GrainsWest Fall 2020

Fall 2020 grainswest.com 29 Heavy crop residue in combination with excess moisture has become a complicating factor in various areas of Alberta. TILLAGE LIMITATIONS Agriculture and AgriFood Canada plant pathologist Kelly Turkington points out tillage is not useful in reducing crop diseases. “Many studies have shown that tillage does not reduce disease levels in crops,” said Turkington. “In fact, in some studies it appeared that tillage might have made matters worse.” He cited a cereal grain root rot study in which disease levels were greater in plots where conventional tillage was applied. He suspects the more vibrant soil microbiology in the study’s minimum tillage plots assisted in disease control. Using a disc or cultivator on a field with heavy crop residue would have little or no impact in reducing disease, he said. This proved to be the case in a study he led on disease levels in wheat and barley. “There is potential for residue-borne cereal leaf diseases to be effectively managed under conservation tillage by the use of sound rotations, agronomic practices and careful choice of variety,” he said, summarizing the study’s conclusion. VARIETY SELECTION Shorter stature or semi-dwarf cereal crop varieties can help with residue management. Breeders do their best to help farmers manage residue, said Pat Juskiw, a barley breeder with the Alberta Agriculture and Forestry’s Field Crop Development Centre in Lacombe. “Certainly, in breeding cereal crops there are two important aspects that are kept in mind,” said Juskiw. “That includes developing varieties that have higher yield with the same amount of plant biomass.” This process is referred to as increasing the harvest index of a variety. “The other aspect breeders consider, when possible, is to develop higher yielding but shorter stature varieties,” said Juskiw. “It can be a two-fold approach—higher yield with the same plant biomass and shorter or semi-dwarf varieties.” the soil surface so it warms to improve crop germination. Tillage also helps break up the shallow soil compaction layer so crop roots and moisture can penetrate deeper. And the disturbance can help immobile nutrients such as phosphorus and potassium move deeper into the soil profile so they are available to crop roots. “I know there are several producers in Alberta who are achieving 100-bushel wheat crops, 130-bushel barley crops and 70- to 80-bushel canola crops,” said Solberg. “And one of the keys to these higher yields is occasional tillage.” To determine the potential value of tillage, Solberg suggested two options. A penetrometer can measure the existing degree of soil compaction, and a standard soil test can evaluate nutrient levels in the two top two to six inches. These farmers and agronomists agree it is important to apply common sense regarding tillage and to follow conservation farming practices. They also suggest there may be a place for intelligent tillage to manage heavy residue and improve crop performance. Photo:CourtesyofNicoleMurrayPhotography RESIDUAL ISSUES