Field runoff is a problem that everyone is concerned with – including precision irrigation outfits like CropMetrics – but I would venture to say that no one is more concerned about it than the producer who is paying to grow the crop on these fields. Obviously they need fertilizers and chemicals to grow a productive crop and it is no secret that runoff carries away nutrients and chemicals into regions where they were never intended to go. Because of this expense, producers will never intentionally run off water, but in some instances it seems that there is really nothing that can be done to prevent this runoff.
As a society we rely on these producers to provide us with the food and nutrients we need on a daily basis. So what can we do? Is there really anything we can do to help reduce or eliminate runoff? What if I could offer three different options for the irrigated acre that would greatly reduce or eliminate runoff caused by irrigation while greatly reducing runoff caused by rainfall? Are you interested? If so, continue reading below:
- Runoff caused by rainfall is nearly impossible to manage. It is worse when the fields are already wet when it does rain. This increases not only runoff but nitrogen leaching as well. With VO Pro from CropMetrics producers will have the most precise irrigation scheduling tool available today, claims the company in a recent blog post. Providing a local field specific weather forecast along with a field specific irrigation forecast, preparing for rain is greatly enhanced without risking additional stress to your crops. Knowing your local field specific forecast and the precise development stage of your crop, decisions to irrigate differently or not at all will be easier to make. Leaving room in the profile to absorb water will greatly reduce runoff on irrigated fields. Prior to VO Pro, this type of opportunity has been unavailable to producers, leaving them with only high risk guessing games. Because the risk was so high, producers would continue to irrigate and rightfully so. The risk of not catching a rain has always been high and getting behind with irrigation is just not an option. VO Pro is the first of its kind to give the confidence on irrigated fields to take advantage of rainfall and reduce runoff. This is really the first step needed to enhance the next two runoff reduction options.
- As we all know, tillage practices make quite a bit of difference in water infiltration and runoff. No till has proven to be the best in most cases but is it always the best for maximum yield and profit opportunity? The one thing that we do know is that residue in and on the topsoil reduces runoff. So with that in mind we need to look at the way we manage our surface profiles. In recent years strip till has helped to improve soil conditions in many areas yet in other areas in different soil types, with different topography variability, it may not be the best answer either. Minimum till or vertical till programs seem to work pretty well as they do a good job of chopping up the residue yet leaving the residue on the surface to capture water and hold nutrients. In these conditions evaporation loss is also lessened so water use efficiency is enhanced. But if it is a wet spring or early summer the risk of disease is higher. Therefore managing irrigation timing and application depth will greatly help to reduce wet topsoil’s that lead to increased disease pressure and ultimately increased runoff. So it will be important to make sure and weigh out the risk associated with making a tillage practice change to reduce runoff. It would be our recommendation that you take the time to meet with your local agronomist and CropMetrics Precision Data Specialist (PDS) to make sure your soil types and field conditions are optimized to get the most return to your input investment. If you do decide to make a change from conventional tillage to minimum till, strip till, or no-till, be prepared to do some intense research in your area and make sure the investment in equipment, learning curves, input adjustment requirements, etc. will be profitable at the end of the year.
- Irrigation Runoff Control Scripts (RCS) provide tremendous improvement to runoff problems associated with center pivot irrigation. These VRI scripts are designed to allow a grower to not only do a better job of irrigating the majority of the field, it is designed to take those slopes into account that have caused him to run low application rate rotations in the past. Lets look at a very typical example found in central Nebraska where topography and heavier soils are common causes for irrigation runoff.
In many areas growers are applying low application rates of water because the slopes will not allow them to put on more than .60″ of water in any pass. This greatly limits the opportunity to apply higher rates in other areas of the the field to increase application efficiency (AE). RCS will allow producers to put on higher rates in the good areas of the fields while speeding up going down the slopes. Obviously speeding up going down the slopes will reduce runoff but won’t it decrease yield at the same time? Yes! Therefore we design the pivot to auto-reverse and go back across the slope in the other direction with the same low application rate of water giving the soil time to infiltrate. Three short applications of about .35″ will not run off but if applied in a short amount of time will actually allow the soil to intake nearly .90″ of water into the slopes even after evaporation! Now consider each time the pivot goes around we put on a 1″ base rate instead of .60″ like we had to normally and at the end of a 10″ application season you will save 6 total rotations. That is a lot of reduced wear and tear. Not to mention since AE will improve producers could essentially eliminate one complete rotation for every 10 rotations made while increasing yields in the slopes. This is a win no matter how you look at it!
It is important to note that the three topics we just covered will help decrease run off individually. But it’s the combination of these systems that will bring the best results. True solutions to water issues will never just be a one piece fix all solution. Irrigation efficiency and water optimization is a mindset and a lifestyle that will become a passion once results are truly realized. To begin implementing these solutions on your farm, contact your local CropMetrics Dealer.
SOURCE: CropMetrics April E-Newsletter.