The focus of this project was to explore whether lima beans can be successfully double cropped, thereby increasing total tonnage produced on available Delaware acres. The project was revised to be a commercial sized trial. Two fields (A & B) were planted for 2011. In order to obtain two harvests, the crop had to be planted much earlier than lima beans are normally planted. Early maturing varieties were used. Non-inversion tillage was employed.
The combined yields for Field A were 1316 lbs. per acre. The early crop was severely impacted by drought and heat, while the late crop was simply too late. The plants podded well, but lacked sunlight and heat to fully mature. The combined yields for Field B were 1663 lbs, per acre. As in Field A, the early crop was very low due to drought and heat. The late crop performed relatively well, considering the surviving plants represented about half of a normal stand. The harvested beans were of very good quality. The early harvest (both fields) graded 96 out of a possible score of 100. Late harvest (again, both fields) scored 97. The immature beans on the late beans were simply too small to shell out and did not enter into the product stream, so they did not affect the quality of the beans which were shellable.
Field B yielded 26% more beans than Field A. Field A incurred more cost due to one additional tillage pass prior to the second planting and the cost in labor, fuel, seed, and pre-emergence herbicide for the second planting. Field A incurred about $100 more per acre than Field B, while yielding less.
Double cropping baby lima beans in Delaware seems to have some potential. Ultra-early plantings definitely require irrigation. For a second planted crop to have a chance to mature, the first crop must be harvested around July 14-18, with replanting by July 20. This may not always be possible. Allowing the plants to regrow after first harvest may be a better option, however the issue of harvester traffic damage must be addressed. Stripper harvesters with tracks or tires spaced to fit between the rows will likely cause less permanent damage to the plants resulting in better second crop potential. In addition, in a regrowth scenario, cultivation is problematic due to crop residues left from first harvest. A rotary cultivator may be an option. An additional benefit to this approach would be the incorporation of residues, which may then break down quickly enough to feed the later crop.