Agronomy Library > Event & Field Reports

Avoid Tilling Written-off Crops: Make the Most of a Bad Situation
Author: Rick Taillieu, RTL & Dale Soetaert, Ducks Unlimited Canada
Date Created: July 02, 2002
Last Reviewed: February 22, 2007

The growing season has not been kind to annual crop producers across Alberta in 2002. The extreme lack of precipitation, which has been further accompanied by record high temperatures, has resulted in many crops being written off across much of the province. The time has come for many farmers to begin planning for next year’s crop and conserving moisture and reducing the risk of soil erosion should be their first priority.

Using cultivation to kill off any remaining crop or growing weeds will help conserve whatever moisture is left in the soil profile. However, it also inhibits the soils ability to capture future moisture and leaves the soil surface very vulnerable to both wind and water erosion. Every tillage pass contributes to losses in soil moisture because the soil is exposed to the elements, including direct sunlight and higher wind speed at the soil surface.

Farmers who want to recharge the moisture in their soil profile can do so with effective and economical herbicide applications. Chemfallowing will control the unwanted crops and weeds from depleting the soil of both moisture and nutrient reserves and at the same time leave the soil protected from the elements and thus reduce the risk of soil erosion. Undisturbed land has dramatically greater water infiltration rates and is therefore better able to absorb any rainfall that may come in late spring or early fall. Rainfall simulation experiments have shown that undisturbed land can often absorb one inch of water in as little as minute, while a single cultivation pass can mean the same inch takes seven or more minutes. This reduced infiltration rate often results in run-off and therefore less moisture being stored for future crops.

If conditions stay very dry, there is likely to be very little germination of weeds following a chemical application. Tillage operations, on the other hand, often stimulate weed growth by moving otherwise dormant weed seeds to near the surface and providing good seed to soil contact. If moisture conditions improve, and we receive some rains in August, the standing crop residues will provide you with the opportunity to direct seed a winter cereal crop this fall.

Winter wheat for example, can provide producers with an opportunity to get some seeding done this fall, and allow the crop to take advantage of some snowmelt moisture that would otherwise be un-utilized in spring seeding systems. Winter wheat requires very little moisture to germinate and shallow seeding (less than 1”) allows the crop to emerge with very little rainfall, even in the dry conditions we are experiencing now. A winter wheat crop will also effectively compete with spring germinating weeds, such as wild oats, and allow for increased savings on crop inputs. Spring stands this year looked very promising across the Parkland region of Alberta; drought conditions have hindered its growth, but perhaps not to the extent of other spring seeded cereals. A winter wheat stand also aids in conserving moisture due to the fact that spring tillage is non-existent, allowing for optimal infiltration of moisture in a zero disturbance situation.

Winter wheat production does require direct seeding and standing stubble to aid in winter survival. By spraying out written-off acres and not tilling them, the little bit of vegetative growth that will be left standing in the field, will provide enough stubble cover and snow-trapping potential to increase the chances of winter wheat survival over the winter. Typically, seeding by September 15th can be challenging due to rotational constraints and labour challenges, this year is providing an opportunity to producers to spread their workload through fall seeding and early harvest of next years winter wheat crop.