Nitrogen Use and Crop Productivity Characterized Using Spectroradiometery In Switchgrass Under Different Fertilizer and Harvesting Regimes.

Nitrogen and water are some of the most important limitations for crop production, whether for food or for biofuel purposes. The light energy absorption characteristics of plants in the near-infrared range can be used to predict plant nitrogen and water status.

We assessed the nutrient uptake patterns and losses under different fertilizer application regimes and their effect on productivity. We also evaluated the potential of using spectroradiometry in management of nitrogen and water for switchgrass.

Our results showed that nitrogen and water can be very effectively assessed non-destructively at extensive scales using remote sensing of the crop canopy. The technique can be used to manage fertilizer application and harvest time so as to minimize nutrient losses without compromising yields. The differences in plant water and nitrogen uptake under different harvest scenarios have important implications for nutrient export and evapotranspiration losses. An integrated analysis of plant spectra for both nitrogen and water effects can provide meaningful management tool at commercial scales to manage two most important inputs. The spectral signatures can also be used to identify nutrient deficiencies and water stress.