DRYLAND CORN VS GRAIN-SORGHUM IN WESTERN KANSAS

Dryland crop yields in the U.S. Great Plains are limited by low precip itation and high potential evapotranspiration. In western Kansas wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench ] are grown commonly, whereas corn (Zea mays L.) is believed to lack s ufficient drought and heat tolerance for dryland production. A study w as conducted near Garden City, KS, from 1991 through 1995 to determine whether corn could be grown successfully. No-till (NT) and convention al-till (CT) corn and grain sorghum were compared. In the driest year, sorghum yielded 137% more than corn with CT and 85% more with NT, but in 3 of 5 yr, NT corn yielded from 34% to 112% more than NT sorghum. In the remaining year, CT sorghum yielded more than CT corn, but NT yi elds did not differ. Overall, NT increased corn yields by 28% and net return by 69%, but increased sorghum yields by only 11% add had no eff ect on net return. No-till corn yielded 28% more than NT sorghum and p roduced 169% more net return, whereas CT corn yielded 11% more than CT sorghum and produced 48% more net return. Dryland corn can be grown i n western Kansas if lower yields and returns are accepted in dry years in exchange for yields and returns considerably higher than those of sorghum in favorable years. No tillage will substantially increase yie lds in most years and is essential to assure adequate corn yields in d ry years.