Fall is finally in the air and winter is fast approaching. The golfers seem to be getting better and better with fixing ball marks and common divot filling practices. In the world of sports, baseball and softball season is over and football is now in full swing. The off time between the two sports allowed everyone's fields to fully recover.

Well, with all this wear, it is important to keep in mind the fact that we need to keep our soils in good tilth and that means keeping an eye on soil porosity. This issue is almost entirely devoted to soil porosity and soil health. It is my hope that with understanding of this part of the soil dynamics, we can all achieve a higher degree of health of our turfgrass plants.

This question is really about soil porosity. Soil porosity is a fancy way of saying "what amount of pore space or air space is there in the soil"? According to Dr. Firman E. Bear, in his book titled "Soil Management" from 1927, he explains it in the following manner. In chapter 9, entitled the "Air in Soils" he states that "…giving off of carbon dioxide is a functionality of both the leaves and the roots of crop plants. It is necessary, therefore that ventilation processes be in operation to effect a change in the air at all points in contact with plants, in order to prevent the accumulation of the respiratory product. For the leaves of plants, this is accomplished through the action of winds and air currents. In the soil, the processes of ventilation are more complicated. Special attention must be given to this problem in order that the air in contact with the roots of plants may be more frequently renewed." In other words, the air space around the roots is just as critical as the air space around the grass blades and every effort must me made to keep the air spaces within the soil open and the air exchange process going.

Dr. Bear continues "… the pore space in soils, as previously indicated, amounts to from 30 to 50 percent of the total volume. Part of this space is taken up by water, and the remainder by air. As the quantity of water is increased, the rate of diffusion of the constituent gases between the atmosphere and the soil is very much reduced. A point is finally reached at which most crop plants begin to show signs of injury." The problem with turfgrass areas is that when compaction approaches above 60% on the Penetrometer, the pore space is reduced to 40%. The addition of water further decreases this available pore space until the roots are no longer able to breathe. This puts the grass under stress and causes the slowing of respiration. If the air space is not increased or the water percentage is not decreased, the respiratory product or gases build up causing injury to the turfgrass plant.

Often this process is repeated on a situation where soil porosity is reduced and water is applied on a daily basis. This trend of root suffocation will often lead to decreased root density and decreased root depth.

The only way to avoid this trend is to measure compaction and monitor soil moisture. The ability to balance the soil porosity and soil moisture will lead to the reduction of stress on the grass plant and in turn, allow for better overall turfgrass health.

Soil porosity is different for each turfgrass area on your property, whether on a golf course or athletic field. Golf courses include different construction methods on the greens, tees and fairways. They may also include different soil types and construction techniques from area to area. Athletic fields similarly have different soil characteristics from field to field and also from replanted area to replanted area.

However considering that all things are equal, and all areas are built the exact same way, things are still not the same. Each turfgrass area contains micro environments of soil that all have different soil porosity. One reading on a turfgrass area with a Penetrometer does not give you the overall percentage of pore space. Likewise, one reading of a soil moisture sensor will not tell you the amount of water in the pore space of the soil. These instruments are designed to give quick readings so you can test several different areas and get an average reading of pore space and also an average reading of soil moisture. Often I see micro variations in the soil moisture within one inch of each reading at the same depth in the soil profile. These micro variations are due to many factors which include aerification holes, wear, foot traffic, insects, layers, slope, insects, earth worms and about 999 other factors.

For compaction readings with the Penetrometer, I also utilize the above "zone" method and take at least six readings. I will then record the average of the readings within that "zone".

In addition to taking readings, I look for any micro variation that are more then five percent different from sample area to sample area within each "zone". In the case of moisture readings, these micro variations are often an early indication of dry spots or hydrophobic conditions starting to develop. When monitoring for compaction with the Penetrometer, I also monitor each sample area within each "zone" for these micro variations in compaction. If I detect a hardness variation of more then five percent I will make additional tests to determine the cause.

If any micro variations are found within each testing "zone", additional tests should be performed to determine the cause of these variations. First a visual inspection with a Mascaro Profile Sampler should be made to compare the normal area with a sample from the area with the micro variation. If no visual clues are evident, then an infiltration test should also be performed to determine the actual effect this micro variation will have on the overall turfgrass health.

Since soil porosity is subject to the additional stresses of wear and mechanized equipment, soil pore space is a challenging thing to preserve to insure adequate air exchange between the atmosphere and the turfgrass roots. Because of this, plant respiration is labored and the grass is now encountering stress. This can also be compounded into more problems as pore space decreases, additional problems develop within the gases that remain trapped in the soil profile.

World renowned turfgrass pathologist, Dr. Houston Couch from Virginia Tech discusses anaerobiosis in his book "Diseases of Turfgrasses"*.

Dr. Couch states, "Anaerobiosis is a dynamic series of events taking place in an oxygen depleted (anaerobic) environment. When the soil becomes anaerobic, there are significant changes in both the form and solubility of nutrient elements. In their reduced state, certain types of these elements are taken up by the plant more rapidly than they can be metabolized, thereby becoming toxic. Others become limited in availability. Water saturated soils promote the growth of anaerobic microorganisms which produce metabolites that are detrimental to plant growth. Ultimately, root systems become dysfunctional in anaerobic soils. As the result, their ability to absorb water and nutrients is reduced significantly, causing the plants to develop symptoms of nutrient deficiency even though adequate levels exist in the soil…"

"Under conditions of prolonged water saturation, layers of biofilm…" also known as black layer "…often develop that further impede the flow of water through the root zone and foster the development of anaerobiosis. …Initially, bacteria attach to the soil and sand particles and to the roots and form a coherent, colorless biofilm. …The enlarging biofilms then extend over the sand and soil particles and merge with neighboring slimes, forming a much larger biomass. …As the biomass continues to enlarge, oxygen is no longer able to penetrate it uniformly and an internal stratification of bacterial species begins to develop. The bacteria near the surfaces of the mass are those that require available oxygen (aerobic), while the innermost portions occupied by anaerobic species."

Dr. Couch continues… "There is a direct relationship between rate of water infiltration and biofilm formation. The acceptable infiltration rate for sand-based golf greens is 6 to 12 inches (15-31 cm) per hour. Sand-based greens become vulnerable to the development of biofilm when the infiltration rate ranges between 2.8 and 7 inches (7.0-17.8 cm) per hour." "…Once anaerobic conditions have been established, denitrification (the conversion of nitrate to unusable nitrogen gas) increases, and manganese, iron and sulfur are reduced to plant non-utilizable forms. Also, toxic byproducts of anaerobic decomposition accumulate."

Dr. Couch Concludes… "A key element in the effective management of anaerobiosis is frequent monitoring of water infiltration rates. Measurement of the rate of water penetration of the thatch and the velocity of its movement through the underlying root zone mixture can be accomplished with a field Infiltrometer. The base-line (initial) infiltration rates for pre-selected locations on each green should be recorded. Measurements should then be made at these sites at two week intervals throughout the growing season. At the first indication of a decrease, even though it may not appear to be significant, the cause should be identified and appropriate remedial measures taken immediately."

As this issue shows that what's old is often new again. My first article in this newsletter contains quotes from Dr. Firman E. Bear, in his book titled "Soil Management" from 1927. Often we get too involved in technology to realize that plants have not changed much in the past 8 million years. Sure, there are new cultivars and new and improved strains but the basic principals still apply.

Here is a quote from a more recent publication "It is obvious that the demands of golfers to have green turf have greatly encouraged Poa annua by virtue of the large quantities of water applied to turf to "keep it green." Under natural conditions bluegrass, fescue and bent become brown during their resting stage when summer drought hits. The playing quality of brown turf is unimpaired, but golfers dislike brown, crackly grass so a water system often is installed. Once a water system is installed, the tendency is to use it to excess. Green committee chairmen have been known to say, "Why do we have this expensive water system if we don’t use it?" This is the first step to a Poa annua turf which, because it is poorly understood, is unsatisfactory."

"With increased use of water, the soil is saturated most of the time and the grass must be mowed more often. Heavy machinery operating frequently on wet soil causes compaction by forcing the air out of the pore spaces. With reduced air in the soil, the perennial turf grasses disappear and Poa-annua and weeds are free to develop unhindered by competition. When Poa annua produces seeds in early spring and the plants become yellow and die, crabgrass, knotweed and clover are the logical invaders. Then golfers protest about the condition of the course, forgetting that, in a large measure, they have been responsible."

This is why historical preservation is so important. It's not just preserving objects from the past but ways of thinking and doing things as well. My father, Tom Mascaro used to always say that "you should learn from the mistakes of others because you will never live long enough to make them all yourself".

Subject: Microsoft -vs. - General Motors

Bill Gates reportedly compared the computer industry with the auto industry and stated "If GM had kept up with the technology like the computer industry has, we would all be driving $25 cars that got 1,000 miles to the gallon"

In response to Bill's comments, General Motors issued a press release stating, "If GM had developed technology like Microsoft, we would all be driving cars with the following characteristics:

1. For no reason whatsoever, your car would crash twice a day.
2. Every time they repainted the lines in the road, you would have to buy a new car.
3. Occasional your car would die on the freeway for no reason. You would have to pull over to the side of the road, close all the windows, shut off the car, restart it, and reopen the windows before you could continue. For some reason you would simply accept this.
4. Macintosh would make a car that was powered by the sun, was reliable, five times as fast and twice as easy to drive - but would run on only 5% of the roads.
5. The oil, water temperature, and altimeter warning lights would all be replaced by a single "General Protection Fault" warning light.
6. The airbag system would ask "are you sure" before deploying.
7. Occasional, for no reason whatsoever, your car would lock you out and refuse to let you in until you simultaneously lifted the door handle, turned the key and grabbed hold of the radio antenna.
8. Every time GM introduced a new car, car buyers would have to learn to drive all over again because none of the controls would operate in the same manner as the old car.
9. You'd have to press the "Start" button to turn the engine off.

The Golf Course Superintendents Association of America is gearing up for their national show which will be held February 10^th - 15^th 2003 in Atlanta, GA.

Are you looking for that perfect Christmas or holiday present for the lawn lover in your family? Well thanks to a joint partnership with Turf-Tec International and The Bulletproof Lawn Company we have come up with the ultimate holiday package. The Bulletproof Lawn package comes with a Bulletproof Lawn Textbook, a Holey-Fier Lawn Aerifier, a Mini Moisture Meter and a Sprinkler Gauge all for $59.99 plus shipping (typically between $6.00-8.00)

I also want to invite all of you recipients of this newsletter that if you wish to contribute any information that you find interesting or exciting, please send it to me and I will include it along with crediting its source.