Mechanical pod strippers are the predominant method of harvesting lima beans (Phaseolus lunatus L.) for processing. Field losses are high, averaging 20% of potential yield in over 90 tests conducted in commercial fields. The three most significant factors that affect lima bean recovery are the field levelness, the relationship between ground speed and picking reel speed, and the lima bean variety. Further study on the relationship between pod location of four lima bean cultivars and the recovery of lima beans harvested with pod stripper combines was conducted in commercial fields. Pod location was categorized into three distinct zones of the plant. These three zones represented pods falling below the point the mainstem comes out of the ground, the first 5 cm from that point up the main stem, and all other pods higher than 5 cm above the stem. Differences in four cultivar's habits of setting pods in the three zones were established. `M-15' placed more pods in the lower zones than other cultivars. `M-15' also exhibited consistently more harvest loss than other cultivars when harvested with pod stripper combines. Other cultivars set pods higher in the plant and exhibited less harvest loss. With the harvest loss and pod set data, a rating procedure for the harvestability of lima beans was explored. While several potential rating systems demonstrated strong correlation with harvest loss data, a simple rating based on the percentage of pods in the canopy of the plant had the highest correlation coefficient (r = 0.96) with harvest loss. New cultivars can be evaluated for their harvestability characteristics using this rating system.
If the inline PDF is not rendering correctly, you can download the PDF file here.