Critical Periods segments a crop’s growing season into “critical periods” of crop development and provides rainfall, average temperature, and Growing Degree Days during each “critical period”. Every growing crop has periods during its growth that are more sensitive to changes in the environment than at other times. During these sensitive periods, crop yield for food, forage, or fiber, can be more easily affected than at other times during its growth. Two examples of a ‘critical period’ for a crop would be the beginning of ear development in corn, and pod set in soybeans. Saturated soils, drought, or a shortage of nutrients during these periods reduce the plant's ability to produce at optimal levels.
While some crops have more than one clearly defined critical period, the sensitivity of other crops to the environment is far less obvious, as with some root crops. It is also true that what is detrimental for one crop may be growth neutral or even positive for another. For example, corn greatly benefits from cool nights during its grain filling period, while soybeans respond much less positively to the same conditions.
Within Morning Farm Report, each crop is modeled separately and critical periods are treated with special consideration. Although the entire lifecycle of supported crops are modeled in response to environmental factors, during a critical period stress factors, such as extreme heat or drought conditions, are weighted more heavily to adjust the rate of growth and forecasted yield. On the other hand, ideal growing conditions are also given appropriate attention as they may favor significant yield increases.