J U L Y / A U G U S T 2 0 1 9 20 POTATO GROWER matter content, pH), soil health charac- teristics (e.g., aggregate stability, 24- hour CO2 release, protein N, pen- etrometer readings), Verticillium and nematode population assessments, and soil microbiome composition. Nitrogen Fertilizer Management for Potato Production using Remote Sensing This project will develop a remote sens- ing based precision agriculture tool for in-season N management in potato production using a multispectral remote sensing algorithm. The intent of this project is to provide direct vali- dation for a remote sensing based pre- cision agriculture tool that is better able to predict the optimum rate of in- season nitrogen fertilizer than conven- tional management practices, and one that can be utilized at a commercial scale. The overall objectives are to: 1) To improve a prediction algorithm for above ground nitrogen concentration using multispectral ground- based and UAV-based sensors; 2) To validate the agronomic effectiveness of the algo- rithm at determining the need of in- season nitrogen applications compared to conventional methods; and 3) To optimize the algorithm for real-time usage during the growing season. A series of eight N treatments will be evaluated, four of which range from 40 to 320 lb N/A, two at 160 and 220 lb N/A will be based on real time petiole analysis and two at 160 and 220 lb N/A will be based on remote sensing meas- urements. Evaluation of bed planted potatoes for improved nitrogen use efficiency This project is a continuation of a study initiated last year to explore the effects of potato planting configura- tions on N uptake Rather than high density single rows planted with wide spacing between hilled rows, the potential for using lower density plant- ings within narrow rows in beds will be investigated. The study is being con- ducted at a potato seed farm near Staples. Treatments include two plant populations (9,500 and 12,500 plants/A) planted in seven row beds spaced 1.7 ft between rows and four single rows spaced three ft between rows. Three N rates (150, 200 and 250 lb N/A) will be evaluated in both plant- ing systems and populations. Biomass, tuber number, N concentrations and total N uptake will be determined at harvest. Suction tubes have been installed in a subset of treatments to determine if there are differences in nitrate leaching. Effects of ESN Timing and Placement on Potato Yield and Nitrogen Uptake ESN is a polymer-coated urea devel- oped to release nitrogen over a 70-80 day period under Minnesota growing conditions. Use of ESN is considered to be a best management practice because losses of N are minimized during in the early part of the growing season when potato root systems are small. The rec- ommended time to apply ESN is at emergence as a topdress followed by incorporation into the hill. This recom- mendation was based on effectiveness of response in previous studies and convenience of application and incor- poration. However, topdressing ESN followed by hilling often results in ESN prills ending up in the furrow, which may reduce the ability of potato roots to access the N once it is released. The objectives of this study are to: 1) To determine the effects of ESN manage- ment (timing and placement) on pota- to yields and N uptake and 2) To quan- tify the amount of ESN that ends up in the furrow following application. Treatments include: 1) urea topdressed at emergence 2) ESN broadcast pre- plant; 3) ESN banded at planting; 4) ESN topdressed at emergence; 5) ESN banded at emergence. A Field Evaluation of Aspire as a Potassium and Boron Source for Irrigated Potato Production This is a continuing study to evaluate granulated potassium-boron blends as a fertilizer source for potato produc- tion. Potatoes have a high demand for potassium (K), relative to other crops. Potassium can influence the yield and size distribution of potato tubers, as well as their specific gravity and storage characteristics. The importance of K and B in crop production has been well documented. However, because B is a micronutrient and is therefore applied in very small quantities, even applica- tion of this nutrient can be difficult to achieve. Uneven application is a potential problem because the range between deficient and toxic soil con- centrations of B is very narrow. Aspire (Mosaic Co.; 0-0-58-0.5B) is a product developed to facilitate even application of B by combining it in fertilizer gran- ules with K, which, being required in high quantities, is easier to distribute evenly. The objectives of this study are to: (1) evaluate Russet Burbank potato response to Aspire relative to K without B (0-0-60), (2) evaluate the effective- ness of Aspire relative to 0-0-60 blend- ed with supplementary granular B