Variability in crop yields happens for many reasons, sometimes it is environmental such as a weather event or insect damage that occurs only in certain areas or at different intensities throughout a field and only in certain years. This cannot be predicted or managed. The other type of variability is spatial variability that occurs consistently year in and year out. This can be both predicted and managed with today's technology.
When it comes to spatial variability that effect crop yield whatever the variable is it almost always comes back to the soil. Think about it...soil pH, texture, slope and all moisture and nutritional issues that cause variability in crop yield are all soil induced and most of these interact with each other in some way shape or form. This is why we feel so strongly that high density, high quality soil data needs to be the foundation of a successful precision farming operation.
We use the latest in soil mapping technology created by the innovators at Veris Technologies in Salina, Kansas. This technology allows us to collect soil texture, orgainc matter, and pH readings all in one pass along with topographical information to create a data set we can use proprietary methods to create a productivity profile to build on from there.
Once we have a base data layer that provides us information about the spatial variability of a field we then proceed in collecting more data on other variables within those areas. Our soil sampling methods allow us to collect data to target variability in a field to address any deficiencies or issues we may identify adding to yield variability. We strive to balance the cost vs. density question by strategically locating our soil samples. Soil tests are not cheap so grid sampling can be cost prohibitive and usually the compromise is to only pull them every few years. Composite sampling reduces cost while overlooking variability. We target sample and we sample before every crop and keep costs economically feasible.
We understand soil mapping is an investment and margins are tight so we also use data that has been collected on farm from previous seasons. The best indicator of future performance is previous performance...right? It is and that is why yield maps are a great beginning of creating management zones as a way to start managing variability and we work with clients to do this and successfully so. The concern we have over time is as we make changes to production methods those previous years of history become less relative to the new years of data under a variable rate system so we have to account for that.
Other concerns to keep in mind when using yield data are that of the environmental variability that is out of our control year to year that influences yield maps differently every season. We thoroughly clean the yield data we use and eliminate any suspect years to ensure that we provide the best start possible using this type of data.
By the time we get to this point we usually have numerous layers of data in hand for a given field. We have identified slope and textural differences along with any red flags with regards to pH and nutrient levels. Once a plan is in place for the intended crop with fertilizer and seed products chosen we use our in house management zones and proprietary algorithms to assist in making a tailored recommendation for each product.
We strive to provide our clients positive results. We collect, clean and calibrate yield data at the end of the year and cross reference to as applied data to measure ROI and build a history for improving recommendations and decisions for future seasons. We want to learn from every acre every season!
We set out to apply the optimum rate of every nutrient the client has the ability to control the rate, whether it is applied pre-plant or on the planter or applied in season. Our average field has three products variable rate applied and some have as many as six variable rate applications per season!
We have seen some phenomenal results on variable rate fertility programs reducing rates by over 25% in some cases and still exceeding the yield goals we set out for.
It has long been my opinion that the easiest and fastest way to see a positive ROI in precision ag is to start with variable rate seeding. Most planters that have been purchased in the last few years come capable of varying the seed rate on the go using a prescription, so it's really just waiting for an Rx to be plugged in! Not to mention the fact that outside of land seed is one of the highest cost inputs you purchase every year. We have seen consistent results both irrigated and dry land on variable rate seeding with increased yields on lower average rates. So there is a reduction in seed cost and increase in productivity? Yes it has been common. We have seen returns over $20 per acre after seed savings and yield increase are factored in.
Land and ground water are the two most critical resources we use in crop production as both are finite. With irrigation in our region relying on the Ogallala Aquifer and knowing its decline over the previous decades of use there is no better time to improve our management of this resource than now! We have been able to use soil moisture senors to better the rate and timing of irrigation applications in an effort to reduce the amount of ground water pumped for crop production while maintaining crop yields by knowing when the soil contains enough moisture to sustain the crop and knowing when we need to turn on to recharge the root zone.