The Effectiveness of Nitrogen Recommendation Strategies for Corn in Creating Variable Rate Prescriptions Using Precision Agriculture Technologies
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Date
2014-05
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The Ohio State University
Abstract
Nitrogen is one of the primary macronutrients required for plant growth, and is often the most limiting factor in plant nutrition. In corn production, nitrogen fertilizer must be applied in order to supplement the nitrogen that is available in the soil. Due to nitrogen’s mobile nature in the soil, and the effect of temperature and rainfall on its availability to plants, it is difficult to predict the optimum rate that should be applied to reach yield potential while avoiding over-application and environmental risk from off-site movement. The Ohio State University Extension currently recommends using an economic optimum rate calculation to predict the optimum application rate. However, with the increasing use of precision agriculture technology that utilizes GPS to allow for site-specific management, there is an interest in using variable-rate technology to further optimize nitrogen applications. The objectives of this study are to describe the variability of optimum nitrogen rates across soil types and productivity zones, evaluate the effectiveness of prediction methods in identifying the optimal rate in each zone, and describe the ability of these prediction methods in developing variable-rate prescriptions. Five fields were selected as testing sites, with three replicated test blocks in each field. Test blocks were placed in high, medium, and low yielding zones in each field based on yield history. Utilizing test strips ranging from 0 to 220 pounds of nitrogen applied, the economic optimum rate was calculated after yield data was collected at harvest. Current Ohio State nitrogen recommendations, Tri-State fertilizer recommendations, Brookside Labs potential nitrogen analysis soil test, the pre-sidedress nitrogen soil test, normalized yield history, and estimated crop removal were all evaluated in their ability to predict optimum nitrogen rates.
Description
Honorable Mention at the 2014 Denman Undergraduate Research Forum
Keywords
Agriculture, Precision Agriculture, Corn, Nitrogen, Fertilizer, GPS, Variable-Rate Application