Wheat growers face many economic and environmental challenges, but arguably their greatest challenge is the efficient use of fertilizer. Growers need to apply nitrogen-based fertilizer in sufficient quantities to achieve the highest possible crop yields without over-applying – a situation that could lead to serious environmental effects. In wheat, a critical factor comes down to timing in order to determine how efficiently plants will use nitrogen fertilizer. Current methods for determining the optimum timing of nitrogen fertilizer application can be costly, time consuming, and difficult.
To assist wheat growers, scientists at North Carolina State University recently developed a technique to properly time nitrogen fertilizer applications. The technique? Remote sensing – a relatively new technology to today’s modern agriculture that uses aerial photography and satellite imagery.
In this 2000-2001 study, scientists used remote sensing in the form of infrared aerial photographs to determine when early nitrogen fertilizer applications were required. By relating the infrared reflectance of the crop canopy to wheat tiller density, the scientists were able to differentiate wheat fields that would benefit from early nitrogen fertilizer applications compared to wheat fields that would benefit from standard nitrogen fertilizer applications. They tested 978 field locations, representing a wide range of environmental and climatic conditions. The remote sensing technique was found to accurately time nitrogen fertilizer applications 86% of the time across all field locations. The results of this study are published in the January/February 2003 issue of Agronomy Journal.
Michael Flowers, project scientist, said, “This is one of the first applications of remote sensing technology for nitrogen management available to growers. With the ability to cover large areas in a quick and efficient manner, this remote sensing technique will assist growers in making difficult nitrogen management decisions that affect profitability and environmental stewardship.”
These scientists at North Carolina State University and other institutions around the world are continuing to research remote sensing techniques to improve the efficiency of nitrogen fertilizer applications in crops. These techniques will allow growers to more efficiently apply nitrogen fertilizer, increase profitability, and avoid detrimental environmental effects.