2010 Annual Report 1a.Objectives (from AD-416) Non-destructive estimation of nutritional status of potato canopy using multispectral imaging and prediction of tuber yield and quality response to variable nutrient management under pivot irrigation. 1b.Approach (from AD-416) Spectral characteristics of vegetation are a quantitative measure and can offer a non-destructive method to assess crop nutrition; biomass production; and, in turn, yield and quality of crop products. This type of sensing technology has been successfully developed for detecting nitrogen stress in agronomic crops, such as corn and rice. This technology can be modified for its application to potato production under center pivot irrigation. In this research, the following steps will be used to investigate the feasibility of developing a multispectral imaging based sensing system for estimation of nutritional status of potato canopy under variable nutrient management programs and, in turn, predict biomass production, tuber yields and tuber quality parameters. Furthermore, multispectral image sensing can be an efficient tool of non-destructive evaluation of potential non-uniformity in water distribution through sprinklers in center pivot irrigation system. 1. Collect multispectral images of potato canopy grown under different nutrient management programs; 2. Analyze the spectral characteristics of the canopy and search for a trend of such characteristic change with the corresponding nutrient management programs; 3. Analyze relationships between the spectral information carried in multispectral images and nutritional status of the plants monitored based on the petiole analyses and destructive plant sampling; and 4. Define a calibration equation for quantitatively estimating the level of nutritional statuses based on multispectral images. Documents SCA with WSU. 3.Progress Report The objective of this study was to develop a non-destructive method of evaluation of potato nutritional status using spectral measurement of foliage under different levels of nutrient management. During the first year of this study, portable spectrometer and multi-spectral camera were used to collect spectral data in the field at weekly interval during growing season of potato subject to different nutrient management practices. Leaf samples were also collected for total nitrogen analyses at each measurement of spectral image. Relationship between spectral characteristics and foliar nitrogen content will be evaluated to develop significant relationship. The plant growth stage most sensitive to nutritional characteristics based on spectral measurement will be identified. This relationship when perfected and field validated, based on multi-year and multi-location studies on a range of potato cultivars, can then be used to estimate nutrient content of potato plants by non-destructive spectral measurements. This agreement was established in support of Objective 2 of the inhouse project, the goal being to identify optimal combinations of management practices to lower total production costs while maintaining market quality of irrigated potato-based production systems. This project was monitored via visits, email, and phone calls with the cooperator.