Jim didn’t know what to think. By the third week of June, random areas of stressed, stunted and generally unhealthy malt barley plants had developed in an otherwise healthy field. “I’ve got another barley field close by that is healthy and growing vigorously,” he told me. “I think it could be excessive moisture, nutrient deficiency or chemical damage.”
Jim farms 3,500 acres of canola, lentils, wheat, oats, mustard and malt barley west of Saskatoon. He told me the barley crop had come up fairly evenly, despite excessive moisture that spring, but now many plants in one field were exhibiting signs of stress — stunted growth, yellowed lower leaves, brown-coloured crowns and stunted root development.
When I visited Jim’s farm, I noticed the stressed plants were located randomly throughout the field, sometimes in the same seed row as healthy plants. Half of the field had been seeded on oat stubble and the other half on yellow mustard stubble. Both sides of the field had wet, sandy loam soil, and as we walked from the side of the field seeded on mustard stubble to the side seeded on oat stubble, the soil became more moist and the frequency of stressed barley plants increased.
We immediately dismissed nutrient deficiency as the cause of the unhealthy plants. All of Jim’s barley fields had similar pH and organic matter levels, soil type and texture, and had received the same fertilizer treatment. Micronutrient levels were adequate, there were no issues with salinity and we were not dealing with solonetzic soil.
I wondered if excessive moisture could be a factor. The frequency of stressed barley plants appeared to correspond to wetter parts of the field. However, some plants in the drier areas of the field appeared to be stressed as well. I concluded that moisture was a factor, but not the only one contributing to the crop’s stress.
There were no patterns in the field to suggest that chemical damage such as a sprayer malfunction, a tank-mix error, or sprayer and tank cleanout issues was the catalyst to the crop injury. Symptoms of stress had appeared prior to the application of in-crop herbicide, so that was not the cause of the barley’s injury either.
A close inspection of the plants revealed the true source of the problem. The plants were pale green to yellow in colour, and the lowest internodes were pink to brown. Root development and growth was limited, and the plants looked as though they would not survive.
The discolouration of the internodes was a telling sign, but before I broke the news to Jim, I dug up several plants to submit for laboratory analysis.
What is causing some of Jim’s barley plants to be stunted in development while others appear healthy and vigorous? Send your diagnosis to Grainews, Box 9800, Winnipeg, MB, R3C 3K7; email [email protected] or fax 204-944-5416 c/o Crop Advisor’s Casebook. Best suggestions will be pooled and one winner will be drawn for a chance to win a Grainews cap and a one-year subscription to the magazine. The answer, along with the reasoning which solved the mystery, will appear in the next Crop Advisor’s Solution File. †