Stubble height effects on seasonal microclimate, water balance, and plant development of no-till winter wheat

Abstract

To investigate some of the effects of standing stubble on microclimate and on the energy and water balance in relation to plant development, winter wheat ( Triticum aestivum L.) was seeded directly into spring wheat stubble of three heights: 0 (bare), 15–19, and 30–35 cm. The soil near Sidney, Montana was Williams loam (fine-loamy mixed, frigid family of Typic Argiborolls) a bench mark soil for dryland cropping in the northern Great Plains of the U.S.A. Total wind passage at 9 cm above ground level was 1.5 and 5 times greater over bare as compared with that over short and tall stubble, respectively. Snow accumulation after a late winter storm was 2 and 4 times greater on short and tall stubble treatments, respectively, than on the bare plots. The first overwinter soil recharge was 3 cm more on both stubble treatments, a difference that persisted throughout the growing season. The second overwinter recharge was ca. 1.5 and 4 cm more on short and tall treatments, respectively. Midday net radiation was as much as 15% higher over the bare treatment in the fall and varied from 5 to 11% lower over the bare treatment in the spring, as compared with that over stubble. Stubble albedo was as much as 1.5 times greater than bare albedo in the fall; differences in the spring were small. On heating days, maximum soil surface temperatures were as much as 10°C higher on bare as compared with stubble treatments and soil heat flow as much as 30% greater on bare as compared with stubble treatments; on freezing days, heat flow differences were small.