Drought Risk Lessens for Much of Nebraska -- UNL CropWatch, May 21, 2011
|May 17 U.S. Drought Monitor shows area of abnormally dry farmland in Nebraska decreased in the last week. See drought.unl.edu for more information.|
May 20, 2011
Percent of normal precipitation (in inches) for the period from Oct. 1, 2010 through May 17, 2011. (Source: High Plains Regional Climate Center)
Departure from normal precipitation (in inches) for the period from Oct. 1, 2010 through May 17, 2011. (Source: High Plains Regional Climate Center)
Drought concerns have been alleviated for the northern two-thirds of the state with the abundant rains in late April and early May. The current U.S. Drought Monitor indicates only portions of south central and southeastern Nebraska have abnormally dry conditions. The main emphasis on this region is the long term dryness dating back to last October with deficits ranging from 4-6 inches and percent of normal moisture running less than 70% of normal.
Many areas of central and eastern Nebraska are running 70-80% of normal since last October and have been removed from experiencing abnormally dry conditions that were depiced less than a month ago. Crop demands are still several weeks away from the point where average daily water use exceeds normal daily rainfall. Once we reach that point, the criteria for determining abnormal dryness and drought will change.
Any areas showing October 1-present percent of normal precipitation from 70-80% of normal will be upgraded to abnormally dry conditions. If any area falls below 70% of normal for the same period, moderate drought will be recommended. This criteria will be used through late June as it takes into consideration the combination of fall/spring recharge and early growing season moisture.
During the July-August time frame, short term indicators such as the 30 and 60 day periods become more relevant. We have found that less than 80% of normal moisture during this period, especially in regions having long term deficits, generally suffer corn yield losses in excess of 10% across dryland production. The losses can be even greater across areas that below normal precipitation during the October-April soil moisture recharge period.
Extension State Climatologist