Are you still wrestling with questions over soil fertility issues in your no-tilled pastures? I found an interesting read by Oklahoma State University Extension soil nutrient specialist Brian Arnall, who publishes a blog entitled “Down and Dirty with NPK.”
In this post, Arnall delves into the issue of precision nutrient management in forage systems, and the importance of using soil samples to help arrive at proper decisions, with the goal of “producing the highest quality output with the least amount of input.”
Without a soil sample, he says, fertilizer applications are really guesswork — and with the price of inputs today can you really afford to be guessing?
Arnall shared some data that supports the need to “increase the resolution” or reduce the amount of acres represented in a single soil sample through grid or zone sampling.
He noted a study of 178 fields in the southern Great Plains that showed while the average components of soil fertility were acceptable, there was a fairly significant range in soil pH (1.8 units), Mehlich 3 phosphorus and Bray 1 phosphorus (52 ppm) and soil-test potassium (180 ppm).
You can read more about Arnall’s considerations for grid and zone sampling in his article. But I will share a good point he made about precision technology: Don’t expect yields will be uniform across the field as a result of precise nutrient applications.
In most cases, Arnall says, the goal is to apply the proper amount of nutrients in the right place, which means some field areas can be managed for maximum production, while more yield-limited areas that won’t respond to fertilizer application get the proper amount without dinging yields.
Getting your nutrient applications nailed down this tightly will be difficult without doing proper soil testing, so perhaps now is a good time to evaluate how you’re sampling fields and make the right adjustments.