Rainfall in the northeastern United States can be erratic, causing fluctuations in the supply and quality of potato (Solanum tuberosum L.). To address these problems, yield and quality of potato were studied during three growing seasons to determine their response to soil management treatments designed to increase soil organic matter. The soil management treatments, consisting of rotation crop [oat (Avena sativa L. cv. Porter vs. green manure] and annual soil amendment applications [none vs. 22 t ha−1 compost and 45 t ha−1 manure from beef cattle (Bos taurus L.)], were tested in combination with supplemental irrigation treatments (none, reduced, and moderate) on a Caribou gravelly loam (fine-loamy, mixed, frigid Typic Haplorthod). The green manure consisted of pea (Pisum sativum L. cv. Trapper), oat, and hairy vetch (Vicia villosa Roth) seeded at 168, 56, and 34 kg ha−1, respectively. After a single season, the amendments increased soil organic matter, K, Mg, Ca, cation exchange capacity, and aggregation. Modified-Morgan soil-test P increased and bulk density decreased after two amendment applications. Total yields were significantly increased by the amendment treatment [8.6 t ha−1 (23%), 1993; 8.1 t ha−1 (27%), 1994; and 4.0 t ha−1 (11%) for 1995], and U.S. No. 1 yields were similarly affected. The amendments increased tuber decay incidence during all 3 yr. Irrigation treatments significantly increased total yields by 10 t ha−1 (36%) in 1994 and 11.6 t ha−1 (37%) in 1995, while significantly reducing specific gravity and increasing tuber size. Irrigation also increased tuber decay incidence in 2 of 3 yr. During the time course and under the conditions of this study, the green manure rotation crop had no significant effect on yields or tuber quality compared with the oat rotation. In contrast, soil amendment and supplemental irrigation proved to be management tools that could rapidly affect productivity in this agricultural system.
Publ. no. 2340. Research supported by Northeast SARE/ACE Grant LNE93-36/ANE93.18, Aroostook Water and Soil Management Board/U.S. Army Corps of Engineers (Appropriations 013-01A-2005-012 and 014-01A-2005-012), the Univ. of Maine Potato Ecosystem Project, and the Maine Potato Board.