Happy Thursday to you!  How is the week progressing for everyone?  Football and soccer training camps are started up at nearly all levels, so there is no doubt there are some weary colleagues among us.  I hope we are all finding success in field performance though!

It’s been another great week here around the Nation’s Capital.  I was out in Dallas, TX to visit with some of the best field and grass guys I know.  And WOW the gorgeous bermudagrass that I got to see and the things I learned.  Thank you to all of them for their precious time!!

We will finish our discussion on growing strong, healthy and durable turfgrass today.  But obviously this isn’t the “end” of the discussion.  It is only the beginning!  With the need for increased revenues and the demand from so many user groups, high traffic athletic fields is the new challenge for us as field managers to meet… at all levels. Yes it means more challenges, but in the end I see it as a huge boost for our industry as we will step up and meet the challenge.

Thank You to everyone that has engaged me in conversation over these topics, WOW the good ideas that we have created!  Today we build on nutrient management with a discussion about the success we have in utilizing bio-stimulants for natural growth and

Bio-stimulants

To start, lets establish what I mean when using the phrase “bio-stimulant”.  Bio-stimulants are organic products that aid in plant metabolic processes such as respiration and photosynthesis.  Bio-stimulants include natural-occurring ingredients such as plant hormones, carbohydrates, amino acids, and anti-oxidants.

Plant Hormones: 
Plant hormones serve as “signaling molecules” for plant growth.  They carry messages from one part of the plant to the other.  There are 5 growth hormones in turfgrass, but we primarily focus on 3:  auxins, cytokynins and gibberellins.

Auxins signal root growth and development, and work with cytokynins to initiate shoot growth.  Gibberellins help supply food for new cell growth and promotes cell division and elongation in the leaf blade of the grass plant.

With this understanding of plant hormones, the illustration of how we utilize them for natural and healthy plant growth becomes basic.  When root development and density is needed, auxins and cytokynins are applied to drive roots and shoots.  If recovery or grow-in is required, cytokynins and gibberellins are used to promote vertical growth through leaf elongation.  When used in proper balance, these three (five total) hormones work together with proper nutrient management to reach the end goal of creating a strong, healthy and durable grass plants.

Additional Benefits from Amino Acids/ Carbohydrates/ Anti-Oxidants
Bio-stimulants can also assist plants in dealing with heavy traffic and stress, in particular heat (summer stress) or low light (early and late season growth).  In times of stress, plant respiration is burning more energy than photosynthesis can produce.  The plant turns to its stored reserves (roots) to balance out the deficit of energy, leading to a weaker plant.  Bio-stimulants can assist the processes to lessen the demand on the plant roots for energy in route to creating a strong, healthy and durable plant- more naturally.

Growth Regulators become Growth Distributors
Continuing our discussion of the plant’s biological systems, we have also had tremendous success with using growth regulators as we strive to produce a strong, healthy and durable plant.

When I started using growth regulators, I had an extreme fear of them causing more damage than harm in a high traffic field situation.  What if I couldn’t get the field to grow at all?  Because of that fear, I started using trinexapac- ethyl (Primo) at ½ of the ½ rate.  (¼ of the recommended rate)

Curiosity exploded when even at that low rate, the density of the turfgrass stand increased.  Most evident was seeing the same amount of clipping yields in our baskets from mowing.  The clippings were coming from lateral growth from the increased density instead of from vertical growth though.

Since then, I have decided they we should no longer call them growth regulators…. They are instead growth distributors.  There is a negative connotation to growth regulator.  So now when I refer to “growth distributors”, we will feel positive about them!

With further exploration of growth distributors, we began using flurprimidol (Cutless).  Trinexapac-ethyl (Primo) is blocking the production of gibberellic acid late in its production cycle.  Cutless is blocking gibberellic acid early in its production.  What does that mean?  Well… to me it seems like if we block the GA earlier, we will actually have MORE energy to re-direct because the plant has used less energy to produce any GA.  So ultimately there is more energy to distribute to the rest of the plant.

Is that a scientific explanation?  HHmm.. NO haha.  But it sure seems to make sense.

The results of using Cutless have been even more impressive than using Primo-  Wide, dense, and traffic tolerant leaf blades on all plants.  Our mowing has been reduced some as well, but not dramatically.  The density promoted when mowing between ¾” and 1 ¼” on Kentucky bluegrass and at ½” on bermudagrass still yields mowing clippings nearly every day.

With the use of bio-stimulants in conjunction with plant growth distributors, we feel like our program has control over plant growth processes throughout the year.  Different demands on fields (for example, youth soccer clinics vs. men’s lacrosse) and unpredictable weather conditions changes the needs of the turfgrass plant almost daily.  But using these products and monitoring the plant processes at all times sets the “diet” for maintained a strong, healthy and durable plant!!

Cheerful early week greetings to you!  I am glad we can get together and talk again.  Today we are continuing in our discussion on creating a strong, durable and healthy grass plant to withstand heavy traffic.  We have talked about my favorite topic, aeration.  Now let’s explore our approach to nutrient management used in our journey towards producing strong, durable and healthy turfgrass.

Our nutrient management thoughts break down into 2 parts.

1) Maintaining nitrogen in consistent, low levels

2) Using nutrients that are essential for plants under heavy traffic

Maintaining nitrogen in consistent, low levels

Nitrogen is one of three key macronutrients required for maintained plant growth and health. Because nitrogen is key in producing proteins, it should always be present.

However, excessive nitrogen leads to faster growth, which is a factor in turfgrass destruction on high-traffic fields.  The faster growth actually weakens cell walls of the plant. Just as an adolescent child who is growing quickly can have weak bones, the plant’s cell walls become weak.  The weak cell walls are easily invaded by pathogens and punctured and/ or ruptured by traffic.

Just 1 weekend play of moderate play (10-15 matches) on lush, fast growing turfgrass will lead to widespread damage via ruptured cell walls.  Following the weekend, the turf will be very matted down and appear “smashed” and weak.  Within 2-3 days, the turf will begin to turn to a straw color and thin out.  This is especially true on referee lines and around the bench areas where the continuous foot pounding first ruptures the leaf blades.

So then comes the big question of “how much nitrogen”??

The approach we take to that answer that question is approaching nitrogen feeding on a weekly basis.  The maximum amount of plant available nitrogen in 1 week that SoccerPlex grass (Patriot bermuda or Kentucky bluegrass) is to receive is .125 (1/8) of 1 lb.  During the heat of the summer, bermudagrass is given up to .125 while the bluegrass is reduced to around .05 (1/2 of 1/10th) .  Then spring and fall release goals are reversed-  bluegrass to receive up to .125 and the bermudagrass cut back to .05.

At the end of the growing season (approx. 8 months), both grasses will average somewhere between 3.4 lbs of total nitrogen.  The nitrogen comes from slow release granular sources that give us such control and from foliar sprays that include nitrogen, also giving us control.

Monitoring estimated nitrogen release (ENR) potential from the organic in the root zone is also important in reaching the desired weekly nitrogen release amount.  Native soil fields that have high levels of organic matter containing carbon. As summer temperatures rise and soil microbial activity increases, organic matter breaks down and releases the carbon into the soil as a natural nitrogen source.

Nutrients Essential for Plants Under Heavy Traffic

Maintaining adequate levels of all other plant essential nutrients outside of N, both macro and micro, is also important.  Soil testing at least 4 times a year allows us confirm that our root zone is balanced.   But our K management, in conjunction with Ca, Si, and Mn has played the biggest role in producing turfgrass plants that withstand heavy traffic.

Potassium (K) is key for plant strength and durability during times of drought and heat stress.  K also aids in balancing other elements in the plant when sodium, chloride, and bi-carbonate levels get high in the soil due to poor irrigation water and lack of drainage in  native soil fields.  K release for Kentucky bluegrass during the 4 stressful summer months is .2 lbs of K/ week.  (Note that this is higher than our N release levels).  Year end totals for K are equal to N on a 1:1 ratio.

Si, Ca and Mn also all add to plant strength and health through frequent application in plant available amounts.  Potassium silicate allows us to reinforce our cell walls to withstand the traffic and stress by producing a rigid, strong leaf blade and strong, fibrous roots.  Calcium works hand-in-hand with the K and Si aiding in cell division and stress resistance, while manganese is essential in the photosynthetic process, especially for a plant under traffic and stress.

Between maintaining nitrogen in consistent, low levels in conjunction with using plant essential nutrients for heavy traffic, we are able to maintain strong, durable and healthy turfgrass.  The strong plants also require less water because of deeper roots and less fungicide because of a strong immune system and reinforced cell wall protecting against invasion.  So in the end, the strong, durable and healthy plants allow us to decrease inputs all the way around.

What thoughts come to your mind as your read about our successes?  Do you see the same?  Are there other components that we can be considering as part of the process?  Next time we talk, I will share about the final part of our approach to creating strong, durable and healthy plants-  bio-stimulant utilization and growth regulator usage.  I look forward to the ideas that you share with us!!