Finding the Middle Ground: Zoysia in the Mid-Atlantic States (Type: articles)

Golf Course Management magazine, August 2013

Golf courses in the Mid-Atlantic states are turning to Zeon Zoysia for its looks, playability and environmentally friendly properties.

Brazil’s Green Grass awarded sod production contract to grow Zeon Zoysia for Rio 2016 Olympic Golf Course

August 2, 2013

Green Grass sod farm of Brazil was awarded the contract to grow Zeon Zoysia grass for the fairways, tees and roughs of the new golf course under construction for the Olympics to be held in Rio in 2016. The 2016 Games marks golf’s return as an Olympic sport after more than a century’s absence.

Bladerunner Releases Lowrider Zoysia Series (Type: articles)

TURF NEWS magazine, July/August, 2013

Bladerunner Farms releases new Lowrider series of zoysia grass.

A Zeal for Zoysia (Type: articles)

Landscapes magazine, Summer 2013

On one of the sports world’s biggest stages — the Summer Olympic Games — Turf Breeder David Doguet of Bladerunner Farms hopes to shine a spotlight on zoysia grass.

Salinity Issues are closer than you think. (Type: post)

by Dr. Milt Engelke

Global warming, extended drought conditions, extended extreme temperatures, poor irrigation waters all add up to an increase in abiotic stresses on the golf course. It is often cited that bentgrasses go into late summer decline due to a prolonged heat stress, we see a definite reduction in the depth of rooting and often to the point that few if any roots are available to support plant growth.

Over the past 25 years I have made numerous observations on the decline of turf in late season and it is almost always associated with high temperatures, prolonged dry period, excessive irrigation, thatch accumulation in the upper root zone, and generally poor water management techniques. Examination of the root zone reveals an increase in the level of organic matter in the upper profile top 4” (0-10 cm). These past couple of years have also been revealing to the crux of the problem. Yes the situation is almost always associated with prolonged dry periods, and high ambient temperatures. The turf surface often seals up and even with excessive irrigation there is poor soil infiltration. From an environmental stand point it is important to understand the water cycle. The key point to understand is how water moves through the soil profile, and to understand that water is the carrier for all nutrients and other soluble chemical compounds (salts).

For a closer look at the water cycle let’s start with either a natural rainfall event or possibly even an irrigation event. Water in its liquid phase (droplets) is applied to the surface of the ground. Generally through gravitational forces the water droplet enters the soil through channels or vent holes created by insect bores (earth worms) , macropores associated with soil particle composition and arrangement or vacated root channels. In essence these channels provide the entrance and exits points for water penetration, water evaporation and gas exchange. By shear nature of the composition and arrangement of soil particles the root zone profile is also noted for having considerable pore space, space between soil particles. The total pore space is 9

relatively constant among most soils and ranges between 35 – 55% by volume. The type of pores (either macorpores or micropores) created in the soil root zone is dependent on the soil particles in the root zone. Clay particles which are magnitudes smaller than sand grains when stacked together create small pore spaces, whereas sand particles aligned together have much larger pores (macropores). The micropores retain water through adhesive forces also provide water to the plants (roots) and microbes in the soil. The macropores will contain primarily soil gases (Nitrogen, Oxygen and Carbon dioxide) as the water molecule is moved through gravitational forces and leaves the pore space and is replaced by soil gases (air) following complete saturation.

The water molecule (rain drop) enters into the soil through surface pores space and by gravity moves downward past all the soil particles and in the process will also dissolve any soluble chemical compounds. Depending on the rate of infiltration and the volume of water applied these soluble compounds (fertilizer, salts, etc) will be moved into the soil root zone. High infiltration rates and large volumes of water can move these compounds deep into and possibly through the root zone. These compounds (nutrients) are distributed through the root zone and become available for uptake by plant root hairs.

The moisture with nutrients are absorbed and redistributed to the plant to support plant growth and development. The movement of the water molecule through the plant also aids the plant in being able to cool itself. The water molecule releases the nutrients to the plant biological functions and then leaves the

plant through the process known as transpiration. Essentially transpiration is the movement of water through the plant exiting the stomata or pores in the leaf surface as water droplets (liquid phase). The water droplet sitting on the leaf tissue is exposed to an environment which has a lower water content and therefore will evaporate (gas phase). The change from liquid phase (water droplet) to gas phase (humidity) results in major heat exchange which allows the plant surface to be cooler. Air flow across the leaf surface is important to allow the water droplet to evaporate to a drier micro climate enabling the cooling process as well.

Simultaneously water is moving through the soil profile by capillary action from micro-pore to micro-pore regardless of the direction. Capillary water flow moves from wet areas to dry areas and during prolonged dry weather the drier micro-climate is near or at the turfgrass canopy (soil – turf surface). Although these water molecules are not moving through the plant, they still contain a major soluble supply of compounds (salts). Since salts will not volatilize (evaporate), they are deposited on the surface of the soil or thatch of the turf where over a

period of time they will accumulate. The rate of accumulation is dependent on 1) relative ambient humidity, 2) surface air flow, and 3) concentration of compounds in the root zone. Periodic rains will re-dissolve these salts and move them proportionately downward away from the crown area of the plant. A significant rain event following a dry period will often be noted by having a flush of new growth and rejuvenation of the turf, followed by a gradual decline in turf as the salts again accumulate.

To often misunderstood is the impact of the water source. The use of effluent and brackish waters definitely accelerate the process of salt accumulation since more salts are

being applied to the turf. It is important to understand however that turfs being irrigated with potable water supplies will also be vulnerable to salt build up in the soil profile over time. It may take a bit longer however the accumulation of salts will occur just the same. These salts have the same impact on the turf. 1) Sodium (Na) based salts will interact with clay and silt particles and cause a flocculation of the soil surface, destroy soil structure and create a layering effect which can seal the surface preventing water infiltration and impeded gas exchange, and 2) create a negative chemical viagra online environment with excessive salts (salinity) in which many of our plants can not tolerate and will cease to

grow. Learning to recognize these conditions can often make the difference between having plants exposed to unnecessary abiotic stresses.

A quick Google search will reveal the possibility of numerous inexpensive instruments which have evolved over the past few years which greatly aids the ability to filed monitor the relative level of salinity and total dissolved salts. My personal favorite for field assay are variations of the unit on the left which has the ability stop canadian pharmacy spam to log data, simultaneously monitor soil temperatures and most importantly is merely inserted into the soil profile for an instant relative reading. Under field assay conditions I suggest the value read on the meter is relative. The first reading of a site provides a reference base to establish back grounding or a start point. A second reading taken after a period of time provides a relative change in the electro-conductivity of the area and suggest the rate at which salts are being accumulated. It is also possible with this unit to determine with some degree of precision where the salts are accumulating or where they have been moved to following a rain or irrigation event.

Once recognized, the process to remediate the saline soils viagra sample has multiple possibilities. Aeration, venting, flushing and chemical exchange process aid in salt remediation. Most of the salts will accumulate in the micropore space created by the accumulation of organic material in the upper root zone.

Aeration – or the process of extraction with a core aerifier targets the management of the organic layer in the upper root zone. By itself, core aeration is an ineffective method of removing salts, however it is an important and essential process to keep the accumulation of organic matter (thatch) in check.

Venting, or the process of creating vertical air channels and optimizing macropore space is likewise important in organic matter management and providing exchange sites for movement of soil water and soil air. It turns out venting, or if you will “sub-surface soil cultivation, or manufacturing macro pores” is one of the most important cultural management practices which will enhance root zone performance regardless of greens construction methodology, or age of greens.

Flushing or leaching of soil cialis canada salts on the other hand will directly impact the movement of salts deeper into the soil profile away from the crown and immediate root zone of the plant depending on how effectively water can be introduced into the saline soil environment. Low to moderate levels of OM, and the presence of vent shafts greatly aids both water flow (entrance) and air exchange. Salts can be re-dissolved and through gravity or siphon will be drawn deeper into the ground. A proper drainage system such as created by the use of the USGA root zone soil profile can be an effective way to completely eliminate excessive salts. An understanding of the perched water table, helps to understand the value of flushing the salts from the soil profile, however as greens age the ability to flush greens changes due to the dynamics of the greens construction itself. Depth of root zone and a major shift in porosity to micropores impedes the movement of salts and oxygen in the soil profile.

A major alternative to flushing greens and for that matter greens construction is now on the horizon with the advent of a new generation of grasses which have the ability to extract salts from the soil profile, up through the plant to the leaves where they can be mechanically removed, rather than requiring 20 – 30% more available water to manage the salts. The case in point is demonstrated by the photo below which is a sand based green built in 1972 and was irrigated with a saline water source through 2005. This photo was taken in 2006. A major drought in the area resulted in the saline levels of the irrigation source to increase dramatically, and with poor internal drainage in the aged green the saline levels of the greens through the soil profile increased to near 17000 ppm (half of sea water). The soils failed, the bentgrass failed and the putting surface was mostly salt/sand combination. In the spring of 2006 a portion of the greens were planted to Diamond zoysiagrass, notable the solid turf area in the photo below.

Soils on this site were approaching 17,000 ppm where anything in excess of 3500 pm is considered highly toxic to the plant. The example demonstrates one of our grasses ‘Diamond’ Zoysiagrass surviving in heavily saline soils and further when the leaf tissue was analyzed it demonstrated the salt glands had removed up to 10,000 ppm every mowing. The grass survives on less water, does not require water to leach the salts and will aid in remediating poor quality soils and water supplies.

The remarkable understanding is the presence of salt glands in the leaf tissue which help to extract the salts from the soil profile into the plant. This is a remedial process and over time actually removes salts from the soil. In 2007 these golf course greens were solid sodded to Diamond zoysiagrass with

continued use of the same saline water supply. By 2009 a check of the soil profile failed to identify any appreciable levels of salts (they had been removed through-out the profile).

Studies are underway now to compare the salinity tolerance mechanism with other grasses such as the paspalums, however keep in mind that Paspalums can survive in the presence of high salt levels, eventually the soils must be flushed to avoid soil failure. With Dynasty

and zoysiagrasses with exceptional salt gland activity (Diamond), the saline levels of the soil never reach a critical point and therefore less water is required for long term maintenance. It is important to understand the differences between varieties of grasses, as not all zoysiagrasses will have the same level of salt gland activity, but all zoysiagrasses extract salt from the soil water and soil profile the same way.

Bladerunner Farms Releases the Lowrider Zoysiasgrass Series

May 1, 2013

Bladerunner Farms announces the release of two new zoysiagrasses in the Lowrider Series. Because of their lateral growth pattern, they “ride low” along the ground, these zoysiagrasses require very little mowing — something homeowners will appreciate.

Zoysiagrass: Disease issues and unrealistic fertility practices go hand-in-hand (Type: post)

By Dr. Milt Engelke

Professor Emeritus, Texas A&M University

Consulting Agronomist

“Meant for the insiders only.”

Since this is an “inside” message, I will tell you in my opinion that the biggest problem we have with guys wanting to make a hit with zoysiagrass is the mentality that more soluble nitrogen will encourage the grass to grow faster. The crux of the problem is the use of excessive nitrogen fertilizer. It is important, regardless of the climate, to understand that

excessive means different things to different grasses. Zoysiagrasses are slower growing and will not respond to nitrogen the way that Bermuda or paspalums do! Having said that, zoysiagrass also has a much reduced need for nitrogen and so the amount of nitrogen provided to either Bermuda or paspalum would be considered excessive. Further, the timing and form of the nutrient is very important as the microenvironment includes many other critters that also depend and take advantage of the presence of free Nitrogen.

As pointed out, high humidity and heat also compound the problem as the patch disease organism requires free moisture and optimum temperatures to flourish. Most often in the sub-temperate climates as we have in the southern does viagra lower blood pressure US, the patch diseases are most rampant in late fall or early spring. We must recognize that the soil temperatures are cold even though the canopy and turf temperatures may be much warmer. When soil temperatures are below 65 F (18C) the plant is not growing at its optimum and when canopy temperatures warm up, the pathogen can easily outgrow the grass. These soil temperatures are recognized in the late spring and early fall. When combined with spring or fall rains, the pathogen will outgrow the grass. Where high humidity and temperature are persistent such as in the tropical climates (the Philippines as one example), it becomes much more important to recognize the application of free nitrogen (soluble) not only feeds the turf, but also feeds the pathogen and it’s like putting gasoline on the fire.

I mentioned quantity as being part of the problem, the form in which Nitrogen is delivered is equally important. I recommend the use of slow release type (organic, sulfur coated or polyon type carriers) which does not provide the free nitrogen element into the turf canopy. The slow release fertilizers allow for the fertilizer to be migrated deeper into the turf canopy and soil surface before release and well below where the pathogen thrives. Further combine the use of less fertilizer in buy cialis online a slow release format with a good cultural program that will open the turf canopy (specifically grooming, vs verticutting). The open canopy will dry more quickly following rain. A micro environment with a drier canopy, little or no free nitrogen will reduce the incidence and severity of disease.

One of the best programs that I support and recommend is the use of turf groomers (set 10 – 30% below Height of Cut HOC) continuously with mowing. The groomer results in less thatch, more vertical growth and a much drier canopy reducing the pathogens’ ability to dominate and cause disease. It is possible to find nearly any pathogenic organism in a turf canopy at any time. It is when the environmental conditions favor the pathogen over other organisms (including the plant) that disease outbreaks become an issue.

Zoysiagrass can really be considered the native grass of the warm season world as it is indigenous to nearly every climatic condition in the tropical to sub-temperate growth zones.

We continually respond to questions from these many different environmental conditions and stress the concept of understanding the basics. Zoysiagrasses require less N than most other warm season grasses! The pharmacy canada pathogenic organisms which plague zoysiagrass are ever present and we must understand how our cultural practices impact these living organisms as well. There is an optimum environment for growing grass, and there is an optimum environment for diseases to dominate. The cultural program must be managed around these limitations. When we discuss good cultural programs for the zoysiagrasses it is important that we continue to emphasize that other organisms can impact the outcome as well. Yes we can use various

chemistries – for Patch such as Heritage, Prostar and others — but those chemicals

also impact the native microorganism population and can put

us into a Catch 22 approach to turfgrass management. Let’s help the guys understand that properly managed, zoysiagrass is one of the easiest to deal with by minimal inputs.

Bottom Line: Control soil moisture through having good internal (venting soils to maximize soil porosity) and surface drainage; control canopy moisture by properly grooming the turf and encouraging vertical growth so excessive moisture can escape; apply nutrients as needed by the plant and in a form that will provide optimum delivery to the root zone where the active growing turf can take it up, not on the leaf surface or upper canopy where pathogenic organisms optimize development.

Hawaiian Turfgrass Named Exclusive Licensed Producer of Zeon Zoysia in Hawaii (Type: articles)

TURF magazine, April 29, 2013

Hawaiian Turfgrass has been named the state of Hawaii’s exclusive licensed sod producer of Zeon Zoysiagrass. The grass is grown at the Hawaiian Turfgrass sod farm in Miliani on O’ahu. Zeon Zoysia sod will be ready for harvest in the summer of 2014. Zeon Zoysia is suitable for use as a home lawn yet is fine-textured and durable enough for use on sports fields and golf courses.

Root Zone Management in Warm Season Grasses (Type: post)

M. C. Engelke, Ph. D.

Professor Emeritus, Texas A&M University

Consulting Agronomist

Growing turfgrass today is considerably easier today with the development of a new generation of grasses. Improvements in density, texture, low mowing tolerance have emerged with the released new bermudagrasses such as Champion, TifEgle, Miniverdi and even Novaturf in Australia. In the viagra for the brain past few years we have see greater use of the Paspalum as they

are noted for ability to handle saline soil and water situation but are generally weak contenders under low light conditions. We’re seeing considerable attention be directed to the zoysiagrasses for another alternative and over the new few sessions I will present information on all of the above, but this article will concentrate on what I believe is the number one cause of failure on most golf courses regardless of the grass or the utility. The problem is the root zone and or failure of the root zone.

The bottom line however, it is not just having improved genetics being able to handle more intense use and conditions. The first line of defense regardless of the genetics requires having a deep appreciation for HOW the factors of the environment and cultural practices used impact plant performance. In order to maximize performance of either the new genetics or even the existing cultivars performance, it is important to

understand the environmental limitations and how our cultural practices will help us overcome these limitations.

#1 – Enhancing the Heat tolerance of grasses through cultural practices.

The turfgrass plant has the ability to handle higher temperatures through its self-induced cooling mechanism referred to as transpiration or transpirational cooling. This amounts to the plant absorbing moisture in the root zone and transporting that moisture up through the plant to the stomata where the plant “excretes” the moisture as water droplets to the leaf surface. As the droplet (liquid) evaporates and becomes a vapor (gas) there is considerable loss of latent heat from the leaf surface. This loss of heat cools the leaf surface. This cooling effect occurs when the water droplets goes from liquid phase to gas phase by simple evaporation. The rate at which this occurs is highly dependent of the humidity of the microclimate surrounding the leaf surface itself. The lower the humidity, the faster the rate of evaporation, i.e., going from liquid to vapor, the greater the heat loss. During prolonged dry periods, the plant has the ability of moving considerable amount of water in this fashion. In contrast, consider when the humidity around the leaf tissue is higher (75-80%), the rate of evaporation from the leaf surface is considerably reduced, reducing the plants’ ability to cool itself. In order to maximize this cooling effect, it is imperative to make certain there is ample air movement at the surface of the turfgrass canopy. Moving air will enhance the moisture differential between the leaf surface where the droplet is evaporating into the ambient air. In other words you need to be certain that there is sufficient air movement at the canopy level to remove the evaporating water. Fans and sub-surface mechanical equipment such as the Sub-Air™ aid in this process.

The critical issue is that the plant must be able to access moisture and oxygen in the soil profile. The composition of the root zone will impact the availability of each. If either one is limiting plant growth will also be limited. Error on the side of insufficient moisture and the plant will die for drought stress; error on the side of excessive moisture and the plant will suffocate from the lack of oxygen. A balance is essential.

#2 – The Characteristics of the Root Zone influence organic matter management.

The root zone is made up of sand, silt and clay. The proportion of each determines the soil classification, and also determines how moisture and gases are made available. Let’s start with understanding that pore space is created through the arrangement of adjacent soil particles.

A pure sand root zone (0.25 mm and above) would be comparable to having a room full of soccerballs. Imagine the size of pores existing between these relative large particles. These pores would generally refer to as macropores. Large spaces that are predominately occupied by soil air (Nitrogen (78%), Oxygen (~21%) and Carbon Dioxide (~1%)). The soil particles are large enough that a film of water will be attracted to the outer edges, but due to the size of the particle the water molecule is loosely held. Any water which accumulates in this pore space is quickly drained away by gravity; and is also known as gravitational water. Once the gravitational water leaves, air is drawn in behind.At field capacity, the volumetric water content of sand soils will generally be 3 – 5%. Adhering to USGA specifications for a sand root zone the pure sand content would hold approximately 5.4% moisture (Table 1). If the soil particles are silt, or clay the size of the pores space is incrementally smaller. The smaller the soil particle is, the smaller the pore space. The tension or forces holding the film of water around the soil particle is directly related to the distance to the center of the particle. Clay particles which are quite small in comparison to sand particles hold water very tightly.(42% vs 5.4%). The total porosity may not differ significantly between sand and clay soils, however the type of pore space certainly does. The smaller the particle size, the smaller the pore spaces (micropores), the higher the field capacity or ability to hold water.

A plant will extract moisture from the soil to satisfy its needs, to a point. The soil particle has the ability to keep a portion of the water away from the plant, and that amount of water is classified as the point of permanent wilt in the plant, and the plant will die or go into dormancy if that condition persist for even a brief period of time. In a clay soil, the plant can reach permanent wilt (die) with the volumetric water content still be around 30%. , Whereas with sand, less water is held. The amount of available water in a soil profile is therefore dependent on the physical make up of the soil. Note that in silt loam soils nearly 18% of the total water is available for plant and microbial growth and development. Know that some of our best agricultural soils are silt loam – with water release being a major reason.

Plant and microbial available water is therefore held in the micropores and the adhesive forces on the water molecules are strong enough that space in a dry micropore can draw water from a wetter pore – this would also be known as capillary movement and it can move in any direction (wet to dry), whereas gravitational waters move only downward.

Table. Field capacity and available water content based on soil type.

Sand/OM11.03.17.90.9Pure Sand5.42.03.40.4

Adopted from USGA Green Section report

Table 1 also refers to the % water content assuming field capacity. Field capacity is technically defined as the quantity of water which is retained in the soil pores following complete saturation and sufficient time to permit gravitational waters to evacuate (24 hours). As the gravitational waters flow downward through the profile, soil air is drawn into the macropores space. The water remaining in the micropore space represents those waters attributing to the soils capacity to hold water. Under drought conditions the water level of the soil profile is likely to be well below field capacity. Plants will begin to show stress when they cannot extract sufficient moisture to sustain biological functions. Obviously the best way to maximize effective plant available soil moisture is to maximize the root depth, density, and availability of macropore space for gas exchange. Constant or excessive application of water through irrigation, improper syringing, high rainfall zones or other means can have a negative effect on soil air content as the macropores will be holding more water reducing essential soil oxygen. As the root zone ages there is also an accumulation of organic matters which are interlaced in these macropores. Organic matter’s mere presence in these pore spaces changes the characteristics of the space and will create more micropores, hence increasing the root zones water holding capacity. This alone is a major reason to have an effective cultural program to balance organic matter in the root zone.

In the heat of the summer time, which also coincides with increased irrigation practices we often note the reduction in root depth and root density. Regardless of the grass, the lack of soil oxygen will result in the loss of roots!. Root depth may be as little as 10 mm or less, the turf will thin, and oftentimes be accompanied with algal growth on the surface. Consider the following possibilities as to what has caused this problem. Seasonal top grow is paralleled with the increase in rooting, stolon development, and where appropriate, rhizome development. The process is cyclic where new tissue is developed and old tissue will die. The rate of growth and death is accelerated during the growing season accounting for an accumulation viagra of both live and dead organic matter.

As plants expand into the soil profile, the obvious space to occupy is the macropores and again this growth will change the very characteristic of the water holding capacity of the pores. If the dying plant tissue is not decomposed at the rate new tissue is generated we will have a net gain in the level of organic matter or as some may call it thatch.

Management of Organic matter is essentially accomplished by three quite simple cultural practices. Two are quite obvious and over the years have been the discussion in a good many club houses and maintenance facilities – namely aerification and top dressing. Mention either of those around the golfer and you can create a battle. Aerification is the simple process of extracting organic matter from the root zone profile. Simple in concept and practice, yet aerification is the one practice which is the most despised and most difficult to get scheduled around the play. Organic matter is going to accumulate! Through core aeration (extraction), and sand top dressing (dilution) a significant portion of the organic matter can be kept in balance. Depending on other cultural practices such as increased summer irrigation, syringing and or hand watering, the impact of the remaining organic matter can influence the plants’ ability to maintain the dense deep root structure required to support plant growth and development during temperature and moisture stress period. Too often the frequency of core aerification is limited to once in the spring and once in the fall. Our industry has rapidly adopted an attitude of high frequency light applications of top dressing sands to lessen the impact of infrequent heavy sand applications. Yet we still see a major reduction in rooting during the heat of the summer.

Here is what I think is happening and my experiences over the years helps drive the point home. Many of the states this past year experienced a modest temperature rise, but the greatest impact came from a prolonged drought period. The term of evapo-transpiration (ET) comes into serious play during drought periods with ET rates reaching and exceeding 3 mm daily. And as a consequence, what is also happening is the water evaporates from the soil surface, the soluble nutrients in the water are precipitated (salt) and left behind in the thatch layer. The resulting abiotic stress predisposes the plant to other issues including pathogenic organismso;olkiklio, and then the rush is that now we have something obvious to blame and to treat. We have fungicides to control the disease but we haven’t addressed the real problem. So two things happen during the heat of the summer growing season, a) thatch accumulates which is plugging up the macopores and with retention of more soil water that in turn reduces the available soil oxygen to both the roots and soil microbes (more on them later) and b) the accumulation of salts in the upper layer of the profile which will impact the soil character destroying soil structure (pore space) by sealing the surface and preventing water or oxygen to enter. Further the negative effect of high salts (osmotic stress) in the crown layer will reduce the plants ability to recover and develop new leaf tissue and roots.

So what do we do about it? Simple, address the organic matter accumulation issue head on. Earlier I mentioned there are three quite simple cultural practices in maintaining organic matter and I mentioned: a) core aerification or extraction; b) sand top dressing or dilution of the organic; and c) what I personally believe may be the more important is the decomposition of organic matter by stimulating and maximizing microbial activity. The limiting factors for microbial growth and activity are quite similar to those impacting plant root growth, development and persistence – availability of adequate moisture, essential oxygen and a balanced nutritional profile. In the heat of the summer, when the plants are experiencing maximum growth potential, the demand for more moisture, nutrients

and oxygen in the

root zone has increased. By mishandling our watering, and failing to recognize the negative impacts of salt and organic matter accumulation, the abiotic stress levels of the plant are substantially increased causing loss of microbial activity, reduction in decomposition of OM, increase in Volumetric Water Content of the root zone and suffocation of the existing roots. If we reduce abiotic stress then we can maximize biological activity in the root zone and support stronger healthier plant root growth and persistence.

How is this best accomplished? Simple aerify more!. More easily said than done yet let’s keep in mind what aerification is really all about. And let’s keep in mind that roots will follow the aerification holes. Let’s consider that it is not the holes caused by aerification as much as the roots are following the macropore space. Solid tine aerification will create more macorpores by making vertical shafts or VENTS into the root zone. Since aerification has a rather bad connotation to most golfers I have adopted the term of venting greens through the heat of the summer. Venting is done with one primary purpose in mind – create macropores. An abundance of macropores and vertical shafts are highly beneficial for allowing water in to aid in flushing salts out, allowing water out through evaporation, hence accelerate drying during wet periods, and maximizing the balance in soil gas exchange. A soil at or slight below field capacity is cooler, reducing abiotic temperature stress on root growth and development and these vents aid in maintaining temperature, moisture and oxygen to support microbial decomposition of the organic matter.

Technology has changed rapidly in our industry in response to many of our needs. We have raised the bar on activity and expectation. As defined in the statements above a couple of simple issues can be addressed with technologies some of which were actually developed here in Australia.

The soil moisture probe – marketed in the U.S. as the TDR Soil Mositure probe (TDR 100 shown) Other models even with GPS capability are available and all have the capability of reading either Volumetric Water Content (available water in the soil at the time and depth of reading), or the Relative Water Content to aid in irrigation scheduling. The interesting statistic to keep in mind when measure soil moisture content is the indirect measure of the microspace available. The higher the VWC, the more micropores which can also be directly related to the level of organic matter being accumulated. Location and historical (time) monitoring can tell you a lot about the health and potential performance of your greens. If the VWC stays too high following irrigation it may suggest your entering a period of oxygen deprivation and it is time to Vent.

The other piece of monitoring equipment I appreciate is the EC 110 salinity probe. This unit serves as a data logger as well and records temperature along with electrical conductivity in a couple of different modes. Always amusing to me are the individuals who want to know the exact EC levels of the profile and are insistent on such information when in a practical world it is really irrelevant. What is important is the progression (rate and level) of increases over time (ie, track and record it on your own course or field). When the crown area of the plant reaches a certain level of salinity the plant will stop growing, water may cease to penetrate and it may be time to take remedial action to reduce the salt levels. Also use care in having soils labs analyze for salinity levels in the soil. Too often the practice of soil analysis involves removal of the non-soil thatch at the surface and discarding it. The salts accumulate in turf in the thatch, therefore measure it in the thatch. Further when using a brackish or effluent water supply be aware that the rate of increase in EC may be quicker, but those with good water can also have salinity problems during prolonged drought periods. Much of the salts are either from fertilizers, decomposition of organic matter, or mineralization of soil nutrients.

Now back to the generation of macropores. Frequency of Venting is dependent on the equipment used. Personally I recommend the venting process within a day or two of the previous vent hole closing. Why plant roots and microbes like a maximum amount of oxygen. The cross tine, or quad time both popular solid tines have an active open vertical vent for 1 – 2 days. It is not practical to be venting that often, so a change in equipment might well be in order.

I had the opportunity to work with the engineers at Jacobsen a few years ago to develop a serious tine for venting. The resulting Ventine™ as compared to a Sharpie marker below measures 9.5 mm (3/8”) thick by 19.0 mm (3/4”) wide with varying lengths depending on the capability of the equipment.

The Ventine™ is on the top whereas the lower tine is from the Planetair™ machine which likewise will provide for some excellent summer bentgrass management of the root zone. The critical issue with the Ventine™ is the duration the integrity of the ‘vent’ will extend up to 10 days without disturbing the surface area. This makes venting every couple of weeks practical especially during the stress periods of the years. The important issue is maximizing the macropores. Other distributors are manufacturing similar tines with the same success. The Planetair™ is a towed behind a high production device that creates vents with the curved blade demonstrated with minimal surface disruption. The towing unit has a roller front and rear to minimize the amount for puckering of the turf. The duration of the resulting hole is still in question but definitely looks appealing in preliminary trials.

This last picture in this series shows a green which is 23 years old, was originally constructed to USGA specifications and now has a root zone of 43 cm (17” for the yanks) not 30 cm (12 “) yet there is no evidence of an organic layer throughout the profile and the roots are extending below the depth of the soil probe by several inches. These greens were suffering from moderate to severe organic layer in the year 2000 when we started working with the Ventine™. Today, we have been able to maximize root persistence through the combination of judiciously monitoring salts, frequent venting, core extraction only in the spring of the year and grooming the greens with the proper equipment and light frequent top dressing. The key to managing bentgrass in humid hot conditions is to maintain a root system which has access to water and oxygen.

JaMur Zoysia Grass Now Available in Barbados

April 5, 2013

Apes Hill Club Nursery in Barbados, a licensed sod producer of JaMur Zoysia grass in the Caribbean, now has the grass available for harvest for use on home lawns, golf courses and sports fields. The grass was developed by Bladerunner Farms.