Is Compaction putting the squeeze on your yield?

The following blog article was originally posted by our dealer Precision Agronomy Solutions serving central Nebraska. We thank the agronomic leadership of this elite water management team of Nick Lammers, Matt Maloney, and Curt Maloney for their harvest insights.

 Hopefully, things have been progressing well with your harvest this season. The weather has been working in our favor for most of fall. We have had a couple of questions pop up on why there are differences in yield and plant health in areas of the field where we over watered because of leaky main lines or drip tape, pivot overlap, or other situations. The question is always then, did we not put enough water on the field? And certainly, that would be something that would come to mind and should be investigated. 

 When we visited those fields, we found that there were root abnormalities in most of those situations. This was usually due to compaction in the field, and looked like the pictures in [Figure 1]. The root development was primarily just down the seed trench. This can often be the result of sidewall compaction during planting. When we have root systems that are limited in their growth from sidewall compaction or other compaction variables, we not only reduce root development, but also affect the soil water content of the soil.

Figure 1 – Root development effected by compaction.

Compacted soil has less over all pore space and less means of storing water. [Figure 3 below]. So when you add a reduced root system to a situation where we have less water storage and less ability to move water from the wetter deep parts of the field to the drier layers, it can create problems and potentially reduce yields. In some situations where parts of the field were saturated because of excess water, the plants were able to use that to their advantage and still produce better yields. But, maintaining a saturated soil all season on a full quarter would be impossible economically or even physically for most systems. 

Figure 3

Kevin Keller, Dekalb technical agronomist, also investigated many fields that showed similar symptoms. In a field near Shelton, NE, he found root system problems which resulted in wide yield variances. [Figure 4 below]

Figure 4 – Root development in relation to yield.
Smaller corn ears effected by soil compaction.

Kevin believes that we have been compacting our soils the over the past 3 years, but because of the abundant rainfall we had not seen the effects as it relates to water uptake. Even this year when we planted, we had dry soils at the very top, but it was wet enough below that we ended up with situations like above. This field received abundant irrigation (most of us would consider it to be excessive irritation) but the grower was still seeing wide yield variability in the field. And the overall yields were far below what he had expected to get this year. Part of the reduction in yield comes from lack of fertility also. When plants do not have the root system to absorb water, they also do not have the ability to bring in adequate nutrients, creating even more yield issues. 

When we have situations like this it always bears spending some time trying to figure out what is going on, so we know how to fix it, and it does not happen again. We do not want to just go for an easy answer like putting on more water, because that will not fix the problem. We need to look at what the underlying problem is and find solutions to that. Managing water with the technology we have works well. Most of the fields we had this year had average or better than average yields even with the much drier than normal conditions we faced. If compaction was an issue for a field you had, give us a call and we can discuss possible solutions for those situations.



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