No Till notes: 'Water Conservation, Part 4'

As I mentioned in previous articles we view water conservation on our farm as a systems approach to saving water. Thus far I have talked about utilizing no-till crop production techniques to minimize soil disturbance and adopting a dynamic crop rotation.

Another component to water conservation we have implemented is to produce a forage crop following our irrigated winter wheat harvest. I struggled with this decision since we are producing another crop on our irrigated acres which will require some irrigation. This contradicts our whole idea of conserving water, but I think the benefits to soil health will offset any additional irrigation required to produce the forage crop.

We decided to incorporate a forage crop into our rotation for two different reasons. By producing a forage crop we will be able to manage the amount of residues left in the field for our edible bean planting the following growing season.

We feel the winter wheat residues are difficult to plant into if they lie in the field over the winter and early spring. The winter wheat residues tend to fall over at this point and getting our drill to consistently cut through them is difficult.

We felt by planting a forage crop and grazing the crop we could begin the degradation process of the winter wheat stubble earlier. By knocking down some of the stubble with the drill during planting of the forage crop the soil microbes can begin consuming the stubble.

Growing a forage crop also creates a humid environment which helps deteriorate some wheat residue as well. The livestock will also consume some of the winter wheat stubble as they graze the forage crop. By growing the forage crop we are able to manage the amount of residues we want left in the field to seed edible beans into.

The diverse forages following our winter wheat harvest also add more plant diversity into our rotation. We are able to maintain a living root in the soil for an extended period of time by planting these forages which creates more organic matter in the soil. We are also able to produce more biomass on the soil surface. This should allow us to put more carbon into the soil and increase the organic matter content of the soil.

If we can increase the organic matter content of the soil, our soil should perform at a higher level when it comes to moisture management. Increasing the organic matter should improve soil aggregation, water holding capacity and improve soil structure. All these benefits improve the soil’s ability to infiltrate and store additional water.

These diverse forages should also improve the diversity and populations of soil microbes. This will result in increased nutrient cycling for the following crops. I think the end result of producing these forages will be healthier soil over time which will give us a higher performing soil to work with.

The most irrigation we have pumped to produce these forage crops following winter wheat harvest has been 5 inches. During this time we didn’t receive any moisture at all during July, August and September. We had to water the forage crop to get germination established, and had to apply additional water during the growing season.

We have also had to water the forage crop very little following winter wheat harvest. At times there is enough moisture to get the crop germinated and timely rains have fallen where we have pumped as little as half an inch of irrigation to produce the forage crop. Water use will vary depending on the precipitation received in the late summer and early fall.

I’m fairly confident over time that the benefits of improved soil health will offset the irrigation required to produce these forage crops and will result in a net decrease in the amount of irrigation we use in our rotation. We’ll learn more over time if our management decision is a good one.