Leaving 30% crop residue has been proven to minimize top soil losses from wind and water erosion. But what does 30% soil cover look like? Do certain tillage implements leave less than 30% crop residue? Crop residue in the form of corn stalks or cereal straw, or green cover (growing crops or cover crops) are all effective ways to achieve 30% cover. In a demonstration at the Outdoor Farm Show in 2012 we learned that if we remove straw from a cereal crop and follow with any type of tillage we retain less than 30% residue. However, the tillage action stimulated a more uniform germination of volunteer cereals which increased total soil cover to well over 30%. The following photographs illustrate crop residue cover after tillage action on two differently managed field scenarios.
Above: The residue remaining after cereal harvest with straw spread back on the field.
Scenario # 1 – Cereal crop harvested, straw removed and 3 tillage systems evaluated.
TILLAGE SYSTEM : VERTICAL TILLAGE IMPLEMENT
Above: 25% crop residue remaining after a cereal crop was harvested, straw was removed and the field was worked with a Salford RTS vertical tillage implement.
TILLAGE SYSTEM : DISK
Above: 18% crop residue remaining after a cereal crop was harvested, straw was removed and the field was worked with a disk.
TILLAGE SYSTEM : CHISEL PLOW
Above: 16% crop residue remaining after a cereal crop was harvested, straw was removed and the field was worked with a chisel plow.
Scenario # 2- Cereal crop harvested, straw left and 3 tillage systems evaluated.
TILLAGE SYSTEM : VERTICAL TILLAGE IMPLEMENT
Above: 70% crop residue remaining after a cereal crop was harvested, straw was spread and the field was worked with a Salford RTS vertical tillage implement.
TILLAGE SYSTEM : DISK
Above: 53% crop residue remaining after a cereal crop was harvested, straw was spread and the field was worked with a disk.
TILLAGE SYSTEM : CHISEL PLOW
Above: 36% crop residue remaining after a cereal crop was harvested, straw was spread and the field was worked with a chisel plow.
Key Learnings from Demonstration:
- If the straw is removed and followed with any type of tillage, it is difficult to achieve 30% residue cover. Allowing volunteer cereals to grow or seeding a cover crop will get you over 30% cover.
- 30% soil cover after harvest does not mean 30% will be remaining in the spring. Residue management ranging from type of residue, form of tillage, modifications or adjustments to tillage equipment and combinations using cover crops will all impact the amount of soil cover.
Source: Fieldcropnews