Remote Sensing of Optimal Water and Nutrient Management for Crop Production

Precision irrigation and fertilization management are critical to maximizing productivity while minimizing resource use. Insufficient irrigation and fertilization reduces yields and quality, while excess irrigation wastes increasingly scarce water, and excess fertilization can lead to contamination of groundwater, soil and air. Optimizing these management decisions is difficult given the tools typically used to manage large farms. Most decisions about irrigation and fertilizer application on farms are made on the basis of field management experience and a small number of soil and leaf samples. While soil/leaf samples can be accurate, they usually have high operational cost and limited spatial coverage, leading to sub-optimal irrigation and fertilizer application for different areas within the field. Existing commercial aerial photography efforts can provide much better spatial resolution, but are difficult to translate into recommendations for field management.We aim to develop a method for using aerial imagery at select wavelengths to provide quantitative recommendations on amounts of resources to apply, and to estimate how crop yields will be affected. To develop this method, we will start by focusing on almonds, and collect both ground and aerial data during the course of the California almond growing season over a field with a variety of irrigation and fertilization treatment blocks. We will study how our aerial measurements relate to both water/fertilizer input, as well as year end yields. This method provides an avenue for inexpensively measuring water and nutrient needs over a large area, and offers potential for maintaining or increasing yields while decreasing resource use, and reducing associated environmental impacts.