Spring P, K applications effective, too

There has been some uncertainty about which crops to plant in 2015, so you may have held off applying all of your fertilizer.

Spring P, K applications effective, too

There has been some uncertainty about which crops to plant in 2015, so you may have held off applying all of your fertilizer.

The good news is that spring applications of phosphorus and potassium can be just as effective as fall applications in the Northern Plains, if they are made in a timely manner before secondary tillage and planting.

Also, sidedressing equipment is becoming more widely available and can be used to apply nitrogen and sulfur after you get crops planted.

No matter what crop you plant, I see firsthand the power of well-fertilized cropland. When crops have adequate amounts of fertilizer, yields are higher in both good production years and in poor production years.

Current corn hybrids can produce very fast vegetative growth and set themselves up well for pollination and kernel set, even in the hot and dry conditions of late summer.

However, rapid stalk growth and stalk elongation requires K to build structure in cell walls, and P aids in rapid growth and development.

Both P and K are relatively stable in soils and can be banked in many soils for later use, if economically advantageous. Banded P and K applications are best suited for specific situations, including soils that are slow to warm in the spring, and soils that are managed under no-till or conservation tillage.

Access to intensive soil sampling information will make it possible spend fertilizer dollars on an acre-by-acre basis to get the most responsive whole-field yields. P and K are considered immobile nutrients and have some permanency in the soil. If you have not already done so, it is time to conduct and examine soil tests to maximize returns.

Crop residue removal alone should not be the basis of P and K applications. Rates should be based on intensively sampled soil test values, with an eye on the relative incline or decline of the soil test value over time.

If your goal is to get to a higher soil test level, then managing for a slight incline will be favorable.

Soils are complex and release fertility at different rates. Relying strictly on crop removal for fertilizer application rates makes the false assumption that soils are like bank accounts, and the balance can be deduced from a simple deposit-and-withdrawal equation.

Fore is a field agronomist for DuPont Pioneer. He covers northern North Dakota. Contact him at [email protected]. Written with support from Jes Rollins, DuPont Pioneer tech services assistant. Follow local DuPont Pioneer agronomists on Twitter @PioneerNDakota @PioneerSDakota.

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SPRING RUN: Applications of P and K are spread on a field before planting and secondary tillage.

This article published in the January, 2015 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2015.

Crop Management

Nutrient Management

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