2011 Special Section: Fertilization of Sunflower
Tuesday, February 1, 2011
filed under: Fertility
Maximizing input efficiency and yield is a common motto in agriculture today — and in this special insert on sunflower fertility. Leaving things to “chance” is not acceptable in high-management agriculture. An important management component in achieving high yield in sunflower is fertility.
It appears in the discussion that follows that fertility in sunflower is not an exact science. Some of the most significant early fertility research was done in the 1970s by North Dakota State University soil scientist Joseph Zubriski. His work remains a primary resource for recommendations of basic fertility inputs throughout the production region, from Manitoba to Texas, and it has served this industry well. Additional research has mostly “nibbled around the edges.”
But a great deal has changed since Zubriski’s work took place. Here are just a few examples:
• Fallow is no longer part of most rotations.
• Corn is a common part of many sunflower rotations.
• No-till and minimum-till systems are very common.
• Sunflower is grown over a much broader geographic
region with a host of different soil types.
• Fertilizer application equipment is dramatically different.
• And, of course, sunflower hybrids are improved as well.
Zubriski’s work highlighted the effect of nitrogen on sunflower yield, and the 50-lb recommendation for 1,000 lbs of yield continues to be the general rule. The attached stories attempt to take the reader to another level of understanding for fertility decision making.
The first area is soil testing. This technology is rapidly changing. The common system of soil sampling with probes and laboratory analysis is being enhanced and, in some cases, updated with electronic devices that take into account field topography and production zones within a field. All of this lends itself to variable rates of fertilization and variable plant populations within a field — all in an effort to maximize yield and lower costs.
Another issue of expanding interest is the use of minor constituents to maximize yield. You will find here discussion relating to zinc, sulfur, boron and other minor elements. This is an area of fertility recommendation that is likely to change in the coming years as we gain a better understanding of where and how these components fit into intensive sunflower production.
An exciting area of discussion is what can be expected in fertility carryover from the previous crops. We know that sunflower is deep rooted and can utilize unused N at levels six feet below the surface. Then there is the breaking down of the previous crops’ residue and its availability to sunflower in the reproductive stage.
A likely conclusion emanating from the information contained on the following pages is that there is no “one size fits all” rule when it comes to sunflower fertility. There are many variables, as you well understand, and these are highlighted in the following pages.
We look forward to your comments and questions, and we have set up a page on the NSA website where you can do just that. You can go to www.sunflowernsa.com under the “Grower” section and then go to “Surveys.” This is a learning process for all of us, and we look forward to your participation in the conversation. — Larry Kleingartner