From the 1930s Dust Bowl to the 2012 drought: What can we learn?
November 19, 2012
The recent drought experienced throughout much of the United States has many similarities to the conditions during the Dust Bowl of the 1930s. The Dust Bowl, also called the Dirty Thirties, was a period of severe dust storms brought on by drought and poor farming methods. The period spanned several years, but conditions were especially bad in 1934 and 1936. While soil management practices are better over 80 years later, high temperatures and water shortages this past year created crop losses and poor environmental conditions that echoed the Dust Bowl.
At a special session at the recent American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America Annual Meetings, three prominent researchers highlighted the comparisons between the 2012 drought and the Dust Bowl, and discussed ways in which we can learn from both phenomena. With more than one-third of the United States in severe drought or worse in August of this year and the threat of rising food prices looming, understanding the risks and impacts of drought is necessary.
Dennis Todey, extension state climatologist from South Dakota State University, focused on the causes and lessons of the 2012 drought. The combination of a dry fall and high temperatures early in the spring kick-started the drought, he said. With a hotter than average March, many plants began emerging earlier than usual. This premature start used up the little soil moisture that was available, setting the stage for severe water shortages later in the summer. Even with sufficient rainfall, evaporation and plant transpiration from the fields into the atmosphere were high due to the hot temperatures throughout the growing season.
While the use of certain crop varieties was able to alleviate a portion of the effects of the drought, Todey stressed that drought-tolerant plants are only that – tolerant. In the most severe areas of drought where water was extremely limited and temperatures were high, even drought-resistant plants suffered.
So what can be done to better manage similar conditions in the future? The extreme variability associated with weather patterns makes management decisions difficult. In order to make better predictions about growing season conditions, researchers need to more fully understand this variability and find ways to help producers plan. That is a tall order, said Todey, as variability may increase with climate change, and making predictions could become even more difficult.
With that challenge put before the group, Jerry Hatfield, plant physiologist with the USDA-Agricultural Research Service (ARS), addressed the situation in the Midwest. He explained that effects of the drought in the Midwest were variable with some counties experiencing a 90% yield loss but other areas seeing only a 5% loss. The bottom line, Hatfield said, was that the soils with better water-holding capacity produced higher yields. Conservation-tilled and no-till fields saw better yields than conventional, tilled fields.
While some soil management practices seemed to help in areas where the drought was moderate, questions about next year are already being raised. With all of the soil water having been used this year to ward off drought conditions, Hatfield said it would take above normal precipitation to recharge the soils and get them ready for another growing season.
What if the precipitation doesn’t come – are there other tactics to use? Hatfield mentioned several questions that growers are now considering to better prepare for drought conditions: Should they reduce how much they plant or the rate of planting? Should they use shorter season corn in case water becomes limited later in the season? Should they plant something that can tolerate less water?
In the end, Hatfield echoed a familiar message – we need more reliable forecasts. With better forecasting capabilities, precipitation could be used as a factor in deciding management practices that may help avoid large crop losses in future droughts.
Jorge Delgado, also with the USDA-ARS, then addressed circumstances in the western region of the United States and again talked about variability. While parts of the western United States were very dry during the summer, the Pacific Northwest actually received higher than normal precipitation. Idaho had a highly productive year with plenty of water and moderate levels of heat. Areas of Colorado, meanwhile, saw lower yield even with full irrigation due to heat stress, and some farmers had to abandon crops once they ran out of water.
To address variability and stop future crop loss, some producers are already trying new techniques. Farmers in Texas are putting plastic below the plants to try to capture and hold the limited water. In Colorado, growers are switching to no-till winter wheat fields.
So what will it take to overcome drought and variable soil conditions throughout the United States? A recent paper by Rattan Lal proposed several questions to keep in mind: Are our current practices sustainable, especially under conditions of harsh, uncertain, and abruptly changing climate? Are our agriculture policies compatible with reality?
Delgado reiterated these questions and highlighted the importance of communicating and asking questions of each other. With continuous dialogue between researchers, land managers, and policy makers, he said, we can be better prepared to deal with drought and Dust Bowl-like conditions in the future. Hopefully, with increased communication and collaboration, finding ways to more accurately predict drought conditions and solutions to better deal with those conditions is on the horizon.