When it comes to high-yielding soybeans, fertility is absolutely critical. I can’t say it any simpler than that.
For many years, soybeans were actually revered for their ability to scavenge for the crop nutrients they needed to produce average yields. With little or no added fertilizer, you could still get a decent crop. Thankfully, we now see far fewer growers practicing the ‘scavenger’ approach, and if we want to consistently get higher yields, it has to be completely scrubbed from our management handbook.
If you look closely at the history of soybean yields in Ontario you’ll see there has always been ample evidence that soybeans pay handsome rewards for higher fertility and stronger management.
During my career, I’ve always noted how livestock producers consistently produced top soybean yields. Whether you’re a dairy, poultry or pork producer, the annual application of high-nutrient manure is an obvious contributor here, but there’s more to the story. For these farmers, it’s also important to acknowledge the importance of more diverse rotations, including forages. Not only do forages pack a nutritional punch, but we’ve also come to appreciate their role in creating better soil health, which is a key contributor to high-yield soybean environments.
Understanding soybean soil nutrient removal
We’ve also learned that soybeans are a nutrient dense crop. Basically, this means that soybeans have high removal rates and draw huge amounts of nutrients from the soil – much more than corn on a per bushel basis. For example, when you compare the two crops, a bushel of soybeans has a nitrogen density four times that of corn. A bushel of soybeans requires twice the amount of phosphorous and five times the potassium. If we do the math, 50-bushel soybeans and 185-bushel corn are making very similar withdrawals from your soil nutrient bank account.
So what does all this mean for soybean growers, especially the vast majority who do not farm livestock and have shorter, less diverse rotations? It really starts with intensifying your soil fertility management. We’ll tackle how to do that in other articles and blogs here at Soy Masters, but let’s start with maintaining and establishing good soil health as well as good base fertility.
Establishing good base fertility
Basically, what we need is healthy soil that promotes the uptake of adequate available nutrients. We need three to four percent organic matter (depending on soil type) and soil tests should show a minimum of 20 to 30 PPM for phosphorus and 100 to 125 PPM for potassium. More diverse rotations will certainly help. In a future blog, we’ll explore some work on rotational benefits by Dr. David Hooker, research agronomist and associate professor at University of Guelph-Ridgetown Campus. I would also encourage you to read this blog to see how Ontario grower Greg Iler manages his rotation for optimum soil health.
When it comes to optimizing fertility, we’ll explore the need to consider the macro and micronutrient requirements of the crop as well as seed and foliar nutrient application options.
Growers really do have the capability to intensively manage fertility and help reach that 60-bushel goal. It’s a much better option than just letting the crop scavenge for average yields.