Why Direct Harvest Dry Edible Beans?
By John Thomas, Extension Educator, Box Butte Co
John A. Smith, Professor Emeritus
In recent years more growers in the central high plains are moving toward direct harvest of dry edible beans instead of the conventional method of undercutting or rodding, windrowing, and then combining. Direct harvest is accomplished by one pass with the combine. Other growing regions such as North Dakota, Michigan and Canada are using direct harvest for the majority of their dry bean harvest.
Following are some reasons to consider direct harvest:
- Fewer harvest operations. This can translate into time and money saved.
- Early morning cutting and windrowing operations when the vines are tough are not needed. This is a labor consideration.
- Risk of wind moving windrows or rain mudding in or damaging the pods after cutting is eliminated.
- No soil disturbance and more residues remain in the field.
- Less soil through the combine if direct harvesting correctly.
With all these advantages then, why isn’t everyone direct harvesting? Every production system has pros and cons that growers have to weigh to see if it fits their operations. Some of the reasons people aren’t direct harvesting include:
- Normally need to wait longer to get the crop out of the field, although crop desiccants can reduce this waiting time.
- Need to learn a new production system.
- Need to buy a new or different combine header.
- A neighbor or nearby grower had a disaster.
- Total harvest loss will be higher.
- Special insurance considerations apply, but this may be changing.
Harvest loss is often the major concern with direct harvest of dry beans. Using the conventional harvest method, an average yield loss of about 1½ bushels per acre total harvest loss can be expected in good conditions. This is based on research done in a two-year study on 24 farms by the University of Nebraska Panhandle Center. If conditions are poor with significant wind or rain after cutting, bean yield losses can go up significantly.
Further data gathered by the Panhandle Center indicate that direct harvest losses for pintos would average about 3½ bushels per acre and great northerns around 4 bushels per acre if good field practices are followed. Many factors play into this harvest loss but with proper level field conditions, good weed control, suitable upright bean varieties, the correct combine header and favorable weather, total harvest losses can be minimized to a generally acceptable level.
The following are some data collected from the 2012 season in the Panhandle. The Stateline Producers Cooperative in cooperation with UNL and Roger Rasmussen had a direct harvest variety trial near Hay Springs, with eight varieties replicated two times. The beans were planted with a drill at 10-inch row spacing. The actual plant populations ranged from 75,000 to 108,000 plants per acre. The varieties were planted on June 2 and harvested Oct. 2 without the use of a desiccant. The study was harvested with a 20-foot MacDon Draper Head, except the second treatment of Sinaloa, which was harvested with a MacDon Swather and a Pickett Combine.
Harvest losses varied considerably across the varieties (Figure 1 below). As indicated by the growth habits noted toward the bottom of each yield bar, the more prostrate 3a and 3b type beans generally had the greatest yield loss. The more upright 2b growth types had less yield loss. The treatment in this study with the least harvest loss was Sinaloa harvested with the MacDon Swather and Pickett Combine.
With direct harvest 99-217 had the least harvest loss (2 bushels per acre) and windbreaker had the greatest harvest loss (9.98 bushels per acre). This data demonstrates the need to have a good upright variety that holds the pods up above the soil surface.
Yield loss at harvest is not the only consideration. What you actually haul into town to sell after harvest is the bottom line. The final yields after harvest loss are shown in Figure 2 below. Windbreaker, which had the greatest yield loss, had a final overall yield near the top of the trial, 65.6 bushels per acre. This yield didn’t differ significantly from the highest yield, which was ND307 at 68.2 bushels per acre.
Sinaloa, on the other hand, had one of the lowest harvest losses but yielded toward the middle of the study, 60.7 bushels per acre. The take-home message is to choose a good-yielding variety of upright structure and do all you can to minimize harvest loss by using all the farming practices that benefit direct harvest.
During the fall of 2012 eight different fields being direct harvested were visited and yield loss counts were taken. This data is presented in Figure 3 below as an example of total harvest losses occurring in fields in the Panhandle. Some individuals were new to direct harvest and some had been involved for multiple years.
Total harvest loss ranged from 2.6 to 7.02 bushels per acre on the direct harvest fields sampled. The growth habit of the bean variety is noted at the base of the yield bar as in the other graphs. As noted before greater harvest losses were generally found with the more prostrate type 3 growth habits. The 2b upright bean habit is most suitable for direct harvest.
For successful direct harvest, focus on a upright variety with good height and long branches, very level soil surface, early uniform vigorous plants, good herbicide weed control, and a combine header that has been designed for direct harvest of dry edible beans.
Header losses compared for different varieties of dry beans direct harvested in a 2012 field trial.
Yield compared for different varieties of dry beans direct harvested in a 2012 field trial.
Harvest losses compared in eight different farms where beans were direct harvested in 2012