Winter Wheat Productivity is Affected by Selection of Summer Fallow Replacement Crops.
Drew Lyon, Univ. of Nebraska, Panhandle Res. & Ext. Ctr., 4502 Ave. I, Scottsbluff, NE 69361 and David Nielsen, USDA-ARS,Central Grt Plns.Res, 40335 County Rd. GG, Akron, CO 80720, United States of America.
Producers in the Central Great Plains are interested in reducing or eliminating the use of summer fallow. The objective of this study was to quantify winter wheat (Triticum aestivum L.) yields following short-season spring-planted crops used to replace summer fallow. The study was conducted on silt loam soils in 2004 thru 2006 at Sidney, NE and Akron, CO. Three differential soil water levels were established prior to spring planting through use of supplemental irrigation. Four crops [pea (Pisum sativum L.) for grain, spring triticale (X Triticosecale rimpaui Wittm.) for forage, proso millet (Panicum miliaceum L.) for grain, and foxtail millet (Setaria italica L. Beauv.) for forage] were no-till seeded into corn (Zea mays L.) residue in a split-plot design with 4 replications per location. Winter wheat was seeded across the entire area in the fall after spring crops were harvested. Water use by wheat was greatest in treatments with the greatest soil water prior to planting the spring crop. Water use by wheat was also greater following early-planted spring crops, pea and triticale, than after late-planted spring crops, proso and foxtail millets. In general, wheat yield increased as total water use by the wheat crop increased; however, terminal drought at Sidney in 2006 resulted in greater grain yield and harvest index following the late-planted spring crops than the early-planted spring crops, despite lower seasonal water use. Growers wishing to eliminate summer fallow prior to winter wheat seeding should use a crop of short duration that is planted in early spring into a soil profile containing adequate stored water.