|Johnson, Gregory - MSU-BOZEMAN|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Proceedings
Publication Acceptance Date: July 28, 2004
Publication Date: October 1, 2005
Citation: Lenssen, A.W., Johnson, G.D. 2005. Yield, quality, water use, and weeds in annual forage-spring durum cropping systems. ASA-CSSA-SSSA Annual Meeting Abstracts. Agronomy Abstracts. Abstract number 6047. CD-ROM. Technical Abstract: Summer fallow in the northern Great Plains results in poor precipitation use efficiency and soil degradation. We are conducting a field trial near Froid, Montana, of spring durum in rotation with summer fallow or the annual hay crops, barley, barley with pea, and foxtail millet. Continuous dryland alfalfa also is included. Over three years, replacing summer fallow with barley or barley with pea produced about 2.5 mt ha<sup>-1</sup> of forage while decreasing subsequent durum yield about 0.2 mt ha <sup>-1</sup>. Water use for durum was similar among rotations. However, nitrogen fertilizer requirement was higher and fertilizer use efficiency lower for durum following foxtail millet compared to durum in other rotations. Grain protein concentration was highest for durum following summer fallow, while other rotations had similar and acceptable grain quality. Weed densities in durum did not vary by rotation. Herbicides were not used in forage crops but weed densities, primarily green foxtail, did not vary among entries. However, weed biomass averaged 1.8 mt ha<sup>-1</sup> with foxtail millet, about 10X greater than for the earlier planted cool-season annuals. Forage quality of green foxtail and foxtail millet were similar.