Drought mitigation options for growers

Despite soil-parching drought, green sweet corn plants in the background tower above protective organic mulch in a cornfield in Beltsville, Md. In the foreground, Plant Physiologist John Teasdale inspects corn planted in bare soil that won’t be worth harvesting. Some growers have adopted vetch systems for tomatoes, and researchers are testing similar cover-crop systems for peppers, cantaloupes, snap beans and other vegetables.

For some growers, 2007 held a truckload of challenges—late freezes and drought were just a couple. In many areas, rainfall deficits continued into the new year. The U.S. Drought Mitigation Center at the University of Nebraska-Lincoln says that portions of the West, Midwest and South are currently suffering from conditions ranging from abnormally dry to exceptional drought. The worst–hit areas include Texas, especially the southern part of the state, which is the only U.S. region in exceptional drought. Portions of southeastern states from Alabama to Virginia are heavily impacted, along with North Dakota.

The Climate Prediction Center expects significant relief in Florida and a general easing throughout the Southeast in the near future. Many areas now affected are expected to receive some rain over the next few months. Long-term estimates indicate that the Carolinas and neighboring states will continue to experience drought conditions. The West will also be dry, with improvement anticipated in the Midwest.

Growers cope with drought

Tom Saunders is among those who may be dealing with dry conditions into the future. He, his father and brothers operate a 150-acre orchard of apples, peaches and pears, along with a 400-greenhouse container nursery in Piney River, Va. Saunders says learning to practice water conservation has been vital.

“We have put a lot of money and capital investment into irrigation ponds,” he says. “Our nursery relies on a live water source; if the supply drops, we need to have something to fall back on.”

The farm recently completed two ponds, one in the field and another in the nursery. The pond in the field provides additional water storage, while the nursery pond captures runoff for reuse.

“We used a lot of [the runoff] last year,” Saunders says. “Knowing you have it makes you sleep better at night.”

Although recycling water can increase disease pressure, he manages the problem by chlorinating it. He reduces water needs by growing on plastic and shading plants with canopies as quickly as possible.

Cyclic irrigation, the practice of delivering a plant’s daily water needs in several small quantities, has been successful for Saunders. He further maximizes water efficiency by irrigating at night to avoid the affects of wind and high temperatures. He adds that the practice has a side benefit of reducing fertilizer requirements.

The view from Florida

Florida growers have also battled dry conditions for close to two years in some regions. Alan Peirce of the Florida Fruit and Vegetable Association (FFVA) says that the future looks wetter, giving farmers an opportunity to recover and to take steps towards mitigating future drought effects. He points out that, as often is the case, certain locations have been heavily impacted while others have received close to normal rainfall.

As manager of government affairs for FFVA, Peirce works with the state’s five regional water management districts on behalf of growers. These districts set water permit amounts based upon normal rainfall; when Mother Nature is less generous, growers may not be able to access enough water for supplemental irrigation. He says that growers have adapted by utilizing the most efficient low volume irrigation systems, such as drip and microjet. Tailwater recovery systems have worked well in some areas, as have shallow horizontal wells that collect water from unconfined surficial aquifers. Some municipalities make reclaimed water available to agriculture and other industries with high water needs. Other coping strategies include using plastic mulch to reduce losses through evaporation and seeking out improved varieties that have lower water needs. Some growers have reduced acreage or converted to alternative crops due to water issues.

The Florida water districts have lent a hand to growers through several programs. Cost share assistance may be available to those modifying their irrigation methods. The Southwest Florida Water Management District, in conjunction with the state department of agriculture, offers a FARMS cost share program that has funded many projects designed to reduce the demand on groundwater for irrigation and freeze protection. Some of the districts also sponsor mobile irrigation labs, which provide irrigation system evaluations to insure efficient operation.

Coping strategies from the Sustainable Agriculture Network

In its publication, “Smart Water Use for Your Farm or Ranch,” the Sustainable Agriculture Network (SAN) outlines an overall strategy for water conservation. It combines management of soil, plants and water to help combat dry conditions.

By building soil quality, a porous soil is developed that traps water for effective irrigation of crops. Boost organic matter by applying manure and/or composts. Use cover crops to build up nutrients as the plants die. Reducing tillage helps prevent loss of organic matter.

Plant management includes choosing drought-tolerant varieties and crop rotation. Combined with a strong cover crop program, water can be better maintained within the soil and erosion is reduced.

Increase irrigation efficiency by using timers and/or soil moisture monitors. Farmers in New Mexico using a traditional ditch/dam method enjoyed greatly improved results thanks to a Sustainable Agriculture Research and Education (SARE) program grant. An aboveground gated pipe method was an inexpensive and simple–to–operate solution. The pipes contain holes covered by slide gates that control water flow.

Combining fruit and vegetable production with aquaculture can improve water efficiency and crop quality; it also adds a new revenue source from the fish grown. Such a water cycling/aquaculture project was tested on an Arizona farm. Shrimp ponds and olive trees were chosen to test the outcome of running water through two systems. After circulating through the ponds and picking up nutrients from the shrimp, the water was redirected to the trees, which showed improved canopy height and trunk circumference over trees irrigated with well water. By the second year, the ponds yielded 100 percent of the trees’ nitrogen needs. The shrimp pond sludge was found to effectively replace nitrogen and potassium fertilizers for tomatoes.

The publication is available online at www.sare.org/publications/water.htm.

“Crops are not generally lost due to droughts, but yields can be affected and pumping costs can affect the cost of production,” Peirce says. “Droughts can have a significant economic impact on agriculture.”

With periodic or ongoing drought forecast in many locations, planning ahead can help growers cope. “Agriculture will continue to make [the] changes that are needed,” Peirce predicts.

The author is a freelance writer based in Greensboro, N.C.

Tips from the Natural Resources Conservation Service

The Natural Resources Conservation Service suggests the following steps in planning for drought management:

• Choose the irrigation system that reduces water loss caused by evaporation, percolation and runoff.
• Maximize the efficiency of existing irrigation systems.
• Build a water storage system to hold water for use in irrigation.
• Store water in ditches along fields.
• Use water measurement devices to track use.
• Use water from deep aquifers rather than surface water.
• Use conservation tillage.
• Minimize runoff.
• Monitor soil moisture.
• Maintain buffers, filter strips, grassed waterways and other types of conservation buffers near water sources
• Plant crops that withstand dryness, hold water and reduce the need for irrigation.
• Rotate crops in ways that increase the amount of water that enters the soil.
• Use cropping systems that are less water dependent.

 

Resources

Learn more about drought management from your cooperative extension service and state department of agriculture. These Web sites also provide information:

National Oceanic and Atmospheric Association: www.noaa.gov/

Drought Monitor: www.drought.unl.edu/dm/monitor.html

Drought Calculator: http://www.lwf.ncdc.noaa.gov/oa/climate/research/drought/drought.html

State/Regional Moisture Status: http://www.lwf.ncdc.noaa.gov/oa/climate/research/prelim/drought/state-reg-moisture-status.html

National Drought Mitigation Center: www.drought.unl.edu/

Farm Service Agency Disaster Assistance Programs: www.disaster.fsa.usda.gov

Conservation:

www.wateruseitwisely.com

www.waterinfo.org

Emergency Watershed Protection Program: www.nrcs.usda.gov/programs/ewp/index.html

Noninsured Crop Disaster Assistance Program:

www.fsa.usda.gov/FSA/newsreleases

USDA Crop Insurance: www.rma.usda.gov/policies/