Growing Magazine - April, 2012
Water Management For Productive Orchards
Water is an issue for all growing operations, regardless of their size. Sometimes the problem is too little water, as was the case across much of the South with the severe drought the last few years. Other times the issue is too much water, directing it and making use of it before it washes precious nutrients away from the orchard.
A recent discussion on Twitter focused on the issue of water. The chat opened with a question as to what the biggest issues were. Richard Mason in Kentucky responded: "Very wet season last year. Not great [for] organic produce farmers as it causes crops to rot in the field faster than you can harvest." Trevor Smith, a Coffee County, Ga., watermelon, cotton and peanut farmer, added, "All of our irrigation ponds are dry right now. Severe drought, especially for this time of year."
A buffer strip along the left side of this field slows water before it runs into a stream. This is an effective strategy for many orchards.
PHOTOS BY JAN HOADLEY.
At Steele Orchards, near Cullman, Ala., Linda Steele notes that "water is an issue, depending on the rootstock; especially [the] dwarf varieties, [they] need more water, [and] we will need to irrigate, which we've never had to do before." She adds, "We're trying a trellis type of growing apples, and even irrigated new rootstocks [last year]."
That met with challenges beyond water, she notes, as they were in a cooler when the tornadoes went through Alabama in April 2011. Like many in the region, the Steeles were without power, which meant the coolers didn't work and the rootstock became stressed. However, the decision was made to plant them anyway.
At one point they used water they had washed apples in, but there wasn't enough water. "A pump was more involved than what it was worth," she notes. One of the orchard's peach varieties is usually ready for a July market, but if the rains don't come when needed in June it will affect the size of the fruit.
Chiles Peach Orchard, near Crozet, Va., is a family operation with the third, fourth and fifth generations active on the farm. Henry Chiles says, "We use low-volume irrigation to conserve water." He notes that they used to use overhead sprinklers, but have found that with drip irrigation versus overhead there's about a 90 percent savings in water use.
He notes that they also monitor the trees, so only trees that need it are watered. The farm also breaks up the subsoil so water doesn't run off, and they make better use of the water that's available.
As with any industry, technology changes things. Chiles notes the difference in filters used for drip, saying the technology for filtering is better than it was 10 years ago.
To combat the problem of too much water, Chiles says, "If there are wet spots we use some tile, but not very much."
The Almond Board of California's website (www.almondboard.com) discusses water issues in its section on orchard management. The website states: "The choice of an irrigation system depends on a number of factors including the types of soils, the variety of almonds grown, the disease and pest pressures, frost potential and protection, as well as the cost and availability of water."
While this is a focused application in a specific part of the country, it pays to seek advice from those who have been there rather than trying to reinvent the wheel.
Soil conservation is also a factor. Rob Wallbridge commented on the Twitter chat: "Farms of all sizes can work to increase organic matter levels in their soils. A 1 percent increase [in organic matter] holds 1 inch of rain!" This can make a big difference in times of drought when water is scarce.
It's important to remember that organic matter in the soil serves as a storage area for nutrients and water, aids in reducing compaction, and increases water infiltration into the soil. It acts like a sponge, but it isn't a quick fix. Composted material is just one way to add readily available nutrients.
Eddie Funderburg, of the Samuel Roberts Noble Foundation, says, "Many times we think of organic matter as the plant and animal residues we incorporate into the soil. We see a pile of leaves, manure or plant parts and think, 'Wow! I'm adding a lot of organic matter to the soil.' This is actually organic material, not organic matter. What's the difference between organic material and organic matter? Organic material is anything that was alive and is now in or on the soil. For it to become organic matter, it must be decomposed into humus. Humus is organic material that has been converted by microorganisms to a resistant state of decomposition. Organic material is unstable in the soil, changing form and mass readily as it decomposes."
Organic matter changes the soil structure, allowing the soil to better retain water, making use of it for the plants, or in this case trees, that are nourished from it. Such a big improvement can be made by adding organic matter that the University of Minnesota states that on sandy soils in a dry year it can mean the difference between crop failure and crop survival. That could be a huge benefit to orchards in the South, especially those that have experienced record drought recently.
One way to add organic matter is the use of a cover crop. This can be a drawback for orchards, as the cover crop would compete with trees for water, and the organic material may attract pests.
The University of California, Davis, notes that legume cover crops break down quickly once mowed. Winter cover crops can make use of winter moisture, and a spring or summer mowing makes the organic material available for breaking down to organic matter. The roots also add matter to the soil.
Perhaps few operations deal with growing on the level of Stark Brothers, a Missouri operation that is known for their part in bringing trees to small and backyard growers. With a balance of fruit, nut and landscape trees as well as berries, and almost 200 years of history, there's a lot of experience and knowledge of how to create long-term success. A reputation for trees that grow in a variety of conditions means they know the importance of the basics, including water.
Stark Brothers' Chief Production Officer Elmer Kidd says, "The biggest change we have witnessed in fruit orchards in the past 10 to 20 years has been the increase in the propagation of dwarf fruit trees. Dwarf fruit trees tend to have more shallow root systems and, therefore, have an increased need for regular watering.
"We are fortunate to live in an area [northeastern Missouri] that receives adequate rainfall for our orchards. We utilize active weed management to avoid the misuse of what water we do provide our fruit trees. Other than that, we use drip irrigation in orchards like our new espaliered apple orchard to maximize the use of the water."
Although many recommend using reclaimed or recaptured water, Kidd is cautious. "It is a method that works for some people, but we avoid it here because of what may remain in the reused water. Naturally occurring elements like nitrogen, which is rather salty, and phosphates (things found in fertilizers) will not be completely broken down, and will still exist in the reclaimed water. It would not be most beneficial for the trees. There is the condition of 'reclaimed from where?' We would be much more comfortable reclaiming water from the greenhouse roof than we would be reclaiming the water that was applied to the plants already. Fruit trees do not require the amount of nutrients that they may end up taking in again with reclaimed water," he explains.
To handle excess water, Kidd notes, "Our orchards have had tiling in place for years and years, and it is certainly a good method for dealing with growing areas that have a tendency to become too wet."
Poor water quality, be it high salinity or high bacteria counts, hurts growers. Making the best use of available water means managing irrigation, as well as planning for excess water and balancing both by protecting water quality. There are several ways to do that, and it may vary depending on the size of the orchard and to some degree the specific crop:
Vegetated buffer ditches or strips
These slow the water, and as it slows it is more apt to sink in rather than run off. This reduces erosion, nutrient loss and wasted water. It doesn't need to be a deep ditch; shallow channels are just as effective. Typically located at the lower end of the field, and if the field experiences excessive runoff, consider a holding pond to capture the water.
The use of drip irrigation or micro sprinklers reduces water waste.
A nutrient management program not only keeps trees healthy, but also avoids waste from having an excess of nutrients the orchard doesn't need.
Breaking up the soil
Spring chores may include a trip through the orchard with a spring tooth harrow, breaking up the surface enough to allow for additional water holding capacity.
Water is critical to an orchard's survival. Review your water management program for the best possible future for your orchard.
Jan Hoadley is a freelance writer based in Alabama.