Stubble Type (Crop Sequence)
What’s the best crop to plant before growing soybeans, peas and dry beans? We can look to MASC data to see historic yield responses to planting these crops following various previous crops.
For soybeans, yield responses have been greatest following winter wheat, spring wheat or navy beans. For peas, yield responses have been greatest following canola or soybeans, and navy beans report yield increases of more than 110% following potatoes, corn or spring wheat.
The following results from individual research projects provide some insight into how to best manage previous crop residues.
Before Growing Soybeans
From 2017 to 2021, six tillage treatments (fall tilled, fall burned, short standing stubble with and without straw and long standing stubble with and without straw) were evaluated before growing soybeans at Brandon, Carberry and Indian Head.
Direct-seeded soybeans yielded the same or greater than the tilled and burned treatments. Tall standing stubble also resulted in similar or greater yields than shorter stubble. Removing wheat straw before seeding soybeans resulted in similar or greater yields than chopping and returning the straw. Days to emergence among tillage treatments varied by one day or less on average. Soil temperatures at seeding varied by 1 to 3°C among treatments and tillage and burning commonly resulted in drier soils.
Seeding into corn residue can be particularly challenging. From 2015 to 2016, four on-farm trials compared four different tillage strategies (conventional double disc, vertical till high disturbance, vertical till low disturbance and strip till. Among these different treatments, there was no effect on soybean emergence or plant stand 75% of the time. While there were no yield differences due to the different tillage treatments, economic analysis indicated time and cost savings in favour of strip till.
Before Growing Peas
Research at Carman and Roblin (2020-2024) has been ongoing investigating the combination of preceding crop, tillage vs. direct seed and phosphorus fertilize rate and placement on pea yield. Stay tuned for results from this project soon!
Before Growing Dry Beans
From 2017 to 2020, pinto beans were planted into four crop residues (wheat, canola, corn and pinto beans) that had been split into tilled and direct seeded treatments.
Preceding crop did not affect pinto bean yield, but there was greater grassy weed pressure following corn than wheat and root rot severity was the greatest in beans following beans.
Direct-seeded pintos yielded 10-17% greater than pintos in tilled stubble at two site-years, likely due to moisture conservation benefits. Grassy weed densities were also greater in tilled residue treatments.