2013 Annual Report
Objective 1. Develop management strategies to enhance yields and quality of sustainable irrigated specialty crop production. Sub-objective 1.A. Determine the agronomic efficacy, effects on soil quality, greenhouse gas emissions, weed management and food safety of biofertilizers derived from bioenergy production of animal manures and municipal waste water treatment residuals to provide economic use of these byproducts as alternatives to synthetic fertilizers in potato based production systems. Sub-objective 1.B. Develop rapid non-destructive techniques for early detection of water and nutrient stresses in potato by hyperspectral imaging of the crop canopy.
Objective 2. Develop management strategies for production of short-season high phytonutrient potatoes including the developmentally young potatoes termed “baby potatoes” to improve farm profitability and diversity of production. Sub-objective 2.A. Determine optimum nitrogen fertilizer management to increase tuber set, yield of small tubers, phytonutrient levels, and to maximize efficacy of vine kill and skin set in early potato. Sub-objective 2.B. Identify and develop effective vine kill methods that improve and hasten skin set and enhance phytonutrient levels in early potato.
Hypothesis 2.A. Soil and plant N status affect timing and amount of tuber set, size, vigor of vine growth, phytonutrient levels, ease of vine kill, and skin set following vine kill in early potato production. Bintje and Ciklamen potatoes will be grown as an early crop at the ARS Research Field Station. Petiole N samples will be taken at weekly intervals until vine kill. Total tuber yield, numbers, and size distribution will be determined at harvest. Tuber size will be categorized into < 25 cm, 25 to 38 cm, and > 38 cm diameter size classes. Phytonutrient assessments will identify N levels and vine kill methods that result in tubers with higher amounts of phenylpropanoids or carotenoids, anthocyanins, antioxidants, chlorogenic acid, aromatic amino acids, glycoalkaloids, reducing sugars and asparagine. Hypothesis 2.B. Vine kill method affects the level of vine kill, speed of skin set, resistance to skinning and phytonutrient levels in early potato. Mechanical, chemical, and combinations of the vine kill methods will be evaluated for vine kill, speed of skin set, and tuber yield, size distribution, and quality of tubers in the 25 to 38 mm diameter size classes. Mechanical treatments include flail chopping, undercutting, and rolling with a roller-crimper. Chemical desiccation tests include sulfuric acid, diquat, glufosinate, carfentrazone, and pyraflufen. Skin set will be rated after rolling tubers down a 2.2 m metal diamond grid ramp placed at a 13° angle to promote skinning. Resources in years 4 and 5 may be re-directed toward testing production of second crops following early harvested potato.