Top Five Management Strategies to Improve Corn Profitability

You must provide numerous resources and management to optimize the opportunity for corn to produce high yields. Of course, favorable weather plays a huge role as well, and we have experienced our share of challenges the past few years. Most importantly, prevalent rainfall restricts planting progress, stand development, nutrient relations, and crop growth and health during the season. This article describes key strategies we can use to limit these risks and improve corn yield potential. The MSU Corn Verification Program has played a major role identifying many of these factors, and is used to demonstrate the value of implementing new practices and develop strategies to improve Mississippi corn profitability.

1. Abundant soil moisture is normally our most troublesome issue restricting planting and getting that critical, good stand. Not only can wet soil delay planting, but it will hinder stand establishment and create soil compaction that will limit productivity. Both these issues cannot be overcome during the season, despite our best efforts. Stale seedbed cropping systems are intended to mitigate our prevalent spring rainfall, but we also need to use common sense and hope we are eventually blessed with favorable weather. Pushing the planting envelop when soils are marginally wet produce tire traffic and planter compaction that can seriously inhibit root growth and yield – as plants don’t do well growing in soil nearly the consistency of concrete. You simply have to be patient enough to avoid these problems. We suggest seeding at a moderate 1 ½ to 2 inch depth, as deeper planting will delay emergence and expose seeds to cooler and wetter soil, which will impede seedling growth and lead to stand problems, including emergence variability. Furthermore, minimizing the aggressiveness of a pre-plant harrow or do-all operation, will also help maintain raised bed height and its effectiveness in relieving soil saturation.
   

   Tire traffic compaction resulting from planting in wet soil will stunt development and reduce yield.

2. Fertility is the foundation for plant health and is the food needed to grow big yields – if you don’t supply high fertility, you are not in the game. Unfortunately, fertility is often the first item cut when budgets are tight, and this has negative consequences. Crop response to numerous inputs will falter whenever any nutrient becomes limiting. Although nitrogen gets the most attention, we see a lot more corn production issues associated with inadequate phosphorus, potassium, sulfur, zinc and magnesium in Mississippi. Soil testing is key to identifying most fertility needs (except for N and S) and more frequent soil and perhaps plant tissue analyses are needed to address fertility needs in crop rotation systems, because crop needs are different and corn needs may exceed other crops. Also, nutrient availability may differ considering depending on the fertilizer source, application method, and timing of application. Thus, crop response for many nutrients may be much more modest, especially intitally, than what you would expect with nitrogen or sulfur, which are mobile in the soil. Neutral soil pH is also paramount, because it will restrict availability of many nutrients, if it becomes either acidic or alkaline.
   

   Soil and plant tissue sampling are critical to monitor crop nutrient availability.

3. Starter fertilizer serves as an important supplement to most high-yield programs, particularly in reduced tillage systems. Furthermore, they may be particularly important this year due to flooding, as cropland recently exposed to prolonged flooding temporarily reduces phosphorus availability to plants and is known to substantially limit corn productivity. Corn responds to starter fertilizer primarily because it greatly improves phosphorus availability, which is an immobile nutrient, when roots are small. This enhances plant uptake, particularly when growing conditions are cold and wet, increasing early vigor and maturity. Likewise, utilization of Zinc (another immobile nutrient) in starter fertilizer may enhance crop response for the same reason.
   

   Starter fertilizer can enhance growth and yield by improving access of immobile nutrients like phosphorus.

4. Our warm, high rainfall climate greatly increases potential nitrogen loss and limits corn yield, compared to drier and colder climates, particularly in heavier, clay soils. We can greatly improve nitrogen availability by using better application timing, and using appropriate application methods for different nitrogen sources. This may not be necessary every year, but will provide big dividends when we have rain which saturates soils for prolonged periods, promoting tremendous nitrogen loss. Thus, we can improve seasonal availability by applying nitrogen fertilizer at specific times according to corn need. We suggest using a split application strategy where you apply no more than 25% of your seasonal nitrogen just after plants emerge, followed by the bulk of the nitrogen fertilizer just before rapid growth stages (if you are side-dressing), when the plants need it most. Similarly, if you are broadcasting all of your nitrogen, secondary application should commence at the V5 growth stage (12” tall) and proceed at about 10 day intervals until tassel. A pre-tassel application can also be incorporated as simply another split to further conserve nitrogen availability throughout the long season. This strategy reduces fertilizer exposure to saturated soils known to encourage nitrogen loss, leaving more available for the crop.
   

   Nitrogen use efficiency can be substantially improved by “spoon feeding” fertilizer relative to corn needs.

5. It was very apparent that soil saturation was a major limiting factor last year, stunting corn growth during the season and reducing yield potential. Historical records indicate low rainfall during May generally improves Mississippi corn productivity, particularly for irrigated acreage. During this same time, irrigation normally begins, which can greatly compound crop issues associated with soil saturation. Thus, we suggest using very conservative irrigation scheduling prior to tassel for numerous reasons. Corn water needs and sensitivity to drought are both low during rapid vegetative growth stages. Furthermore, corn develops as much as 75% of its roots during this time, and unnecessary soil saturation will significantly retard growth. Furthermore, soil saturation also enhances nitrogen and other nutrient losses. These factors stunt corn growth when ear size is being determined and dramatically reduce resources needed to produce high yield throughout the season.
   

   Unnecessary early season irrigation can hurt crop productivity more than it helps it.