The “Other” Crop & Water Management
Throughout the Midwest, we often hear “Corn is King,” and rightfully so. But as of recently, the “other” main cash crop is beginning to get more attention when it comes to input management. Soybeans have traditionally been planted with little additional thought aside from spraying. Over the last few years, the journey to break through the soybean yield “ceiling” has growers looking at more fertilizer inputs and other management practices similar to the king crop. What about water? In irrigated regions, one of the most common and frequent statements heard is “dryland soybeans out yielded my irrigated soybeans!” Is that the soybean’s fault?? Soybeans have proven to be more sensitive to water at certain growth stages during the season, but they have also proven to respond to proper irrigation just like the king crop. Does it pay to invest in water management technology on this “other crop?”
Soil moisture probes are the first step to optimal irrigation scheduling with any crop, including soybeans. In fact, moisture probes answer the two most challenging times in soybean irrigation management — when to start, and when to stop watering. Starting irrigation too early often leads to the plant’s energy put more towards vegetation, and not enough saved later for reproduction. This single timing is a primary culprit of the yield drag experienced in irrigated soybeans. Soil moisture probes accurately identify soybean rooting activity and depth in relation to available soil water content. Utilizing the CropMetrics system, we have consistently helped growers delay the first soybean irrigation until when the plant really needs it, which has consistently produced higher yields. At the same time, this delay in first irrigation will regularly save 2-3 pivot irrigation rotations. These cost savings, in addition to the increased yields easily pay for the cost of the soil moisture probe technology. Beginning with a soil moisture probe, we are able to focus on maximizing productivity on the majority soil type, which then leads us into the next opportunity below.
Variable Rate Irrigation is another example that is sometimes overlooked with the “other crop”, but can often pay significant returns on investment. Using the same field example (shown above) from our recent Soil WHC Blog Series, this field had an average of 10 bushel less in the heavy soil type zone (blue zone) over the 2 previous years it was in soybeans. This soybean variability was consistent from year to year. The next year we added CropMetrics VRI using the Rx shown above, and by simply reducing our water application by 0.18″ each rotation in the blue zone, we were able to reduce yield variability across the field and improve soybean yields in what was traditionally a lower yielding zone (heaviest soil type).
After VRI, the low yielding zone was only 3 bushel lower than the highest yielding zone, compared to a 10 bushel lag in the previous 2 years. This was a 7 bushel improvement over 15 acres of the field, resulting in $1,050 of increased profit (using $10/bu price). The cost of CropMetrics full service VRI is $5/ac, and the total VRI cost for this half circle pivot is $325. The $725 net profit return for the field is one simple example looking at the improvement from only 1 management zone alone! The improved scheduling and timing of irrigation applications with soil moisture probes, in combination with the proper spatial application of water will in turn have a yield improvement across the entire field.
Don’t blame the “other crop” for lack of yields when irrigating, and instead turn to improved irrigation management to help your soybean crop reach it’s maximum potential. To learn more on how precision irrigation solutions could help you irrigate your soybeans more effectively, contact your local CropMetrics Precision Data Specialist.