Comparing Stacked and Alternate-Year Cropping Systems In a Semiarid Environment.

Diversification of continuous durum system can improve economic and environmental sustainability in semiarid cropping systems, but little is known about the influence of rotation type and management system on durum performance.  We conducted a study from 2005 to 2011 comparing two sets of crops in stacked (durum-durum-canola-pea and durum-durum-flax-pea) and alternate-year (durum-canola-durum-pea and durum-flax-durum-pea) rotations under conventional and ecological management levels on durum yield and characteristics. Continuous durum was included as a control.  Conventional management included preplant tillage, broadcast urea, standard seeding rates, and short durum residue height.  Ecological management included zero tillage, banded urea at planting, greater seeding rates, and tall durum residue height. Average durum grain yield, plant height, and plant stand across years were lower in durum-durum-canola-pea than other rotations under the conventional but not under the ecological management. Overall, rotation type rarely influenced yield or yield components of durum.  Durum yield was greater in three out of six years under the ecological than under the conventional management.  Durum was taller, with more reproductive tillers but fewer seed per head, under the ecological than under the conventional management.  Stacked rotation of durum with pea in the conventional management resulted in reduced durum grain yield and performance compared to other treatments in dryland cropping systems in the northern Great Plains.