OVERTON — Eleven years ago, when Marty Baker moved to East Texas, plastic mulch was used only by the rare grower. Today, Baker – a horticulturist with the Texas Agricultural Extension Service — knows of more than 3,000 acres of melons and vegetables grown using the black plastic film.
For those 11 years, Baker has persistently promoted plasticulture concepts and associated technologies at field days, at growers’ meetings and at county-wide educational events.
By any accounting, the savings in water, not to mention the benefits reaped by producer and melon producers via the simple but effective new technology, have been enormous. Now, with help from Senate Bill 1, Baker, other extension specialists and county extension agents will be able to further refine the technology and expand its use.
At first glance, plasticulture is pretty simple. It saves water the old-fashioned way: it interns it. Black or black plastic sheeting, about the same thickness of a good quality garbage bag, is laid over seedbeds or furrows before planting. The impermeable plastic traps moisture, preventing it from escaping into the air.
Simple in theory, but more is happening than meets the eye, Baker said. During the cool evening and night, moisture condenses on the under surface of the plastic and rains back on the soil.
Used in conjunction with another technique, called “rainfall” capture, plasticulture has been known to carry a crop through to harvest in good shape with next to no rainfall during the entire growing season. With rainfall capture, the plastic is laid over furrows. In the troughs between the raised furrows, holes are punched to allow rain water to enter. When the crop, melons or other produce, is planted several months later, there may be enough water trapped under the plastic to allow it to mature without further rainfall or irrigation.
But plasticulture does more than just trap water. Because it lowers the need for chemical fertilizers and pesticide treatments, the plastic lessens the chance that excesses of such agri-chemicals will leach through East Texas sandy soils and into the water table. Because it shades out unplanted ground, just as conventional mulch does, it prevents weed and grass growth, thereby limiting or completely eliminating the need for herbicides.
The composted chicken litter adds organic matter to East Texas sandy soils, increasing their ability to hold water. Also, the soil nutrients are slowly released into the soil as the chicken litter breaks down, thereby lessening the chance of excess nitrogen and phosphorus leaching into groundwater supplies, according to Baker.
Though the water savings and environmental benefits are substantial, from a grower’s standpoint, plasticulture’s best characteristics are economic.
Despite all these benefits, Baker has had a hard time convincing some East Texas growers it is in their best interests to adopt plasticulture. The material cost for the plastic alone can add $200 to $300 per acre in production expense.
“East Texas has an average annual rainfall of 45 to 68 inches. Some of the old-timers don’t think it’s worth it.”
But the plastic does more for the grower, particular melon growers, than save water. By stabilizing water availability, plasticulture improves melon quality. By shedding heavy rains, the plasticulture prevents melon cracking. Sitting on bare soil, melons may create their own bowl shaped depressions. Heavy rains can collect in the depression. On a bright, sunny East Texas day, the collected water may become hot enough to cause the melons to crack.
“Plastic mulch can prevent diseases, too. When you have melons just sitting on the ground, melons are also at higher risk from plant diseases,” Baker said.
Plasticulture can also give a melon grower a marketing advantage. Because the black or brown plastic absorbs solar energy and warms the soil, it allows the melon grower to plant weeks earlier. An earlier planting means the crop will usually be harvestable for the Texas June 19 and national July 4 holidays.
In the Rio Grande Valley, where water is more scarce, Extension specialists have had an easier time getting growers to adopt plasticulture, said Dr. Frank Dainello, a College Station based Extension horticulturist. That plasticulture made possible earlier marketing has also had a big effect, but water savings was the key, said Dainello, who began working with plasticulture in the 1980s as a Texas Agricultural Experiment Station researcher.
Dainello said the real credit should go to Dr. Tim Hart, who introduced plasticulture technology in the Valley in 1981 or 1982. From Extension demonstration plots, growers quickly realized they could save 25 to 30 percent or more of their water costs using plasticulture. Currently, most of the Valley’s 14,000 to 15,000 acres of melon crops are under plasticulture, making the water savings enormous.
Dainello can take responsibility for developing the rainfall capture techniques. Thistechnology greatly expanded the versatility of plasticulture. Without rainfall capture, growers feared they would lose rainfall because the black plastic shed it.
Dainello is currently looking into adapting plasticulture and rainfall capture to irrigated crops such as cotton and corn. Currently, the economic value of such agronomic crops does not justify the added production costs of using plasticulture. But if water becomes more expensive, which it most certainly will as Texas water needs increase, then Extension specialists such as Dainello and Baker hope to have a technology ready.