It’s unusual to get field work done in the middle of winter in Minnesota. January of 2019 was the exception for us. We are farming a field that has never been grid sampled for fertility. From our past experiences of using this practice since the mid 1980s, we know that grid sampling is the only way to know what is going on in the field on a smaller scale. The field is broken down into 440′ x 440′ grids that are each sampled independently. A map is then generated that shows what each grid needs for fertilizer. Some findings are interesting and show how past farming practices still are visible today.
A couple discoveries of note in this field: 1. The 160 acres was farmed by two different owners for many years. This shows up most dramatically in the pH and zinc levels. The south 80 has extremely low pH in a large number of the grids. The north 80 has extremely low zinc levels in a large number of the grids 2. You can use the Phosphorous levels as an indicator of where the farm site was located and where they hauled the manure. The P levels are much higher in these areas even decades later.
We visited with the coop about our spring fertilizer needs in early January and asked them if lime was ever applied in the winter. They said that usually it could be done in March if conditions allow. A day later they called to say that the applicator was able to do the lime right now if we had an area that they could access to pile the lime without getting stuck in snow drifts. We took the snow blower to the field and cleared a path. They hauled lime in on Saturday, January 11 and spread it on Monday.
Daniel Kaiser and Fabian Fernandez University of Minnesota Soil Fertility Specialists
Over the winter we have done intensive data compilation and analysis and have a few updates to the corn guidelines publication. The primary update is on nitrogen application rates for corn following corn and corn following soybean. The updated publication is not finished yet, so this article will serve as the current rate guidelines starting spring of 2016.
During plating season we carry ATS liquid fertilizer on our tractor. The fertilizer is surface applied in a stream over the seed furrow behind the planter closing wheels. ATS is applies at a rate of 8 gpa so it is imperative that we carry enough to avoid stopping planting progress to refill tanks. We started our with 450 gallon tanks tucked between the tracks on our JD8310T tracked tractor. We were filling more often with fertilizer than we were with seed corn. We then added a cart mounted push tank to the front of our tractor to carry another 400 gallons of ATS. While not ideal, we already owned the cart and tank so no money was invested in the extra capacity.
Fast forward to 2015 when half way through the season our cart system failed beyond repair. It worked well while it lasted but now it was time to strategize for 2016 and beyond. Our research led us to adopting the idea of mounting outboard saddle tanks to carry another 400 gallons minimum. As we explored the idea, we decided that the ideal tank size would be 250 gallons on each size so we have room to easily carry 800 gallons on the tractor without having to fill each tank to capacity and risk overflowing fertilizer on the ground as well as on the steel with rusts easily when coated with fertilizer. Continue reading →