Evaluation of water and nutrient deficiency for fertigation using NIR image

For an application of the remote sensing technique on agriculture, an image taken from an artificial satellite is used widely. The image would not be useful in a field-scale precision agriculture due to the limited power of resolution. For the purpose that remote sensing is adopted in a field-scale precision agriculture, the resolution should be increased or an image taken by another technique should be used. In this study, an image of plants was taken by using a digital camera with a band-pass filter. The image was analyzed related with soil moisture and nutrient condition. Broccoli was planted in nine pots different in soil moisture and nutrient condition. An image of plants in a pot was taken by using a digital camera with a band-pass filter (visible range [550, 650, 680, 750nm], NIR range [780, 800nm]) and captured into a personal computer. The digital images were analyzed with computer software to find the reflection characteristics of visible and near infrared rays depending on deficiencies in soil moisture and nutrient. Frequency distribution of brightness was used to evaluate an influence of soil moisture and nutrient deficit from images. The influence due to soil moisture deficit was significantly found in near infrared images (780 and 800 nm) while the difference affected by the nutrient deficit was difficult to be detected with the proposed procedure.