Why In-furrow Fertilizer Makes Sense

Jump Start Your Crops with Starter Fertilizer

Pop-up fertilizer, or starter fertilizer applied in-furrow, is an excellent way to ensure your plants get a strong start. By placing essential nutrients for early development (especially phosphorus) close to the limited root system of the seedling, you can achieve faster early stage growth. This gives your crop a solid foundation and provides a measure of insurance against early stresses on the plant that may otherwise stunt growth and reduce yield potential.

Starter fertilizer is generally recommended for corn, especially in the northern United States where crops are often planted into the cold, wet soil in early spring, regardless of soil fertility. Cold, wet soils reduce root growth rate, microbial activity, nutrient mobility and nutrient mineralization, making it harder to get nutrients to the small root systems of seedlings. Pop-up fertilizer is also encouraged for no-till and reduced tillage applications as these soils generally remain colder and wetter longer due to the insulating effects of the surface mulch.

Placing your nutrients close to the seedlings speed early development until the nodal roots can develop. Research studies show that plants reached tasseling and silking faster, had a longer grain filling period and often achieved 4-5 bushel per acre higher yields. Grain moisture at harvest was drier by 1.7 percentage points on average, saving on drying costs.

Phosphorus: your in-furrow secret weapon

Phosphorus is incredibly important to establishing vigorous early root growth and healthy dark green plants. The problem is that P is non-mobile, so it can’t move down to your roots when broadcast on the soil’s surface.

Studies show that P applied in-furrow has much more availability to your plants and can be applied at ½ the rate of broadcast to achieve the same results. That savings should be deducted from the overall fertilizer plan for the year, which is a real savings in fertilizer cost.

Does in-furrow fertilizer make sense for you?

Starter fertilizer is an excellent choice for farmers under many conditions. In an average year, farmers commonly report increased yields of 4-5 bushel per acre. However, there is no guarantee of significantly increased yields. Most of the benefits of starter fertilizer show up in the early stages of the plant’s life and may not always have an obvious impact during their adult stages. Adult plants have been shown to grow 40% bigger and be more stress resistant.

Many farmers choose to use starter fertilizer every year as a kind of insurance to give their crop a fast, uniform emergence. This strong start allows plants to better handle any stresses the growing season may bring. However, under ideal growing conditions, you may not see a big difference in yield. In general, the worse the year, the more the starter fertilizer will boost your yields.

Corn seems to respond the best to pop-up fertilizer. It is generally not recommended for use with soybeans or small grains (unless soils are cold and wet). Also, if your field is already overly rich in nutrients, adding more won’t help much. If your soil temperatures are above 60 degrees at seed depth, you will likely not see a major increase in yield, unless you planted late or needed to fertilize anyway.

Starter fertilizers will work best if ANY of the following conditions apply:

You are planting corn in the northern United States.
Research shows that corn responds the best to in-furrow fertilizer. Also, farms in the northern U.S. corn belt tend to get an outsized benefit from starter fertilizer.
You are planting when soil temps are low.
If the soil temp is between 45-55 degrees fahrenheit at seed depth, starter fertilizer will help your plants emerge faster and more evenly across your fields.
You use no-till or reduced tillage farming methods.
Research studies have consistently proven in-furrow fertilizer provides a significant increase in yields with no-till and reduced tillage farming regardless of location.
Your soil is low on N or P.
Pop-up fertilizer won’t eliminate broadcast fertilizer, but you will get an additional benefit by placing it in-furrow, especially with P, which is non-mobile. It is recommended you reduce the amount of P used by 50% if applied in-furrow (vs. broadcast) because of this added effectiveness.
You have dry, coarse-textured or low-organic soil.
Starter Fertilizer can make a major difference in coarser soils that don’t have high organic content. It also has been shown that plants need less heat to begin pollination, which helps dryland corn production.
You are planting late.
A Wisconsin study showed significant increased yields when starter fertilizer was used in years where planting was delayed.

Does starter fertilizer save money?

Starter fertilizer is an excellent way to ensure early plant growth and get the most from your fertilizer expenses. Applying starter fertilizer usually won’t eliminate broadcast fertilizer from your budget, but it can reduce the overall amount of fertilizer needed over the entire year.

With starter fertilizer, a little goes a long way. It is applied at much much lower rates than broadcast fertilizer. It is generally deducted from the total amount of fertilizer added over the course of the year, so there is generally no additional cost for the fertilizer.

However, P is much more available to your plants when applied at the root level. It is recommended that you reduce the amount of P by 50% when added as a starter. This can add up to significant savings in your annual fertilizer bill, especially at current fertilizer prices.

What kind of fertilizer is best for in-furrow application?

Most high quality fertilizer that contains at least nitrogen and phosphorus will work well as a starter. While P and N may be the star of the show, in-furrow application is also a great way to get your micronutrients directly to your plants’ root systems. Immobile nutrients like phosphorus, potassium and zinc are especially effective when placed near your plants’ roots.

That being said, corn yields are mostly impacted by nutrients in the shortest supply. Work with your agronomist to come up with the right mix of in-furrow and broadcast fertilizer for your field.

Are there any drawbacks to using pop-up fertilizer?

While most fertilizer is safe to apply in-furrow, there are a few general rules to keep in mind when choosing your fertilizers. Certain fertilizers do have the potential to reduce germination when placed in direct contact with the seed.

As a general rule, never apply more than 5 pounds of N+K2O on soils having cation exchange capacities (CECs) of 5 meq/100g. Avoid urea and diammonium phosphate which can react in the soil to produce free ammonia that may burn the seedling’s tissues. Too much nitrogen, sulfur and boron applied near the seed can also reduce germination. Lastly, watch out for fertilizers that can create salt build ups in drier soils, like ammonium thiosulfate.