Beyond just keeping cereal growers out of their fields, cold, wet seasons, such as spring 2011, have great potential to limit crop growth and yield. Years of research confirm that weather is the number one factor influencing crop growth, which starts with the roots. At the same time, environmental conditions affect the development of yield-robbing diseases that attack crops.

Limited resources
Cold, wet conditions impose yield limits due to limited resources for growth, as university research explains.

· Cool temperatures translate into fewer Growing Degree Days (GDDs), the accumulation of heat energy that drives plant growth. With less energy to grow, especially early in the season, root growth is stunted, reducing total yield potential.

· Wet or waterlogged soils make critical nutrients, such as nitrogen and phosphorus, less available to roots for uptake into the plant, according to Montana State University research. These and other nutrients are more likely to leach in wet soils, as well.

· Wet soils are more susceptible to compaction, which limits root growth. If wet soils dry out very quickly, they also can harden or crust over, making it difficult for roots to penetrate deeper or for seedlings to emerge.

All these factors are critical to allow cereal crops to produce quality grain. Limits at any point in the growing season can have a permanent yield impact. For example, once the crop heads out, most energy goes into kernel development. The root system to support that development has already been established, and if it was restricted earlier in the season, the ability to gather resources for kernel growth will be limited.

Disease pressure
Cold, wet soils harbor yield-robbing diseases that attack seeds and roots. High-moisture environments favor disease development, and cool temperatures limit growth so plants are more vulnerable to infection. For example, university experts site Rhizoctonia solani, decay, wheat mosaic virus (carried by fungal organisms) and Pythium as diseases that are more common in these conditions.

Weather does much more than dictate field work timing. It causes physiological responses in the crop that impact yield. And so, experts recommend waiting for warmer temperatures, if possible, and using seed treatment fungicides when planting in cool, wet environments. Syngenta is testing a new, experimental seed treatment fungicide set to be registered in 2012 that will offer a novel mode of action to enhance disease protection, particularly against Rhizoctonia.

Syngenta

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