Cooperators: Blaine Hanson and Stephen Kaffka
Introduction: Irrigation water for field crop production will become increasingly limited in California. Drip irrigation has been shown to reduce irrigation water needs compared to sprinkler or furrow systems for a variety of crops under some circumstances. At times, reduced water use also is correlated with increased yields compared to other irrigation alternatives because of improved grower ability to apply water, nutrients and pesticides in a timely manner. Currently, drip technology is used with vegetable and fruit crops primarily, but a sugarbeet crop has been produced successfully in California using drip irrigation in District 7. There has been little, if any work evaluating the effectiveness of drip irrigation with sugarbeet.
In addition to the possiblities for water conservation, drip irrigation may have a role in reducing losses to root rots and rhizomania (Beet Necrotic Yellow Vein Virus) in sugarbeet crops. During the warm summer months, sugarbeet must be irrigated frequently, resulting in long periods when soils are saturated and temperatures are high. Such conditions are conducive to the development of many of the common root rot organisms and to losses to rhizomania. By lowering soil water potentials near sugarbeet roots, the activity of Polymyxa betae K., the vector of the BNYVV, also may be significantly reduced.
There has not been any work to date examining the use of drip irrigation systems with sugarbeet, nor any field-based work examining the relationship between soil saturation and common root rot pathogens oer with rhizomania. The cost of drip irrigation systems has been declining due to new concepts and materials. If advantages from the use of drip irrigation can be demonstrated for several different field and vegetable crops, the use of drip may become a consideration for more producers. If sugarbeet can be shown to be well adapted to drip irrigation, producers with drip systems established may consider using sugarbeets in their crop rotations.
Objectives: This study sought to characterize
the use of drip irrigation with sugarbeet, and to measure the moisture
characteristics of the soil profile in which the beet crop develops. The
occurrence of pathogenic organisms will also be evaluated. Specific objectives
were to:
2. characterize soil profile moisture patterns and measure soil moisture potentials at different locations in the profile under the different irrigation treatments, and
3. contrast differences in water use, crop growth, yield and disease incidence in drip and furrow irrigated plots.
Results:
1. Yield. There were significant differences between individual irrigation treatments with the highest yielding treatment being 2x-Weekly irrigation at 0 inch depth (6158 lbs.sucrose per acre) and the lowest being Daily irrigation at 12 inch depth (5185 lbs.sucrose per acre). See Table 1.
When treatments were aggregated by irrigation frequency, there was a trend towards higher sugar yields with less frequent irrigation (figure 1), but this trend was not significant. Similarly, when aggregated by depth, the deepest drip lines tended to result in the lowest yield overall, but not significantly so (figure 2).
There were no other significant crop yield or quality trends related to irrigation treatments. Root rots were not observed in any of the treatments.
Average yields from the furrow irrigated treatments, at 6,113 lbs. sucrose per acre, were significantly higher than all but one of the drip treatments.
2. Water use.
Discussion:
Conclusions:
Table 1. Mean sugar yields for individual irrigation
treatments
| Irrigation Treatment |
|
| 2x-Weekly (0") | 6158 |
| Weekly (0") | 5693 |
| Weekly (6") | 5654 |
| Daily (0") | 5582 |
| 2x-Weekly (6") | 5507 |
| 2x-Weekly (12") | 5446 |
| Weekly (12") | 5363 |
| Daily (6") | 5320 |
| Daily (12") | 5185 |
| LSD(0.05) | 612 |
| Furrow Irrigation | 6113 |