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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #200503
Title: Predicting Nitrogen Fertilizer Recommendations for Corn using an Active Sensor

Author
item DELLINGER, A - PENN STATE UNIV
item Schmidt, John
item BEEGLE, D - PENN STATE UNIV

Submitted to: Journal of Soil and Water Conservation
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2006
Publication Date: 7/20/2006
Citation: Dellinger, A., Schmidt, J.P., Beegle, D. 2006. Predicting Nitrogen Fertilizer Recommendations for Corn using an Active Sensor. Soil & Water Conservation Society Annual Conference. Journal of Soil and Water Conservation. 61(3):211.

Interpretive Summary: An interpretive summary is not required.

Technical Abstract: Active sensors, mounted on typical agricultural equipment, can be used to measure N (nitrogen) status in corn (Zea mays L.). This gives a producer the potential to improve N fertilizer recommendations that will reduce nitrate loss to the environment. This study examines the relationship between remotely sensed data and corn yield and considers ways in which to translate this information into sound sidedress N recommendations for corn. Four research sites with unique cropping histories in Centre County, PA were planted to corn in 2005 with three different pre-plant treatments (zero, 56 kg N per ha as ammonium nitrate (AN), and approximately 56 kg N per ha as manure) and seven sidedress rates (0, 22, 45, 90, 135, 180, and 280 kg N per ha as AN) in 9.1 x 4.5 m plots. Nitrogen fertilizer and manure was surface applied. From early May until mid-July, georeferenced canopy reflectance data in the 590nm and 880nm wavelengths were taken each week from the third row of each six-row plot. Inorganic soil N, chlorophyll meter readings, late-season stalk nitrate samples, and grain yield were measured. Preliminary results from two field sites suggest a significant relationship between light reflectance and the Economic Optimum N Rate (EONR; r2=0.984). The EONR in a field following corn for the zero and manure pre-plant treatments were 150 and 132 kg N per ha, respectively; whereas in a field after soybeans, the respective EONR's were 34 and 48 kg N per ha. Initial results indicate that employing a ground-based active sensor appears to be a viable option for predicting sidedress N rates for commonly used field-scale recommendations.