Wheat stubble height affects no-till row crop yields
Producers using a no-till wheat/row crop/fallow rotation may find that row crop yields in such a rotation are higher (in years with relatively normal weather) when the wheat stubble height is taller. K-State research in western Kansas by Lucas Haag, Agronomy graduate student, and Alan Schlegel, Agronomist-In-Charge at the Southwest Research-Extension Center-Tribune, has found that corn grain yields increased as stubble height increased. Grain sorghum yield response to stubble height was less apparent, but exhibited a response to moderately higher cutting heights.
Wheat residue provides numerous benefits, including evaporation suppression, delayed weed growth, improved capture of winter snowfall, and reduced soil erosion. Stubble height affects wind velocity profile, surface radiation interception, and surface temperatures, all of which will reduce evaporation potential and increase winter snow catch. Taller wheat stubble is also beneficial to pheasants in postharvest and overwinter fallow periods.
Using stripper headers provides taller wheat stubble than previously attainable with conventional headers. In theory, increasing wheat cutting heights or using a stripper header should further improve the effectiveness of standing wheat stubble. The purpose of our research was to evaluate the actual effect of wheat stubble height on subsequent summer row crop yields.
Studies were conducted from 2007 through 2010 at the Southwest Research-Extension
Center dryland station near Tribune. Corn and grain sorghum were planted into standing wheat stubble of three heights: short, optimal, and stripped.
* The short cut treatment was half of optimal cutter bar height.
* Optimal cutter bar height is the height necessary to maximize both grain harvested and standing stubble remaining (typically two-thirds of total plant height).
* The third treatment was stubble remaining after stripper header harvest.
In 2007, these heights were 7, 14, and 22 inches. In 2008, heights of 10, 20, and 30 inches were obtained. In 2009 the heights were 7, 14, and 23 inches. In 2010 the stubble measured 8, 16, and 25 inches. Corn was seeded at the rate of 15,000 seeds per acre, and grain sorghum was seeded at the rate of 33,000 seeds/acre. In 2010 the sorghum plots were split and an additional seeding rate of 41,000 seeds/a was added to the study. Nitrogen was applied to all plots at a rate of 80 to 100 lb/acre. Starter fertilizer (10-34-0) was applied in-row at rates of 7 and 9 gal/a for corn and sorghum, respectively. Plots measured 40 ft × 60 ft. Soil water measurements were obtained by neutron attenuation to a depth of 6 feet in 1-foot increments at seeding and harvest to determine water use and water use efficiency (WUE).