5 man-hours are required to move pipe each time the field is irrigated.
For the field length and shape shown, the lateral pipe size required is 4-inch, and the main line size required is 6-inch.
A pump capacity of 425 gallons per minute would supply an application rate of 0.28 inches per hour when two laterals are irrigated per set.
When operated for four hours , the total application to each set is just over one inch of water.
In the above example, only one inch of water could be applied per week, unless the pipe was moved and the system operated over the weekend.
Thus, the system shown only has the capacity to supply about one-half the crop water requirements during peak water use periods.
In terms of size , the 30 acre example is a relatively small system indicating that hand-move portable systems are not practical for irrigating large acreage.
There are, however, practical applications for portable, hand-move systems.
Some practical applications include the irrigation of:
plant beds such as tobacco or sweet potato beds, which are typically moved from one year to the next;
small acreage of high cash-value crops which also need to be rotated from year to year making solid set or permanent systems unsuitable;
small scattered fields separated by non-cropped areas; and
establishment and maintenance of lawns, turf areas, fruit and/or nursery trees and/or shrubs that require only an occasional irrigation, most often immediately after seeding or transplanting.
The labor required for moving pipe, and the introduction of other types of irrigation systems have diminished the popularity of hand-move potable systems.
Instead, growers have shifted to solid-set and permanent systems.
SOLID-SET AND PERMANENT IRRIGATION SYSTEMS
The solid-set system uses aluminum pipe, but instead of moving lateral lines once or twice a day as is done with portable systems, enough lateral pipe is purchased so that pipe may be left in place during the irrigation season.
Main line for the solid-set system can be aluminum pipe or buried polyvinyl chloride plastic pipe.
The permanent system normally uses buried main and lateral lines.
However, some growers use above ground PVC plastic lateral lines.
These systems are used more in orchards where the system is installed after the orchard is planted and in some container nursery operations.
Permanent systems have been used for many years to irrigate turf areas such as golf courses, recreational playing fields, and commercial and residential turf.
In more recent years, these systems have been used for agricultural irrigation to include nursery crop production.
Most of the solid-set and permanent systems for agricultural irrigation are used on high value crops such as nursery crops, tree fruits, small fruits, vegetables, and, to a small extent, tobacco.
Many of the systems for fruits and vegetables are also used for environmental modification such as frost/freeze protection and crop cooling.
These uses require a dependable water supply during the critical environmental period.
For crop cooling, it may be possible to cycle the system on and off to reduce the total volume of water pumped.
Solid-set and permanent systems designed for frost/freeze protection and crop cooling normally use small sprinklers and application rates in the range of 0.12to 0.25inch per hour.
Normally, single nozzle sprinklers are used on spacing's of 40 feet by 40 feet to 66 feet by 72 feet.
Spacing's are normally 50 to 65 percent of sprinkler wetted diameter.
Lateral spacing's and sprinkler spacing's on the lateral are adjusted to meet row and tree spacing's.
Sprinkler pressures are normally 10 to 15 psi higher than those used for irrigation to give small droplets and therefore, better coverage and higher sprinkler rotation speeds.
Frost/freeze protection using sprinkler irrigation operates on the principle of latent heat of fusion.
Water, as it changes state from liquid to solid, generates heat.
The heat being given off maintains the temperature of the plant near 32 F if adequate water is being applied.
Higher sprinkler pressure provides smaller droplets and faster sprinkler rotation and, therefore, better
protection.
But, windy conditions reduce the added protection of smaller droplets because wind causes evaporation.
The heat required to evaporate water is 7.5 times the heat given off when water freezes.
Just as smaller droplets freeze faster which improves frost/freeze protection, smaller droplets also evaporate faster.
Thus high pressure resulting in small droplets should not be used where windy conditions occur frequently.
Also, lateral line spacing's and sprinkler spacing's along the lateral should be reduced where windy conditions are prevalent.
Good frost/freeze protection requires that liquid water be available on the plant at all times.
Figure 2 shows a typical layout for a solid-set system for frost/freeze protection of strawberries.
A triangular sprinkler spacing is used.
Sprinklers are spaced 60 feet on the lateral and laterals are 60 feet apart.
The first and last laterals are 30 feet from the edge of the field.
Using the triangular spacing requires that the first and last sprinkler on every other lateral be on the edge of the field.
Lateral pipe size is 2-inch aluminum.
Main line size is 8inch aluminum.
Pump capacity required to provide frost/freeze protection for the acreage and setup shown in Figure 2 is about 900 gpm.
Figure 2.
Schematic of a layout of a solid-set irrigation system for frost/freeze protection of strawberries.
In the last several years, a number of solid-act and permanent systems have been installed for land application of nutrient-rich effluent.
Several agencies are promoting this practice as an environmentally safe method to utilize this resource.
Some land application systems are being installed on golf courses and public turf areas.
This is an approved practice in many states.
North Carolina Cost Share funds are being used to fund one intensively grazed, land application of nutrient-rich effluent demonstration in each county.
These areas are normally grazed, but producers may elect to produce hay crops rather than use the fields for grazing.
Sprinkler spacing's on land application systems are typically in the range of 80 feet by 80 feet, using single-nozzle sprinklers.
Other spacing's can be used and some of the sites use gun sprinklers on wider spacing's.
Normal spacing is 60 to 70 percent of sprinkler wetted diameter.
Figure 3 shows a typical layout for a permanent irrigation system for land application of nutrient-rich effluent.
Sprinkler spacing is 80 feet on the lateral.
Spacing of laterals is also 80 feet.
Lateral pipe size is 2.5 inch.
Main pipe size is 3 inch.
One lateral is usually operated at one time.
Sprinklers may be located on each lateral; or, sprinklers may be moved from one lateral to another lateral.
By moving sprinklers, initial system cost is reduced.
To operate one
lateral as shown, pump capacity required is about 120 gpm.
Note that there is a 70-foot border around the edge of the field to insure that no effluent is applied outside the field.
Figure 3.
Schematic layout of a permanent irrigation system used to land apply nutrientrich effluent.
General guidelines have been established and should be followed when designing hand-move, solid-set, and permanent systems.
For portable hand-move aluminum pipe systems, friction loss in the main and/or supply pipe should not exceed 2.0 psi for 100 feet of pipe.
For lines that are greater than 1500 feet in length, friction loss should not exceed 1.0 to 1.5 psi per 100 feet.
For PVC plastic pipe main and/or supply lines, flow velocity is the limiting factor rather than friction loss.
Velocity should not exceed 5 feet per second to prevent pipe failure due to water hammer.
Water hammer describes the buildup and sudden release of pressure that occurs when air is trapped in the pipe.
The buildup and release of the pressure increases as the velocity of the flowing water increases.
Friction loss in aluminum and plastic lateral lines should not exceed 20 percent of recommended sprinkler operating pressure.
Following this rule will assure reasonably uniform water distribution.
As sprinkler pressure is reduced, due to friction loss down the lateral line, the volume of water applied by the sprinkler and the diameter of coverage is reduced.
Most portable, solid-set and permanent sprinkler systems are medium to moderately-high in energy consumption, depending on whether small sprinklers or gun sprinklers are used.
Certainly, gun sprinklers will require higher pressures, increasing the power required.
Many of the portable systems use gun sprinklers.
Some growers are willing to trade off the higher energy costs for the savings in labor costs.
There are some gun sprinklers that will operate satisfactorily at lower pressures and some growers are using these, but they have reduced radius of coverage and, therefore, higher application rates, assuming equal flow rates.
There are some low pressure impact sprinklers that have been marketed for the last several years.
They also have reduced radius of coverage and this may increase the application rate.
Fuel costs are computed based on the energy required to deliver the required flow rate at the desired operating pressure.
To compute horsepower requirements, use the formula shown in the box at the top of the next column.
[TDH X Flow ]/ [3960 X Pump Efficiency]

This is done to provide more uniform water distribution around the edges of the field.

Figure 1.

Schematic of a portable hand-move aluminum pipe irrigation system.

Laterals and sprinklers are typically moved twice per day which requires 4.5 days to irrigate the 30-acre field shown in Figure 1.

Each setup and movement of the pipe is referred to as a "set".

Approximately 22.5 man-hours are required to move pipe each time the field is irrigated.

For the field length and shape shown, the lateral pipe size required is 4-inch, and the main line size required is 6-inch.

A pump capacity of 425 gallons per minute would supply an application rate of 0.28 inches per hour when two laterals are irrigated per set.

When operated for four hours , the total application to each set is just over one inch of water.

In the above example, only one inch of water could be applied per week, unless the pipe was moved and the system operated over the weekend.

Thus, the system shown only has the capacity to supply about one-half the crop water requirements during peak water use periods.

In terms of size , the 30 acre example is a relatively small system indicating that hand-move portable systems are not practical for irrigating large acreage.

There are, however, practical applications for portable, hand-move systems.

Some practical applications include the irrigation of:

plant beds such as tobacco or sweet potato beds, which are typically moved from one year to the next;

small acreage of high cash-value crops which also need to be rotated from year to year making solid set or permanent systems unsuitable;

small scattered fields separated by non-cropped areas; and

establishment and maintenance of lawns, turf areas, fruit and/or nursery trees and/or shrubs that require only an occasional irrigation, most often immediately after seeding or transplanting.

The labor required for moving pipe, and the introduction of other types of irrigation systems have diminished the popularity of hand-move potable systems.

Instead, growers have shifted to solid-set and permanent systems.

SOLID-SET AND PERMANENT IRRIGATION SYSTEMS

The solid-set system uses aluminum pipe, but instead of moving lateral lines once or twice a day as is done with portable systems, enough lateral pipe is purchased so that pipe may be left in place during the irrigation season.

Main line for the solid-set system can be aluminum pipe or buried polyvinyl chloride plastic pipe.

The permanent system normally uses buried main and lateral lines.

However, some growers use above ground PVC plastic lateral lines.

These systems are used more in orchards where the system is installed after the orchard is planted and in some container nursery operations.

Permanent systems have been used for many years to irrigate turf areas such as golf courses, recreational playing fields, and commercial and residential turf.

In more recent years, these systems have been used for agricultural irrigation to include nursery crop production.

Most of the solid-set and permanent systems for agricultural irrigation are used on high value crops such as nursery crops, tree fruits, small fruits, vegetables, and, to a small extent, tobacco.

Many of the systems for fruits and vegetables are also used for environmental modification such as frost/freeze protection and crop cooling.

These uses require a dependable water supply during the critical environmental period.

For crop cooling, it may be possible to cycle the system on and off to reduce the total volume of water pumped.

Solid-set and permanent systems designed for frost/freeze protection and crop cooling normally use small sprinklers and application rates in the range of 0.12to 0.25inch per hour.

Normally, single nozzle sprinklers are used on spacing's of 40 feet by 40 feet to 66 feet by 72 feet.

Spacing's are normally 50 to 65 percent of sprinkler wetted diameter.

Lateral spacing's and sprinkler spacing's on the lateral are adjusted to meet row and tree spacing's.

Sprinkler pressures are normally 10 to 15 psi higher than those used for irrigation to give small droplets and therefore, better coverage and higher sprinkler rotation speeds.

Frost/freeze protection using sprinkler irrigation operates on the principle of latent heat of fusion.

Water, as it changes state from liquid to solid, generates heat.

The heat being given off maintains the temperature of the plant near 32 F if adequate water is being applied.

Higher sprinkler pressure provides smaller droplets and faster sprinkler rotation and, therefore, better

protection.

But, windy conditions reduce the added protection of smaller droplets because wind causes evaporation.

The heat required to evaporate water is 7.5 times the heat given off when water freezes.

Just as smaller droplets freeze faster which improves frost/freeze protection, smaller droplets also evaporate faster.

Thus high pressure resulting in small droplets should not be used where windy conditions occur frequently.

Also, lateral line spacing's and sprinkler spacing's along the lateral should be reduced where windy conditions are prevalent.

Good frost/freeze protection requires that liquid water be available on the plant at all times.

Figure 2 shows a typical layout for a solid-set system for frost/freeze protection of strawberries.

A triangular sprinkler spacing is used.

Sprinklers are spaced 60 feet on the lateral and laterals are 60 feet apart.

The first and last laterals are 30 feet from the edge of the field.

Using the triangular spacing requires that the first and last sprinkler on every other lateral be on the edge of the field.

Lateral pipe size is 2-inch aluminum.

Main line size is 8inch aluminum.

Pump capacity required to provide frost/freeze protection for the acreage and setup shown in Figure 2 is about 900 gpm.

Figure 2.

Schematic of a layout of a solid-set irrigation system for frost/freeze protection of strawberries.

In the last several years, a number of solid-act and permanent systems have been installed for land application of nutrient-rich effluent.

Several agencies are promoting this practice as an environmentally safe method to utilize this resource.

Some land application systems are being installed on golf courses and public turf areas.

This is an approved practice in many states.

North Carolina Cost Share funds are being used to fund one intensively grazed, land application of nutrient-rich effluent demonstration in each county.

These areas are normally grazed, but producers may elect to produce hay crops rather than use the fields for grazing.

Sprinkler spacing's on land application systems are typically in the range of 80 feet by 80 feet, using single-nozzle sprinklers.

Other spacing's can be used and some of the sites use gun sprinklers on wider spacing's.

Normal spacing is 60 to 70 percent of sprinkler wetted diameter.

Figure 3 shows a typical layout for a permanent irrigation system for land application of nutrient-rich effluent.

Sprinkler spacing is 80 feet on the lateral.

Spacing of laterals is also 80 feet.

Lateral pipe size is 2.5 inch.

Main pipe size is 3 inch.

One lateral is usually operated at one time.

Sprinklers may be located on each lateral; or, sprinklers may be moved from one lateral to another lateral.

By moving sprinklers, initial system cost is reduced.

To operate one

lateral as shown, pump capacity required is about 120 gpm.

Note that there is a 70-foot border around the edge of the field to insure that no effluent is applied outside the field.

Figure 3.

Schematic layout of a permanent irrigation system used to land apply nutrientrich effluent.

General guidelines have been established and should be followed when designing hand-move, solid-set, and permanent systems.

For portable hand-move aluminum pipe systems, friction loss in the main and/or supply pipe should not exceed 2.0 psi for 100 feet of pipe.

For lines that are greater than 1500 feet in length, friction loss should not exceed 1.0 to 1.5 psi per 100 feet.

For PVC plastic pipe main and/or supply lines, flow velocity is the limiting factor rather than friction loss.

Velocity should not exceed 5 feet per second to prevent pipe failure due to water hammer.

Water hammer describes the buildup and sudden release of pressure that occurs when air is trapped in the pipe.

The buildup and release of the pressure increases as the velocity of the flowing water increases.

Friction loss in aluminum and plastic lateral lines should not exceed 20 percent of recommended sprinkler operating pressure.

Following this rule will assure reasonably uniform water distribution.

As sprinkler pressure is reduced, due to friction loss down the lateral line, the volume of water applied by the sprinkler and the diameter of coverage is reduced.

Most portable, solid-set and permanent sprinkler systems are medium to moderately-high in energy consumption, depending on whether small sprinklers or gun sprinklers are used.

Certainly, gun sprinklers will require higher pressures, increasing the power required.

Many of the portable systems use gun sprinklers.

Some growers are willing to trade off the higher energy costs for the savings in labor costs.

There are some gun sprinklers that will operate satisfactorily at lower pressures and some growers are using these, but they have reduced radius of coverage and, therefore, higher application rates, assuming equal flow rates.

There are some low pressure impact sprinklers that have been marketed for the last several years.

They also have reduced radius of coverage and this may increase the application rate.

Fuel costs are computed based on the energy required to deliver the required flow rate at the desired operating pressure.

To compute horsepower requirements, use the formula shown in the box at the top of the next column.

[TDH X Flow ]/ [3960 X Pump Efficiency]