Adaptive Wheat Management: A System for Managing Wheat Based On Plant Physiology and Growth Responses to Environmental Conditions.

In many ways, wheat (Triticum aestivumL.) is a difficult crop to manage due to its ability to adapt to changing environmental conditions. Wheat may start out the fall with good stands and the foundation for high yield, but this could be lost if tillers are aborted from GS30 to 40 due to drought or nutrient stress. Likewise, wheat with dense stands and large numbers of kernels per head can lose yield quickly when stress occurs in May due to disease. Therefore, instead of a standard prescription management system similar to those in use today, an adaptive management system that changes from season to season based on conditions and weather predictions should be considered. This adaptive management system does not focus on average recommendations, but focuses on current and predicted conditions to select the best management choice for the season, which may be different from what was done in previous growing seasons.

The key to this adaptive management system is the ability to understand plant growth in response to the environment, and the ability to predict and adjust for weather conditions occurring over the next four weeks. A current study examining tiller responses in the southeastern US and how they are impacted by temperature and nitrogen will be used extensively in this system. Little research has been done in North Carolina quantifying kernel set in response to growing conditions; therefore, a component of this study will examine the influence of plant density, light interception, fungicide, and N rate on kernel development.

Research was conducted at the Tidewater Research Station in Plymouth, NC. Six treatments were included to test these factors. The first treatment is an untreated control with a standard seeding rate of 25 seeds/row ft. and an application of 10 gal 11-37-0 at planting. In the second treatment, the fungicide Quilt was applied at 14 oz/a at GS70 to examine the role of fungicide in keeping leaves healthy and increasing seed weight. Treatment three involves applying 10 lbs. of N at GS70 to examine the role of nutrition in plant health and seed weight. Shading was applied from pollination to harvest in treatment 4 to examine the effect of light interception on grain weight. Treatment five was a low seeding rate thinned. Plots were planted at a low seeding rate of 10 seeds/row ft., and tillers were trimmed from main plants. Treatment six involved a high seeding rate of 35 seeds/row ft. with an additional 60 lbs. of N applied in late December. Samples consisting of 15 plants per plot were taken at intervals from GS70 to maturity. Plant weight, seed number, and seed weight were all measured.

Among the first five sampling dates, there was no significant difference in seed weight except for the shaded treatment which was significantly lower. At the final sampling date, the low seeding rate had the highest seed weight, while the shaded plots had the lowest seed weights. The plots treated with fungicide at GS70 had the highest yield, while the shaded plots and low seeding rate had the lowest yield.