ReachOut: The More We Know, The More We Don’t Know At All

Mike Zwingman

Mike Zwingman

Technology today is advancing at such a quick pace that it often outstrips our capacity to understand it.  This doesn’t mean that we’re dumb.  It means that we are on the bleeding edge of technology, moving so quickly forward that even our five year olds are adopting it at a staggering rate.

This same idea—that technology is outpacing our capacity to understand and apply it—can be said about nutrient management.  Given the breakneck speed of advancement, might it be possible (even probable) that fertilization practices developed decades ago no longer suffice the increased nutrient demands of today’s elite genetics, which make way for insect protections, yield potential, and plant populations nearly double what they were way back when?

The answer to that question, friends, I promise by the end of this article.

This is the first installment in a brief series of articles to help us get to better know our nutrients, including their primary functions, how they are taken up by the plant, how they interact with the soil, what forms they come in, and what actions we can take to remediate any problems we have.  Recommendations based on past research have been fundamentally vital for us to achieve the level of agricultural success we have today, but it is time to blaze a new trail and developing piece by piece a better understanding of how a higher yielding system works is where we start.  This is evolution, not revolution.

As we discuss each nutrient, we’ll talk about it in terms of its four R’s: its right source, right rate, right timing, and right placement.  We’ll talk much about demand curves so that we may minimize stresses by providing the ample nutrient supply required by higher yielding systems.  We’ll talk about where nutrients end up and how they get there, how they travel from soil to seed and how they sometimes are stored in plant tissues to be later allocated.  We’ll explore concepts like nutrient pairing, interaction, and competition based on different ratios of nutrients in the soil and plant.

Perhaps this particular evolution of our thought process doesn’t strike you as immediately critical today.  You might be thinking to yourself, “My yields keep going up, and I haven’t had to change my fertility program yet.”  Therein lies the lesson, I think.  If I’ve learned anything in my time, it’s to watch out for the “yets”.  We might not have crossed this threshold yet, but our understanding and mastery of the complex process of nutrient uptake and utilization is crucial for us to meet the future food needs of a growing world.  Our optimization of fertilizer rates, sources, and application timings will be a vital part of meeting this need, and we will need to improve our understanding of nutrient uptake timing and rates and nutrient partitioning and remobilization by plants to meet growing demands.

Improved agronomic practices, crop breeding, and advances in biotechnology during the last half century or so have allowed us to realize exponentially higher yields than ever before.  However, these increased yields have come with significant cost: these same last few decades have seen frightening drops in soil macro- and micronutrient levels.  The latest summary from the International Plant Nutrition Institute  (IPNI) shows that within the past five years, an increasing percentage of U.S. production acres have soils that have dropped near to or below critical P, K, S, and Zn thresholds (Fixen et al., 2010).

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When you couple increasingly yielding hybrids with decreasing fertility levels, it suggests that we have not correctly matched nutrient uptake and removal with proper maintenance fertilizer applications.  Thus the answer to our initial question about the suitability of decades old fertilization practices for today.  Technology has outpaced application.Header1

So yes, friends, we do need to evolve our thought processes to develop a better understanding of nutrients.  We should do so to achieve maximum profitability as well as minimal environmental impact.  The two aims go hand in hand and I hope that you journey along with me over the next few weeks as we take the first important steps toward achieving both.