Spring crops direly need a drink
Dry and dusty conditions have become the norm across the Cornbelt, with increased reports of short topsoil and subsoil moisture, as well as more frequent reports of corn leaves curling earlier in the afternoon as the plant attempts to save moisture. However, in that process, photosynthesis is curtailed and crop progress slows down. The Cornbelt needs a drink of water for the crop that is in the ground and some moisture before unplanted fields—primarily soybeans—can be planted.
The USDA’s Crop Progress report for last week began to indicate concerning levels of soil moisture that were rapidly declining. A state by state summary was provided after the weekly USDA report. Interested readers can compare the week to week reports of dry soils and stressed crops with the current week summary, when available.
Of possibly greater value are the vegetation maps provided by the Ecology & Agriculture Spatial Analysis Laboratory ((EASAL) unit at Kansas State University. From this weekly report, one can look at the changes in vegetation greenness (biomass) relative to the previous week, year and average since 1989. This report was first developed by Dr. Kevin Price in 1995. It can be used to assess plant growth rates relative to the 21 year average. The objective of the report is to provide users with a means of assessing the relative condition of crops and grassland. The report is used by individual farmers and ranchers, the commodities market, and political leaders for assessing drought impact across their state. It provides weekly vegetation condition assessments at the 250-acre resolution for the conterminous U.S. This series of maps not only show comparisons with periods of better vegetation, but in some cases, show fields that are not yet covered with crops, because of the early date in the season.
At the University of Nebraska, the Drought Monitor team indicates growing regions of dry conditions throughout the Cornbelt when one week is compared to the prior week. The commentary portion of the weather record indicates trends.
For the Midwest: For the week ending May 20, the portion of topsoil moisture rated very short to short jumped at least 20 percentage points in Iowa (from 9 to 44%), Indiana (15 to 43%), Illinois (12 to 33%), Michigan (7 to 32%), and Wisconsin (6 to 30%). As a result, there was a fairly large expansion of abnormally dry conditions (D0) across the central and eastern Corn Belt. Hot weather, short-term dryness, and crop demands were to blame for the rapid depletion of topsoil moisture. On May 18, high temperatures soared to daily-record levels in St. Cloud, Minnesota (94°F), and Eau Claire, Wisconsin (91°F). The following day, May 19 featured daily-record highs in Michigan locations such as Traverse City (92°F) and Alpena (91°F). In contrast, showers developed across the upper Midwest. Although upper Midwestern rainfall coverage was patchy, drought development was arrested in some areas. Little rain fell, however, east of a line from southeastern Nebraska to Lake Superior.