Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2008
Publication Date: July 15, 2008
Citation: Griffin, T.S., Honeycutt, C.W., Larkin, R.P., Halloran, J.M., Olanya, O.M., He, Z. 2008. Modifying Potato Systems to Reduce Yield Constraints. American Society of Agronomy Branch Meeting. CD-ROM. Technical Abstract: There are a number of factors that limit potato productivity in Maine and the northeast U.S., including crop fertility, soil-borne diseases and other crop pests, water availability, and degradation of soil resources. We established a long-term field experiment in Presque Isle in 2004, to establish the relative importance of the factors that impact yield and quality of the potato crop. There are five production systems included in this experiment, including: 1) Industry Standard 2-yr barley potato rotation, 2) Disease Suppressive rotation with mustard and sudangrass green manures, 3) Soil Conserving rotation that minimizes tillage and maximizes soil cover over 3-yr period, 4) Soil Improving, which adds compost to the Soil Conserving system, and 5) Continuous Potato. All of the production systems are managed under both rainfed and irrigated conditions, so we can evaluate the interactions between soil water and production system. In 2006 and 2007, the Disease Suppressive system increased total tuber yield by an average of 10% and marketable yield by 12%. The Soil-Conserving system, which is also a 3-yr rotation, actually reduced tuber yield under both irrigated and rainfed conditions, most likely due to soil nitrogen immobilization. The Soil-Improving system increased total yield by 14-41% and marketable yield by 23-51%, but these yield increases are confined to the rainfed management strategy. The Continuous Potato system reduced yield regardless of water management, due to both increasing disease pressure and soil compaction. Differences in yield between production systems reflect the impact of these systems on the amount and duration of leaf area. This field experiment will continue for at least five more years, and will allow us to identify the primary constraints to potato productivity and to develop alternative practices for reducing those constraints.