Reduced Tillage Implements for Termination of Cover Crops in the Canadian Prairies.

Organic agriculture relies widely on tillage for weed control and termination of cover crops, which can reduce soil quality. The potential to reduce tillage in Canadian organic cropping systems may be realized with new and existing mechanical methods for control of cover crops. The objective of the current study is to compare a blade roller, flail mower and wide blade cultivator (noble blade) with standard tillage for termination of an annual pea-barley green manure cover crop. The experiment is being conducted twice at Carman, MB and Lethbridge, AB from 2010-2012. The green manure is planted and treatments are applied through termination method in year 1, followed by planting of spring wheat in year 2. The effect of termination method on surface residue, soil nitrogen, soil temperature, soil moisture, weed population dynamics and subsequent spring wheat production is being evaluated. In spring 2011 surface residue averaged 3112, 2528 and 2382 kg/ha at Carman and 5210, 2748 and 4242 kg/ha at Lethbridge for the blade roll, flail mow and wide blade treatments, respectively. Excessively wet conditions, delayed seeding and lack of sufficient mulch limited spring wheat production at Carman in 2011. Total broadleaf weed density 28 days after planting (DAP) spring wheat ranged from 58-154 plants/m². Therefore at Carman the wheat was terminated with tillage and re-planted to buckwheat. Buckwheat biomass displayed a large treatment response ranging from 2905-8405 kg/ha 63 DAP, with the lowest biomass occurring in the flail mow and blade roll treatments and highest in the standard tillage treatment. At Lethbridge spring wheat production was successful and unaffected by cover crop termination method with an average yield of 4416 kg/ha (range 4178 to 4531 kg/ha). Preliminary results indicate that potential exists to reduce tillage during termination of cover crops in organic systems, but can be affected by environmental conditions.