Tuesday, June 19, 2012

Drought Information

The newest update of the USDA Drought Monitor has placed Gibson County in a severe drought status.  This means, essentially, that the state climate office and regional climate center find stream flows, soil moisture, precipitation, and other indices of available moisture to be between 6 and 10 per cent of normal conditions. Crop losses in yields are now measurable, and the possibility for hydrologic water shortages is imminent.  As of June 7, the Climate Prediction Center released a prediction of drought persistence for our area through the end of August.  Let us examine some of the potential outcomes and real outcomes of the severe drought in this area.

Homeowners at the current time should consider retiring the lawnmower until conditions improve.  Causing additional stress by mowing while grass is dormant will encourage weeds to outcompete the grass for resources once the drought breaks.  For the time being, irrigated lawns may still be mowed, but those individuals using city water should ensure that no water use restrictions have been put in place concerning landscape irrigation.  The Indiana Department of Homeland Security currently does not report a burn ban in place for Gibson County, but individuals should be using extra caution when attempting to burn due to the excessively dry conditions.  If any landscape features, such as trees, shrubs, lawns, or flowers, wish to be kept viable throughout the foreseeable future, irrigation is advisable.  With the exception of trees, non-irrigated plants showing signs of drought stress should be watered.  Trees tend to mask drought symptoms during a single season and show symptoms in following years.  Therefore, all trees wishing to be retained should receive supplemental water.  The amount of supplemental water to apply should be 1 to 1.5 inches of water at the root zone, applied once every two weeks.  Turf is the exception to this recommendation.  Aaron Patton, Purdue Extension Turfgrass Specialist, recommends that dormant, or already brown, grass be kept dormant but alive with a half-inch of water applied every 2 to 4 weeks.  Actively growing grass can be kept active with at least one inch of water applied each week.  Plants should be watered early in the morning, if possible, to provide ample moisture during the day and minimize evaporation.

Field crops are responding to the drought in disheartening ways.  The leaf curl of corn has continued.  Bob Nielsen, Purdue Extension Corn Specialist, states that the crop predicts row number on the ear of corn to the seventh leaf stage, and the drought can reduce this row number by 2 to 4 rows.  The major impact of drought on yield may be pollination.  Hot and dry weather during tasseling of the corn plant, likely to occur in the next week or so in Gibson County, greatly affects pollen viability of the plant and the need for coinciding silking, or the formation of silks on the corn ear to receive pollen.  Drought can affect the timing of the production of these reproductive structures, thus reducing yields by, potentially, 40 to 50 per cent.  You may also notice this year that corn plants are smaller overall, a drought effect that may allow weed pressure later in the season to have a negative effect on yield.

Soybeans are more resilient in the face of drought.  Much research confirms that yield losses of soybean crops are generally less, as a percentage, than those of their corn neighbors when exposed to droughts of the same nature and length.  However, soybean are affected by drought.  Plant height is currently being impacted, as many earlier planted soybeans are currently in their reproductive growth stages, despite having only four or five mature leaves.  The bean pods of these plants may end up fewer in number and with fewer soybeans inside the pods than in a wetter year.  Other field crops, including forages and melons, are experiencing similar effects unless irrigated.  Hay availability in the area may become an issue in the near future with severe drought conditions, as hay-making ability is reduced while hay demand increases.

More field crop drought information is available at the Chat 'N' Chew Cafe (http://www.agry.purdue.edu/ext/corn/cafe/drought/index.html).

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