No Till Notes - “Bean Day Research”

By Mark Watson, Panhandle No-Till Educator
I attended the Nebraska Dry Bean Grower’s annual field day a few weeks ago and found the field day very interesting. I would like to thank the NDBG and the University of Nebraska Panhandle Research and Extension Center for all their efforts in putting on an informative field day for everyone interested in the production of dry edible beans.
I always learn something new at these field days and feel my time spent at these field days is time spent well. I learned about new varieties of dry beans, herbicide options, and irrigation scheduling that will prove to be very beneficial next year on our farm.
The topic I found most intriguing at the NDBG annual field day was the evapotranspiration (ET) trial that was started by Dean Yonts. Dean recently passed away and his work at the UNL Research and Extension Center will be greatly missed. Dean was a fine gentleman and his passing will leave a void in the agricultural community as well as the community at large.
Dean started a project to study evapotranspiration rates of dry edible beans and compare different levels of irrigation scheduling according to the evapotranspiration rates of the crop. Dean irrigated the dry edible beans at the rates of 100%, 75%, 50%, and 25% of the evapotranspiration rates of the dry beans. He was then collecting data on the yield of the dry beans to compare the irrigation rates to the yields achieved at each level of irrigation.
The interesting part of this study for me was the yield of the 75% irrigation level of ET was almost identical to the 100% level of irrigation scheduling for ET. Evapotranspiration rates are determined by measuring the amount of evaporation that occurs off the soil surface and the plants and the amount of moisture required by the plant during transpiration. A 100% level of irrigation according to the ET would not account for any moisture in the soil.
At the 75% ET irrigation schedule, the edible bean plants are required to use some of the soil moisture available to supply their water requirements. The soil contains enough moisture to supply this additional requirement, so the yields of the 100% ET rate and the 75% ET rate were very similar. There was almost 3.5 inches less irrigation between these two levels which is a significant groundwater pumping savings.
At the 50% irrigation level of ET there was a decline in yield of almost 8 bushels per acre. For producers the significant level of irrigation according to ET rates lies somewhere between the 75% and 50% of ET rates for our most efficient irrigation scheduling. At this level we can maximize yields without pumping any excess irrigation water on the crop. This level of irrigation would also require the dry bean crop to maximize the amount of moisture it can pull from the soil to achieve maximum yield.
As more research is done in this area of irrigation scheduling we should be able to determine the most efficient use of our valuable water resource. The evaporation loss of moisture can be lowered even further with the use of no till crop production practices. If we use a combination of no till crop production practices and irrigation scheduling according to a percentage of ET rates we will be able to make the most efficient use of our water resources and maintain a water supply for generations to come.

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