Prepared by: Bob Hochmuth, UF/IFAS, Regional Extension Agent
University of Florida, North Florida Research and Education Center- Suwannee Valley, Live Oak, FL
Windbreaks in watermelon production have been a standard practice for many years. Cereal rye has been used as a windbreak in watermelon fields for years in the Suwannee Valley of North Florida and also for much of the watermelon production areas up and down the eastern part of the US. Windbreaks are primarily used to reduce damage from wind and blowing sand. Windbreaks are needed because of the timing of the watermelon season stretching the period of the year when winds are guaranteed in Northern Florida, March, and April. In addition to the main justification for using rye windbreaks, and reducing damage from winds, there are many other hidden merits of rye and other winter small grains in our watermelon production system. Let’s review these beneficial points in honor of the role rye windbreaks play in our system.
Rye, when established early, can serve as a windbreak, and protects the young crop from high winds in March and April (Photo 1).
Of the small grain options in much of Central and Northern Florida, rye generally provides the greatest growth during the winter when temperatures are cool. Other small grains such as oats can also be used successfully in place of rye. Small grain windbreaks can be used in a watermelon production system using a few different strategies. Strategies include:
The first method is solid seeding the small grain across the field well in advance of laying plastic, and later rototilling out the strips where the watermelon rows will go. Thus, leaving windbreaks between each row. These tall windbreaks between rows will need to be mowed or disced to terminate them.
The second strategy is seeding the 5-10-ft swaths of small grain only in the areas where the sprayer and harvest vehicles will later travel. This method leaves one strip every 40-60 feet. These strips must be seeded early so the strips have sufficient time to grow in height.
A third strategy is seeding between each row after plastic mulch is laid. This method is helpful in minimizing sand-blasting but is not as effective as an actual windbreak because it does not have time to grow very high before the crop is planted. The small grain between each bed will need to be terminated by mowing, discing, or spraying (Photo 2)
Studies have shown that the effective distance of wind reduction on the lee side (protected side) of a windbreak is at least 10 times the height of the windbreak. So, the taller the windbreak, the greater the distance it provides protection. Windbreaks that are 4 to 5-foot-tall should provide 40-50 feet of protection, assuming the rye strips are perpendicular to the wind direction. Along with just the wind alone, we see great damage when sand is blown too. This fact was very evident in 2022 where we had persistent high winds for several weeks. Watermelon plants on leeward rows closest to the rye strips (only in spray roads) sustained much less damage than rows further from the rye strips.
These wind-associated benefits are very familiar, but rye has some other less known pest-related features as well. Aphids are often found feeding in the rye, but these are grain aphids and pose no threat to watermelon. However, these grain aphids are a food source for many beneficials, mainly lady beetles, parasitic wasps, and syrphid fly larvae. We most frequently see high populations of lady beetles on watermelon rows next to the rye windbreaks
We also commonly see “mummified” aphids which are aphids that were parasitized by tiny parasitic wasps and syrphid fly larvae which consume aphids (Photo 4). Mummified aphids are brownish in color and appear very plump. Syrphid fly larvae are small maggots with relatively flattened bodies.
Cereal rye also produces several compounds in its plant tissues and releases root exudates that inhibit the germination and growth of weed seeds.
These allelopathic effects, together
with cereal rye's ability to smother other plants with cool weather growth, make it an ideal choice for a windbreak. Have you ever noticed there is little to no nutsedge in the rye windbreaks when the rye is actively growing? This allelopathic effect of rye is why few weeds are associated with rye strips, especially when the rye is started early. A healthy rye windbreak, after it is mowed down can also provide cover to the soil keeping the soil cooler and helping shade out weeds in the row middles.