Spectral Reflectance Dynamics For Nutrient Stress Assay -A Brief Review

Abstract

Soil and plant analyses are the main techniques for the estimation of N and P nutrients. These tests are costly, time consuming and do not represent the whole field because of the variability of N and P levels in soil and other factors like moisture, climatic and plant conditions. Because of the large soil variability, traditional testing either becomes unrepresentative or costly because of many samples that need to be collected across fields. With increase in the use of variable rate technology and precision agriculture, multi identify and estimate remotely the nutritional status of plants. and its causes can never be over emphasized. production and are used to increase the productivity of the crop. This necessitates understanding the specific requirement of the crop and strategies for their better management. Monito the stress conditions are extremely important to develop strategies. Remote sensing technique can be used on large scale to monitor the crop under different stress condition. Spectral reflectance forms the basis Measurements with high spectral resolution open up new opportunities to find characteristic spectral features related to the crop status. The nitrogen (N) and phosphorus (P) are major plant nutrient elements that are required to be supp for vegetation production. Determining these nutrients are usually done through soil and plant testing. For precision management of nutrients these techniques are either expensive or inaccurate. Under loss of plant production whereas an oversupply leads to runoff from the paddock causing nitrification or downstream eutrophication. Remote sensing technique can play an important role in analyzing plant nutrients in a timely fashion. The hyperspectral reflectance study revealed different combination of wavelengths in different growth stages of a crop. The hyperspectral remotely sensed estimate provides accurate, timely and fast spatial and temporal measurements of plant N and P.