ASHS 2015 Annual Conference

Can potatoes be grown profitably for organic dry matter production? The objective of this study was to grow potatoes under organic conditions and reduce the cost of seed in western Nebraska. Operational costs would be planting, cultivating, and harvest; estimated at US$70/a. The major and variable cost is seed purchasing. In earlier comparison trials, the cultivar Atlantic was the most promising of the several cultivars and types tested. Using Atlantic, identification of the most profitable seed size and spacing to plant to achieve the right balance between seed cost and yield resulting in the highest net income. No irrigation, fertilization or pesticides were applied. Rain from planting to harvest was 7.9 cm (3.1 in), 42% of normal, and temperature 22.2 oC (72 oF), about 1o above normal. Cut seed-pieces, weighing 34, 57, 64, 71, and 85 g, were planted at 15, 23, 30, 38, and 46 cm apart in rows spaced 91 cm at Scottsbluff, NE following dry bean. The highest yields, >11.2 Mg/ha, and lowest stand, <70%, were obtained when plants were spaced 6 or 9 inches regardless of seed weight. Seed weight did not play a significant role; however seed-pieces >57 g performed the best. Calculating net income, fixed costs were assumed to be $173/ha ($70/a), cut seed cost to be $30/a ($12/a), and sales for dehydration to be $8.80/100 kg ($4/cwt). A profit greater than $247/ha ($100/a) was achieved when seed pieces, < 71 g (< 2.5 oz), were planted 38 or 46 cm (15 or 18 in) apart. This study is continuing, however, it may be economically feasible to grow a crop targeted for potato organic dry matter production in western Nebraska.