Zimmatic center pivots significantly reduce water use when compared to flood or furrow irrigation. See the case study on how much can be saved. The advantages of pivots or laterals over flood irrigation include:
- Labor savings
- Significant water savings, and thus energy savings to pump the water
- Ability to apply chemicals/fertilizers through the pivot for more effective application when needed
- Less habitat for mosquitoes
A soil map for a field in Osceola, Arkansas (Figure 1) shows an area of loamy sand running through the length of the field that would prevent the field from sustaining flood water for traditional rice production. The red circle roughly outlines the area of the field irrigated by a Zimmatic center pivot.
The south half of the field was planted to rice and irrigated with the Zimmatic center pivot. A yield map from one of two combines used to harvest the field (Figure 2) shows the excellent uniformity of the resulting rice crop. Variations in rice yield did not exhibit patterning related to water application by the center pivot (which would appear as arcs or bands through the field).
Close examination of the data did reveal that rice yield increased as the texture of the soil became lighter (Figure 3). The highest yield of 10.6 MT/ha was recorded in the lightest textured soil (Covent fine sandy loam). These results show that rice grown under center pivots can have yields equal to rice grown in traditional flooded fields.
Automatic pivot irrigation systems save on labor inputs. Not only are the systems automatic but you can monitor and control them remotely via the FieldNET telemetry system. Pivots can also easily apply fertilizers eliminating the cost of aerial application of nitrogen. In addition to savings on irrigation labor, the University of Arkansas has shown additional savings in the following areas:
• Survey levees
• Pull leeves
• Install levee gates
• Remove leeve gates
• Tear down levees
• Irrigation labor
• Repair & maintenance
And if you are starting on new land, using pivots save you the costs of initial land survey, laser leveling and other land preparation costs.
Automatic center pivot irrigation systems deliver the precise amount of water required and at the precise moment it is needed for your rice crop. Rice growers in Australia, Brazil and the USA have realized water savings of 20% to 50% with pivot irrigation as compared to traditional flood irrigation. This is accomplished through automated controls and specially designed sprinkler packages. This is especially true because rice is a very shallow-rooted crop where heavy applications of water may cause problems. Pivot irrigation of rice now makes it possible to grow rice on sandier fields that was not possible using flood irrigation.
Pivot irrigation case studies indicate water savings of 20-50% compared to flood irrigation. As this water needs to be pumped, there is a correlation between water savings and energy savings. The Michael McCarty case study in Osceola, Arkansas, USA showed a 37% energy savings for only a water savings of 21%.
By combining Zimmatic center pivots for rice irrigation with Watertronics pump stations, even greater efficiencies can be attained. Only Lindsay offers FieldNET with Pump Control that integrates the pivots and pumps into one control system. This unique product turns pumps on and off with changes in demand while increasing the life of the individual pumps. Each pump station is custom tailored to the specific irrigation project and is factory tested to assure field reliability.
Growing rice under pivot irrigation versus traditional flood methods has many additional benefits besides water, energy and labor savings. One of the greatest benefits is the added flexibility it brings to you farming operations and market potential. The benefits and possibilities include:
• Grow rice on lighter soils that cannot handle traditional flood irrigation
• Open up new areas such as sloping fields or hilly terrain to rice cultivation
• Rotation of rice with other crops to improve soil condition/fertility
• Flexibility of rotating different crops to meet market demands
• Elimination of the need for puddling reduces tillage requirements
• Early season rains less likely to drown germinating rice (direct seeded)
• Fields will dry earlier – Earlier harvest
• Reduced wear and tear on machinery
Using pivots for irrigating rice versus flood irrigation has many positive environmental benefits. The key benefits include:
• Uses less water, conserves a valuable resource
• Eliminates habitats for disease carrying mosquitoes
• Reduces greenhouse gas emissions that is common with flooded field
• Less pumping means less energy consumption and a reduction in emissions
• Allows for crop rotation enhancing soil health
The essentials for successful pivot rice irrigation include:
• Using improved rice genetic varieties
• A comprehensive chemigation/fertigation schedule
• Using the correct sprinkler package designed for irrigating rice
• Rotating crops
• New tracking solutions for better floatation where required
• Remote control & monitoring of pivots for labor and water savings
Managing chemical and fertilizer resources on rice is easier than ever with GrowSmart's line of injection systems. Using a pivot to apply fertilizers and chemicals have many advantages, including:
- Uniform and precise chemical and fertilizer application
- Easy, automatic incorporation and activation of the chemicals
- Potential use of lower amounts of chemicals and reduced application costs when compared to flood irrigated paddy rice
- Reduced operator error and environmental hazard potential due to lower concentrations of chemicals, reduced handling of chemicals and potentially chemical leaching and runoff.