Phosphorous Fertilizer Can Increase Corn Silage Yields in BC

Research conducted by the Pacific Agri-Food Research Center (PARC) in Aggasiz indicates that phosphorous fertilizer, applied at the time of seeding, increases dry matter yield and hastens maturity in corn silage. The results were observed on sites considered to have moderate to high soil phosphorous levels. In 5 out of 6 tests conducted over two years, the value of increased corn silage production outstripped the phosphorous fertilizer cost. Phosphorous fertilization when seeding corn can increase your profits!

Index
Increased Silage Yields
Increased Profits
Faster Plant Maturity
Conclusions

Increased Silage Yields

The research explored the cause of corn exhibiting early season (3-6 leaf stage) phosphorous deficiency on soils thought to have adequate phosphorous. In particular, the research tried to establish a link between soil phosphorous availability, the population of soil Mycorrizae fungus and previous cropping practices.

Actual nitrogen (N) was applied between 180 and 225 pounds per acre, depending on soil test results. Phosphorous fertilizer was then side-baneded at a rate of 60 pounds of P205 per acre (equivalent to 116 pounds of 11-52-0). In order to provide a "control", some of the test acreage received no phosphorous fertilizer at all. Each of the test sites were previously grown to corn, canola or left fallow.

The research indicates that phosphorous fertilzier applications at 60 pounds of P205 per acre can substantially improve corn silage yields. In 1997, phosphorous fertilizer increased dry matter yields between 0.4 and 0.59 tons per acre. On a harvested or "wet" basis yields increased between 1.48 and 2.18 tons per acre. In 1998, phosphorous fertilizer increased "wet" silage yields between 0.8 and 1.41 tons per acre.

Increased Profits

An economic analysis of the increased silage yields reveals that the phosphorous fertilizer applications can be very profitable. The study's application rate is equal to 116 pounds of 11-52-0 per acre, an expense of $24.70 per acre (at the time of publication).

Let's assume that good quality corn silage is worth $30.00 per ton harvested, or "wet". In 1997, phosphorous fertilizer produced increased silage production between $44.40 and $65.40 per acre. In 1998, phosphorous fertilizer increased silage production between $24.60 and $42.90 per acre.

We can make a per acre profit calculation by subtracting the phosphourous fertilizer cost (expense) from the additional value (revenue) generated by the increased silage production. In 5 out of 6 tests over two years, the value of increased silage production outstripped the cost of phosphorous fertilizer. The average 1997 profit increase was $31.40 per acre and the average 1998 profit increase was $10.00 per acre. Phosphorous fertilizer, applied at the time of seeding corn, can increase your profits.

• All the numeric values are expressed "per acre"
• 1997 wet yield calculations are based on 27% dry matter, which is average for the test year harvest results with phosphorous fertilizer
• 1998 wet yield calculations are based on 44% dry matter, which is average for the test year harvest results with phosphorous fertilizer
• All yields are expressed in tons per acre
• Revenue figures are based on increased silage yield per acre valued at $30.00 per ton
• Profits figures are based on the difference between revenue per acre and the cost of phosphorous fertilzier per acre (116 pound sof 11-52-0 per acre)

Faster Plant Maturity

In addition to yield gains, the phosphorous fertilizer also hastened plant maturity, which was reflected in higher dry matter content at the time of harvest. In 1997, dry matter content was 2.2% to 5.3% higher with phosphorous fertilizer. In 1998, dry matter content was 1% to 20% higher with phosphorous. Phosphorous fertilizer can produce corn that matures earlier, potentially enabling you to harvest your corn sooner.

Conclusions

The results of the study are dramatic, indicating that phosphorous fertilizer applied when seeding corn can not only increases yield and dry matter, it can also increases your profits.

But why does phosphorous fertilizer have this effect, particularly on soils considered "moderate to high" in phosphorous? We think the answer to this question stems from the behavior of phosphorous in the soil.

Soil phosphorous is very immobile, perhaps more so than any other nutrient. During cold soil temperatures experienced at the time of seeding corn (or any other crop), it's uptake is restricted. Under these cold soil conditions, its likely that phosphorous from fertilizer is more available for plant consumption than phosphorous from the soil. Increased phosphorous availability results in corn that germinates and emerges with greater vigor. Enhanced early season growth results in higher yields and faster plant maturity.

These research results are quite similar to studies conducted throughout the world. Phosphorous fertilzier is proven to enhance germination, emergence, maturity and yield - even in soils conidered to have "sufficient" (in this case "moderate to high") levels of phosphorous.

That brings up questions concering blanket assertions about "sufficient" soil phosphorous levels. Are such statements based on yield maximization or yield moderation? More importantly, do they even consider the concept of profit maximization?

We almost always recommend phosphorous fertilizer when seeding corn or any other crop. Phorphorous availability will be enhanced, producing crops with better germination, emergence, maturity and yield. But most importantly, as confirmed by independent research in British Columbia, phosphorous fertilizer at the time of seeding can increase your profits.

Source: Bittman, Kowlenko, Hunt. Phosphorous Deficiency in Seedling Corn - Corn Rotation Considerations. Better Crops with Plant Food. Volume LXXXIV (84) 2000, No. 4

The information presented in this publication is the opinion of Okanagan Fertilizer Ltd. Many factors in addition to fertilizer and soil fertility affect crop yield and quality. The information presented herein does not guarantee or imply any stated yield or quality goals.