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Can low-analysis fertilizer pay off?

I stopped for lunch recently in the north Delta and noticed at the checkout counter a brochure for a low-analysis fertilizer. It recommended a 4-1-3 product at 1 pint to 1 quart per acre preplant or as a foliar spray. This product is no different from others on the market in regards to benefits and costs and the needs of soybeans.

Having tested several foliar products, I have never observed a consistent response. I have looked at other tests and have yet to see a consistent response. I am not going to tell you that some of these products will not green up the foliage (at times), but I would refrain from widescale use of them.

An in-field comparison that is not properly replicated will not accurately predict whether or not you get positive results. If you split a field in half for comparison, it may be like flipping a coin. This is an easy way to test an input, but it is not the most accurate way.

When comparing inputs, do so on a moderate scale.

I get concerned when I see these low analyses for all options. Everyone is looking for new yield-increasing inputs, but they are few and far between. It would behoove us all to stick to the basics of crop production and not get caught up looking for a cureall.

Think about it this way: why use a product at 1 pint to 1 quart per acre when many of us do not sample our fields regularly for soil fertility levels, pH or nematodes? Think about the cost versus the amount of nutrients in 1 quart.

I hear, “My crop is not growing, and I think I will spray a little foliar nitrogen to kick it off.” “It only cost $5 dollars.”

Time is the best input for a crop not growing due to saturated soil conditions. If I shoved your head under water, very little growth will occur while you are submerged — death might even occur unless I let you up for air. The same is occurring in saturated fields. Time is the answer, not foliar fertilizers.

You may need fertilizer, but there is a less-expensive way to get it than 1 pint to 1 quart per acre. Take care of the basics. Feed the soil, and the plants will take care of the rest.

For the sake of arguing, let's say you did get a response. Ask yourself, “Did the application pay for itself?”

Although saturated conditions have caused problems, lower-than-average temperatures have had a big impact, too. Cool conditions have affected plant height, particularly on the earliest-planted acreage, but they should not be detrimental to yields.

From a cost standpoint, here's some preliminary data on a nitrogen study on soybeans conducted at Stoneville, Miss., by Larry Heatherly and Jeff Ray (USDA). This represents one year (2002) of data, but the test is being repeated this year.

They are comparing the agronomic and physiological impact of soil-applied nitrogen versus nitrogen fixation by the plant. They are trying to see if early-season nitrogen may be needed to overcome possible nitrogen deficiencies in early-planted soybeans.

They compared zero nitrogen versus 260 pounds of actual nitrogen applied preplant. Yield increases ranged from 5.4 to 6.7 bushels per acre, but the increases did not come close to paying for the additional nitrogen.

This study is more in-depth than I have outlined, but if they saw yield increases ranging from only 5.4 to 6.7 bushels from 260 pounds of only and it did not pay, how many bushels or pounds of yield could we expect from 1 quart of anything.

In another study just completed, Heatherly looked at early-season nitrogen. He applied approximately 30 pounds of preplant only per acre over a three-year period.

In his summary of this study he made this observation: “Application of early-season only to soybeans resulted in more expense, no increase in yields, and smaller net returns.”

In today's economic climate, every input and every trip across the field must be accounted for.

Ask these two questions about everything you do: “Is this essential?” and (above all) “Is it making me money?” If it is a new breakthrough, you do not have to be the first one to test it.

Every season is different, but take care of the basics of crop production and do not let that $5 per acre slip away quite so easily. If it sounds too good to be true, it is!

Alan Blaine is the Mississippi Extension soybean specialist. e-mail: [email protected].

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