Following the drought and dust storms of the 1930s the US federal government’s response was to invest $13.8 million to plant more than 200 million trees and shrubs throughout the Great Plains. These planting were initially established to reduce windblown soil, but research suggests there is an additional benefit that would surprise many agricultural producers.
Windbreaks increase crop yields!
How can this be? Many producers notice the obvious reductions in crop yields in the zone immediately adjacent to windbreaks. But is seeing always believing?
Past research has shown that the crop yield reductions immediately adjacent to windbreaks are more than compensated for by increased yields in the “protected zone” further out from the windbreak. These yield increases were summarized on a worldwide basis as far back as 1986 at the First International Windbreak Conference, held in Lincoln, Nebraska, and documented yield increases from 8% to 23% for corn, wheat and soybeans.
Some economists also suggest that field windbreaks pay for themselves within 10 to 15 years and provide additional income over their remaining life span, even accounting for the land occupied by the windbreak and the yield reductions in the root zone of the trees.
To check the validity of this long-standing research, discourage the removal of shelterbelts and encourage the planting of new ones, a crop yield study is being developed throughout the US Great Plains with cooperation from partners in the Canadian Prairie Provinces.
The Great Plains Crop Yield Study will gather information from electronic yield monitors that are now found in many combines, in order to assess the effects of windbreaks on crop yields.
The study’s idea is to compare multiple years of data from fields with and without windbreaks over a large area and from many farmers. Because we are looking for relative crop yield changes and not absolute numbers, this approach minimizes the variables of rainfall, fertility, crop rotation, and farming methods. The key is that the data already exists with farmers. When combined with GPS, yield monitors can provide crop yield data for virtually every point in a field.
The first step is to find landowners who are willing to share their yield monitor data. Ideally, these data would be from both windbreak-protected and unprotected fields. The fields will be identified on aerial photography and when windbreaks are involved, their effectiveness will be determined. This will involve making a few on-the-ground observations and measurements. Then the landowner can either upload the monitor data to a site for analysis or save it to a storage device for uploading later.
The eventual outcome from this study will be an updating of our knowledge of the windbreak/crop yield interaction. This information will be shared among farmers and conservationists through technical reports, journals, agriculturally related publications, and conferences. By the way the study has been designed, it will not be possible to report comparison yield results for a specific locality. However, if the study can include several years of data, we may in time, be able to answer other questions. For example, do windbreaks have greater, lesser, or no effect during times of drought? Are windbreaks more effective with some crops and less with others? In short, creating a database that spans several years and a wide region may potentially add value to agriculture production beyond the original purpose of the study.
(This article was excerpted from “Kansas Canopy” Issue #49 – Winter, 2013)