Farm and Field

Researchers improving precision of rainfall estimates

Posted: Jul. 15, 2018 12:01 am Updated: Jul. 23, 2018 11:00 am

Meteorologists have known for some time that rainfall forecasts have flaws, as failure to take into account factors such as evaporation can affect their accuracy.

Now researchers from the University of Missouri have developed a system that improves the precision of forecasts by accounting for evaporation in rainfall estimates, particularly for locations 30 miles or more from the nearest National Weather Service radar.

Neil Fox, University of Missouri associate professor of atmospheric science, and doctoral student Quinn Pallardy used dual-polarization radar, which sends two radar beams polarized horizontally and vertically, to differentiate between the sizes of raindrops. The size of a raindrop affects both its evaporation rate and its motion, with smaller raindrops evaporating more quickly but encountering less air resistance.

By combining this information with a model that assessed the humidity of the atmosphere, the researchers were able to develop a tracing method that followed raindrops from the point when they were observed by the radar to when they hit the ground, precisely determining how much evaporation would occur for any given raindrop.

The study found that this method significantly improved the accuracy of rainfall estimates, especially in locations at least 30 miles from the nearest NWS radar. Such areas often have large amounts of agriculture, and farmers depend on accurate rainfall estimates to manage crops.

‘Close-up cow' barns

Cow comfort is key to help avoid heat stress and produce more milk.

"Experienced dairymen tell us that cows that aren't comfortable and cool produce less milk," University of Missouri Extension dairy specialist Reagan Bluel said. "It is not rare for the vulnerable herds to experience a 10- to 20-percent decline in milk production during the hottest of times."

Recent research from the University of Florida found that not only do heat-stressed cows produce less milk than cows given access to shade, sprinklers and fans. Bluel said they also give birth to calves that grow up to produce less milk.

Martin Prairie Farms near Humansville houses cows in three free-stall barns, which give them room to roam in a comfortable environment shielded from precipitation and extreme temperatures.

Freddie and Mary Martin, who own and operate the dairy farm with son and daughter-in-law David and Alana, are expanding to include a compost-bedded pack barn for cows nearing calving. The 125-foot-long "close-up cow" barn offers good ventilation and protection from the elements.

"The key is not to overcrowd,' David said.

A 16-foot feed alley allows easy access for equipment. Tilling the bedding daily aids composting action to reduce odor and disease. The compost can be applied as nutrient-rich fertilizer to fields. Calf hutches line the inside of the pack barn, away from cows. This ensures individualized care for each heifer for the first two weeks.

Nutrition is another key ingredient of the Martins' healthy herd. They add expired fruits and vegetables from local grocers to their total mixed ration.

Most of the feed products come from the farm. Corn silage and wheat are the homegrown stored forages. They devote most of the acreage to mixed grass pasture for grazing or hay, and they buy dry alfalfa off-farm.

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