Bob Dylan penned the words to his smash hit, “The Times They are A-Changin’” in the fall of 1963. The lyrics reflected Dylan’s views on social injustices and the growing awareness that change was inevitable.
As predicted, a lot has changed since the release of Dylan’s song, including the climate. As a child growing up in Tulsa during the 60s, I recall cold snaps lasting longer during the winter months in contrast to present day. We expected snow, and Old Man Winter delivered. Every kid on our block owned a snow sled, and we actually got to use them. Not so much today.
According to the Oklahoma Climatological Survey, annual statewide temperatures during the 60s, 70s and 80s were lower on average than the long-term average going back to 1895. Beginning in the mid-90s, annual statewide temperatures began to rise and have remained above the long-term average to present day. The point is: When it comes to climate, change is inevitable. The climate has been in flux for thousands of years and will continue to change.
Several years ago, I had a conversation with Al Sutherland, former Oklahoma Mesonet Agriculture program coordinator, about extreme weather events and the unpredictable nature of these events that we are currently experiencing. According to Sutherland, many climatologists believe these events are a manifestation of the current round of climate change and will continue to escalate in frequency and magnitude over time. Doesn’t paint a pretty picture for agriculture, does it?
A high tunnel hoop house is moved onto a raised bed plot in preparation for establishing a tomato crop.
Fortunately for specialty crop growers, there is a plethora of crop protection technology available to assist in these changing and challenging times. The application of these technologies enable growers to be better risk managers because they can exercise more control over Mother Nature.
Protected agriculture can be defined as the use of active and passive technologies/practices to protect crops and animals from harsh weather conditions and pests in order to maximize yields and enhance product quality.
Active technology, like greenhouses, require the input of an energy source such as natural gas and/or electricity. While greenhouses offer the highest level of environmental control, they are expensive to install and operate.
Passive technologies provide less protection but can be utilized without the purchase of an energy source. A few of these popular technologies include raised beds equipped with plastic mulch film, floating crop covers, low tunnels and high tunnel hoop houses.
Raised beds, shaped and permanent, protect crops from flooding rains by limiting the occurrence of soil saturation. The same can be said of container culture. The effectiveness of a raised bed growing system is maximized with the use of plastic mulch. With shaped beds, the mulch film cover insures bed integrity by eliminated the possibility of erosion during flooding rains.
Floating crop covers offer protection during frost and freeze events. These covers are light enough to be laid over the top of plants. Various thicknesses (weights) of covers can be used depending on the degree of protection desired. Depending on soil temperature and cover elevation above the soil (plant size), heavy weight covers can provide up to 8 degrees of protection. Lighter weight (thinner) covers that transmit more sunlight are commonly used to hasten crop development during periods of unseasonably cool temperature.
Low tunnels are temporary hoop structures fitted with either floating crop covers or greenhouse film. They typically range in height from 1 to 3 feet depending on crop type and maturity stage. In addition to freeze protection, tunnels equipped with crop covers provide a degree of wind protection. Tunnels equipped with greenhouse film provide protection from wind and rain.
High tunnel hoop houses are low tunnels that have grown up; they are larger, stronger and can do more work. These greenhouse-sized structures are typically covered with a single layer of greenhouse quality polyethylene film. Greenhouse films can be purchased tailored to a grower’s specific needs. Growers can choose a light diffusing film, a cooling film, a thermic (heat retaining) film, an anti-drip film or a combination of the above. They also have a choice of different film thicknesses and types: standard, woven or bubble. Factors used in film selection include crop(s) to be grown, location (latitude), season and service life requirements.
A fully equipped and properly managed hoop house is a working definition of synergy. When equipped with plastic mulch, covered raised beds and low tunnels, a hoop house is capable of providing a degree of crop protection greater than the sum of its parts. This synergy is the product of increasing efficiency with the layering of each technology.
Another protective technology involves the use of netting to shelter crops from hail, to shade crops from intense sunlight and to reduce wind speed. Netting is available in different mesh sizes and strengths depending on its intended use. It is typically suspended over the crop using a network of cables or placed over the top of a low or high tunnel.
The times, they are a changing; there’s no doubt about it. The question is, are you willing to change with the times? Knowing climate-related production risks will continue to increase, will you continue business as usual or will you adopt crop protection technology in order to better manage these risks? The choice is yours.