corn, corn hybrids, corn variety trails, corn performance tests
Yield trials on those corn hybrids currently most popular among farmers are conducted each year by the Agronomy Department of the South Dakota Agricultural Experiment Station. The purpose is to supply farmers and ranchers with information on the relative performing ability of the various hybrids when they are subjected to similar environmental conditions such as rainfall, soil moisture, and fertility level. Such information, when used as a guide in selecting hybrids for planting, can aid the farmer in obtaining maximum yields under his field conditions. In 1957, 14 tests were planted throughout South Dakota. Each contained from 20 to 40 entries planted in replicated plots. Yields, moisture percentages at harvest, and in some cases lodging, were obtained and are presented in the tables in this publication. Most areas of the state entered the 1957 season with extremely low reserves of subsoil moisture. Above normal rainfall over most of the state during the months of April, May, and June supplied adequate moisture for abundant growth of corn. There were only two stations, Brookings and Vermillion, which were below normal moisture for the entire growing season. Highmore and Cottonwood were considerably above normal with a plus 8.67 and 7.42 inches for the growing season, respectively. Although adequate moisture was available, corn was retarded in germination and early growth by low temperatures. All areas in which test plots were grown had below normal temperatures for April, May, and June. This below normal temperature was greatest at Vale during May when this station reported an average departure from normal of a minus 4.6 degrees, while Brookings rep01ted an average minus departure of 4.5 degrees for June. July temperatures were near normal, or slightly below, over most of the state; however, the temperatures dropped in August and September so that all stations rep01ted minus departures from normal for both months. The greatest departures were minus 7.5 and 5.2 degrees at Vermillion and Menno, respectively, during September. The low temperatures during August, September, and October resulted in slow maturing of the corn crop over the entire state. Frost held off until into October in many areas. This lack of a killing frost coupled with the low temperatures caused the corn crop to dry slowly. Many fields of corn were picked too wet for cribbing, and considerable corn was still in the field in December at which time kernels on some of the ears of varieties that were of a long season maturity for the area were turning brown while still on the stalk. The moisture content of all test plots harvested was considerably above long time averages. Late maturing hybrids, though producing more weight at harvest time in each test, were carrying so much moisture it would have required ultimate artificial drying to have cribbed such varieties. This year's results would seem to indicate farmers should use extreme care in selecting a hybrid which is adapted to their length of growing season, and refrain from using those hybrids which require excessive length of season to produce cribbable corn.
South Dakota State State College of Agriculture and Mechanic Arts, Agricultural Experiment Station
Kratochvil, D. E.; Shank, D. B.; and Bonnemanm, "South Dakota Corn Performance Tests, 1957" (1958). Agricultural Experiment Station Circulars. 136.