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The 4R crop nutrient solution

Here’s an approach to keep consumers happy, and to boost farmers’ productivity too

corn crop

Most growers have heard of “The 4Rs” and they know it stands for applying the right source at the right rate, at the right time and to the right place. But there’s still a long way to go to actually implement the concept.

“It seems the time was right for a concept that helped explain how the close attention producers and advisers are paying to best practices for nutrient application is contributing to agricultural sustainability,” says Dr. Tom Bruulsema, a director with the International Plant Nutrition Institute (IPNI). “Of course, we all have a lot to learn. There are immense challenges ahead.”

Still, it’s a tough sell, particularly as we head into 2015. It’s tough to find the optimal balance between the fertility program that is best for this year’s crop, the program that is best for the long-term health and productivity of the soil, and the program that is the most pro-environment.

It gets even tougher when growers are faced with the reality of higher-priced land and lower-priced crops.

The trick is to sort out which approach is best while recognizing that it’s a difficult course to chart. In 2007, Dr. Terry Roberts, then-president of IPNI, wrote an article, “Right product, right rate, right time and right place… the foundation of best management practices for fertilizer,” in which he noted that the 4R Nutrient Stewardship at that time seemed to have more of an environmental urgency than one pertaining to cropping demand or overall soil health.

Seven years later, the focus on the environment certainly remains. But that has to be considered alongside of the cyclical volatility of commodity prices, as well as emerging issues such as residue management and the stark reality that bigger yields create a greater need to replenish soil nutrients.

Yet Bruulsema believes the inaccurate perceptions are abundant on all sides of the issue. Some growers and stakeholders, he says, work under the assumption that there can be little or no change made to the management of crop nutrients without sacrificing yields.

Others assume that all that’s needed is a reduction in the rate of applied nutrients. What’s needed, however, is something that falls in between the two notions.

The concept of 4R Nutrient Stewardship is nothing new, but its implementation comes amid far more controversy than when the idea was introduced 20 years ago.
The concept of 4R Nutrient Stewardship is nothing new, but its implementation comes amid far more controversy than when the idea was introduced 20 years ago. photo: File

“The difference with 4R is that many have come to the realization that to save land for nature, we need to intensify, but intensify sustainably,” says Bruulsema. “For this reason, every change that is a true ‘4R change’ needs to improve environmentally and productively at the same time.”

It isn’t enough to consider the 4R concept as one or two items, where “place” or “time” is the overriding concern. As with the whole sustainability movement, it’s a number of things done together, almost in concert. There are those who point to the discrepancies of soil sampling and the resulting soil test levels. Yet Bruulsema points out that even something like soil testing has to be placed in the proper perspective, before incorporating it into the broader canvas.

Soil testing, Bruulsema says, is only a tool, and in fact, it is only one of the tools that are available to growers to garner information. We also need to be careful not to view soil testing as a scientific principle.

“The soil’s capacity to supply nutrients needs to be assessed,” Bruulsema says, stressing the need to consider any and all approaches. “Depending on the nutrient, the crop and the regional logistical constraints, a soil test may or may not be the best tool for implementing the principle. Soil capacity to supply nutrients can also be assessed by omission plots, by crop sensors, by plant analysis or tissue tests, or other means.”

A better balance

Often, this challenge of balancing the environment, soil health and economic sustainability is borne solely by the grower. But to Bruulsema, the 4R concept requires a shared mandate. When reading through IPNI’s 4R Nutrient Stewardship Communications Guide, the contrast is stark between the simplicity of the concept of the 4Rs and the complexity of its “three pillars of sustainability.” Inside each pillar (social, economic and environmental) is another layer of complexity in its management and implementation.

“The complexity of addressing sustainability is a challenge felt keenly by everyone, ranging from the small producer at the local farmers’ market to Walmart and its supply chain,” says Bruulsema. “But within the 4R concept, we’ve tried to identify the core principles that will hopefully make this challenge manageable. Those core principles involve listening to stakeholders — the people consuming our products — and the people breathing the air and drinking the water we affect.”

It’s essential to get their input on what agriculture’s key performance indicators need to be, and then to empower producers and advisers to choose the practices to make progress on those indicators in a way that’s visible to all involved. Like 4R Nutrient Stewardship concept itself, that is not a new idea. Farmers are always hearing that agriculture has to keep in mind the demands of the consumer for safe food, but also clean air and water. At the same time, there’s also the fundamental economic reality that nothing comes for free. If the consumer wants more from the farmer, they had better be prepared to pay for it, too.

Plus, 4R involves all levels of farm management, including agri-retailers, wholesale suppliers — even governments and universities. All of those participants need to pay attention to the width and breadth of primary production and the value chain, and they must also support the source-rate-time-place choices of growers.

It’s actually within that sphere of agri-retailers and even equipment manufacturers that Bruulsema sees an opportunity for precision ag technology. In driving 4R usage and uptake, we now have the capacity to record and track nutrient performance.

“Precision ag should be transforming nutrient management plans into live, real-time accountability,” says Bruulsema. “I don’t mean that every detail of nutrient application needs to be made public, but we need to be working together to aggregate our data and show our friends and neighbours that we are producing more with less, and improving our efficiency.”

Farm locally, think globally

Of course, North American agriculture can be somewhat myopic in terms of its self-awareness. The United States has introduced large-scale mechanized farming, biotechnology and GPS technology, and Canadian agriculture has been the beneficiary of those developments. But we are not alone in the world anymore (if we ever were), particularly where fertilizers and inputs are concerned.

In 2009, Paul Fixen of IPNI wrote an article outlining the world’s supply of N, P and K (as well as sulphur). For nitrogen, he estimated our reserve capacity will last 55 years (although with newly discovered natural gas reserves suggest this number will increase). For potash, reserve life based on current production levels was 235 years.

World reserves for phosphates were estimated at 93 years, Fixen wrote in 2009. However, a year later, Better Crops, the institute’s publication, offered an update on those estimates, including more than 300 and possibly up to 1,400 years of reserves.

Now, within that same five- or six-year time frame, there have been increased demands for fertilizers from China, which is increasing its corn production — as is Russia. South American farmers have also discovered they can grow corn. And earlier in 2014, there was widespread media attention on the idea of central Africa becoming “the next Cerrado.” All of these players increase the demand for fertilizers and inputs.

“Most pundits agree that world demand for crop products is increasing steeply over the next several decades,” says Bruulsema. “Total demand for fertilizer is thus also on an increasing trend, but as we increase nutrient-use efficiency through the continued implementation of 4R, the increase won’t be quite as steep. The benefits include more production per unit of fertilizer used, and less loss impact on the environment.”

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CG Production Editor

Ralph Pearce

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