Nitrogen fertilizer management decision with the use of active optical sensors for sugar cane, cotton, corn and wheat

Abstract

Crops in general respond strongly to nitrogen available in the soil. Sugar cane, traditionally burned for manual harvesting, has a nitrogen fertilization management relatively known. Nevertheless, on mechanized harvesting, without burning, its behavior is significantly changed. On cotton crop availability of nitrogen in the soil interferes on the quantity and quality of produced fibers. The efficiency of nitrogen use by cereals is about 33%; the rest is lost and affects negatively the environment and farmer. It is also known that wheat protein content is strongly influenced by nitrogen fertilization. Sensors used on remote sensing are able to detect electromagnetic radiation on specific bands and generate information that can estimate, among others, the quantity of nitrogen on crops because spectral reflectance is inversely correlated with the nitrogen on the plants. The project aims to study the behavior and potential of commercial active optic sensors use on sugar cane, cotton, wheat and corn under different nitrogen rates. Due to the increasing number of researches abroad on this topic, the purpose is to evaluate the same process under Brazilian conditions, with crops and varieties here adapted or developed and largely explored and estimate their nitrogen content, for advancing on obtaining adequate parameters for nitrogen fertilizer management. Several experiments are proposed with the help of partners and will measure reflectance response with active sensors on plots under nitrogen rates. It is expected to obtain correlations among reflectance and different nitrogen rates applied to sugar cane and measured on the leaves. For cotton crop it is planned to evaluate nitrogen leaf concentration under different rates applied on plots. It is also expected to obtain the correlations among spectral reflectance and nitrogen rates applied to plots for wheat and corn, and propose rates to be applied based on the use of commercial active optical sensors. At the end it is expected to generate parameters for a possible automation of diagnostic or initiate studies to allow the remote sensing on real time for site specific nitrogen application. (AU)