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| Components of an OHS System |
Proper design of an OHS system is critical. The system must be capable of supplying water and nutrients in a very exacting
manner. Fully automated zone controls and fertilizer injection is essential.
The basic components of an OHS system are as follows:
OHS theoretically includes the irrigation and fertilizer application technology, and OHS systems can certainly be used in classical
grove designs. However, Arapaho recommends adoption of a Advanced Production Systems (APS) approach layered over the
OHS core technology.
The Advanced Production Systems approach includes the following:
Together, OHS and APS will allow Florida citrus growers to achieve high yields early in the life of a new grove. South Africans have
also proven that APS is the most effective way to achieve long-term effective management of Greening.
Costs:
The cost of establishing a grove with full OHS and APS features is much higher than for groves with lower tree density and
manually-operated microjet systems. Larger groves cost less per acre due to spreading the cost of the control system over more
acres. Otherwise, the delivery of water per acre is independent of the number of trees per acre, unlike microjet systems.
Our old cost "rule of thumb" for traditional microjet systems was about $1,000 - 1,200 per acre for the pump station and field
system, although this has been increasing due to the cost of plastics and labor. OHS drip systems will cost around $1,400 -
1,600 per acre, depending on the size of the grove. The biggest cost increase for new grove development will be that of the trees
and planting, due both to increases in the per-tree cost and the requirement for more trees.
Management costs will also be higher due to the requirement of hand labor. The pruning is a combination of hand and machine
as opposed to all mechanical as we now use in Florida. Other operations will require more hand labor as well. On the other
hand, savings will be achieved due to elimination of broadcast fertilizer applications, reduce herbicide costs since water and
fertilizer is applied only to small surface areas, and irrigation operation as result of hands-off automation and less maintenance of
emitters and lines.
Download Arapaho's Cost Comparison Model Here
manner. Fully automated zone controls and fertilizer injection is essential.
The basic components of an OHS system are as follows:
- Drip irrigation system
- Low flow, pressure compensating emitters
- Self-priming pumps
- Electric power (diesel power is possible, but more complicated)
- Automated fertilizer injection
- A minimum of two fertilizer supply tanks
- Control systems capable of full automation of valve operations, and proportionate metering of fertilizer
OHS theoretically includes the irrigation and fertilizer application technology, and OHS systems can certainly be used in classical
grove designs. However, Arapaho recommends adoption of a Advanced Production Systems (APS) approach layered over the
OHS core technology.
The Advanced Production Systems approach includes the following:
- High density plantings - 250 to 400 trees per acre
- Aggressive Psyllid control to reduce tree losses to Greening
- Plant growth, flowering and fruit set management to achieve early production
- Intensive pruning practices designed to maintain dense tree canopy
Together, OHS and APS will allow Florida citrus growers to achieve high yields early in the life of a new grove. South Africans have
also proven that APS is the most effective way to achieve long-term effective management of Greening.
Costs:
The cost of establishing a grove with full OHS and APS features is much higher than for groves with lower tree density and
manually-operated microjet systems. Larger groves cost less per acre due to spreading the cost of the control system over more
acres. Otherwise, the delivery of water per acre is independent of the number of trees per acre, unlike microjet systems.
Our old cost "rule of thumb" for traditional microjet systems was about $1,000 - 1,200 per acre for the pump station and field
system, although this has been increasing due to the cost of plastics and labor. OHS drip systems will cost around $1,400 -
1,600 per acre, depending on the size of the grove. The biggest cost increase for new grove development will be that of the trees
and planting, due both to increases in the per-tree cost and the requirement for more trees.
Management costs will also be higher due to the requirement of hand labor. The pruning is a combination of hand and machine
as opposed to all mechanical as we now use in Florida. Other operations will require more hand labor as well. On the other
hand, savings will be achieved due to elimination of broadcast fertilizer applications, reduce herbicide costs since water and
fertilizer is applied only to small surface areas, and irrigation operation as result of hands-off automation and less maintenance of
emitters and lines.
Download Arapaho's Cost Comparison Model Here
| Below - 4 year old OHS Lemon Planting near Nelspruit, South Africa. This planting produced 500 boxes per acre of seedless lemons 36 months after planting. Greening is present in the grove, but tree losses have been minimal due to psyllid control with Admire injected into the drip system. |