The majority of beans are indeterminate providing several opportunities for reproduction, and those that are determinate are found primarily in the southern states. The yield potential of these plants is quite high, and even with the majority of fruiting forms (blooms, small pods) aborting we still achieve a respectable yield in most instances. Of course we always want more yield.
Achieving yield increase with any bean plant is theoretically easy … it’s simply a matter of having more beans. This can be achieved with higher populations, which in our opinion could be too high already; growing a larger plant, which is desirable so long as the plant does not get leggy; reducing fruit abortion; or by increasing pod fill and test weight. The most common obstacles we’ve observed through the years is excessive abortion and inadequate pod fill, which Is primarily due to weather stress or inadequate nutrient or energy availability during these critical points in the season.
All beans are legumes, but it should always be remembered that they are not legumes until several weeks following emergence. So if our goal is to grow a larger plant frame to achieve additional fruiting sites, we need to have young seedlings emerge with a high level of vigor, which requires a small amount of nitrogen. We usually recommend a small amount of nitrogen prior to or at planting.
Once the bean plant frame is growing as desired, we then turn our attention to reproduction, or the actual setting of the pods. The photo at left illustrates the number of fruiting forms that were initiated at just one stem and branch node. There are at least 16 fruiting forms in the photo, yet even under the best of circumstances we would probably have no more than eight pods actually set and make beans. University research indicates that in most situations from 50% to 70% of all potential fruits abort.
All plants will adjust the number of fruits based upon overall plant vigor, beginning with early initiation and continuing through maturation. The photo at bottom left illustrates how individual pods have developed based upon overall plant energy. Some pods only initiated one or two beans, others three and then at a later point in the season aborted small beans. The greater number of pods, the more difficult it becomes to fill all the pods. Overall, the bean plant has a lot of work to accomplish.
Our goal as managers is to better understand the stress factors that the bean plant has to deal with and when practical, reduce the stress. In most instances this will require supplemental nutrition.
The following products are common inputs into an ISP Bean Program, and will vary based upon individual practices.
Following is a general recommendation outlining some of the more common stress points. It should be noted that the bean plant is highly dynamic, and that not all of the comments are applicable in any given area. The actual program you assemble should be suited to your normal environmental conditions and management practices. In all instances, soil nutrient levels should be more than adequate to support the targeted yield goal. This program is designed around a mid to later May planting date, and all information is provided as a “per acre” basis.
- Prior to, or at planting: 14 to 20 units nitrogen. 16 ounces HV-1, or 1 to 2 gallons PhytoGro Xtra.
- Seed Furrow: 8 to 12 ounces MetaboliK SB, 6 to 10 pounds 10-45-10.
Another option is Pow’r Pak at 1 to 2 gallons per acre.
- Spring weather stress: If weather is excessively stressful, 1to 2 gallons of NRG Bean could be beneficial.
- V2: good results have been seen with ½ gallon PhytoGro Xtra at this stage.
- June: Observe plant growth, notice node spacing and general leaf size.
- July Fruiting to Set Blooms / Pods: If wanting to set fruiting forms, 2 to3 pounds 10-4-10 or 10-20-20, and 2 to 4 ounces HV-1 per foot of plant height.
- Two Weeks Later (Pod Fill): 3 to 4 pounds 28-16-7, 4 ounces HV-1 per foot of height.
- August Fruiting to set Blooms/Pods: Usually is not a recommended application but would be the same as July.
- August Pod fill: If fertigation is available, 15 to 20 pounds nitrogen. If not available, 4 pounds 28-16-7 and 4 ounces HV-1 per foot of plant height. If not available, 4 pounds 28-16-7 and 4 ounces HV-1 per foot of plant height.