First to understand the pelletized lime and what it can do.  This is AgLime which is pulverized to a very fine powder and then made into pellets so that it can be distributed through a fertilizer spreader.  It breaks down very quickly (minutes) as compared to AgLime which may take 3 years.
   
Understanding How to relate AgLime recommendations to Pelletized Lime.
 
Most soil labs give recommendations on how much AgLime is needed to bring the soil PH back to 6.5. 
1. These recommendations are based on (A the Buffer PH figures which are based on the active and inactive calcium in the soil and (B the AgLime to be used.
2. The lbs of AgLime needed gives consideration to the results of multiplying the purity (also known as CCE) of the material and the fineness (how much goes through different sized screens) and this figure gives the ECCE (Effective Calcium Carbonate Equivalent) figure which is between 75-80% in the states of Oklahoma, Kansas and Colorado (each state has figures depending upon the quarry being used).
3. So, if the purity (info from University of Nebraska) is 80% and the fineness is 75% then the ECCE is 60%.
4. Now, to figure it further with the 60% ECCE, for every .1 below the buffer PH of 7.0 it will take 1000 to 1200 lbs per acre to take the base PH up to 6.5.  If it was a buffer PH of 6.5 that would be .5 or 5 tenths below 7.0 and that would call for 5000 to 6000 lbs per acre of AgLime based on the ECCE of 60%.

Now to figure the same problem using the pulverized/pelletized materials.

1. The fineness and the purity must be refigured and the ECCE number will be higher because this material is pulverized to a greater extent (prior to pelletizing).
2. If the fineness figure is changed to reflect that 98% of the material goes through the 60 mesh screen and the purity is changed to 90% (U of N chart) then the ECCE figure changes to 88.6 or let’s just say 90% to round it off.
3. That change is 50% from the 60% ECCE normally used (actually the University figure given is .60 so we’ll go with that) which means that the recommendations will be cut to 600 to 720 lbs per acre per .1 of the Buffer PH needed because of the greater effectiveness of the material because of more smaller particles which breakdown more quickly and easily as they become a part of the soil solution.
4. NOW, the interesting thing is that the above figures are correct for the 98% example given except that the actual figure for this pelletized lime is 75% through a 200 (yes, two zero zero) mesh screen !!
5. Now we’re working with numbers the University doesn’t have, but the scale has to keep sliding as this will be another big drop in the amount of lime needed per .1 of Buffer PH to raise the PH to 6.5. We don’t know exactly because the University bases their figures on the 60 mesh screen instead of offering any working finer screen numbers.
6. However, if we can postulate it would seem that the material going through a 200 mesh screen would be at least twice as effective as the 60 mesh screen materials and therefore the amount of materials needed per .1 of Buffer PH under 7.0 should be around 200-400 lbs per acre or less.

It should be noted that the C.E.C. (Cation Exchange Capacity) of each soil is automatically taken into the formula in order to figure the Buffer PH.  The CEC is a measure of the soil type whether it is sand, loam, clay, silt or a combination.

It also should be noted (if not already understood) that the finer the grind of limestone, the more quickly it breaks down and gets into the soil solution for transportation up into the plant by the microbial activity.

Most of the pulverized material will be used up as plant food (working in conjunction with other soil minerals).  Thus it’s feasible that Nitrogen rates could be cut while still seeing good growth rates.  Generally, the pulverized material is considered a “food” and not a soil builder.  You can use the AgLime to build your soils.

First to understand the pelletized lime and what it can do.  This is AgLime which is pulverized to a very fine powder and then made into pellets so that it can be distributed through a fertilizer spreader.  It breaks down very quickly (minutes) as compared to AgLime which may take 3 years.
   
Understanding How to relate AgLime recommendations to Pelletized Lime.
 
Most soil labs give recommendations on how much AgLime is needed to bring the soil PH back to 6.5. 
1. These recommendations are based on (A the Buffer PH figures which are based on the active and inactive calcium in the soil and (B the AgLime to be used.
2. The lbs of AgLime needed gives consideration to the results of multiplying the purity (also known as CCE) of the material and the fineness (how much goes through different sized screens) and this figure gives the ECCE (Effective Calcium Carbonate Equivalent) figure which is between 75-80% in the states of Oklahoma, Kansas and Colorado (each state has figures depending upon the quarry being used).
3. So, if the purity (info from University of Nebraska) is 80% and the fineness is 75% then the ECCE is 60%.
4. Now, to figure it further with the 60% ECCE, for every .1 below the buffer PH of 7.0 it will take 1000 to 1200 lbs per acre to take the base PH up to 6.5.  If it was a buffer PH of 6.5 that would be .5 or 5 tenths below 7.0 and that would call for 5000 to 6000 lbs per acre of AgLime based on the ECCE of 60%.

Now to figure the same problem using the pulverized/pelletized materials.

1. The fineness and the purity must be refigured and the ECCE number will be higher because this material is pulverized to a greater extent (prior to pelletizing).
2. If the fineness figure is changed to reflect that 98% of the material goes through the 60 mesh screen and the purity is changed to 90% (U of N chart) then the ECCE figure changes to 88.6 or let’s just say 90% to round it off.
3. That change is 50% from the 60% ECCE normally used (actually the University figure given is .60 so we’ll go with that) which means that the recommendations will be cut to 600 to 720 lbs per acre per .1 of the Buffer PH needed because of the greater effectiveness of the material because of more smaller particles which breakdown more quickly and easily as they become a part of the soil solution.
4. NOW, the interesting thing is that the above figures are correct for the 98% example given except that the actual figure for this pelletized lime is 75% through a 200 (yes, two zero zero) mesh screen !!
5. Now we’re working with numbers the University doesn’t have, but the scale has to keep sliding as this will be another big drop in the amount of lime needed per .1 of Buffer PH to raise the PH to 6.5. We don’t know exactly because the University bases their figures on the 60 mesh screen instead of offering any working finer screen numbers.
6. However, if we can postulate it would seem that the material going through a 200 mesh screen would be at least twice as effective as the 60 mesh screen materials and therefore the amount of materials needed per .1 of Buffer PH under 7.0 should be around 200-400 lbs per acre or less.

It should be noted that the C.E.C. (Cation Exchange Capacity) of each soil is automatically taken into the formula in order to figure the Buffer PH.  The CEC is a measure of the soil type whether it is sand, loam, clay, silt or a combination.

It also should be noted (if not already understood) that the finer the grind of limestone, the more quickly it breaks down and gets into the soil solution for transportation up into the plant by the microbial activity.

Most of the pulverized material will be used up as plant food (working in conjunction with other soil minerals).  Thus it’s feasible that Nitrogen rates could be cut while still seeing good growth rates.  Generally, the pulverized material is considered a “food” and not a soil builder.  You can use the AgLime to build your soils.

I should say right at the beginning that I’m not a highly educated man.  I’m just a guy who’s been involved with a narrow slice of agriculture for a number of years and soil testing has been a primary source of information which I can react to in order to offer my customers the best choice to be successful growers.

The most common test is a PH test which does exactly that – measures PH. It’s an easy and usually free test which indicates the acidity or alkalinity of the soil being tested.  It provides good information for checking out potting soils and garden soils in small areas for the leisure time grower. Local nurseries will have suggested materials to help with your situation in that area.

For the larger scale yards, sports fields and finally farm fields, the main type of test (for $10 or so) is a basic mineral test.  From each area to be tested, 1inch “plugs” of the same depth (usually 3-5” or the “root” depth) are pulled with a special tool and are bagged accordingly to represent each separate area you are testing.

This “mineral” test is very basic and has been around for many years. It will tell you approximately how much (in lbs per acre or in parts per million- PPM) of the most important minerals you have in each designated area.  Then, if the lab knows what you are growing in that area, they’ll figure out how many lbs per acre or PPM it takes to grow a viable crop for you and compare the two figures.  This comparison will give positive or negative figures and thus the recommendation for what soil amendments (i.e.  NPK+ _?_) will come from this information.  PH of course is figured and noted.

Another commonly used test is the one using “Base Saturation” methodology.  Samples are taken in the same manner as before.  This test is based on analysis of the smallest particle of soil which can be measured in the lab.  This test measures the % of the major soil nutrients which are attached to this piece of soil.  This measurement gives a very accurate picture of WHY the PH is where it is by making it very obvious as to which major minerals are out of their normal range.  When given the range parameters, it’s easy to pinpoint current and potential problems.

This type of test is more of a chemistry test and allows insight into why the soil is doing what it does in each situation.  Further, this test has a measure of “soil tightness” – usually misunderstood and related to as a measure of compaction, although that’s probably OK – which allows the grower to further understand why his crops are reacting as they are to each different soil.  The Base Saturation “basic” test measures Phosphorus availability using a light soil acid (P1) and a strong soil acid (P2) which further allows the grower to access the strength of his soil microbiology by understanding what’s available easily compared to what it could be with the levels he has in his soil.  The “basic” test also includes trace minerals and organic matter which help further to define each situation.  This is really a terrific test, but it does require a little bit of study to understand the numbers and what they’re saying.

There is a third test available, but is less known, which uses water to extract and measure the available nutrients as compared to the other tests which normally use a acid extraction.  Water extraction is deemed to be most accurate since it almost duplicates the soil situation.  It gives very precise information, but I’ve found it to tell generally same story as the Base Saturation test at a lesser cost !

I’ll admit that I prefer the Base Saturation tests.  They are easy to understand and are very accurate even though the story they tell may not be the one the grower was looking for !  A word to the wise here is necessary.  When ordering these tests be sure to find out what will be included in your information – always ask for sodium to be measured and for trace mineral information and Organic Matter.  You’ll probably pay $20 -- $25 for each sample which you have done (the lab will provide the bags and labels and necessary submittal information and sheets if you ask). Just work out your own deal. 

Some fertilizer dealers may provide soil samples for nothing as part of doing business with them.  Some dealers are even doing the base saturation tests and you need to make sure they will include the sodium, trace minerals and P1 and P2 measurements.  I mention this because they work with the labs on contract and get a deal ($$$$) for samples.  Their deal may be just for the nuts and bolts and not for all of the needed information which generally they don’t understand fully.  Just be sure to ask because otherwise this freebee may not live up to expectations!

Base Saturation testing is usually done by independent labs which are all over the USA.  Some universities use this type of testing, but not many.  More are going to it so you just need to ask.  Just start calling around to find a lab in your area or use the internet search to get direction as it’s full of information.

Base Saturation testing forces the grower to recognize the understated value of the biology of the soil without which NOTHING would grow.  Then it brings up the question(s) as to what to do with which materials to treat the soil microbiology efforts equal to what the grower does with granular amendments.

Which materials am I talking about to work with the soil biology ?  Just drop me a note or call! 

Whichever you do, get started now and learn what’s going on.

Are you confused by the numbers and the percentages (%) ?  Don’t be- as they are rather easy to read and it’s even easy to understand what they are trying to report.

First of all, it is hoped that the same person collected all of the samples for the current tests and all previous tests.  It is also hoped that any tests to be compared to previous ones have been taken at the same time of year.  The depth of the probe needs to be consistent as does the physical amount of the “plug” that’s pulled from the field and dropped in the sample bag.

Base Saturation testing measures the minerals with the smallest amount of soil measurable called a colloid.  The base minerals are attracted to this colloid by the strength of their positive attraction to the negative colloid.  These minerals - Calcium (Ca), Magnesium (Mg), sodium (Na) and Potassium (K) - attach to the colloid through this mutual positive/negative attraction.

A definable range indicates a balanced soil condition which means spaces for air and water between the colloids (due to positive and negative natural forces). Thus, an environment is present for the soil bacteria to thrive, break down minerals, and make space for the roots to establish (resulting in optimum crop performance).   When the limits of the ranges are exceeded it indicates a problem and the plants growing in that soil will grow at a less than normal rate because the soil microbiology will not provide the necessary minerals for the plants. As the soil colloids react to this unbalanced situation, normal air and water functions of the soil change and as the living organisms decrease their function, the plants suffer the consequences.

This loss of space for air and water is called many things, but is generally noted as COMPACTION.  Yes, permanent compaction is caused by the lack of mineral balance in the soil and is only temporarily compacted by mechanical abuse.  Compaction can be temporarily relieved by aeration or deep plowing or other methods, but it will fall back together again because of the original problem.  Only by adding the necessary mineral(s) can the farmer control his compaction problem.

Numerous soil labs across the USA and Canada use Base Saturation soil testing. The generally accepted ranges for the minerals are Calcium (Ca) 65-75%, Magnesium (Mg) 12-18%, Potassium (K) 3-5% and Sodium (Na) <3%.  Hydrogen (H) also shows up when there are open spots on the colloid to be filled with the base minerals and will always show up if the PH is below 7 (usually indicating a need for Calcium). 

In this type of testing, the % numbers for these minerals (generally listed as Calculated Cation Saturation) will always add up to 100.  To me, this has always meant that when using the number 100 to define the sum of 4 “things”, then whatever has the highest percentage must be the most important.  For example, Calcium reading 65 – 75% would be the most important mineral in the soil and Magnesium reading 12 – 18% would be next and so on.

As Calcium gets lower, the % of Magnesium rises and this combination starts to tighten up the soil and thus puts the squeeze on the air and water spaces.  This creates compaction and makes the soil “sticky” (a soil with excess Magnesium sticks to and builds up on wheels and shoes).  This partial plugging of the soil begins to shut down the normal leaching process which gets rid of excessive Sodium, Sulfur and P and K.  As the Sodium builds up, the plant will take in Sodium instead of Potassium causing internal cell development and health of the plant to be affected along with disease control.

Check the Calcium saturation % first and if it’s low, there’s a good chance that the Sodium % will be elevated.  If the Sodium % is higher than the K% then your plants are already in trouble.  The sodium most generally comes from the granular fertilizer being used.  Muriate of Potash contains 40% Chloride and when that breaks down it creates Sodium Chloride (salt) and even some Chlorine (used to kill bacteria in water). Most mineral fertilizers (naturally occurring and thus mined) contain some salt.  An open soil is terribly important to the normal function of growth and regrowth.

Sulfur is a necessary trace mineral and it is used to help balance the soil minerals and in excess, it will be leached away naturally. Gypsum contains both Calcium and Sulfur is the preferred material to combat high Magnesium soils.  Ammonium Sulfate fertilizer is common and has 24 % Sulfur.  Excess Sulfur on a soil test usually points to the compaction problem.  Sulfur is a necessary nutrient that comes from many sources and keeps building up when the soil is compacted and won’t leach. If you don’t believe any other numbers believe this one ! 

Calcium comes from limestone.  Limestone is commonly known as AgLime and usually comes in bulk and is spread at 1-3 tons per acre.  Pelletized limestone is more expensive, but takes less per acre and breaks down immediately.  Liquid lime is a possibility also.  Calcium is a catalyst for Nitrogen and excessive use of nitrogen is what lowers the Calcium in the soil over the years.  When adding Calcium back to your soil you may find that you can cut nitrogen input immediately. It has always been interesting to me that where Anhydrous Ammonia is used, the soils get harder over the years and farmers will complain that they have to keep gearing down their tractor to pull a plow the next year !  Burn up the calcium and the soil tightens up !

If Magnesium is low, additional Magnesium can be found as Mag Sulfate.  This product is also known as Epsom Salts.  It can be dissolved and applied with a sprayer and sometimes an immediate response is seen (a green-up).  Just don’t forget to build the soil by applying the Magnesium Sulfate as granular.  Mg is important for the process of photosynthesis.

The problem of the Sodium getting into the plant instead of the Potassium can be lessened by adding more Potassium while dealing otherwise with the Sodium problem.  It is generally apparent on most soil tests that as the soil gets tighter, mineral availability decreases. Thus, additional minerals are needed to compensate (specifically K). 

CEC is Cation Exchange Capacity which is a measurement of the tightness of the soil.  Or it can be looked at as a measure of the mineral holding capacity of the soil.  Numbers below 5 are usually PGA greens and numbers over 40 can be found on many sod farms.  Normal soils are around 15-20.  If a mineral is adequately available with a CEC of 15, it won’t have nearly that availability at a CEC of 35 !  The warehouse in the soil needs to have additional materials to draw from as the numbers go up.

PH indicates the RESULT of the soil situation based on the mineral levels. It is a trailing indicator and shouldn’t be looked at to define the soil being tested unless the Base Saturation figures have been explored and understood. I’ve found that soils with high sodium % can’t be trusted to give an accurate PH.  So start working with what you know to be accurate.

Lastly, it’s important to note that Magnesium starts compacting the soil as Calcium drops below the 65% Saturation level.  The resultant compaction then begins to slow down mineral availability as noted before.  It is also important to understand that as Magnesium drops below its Saturation level the resultant higher Calcium creates the same darn compaction !    

Calcium and Magnesium are the keys to effective and efficient soil function.  Granular amendments are necessary to rebalance or maintain correct mineral levels.  Liquid amendments (soil and microbial stimulants, adjuvants, moisture retention materials and detox materials among others) can be very effective and part of a long term or a short term special package.  Combined with a granular program the results can be terrific and cost effective.

BUT, it takes time. Get your soil tested using Base Saturation methodology and start learning this week.

Here are some labs I have worked with in the past: 

Midwest Labs
Omaha, Nebraska
402-334-7770

A & L Plains Lab
Lubbock, Texas
806-763-4278

A & L Memphis
Memphis, Tenn
901-527-2790

Use a pre-emergent twice a year.  Usually in March and late September.     Don’t put down a pre-emergent in the fall on the fields you are going to overseed unless the label states that you can !!  Princep or Simazine are 2.

You’ll usually have to do post-emergent treatments on a variety of weeds.  The grassy weeds can be controlled with MSMA, which you’ll have to use a couple of times 7 days apart when the temperature is 80 degrees all day and night. Revolver is a new chemical for grassy weeds.  It will kill most grassy weeds.  The broadleaf weeds can be controlled with Trimec Plus or Trimec Southern as necessary.

These chemicals are just names that I know.  This is not an endorsement.  My suggestion is to have your chemical salesman set up a schedule for your price range and use the products that he knows will work in your area and that he has had experience with.  This is a good way to work as then the salesman is directly involved with the weed killing on your fields and this usually ensures that he will make sure his chemicals work and that your school is in compliance with the state laws that he has to be in compliance with.

Remember, you’ll always have weeds no matter what you do !  The best way to keep them out is to grow thick grass and even then you’ll have a few.  All chemicals will slow or stunt the grass a certain amount so be careful with the timing of applications, temperature, sunshine, moisture and time of day.  The best you can hope for is to be able to treat patches of weeds with just a hand sprayer and that will probably take at least two years of work.

Proper sports field construction usually involves an expensive subsurface drainage system, specialized root zone modification, and subtle surface drainage contours. It is a critical aspect, since improper construction due to cost-cutting results in the higher long-term maintenance costs, problems in maintaining a quality playing surface, frequent loss of turf, and costly reconstruction (Beard, 1973 and 1982). The steps in construction are:

1. Survey and stake.
2. Construct sub grade.
3. Install a subsurface drainage system.
4. Modify root zone:
a construct drainage layer.
b construct coarse sand zone.
c mix and install specified root zone.
5. Install irrigation system.
6. Finish surface contours.
7. Plant
a soil pH adjustment, if needed.
b fertilization based on soil tests.
c plant.
d post-plant care.

By following the suggested specifications of the Texas-USGA Method, tens of thousands of greens have been constructed during the past 30 years and, more recently, many sports fields have been constructed and successfully used throughout the world.

Sub grade.

Contour the sub grade so it conforms to the proposed finished grade, with a tolerance of 25 mm. The sub grade should be 450 mm below the planned finished grade and should be firmed to prevent settling. Care should be taken to ensure that the final sub grade base contours, within the overall slope, drain: gravitational water to the nearest drain line.

Subsurface Drainage System.

A herringbone or gridiron design is utilized, with 100 mm diameter drain lines spaced at 4.2 to 6 m intervals at a minimum grade are with 0.5 percent. The drain line trenches should be cut into the sub grade at as shallow a depth as possible. A 38 to 50 mm depth of 6 to 10 mm diameter crushed stone or gravel is placed in the bottom of the trenches and drainlines laid. Than additional stone or gravel is placed around and over the drain lines to fill the trenches.

Drainage Layer.

Angular, hard, noncalcarious, washed, screened river run gravel or crushed stone involves 6 to 10 mm diameter should be selected for covering the sub grade to a minimum settled depth of 100 mm. The proper sized crushed stone or gravel must be obtained to prevent migration of the same into the gravel or stone bed and thereby preserve the integrity of two distinct layers: the upper high-sand. mix over gravel or crushed stone.

This drainage layer functions in the rapid lateral movement: gravitational water to the drain lines. Also, the porous crushed stone or gravel base prevents the upward capillary rise of salts from the soil base into the root zone. During installation, the crushed stone or gravel is typically dumped from the delivery trucks on the perimeter and then distributed over the construction site by a small, tracked crawler tractor, being careful to avoid driving over and crushing the drain lines.

Course Sand Zone.

A 50 mm the layer of washed, screened, hard, angular course sand holds 1 to 2 mm diameter is carefully spread over the drainage layer. The specific size of the same particles must be within 5 to 7 diameters of the underlying crushed stone or gravel.

Thus, if 6 mm stone or gravel user used, the particle size of the course sand zone should be not less than 1 mm diameter. This course sand design has to be functions:
1. To prevent infiltration of the high sand root zone makes into the spaces between the drainage layer particles.
2. To create a perched hydration zone of plant available water immediately above the drainage layer in be lower portion of the high sand root zone mix. The distinct interface between the course sand zone and be up a 300 mm all of settled high sand root zone mix disrupts the continuity of surface interfaces among the particles and the downward movement of water. When the perched hydration zone above the interface approaches water saturation, the force of gravity overcomes the interface perched effect and the excess water is released downward.

Installation of the course sand zone is best accomplished manually, taking care to Not mix the sand with or into the drainage bed. The course sand is dumped from the delivery trucks on the outside perimeter, and is typically moved across the crushed stone or gravel by wheelbarrows over a path of plywood boards.

This thin course sand layer presents some difficulties in installation. However, this intermediate design is critical to the overall concept and is a modest long-term investment compared to turf failure and rebuilding costs if improperly constructed.

Substitution of a non-biodegradable screen-like material for the course sand intermediate zone has been proprietors. Problems have been observed with these geofabrics which tend to become clogged to the extent that they are impermeable to water and may cease to drain. However, a more open, nonfilter mesh or netting may be used between the intermediate course sand zone and the drainage Layout when using gravel to provide a stabilizing effect during construction. This netting should not be necessary when using angular crushed stone to to the stability of this material.

Ringing the Perimeter.

Polyethylene sheeting should be permanently inserted as a vertical barrier between the outer native soil and be read zone mix. This barrier prevents lateral water transfer into the adjacent dry soil, which would course perimeter turf warter stress.

When the sheeting is extended 100 to 150 mm above the surface during construction, it will also function in preventing erosion of unwanted soil onto the construction area.

Root Zone Mix Installation.

Quality-control is the key to successful execution of root zone modification All root zone mixing should be completed off the construction site, termed off-site mixing. Although it sounds good, in practice the procedure: in-place rotary tilling of the organic and/or components into the high sand component has not been successful.

Every truck load of each component in the soil mix, as well as the gravel and course sand, should be checked at delivery to ensure that the specifications are met.

Off-site mixing includes soil shredding, screening to remove any objectionable stones, and addition of the specified proportions of each mix component. Because of the narrow range in acceptable limits of the physical properties, it is very important that the laboratory recommendations be explicitly followed in mixing the components of the root zone mix. Upon confirmation that the root zonemix has met the specifications, it is transported to the construction site and dumped around the perimeter onto the course sand zone.

A small, crawler tracked tractor with blade then pushes the mix over the area being careful to avoid crushing the drain lines. Be sure the unit is operated with its weight all root zone mix. This reduces the chance of disturbing the lower construction profile.

Caution.

Use of wheeled tractors courses rutting and they are more likely to crush the drain lines than are tracked vehicles. Grade stakes placed in a grid pattern at 3 to 4.5m intervals will aid in constructing the final contours to the specified root zone depth. Success has been achieved by carefully selecting the components of the root zone n-mix and by careful adherence to the construction guidelines.

Texas-USGA Root Zone Mix Specifications.

The greatest problem encountered in maintaining turfgrasses on sports fields is soil compaction. This pressing together of the soil particles into a more dense mass results in impaired drainage of excess water and a loss of proper Aeration needed to provide oxygen for healthy root growth. As a consequence, there is a general decline in turfgrass health, vigour, and recuperative ability following turf injury from wear stresses.

Soil compaction and the resultant negative effects can be minimized by selection of a high sand root zone of the proper particle size distribution and associative key physical and chemical characteristics. The result is minimum proneness to compaction, adequate drainage of excess gravitational water, and proper aeration to provide needed oxygen for root growth and related to soil biological activity.

However, such wise sand root zone's are very droughty due to pour water retention capacity unless a perched hydration zone, such as achieved through the Texas-USGA method, is utilized in the construction specifications. In addition, high sand root zone's tend to have a low cation exchange capacity, thus, the leaching of the the essential plant nutrients is a greater concern, particularly during the initial years following construction. This potential problem can be minimized through the use of slow release nutrient carriers and/or the timely use of foliar feeding techniques.

Composition of the 300 mm settled depth of root zone mix should be selected based on specific physical tests conducted in a reputable physical soil test laboratory. The test report specifies the particular materials and the percentages in which they are to be mixed. They decide characteristics for a Texas-USGA method root zonemix are given in the following paragraphs.

Component Descriptions of Root Zone Mix.

It is important that the three components selected for the root zonemix be free of toxic levels of materials such as heavy metals, persistent crop herbicides, and industrial organic chemicals. Minimal amounts of soluble salts, Boron, and sodium are preferred.

Angular, hard, washed, screened silica sand is strongly suggested. Avoid high pH calcareous sands. The preferred sand component particle size is: 100 percent below 1 mm, 65 percent below are 0.5 mm, 25 percent below 0.25 mm, and five percent below 0.05 mm. Note: the mesh sieved size refers to the U.S. Standard of the United States Department of Agriculture (USDA).

It is suggested that the organic matter source selected be well decomposed and have no more than 15 percent ash or mineral content, preferably less than 10 percent mineral content. Examples include peat humus and ree-sedge peat. The organic material should be shredded to insure mixing uniformity, but not to the degree that the material is pulverized thereby causing reduced soil water infiltration.

Soil Component.

A sand, loamt sand topsoil is suggested. The source should be shredded to insure mixing uniformity and should be screened to remove stone and other debris.

Composite Root Zone Mix.

Particle Size Distribution.

It is suggested that the root zonemix obtained less than 25 percent particles smaller than 0.25 mm, and contain less than five percent silt and three percent clay. The suggested specifications for the particle size distribution of the root zonemix are shown.

Mix Water Infiltration Rate.

The preferred Water Infiltration rate for a laboratory compacted root zone mix using the range of 150 to 300 mm per hour. The right in the laboratory tests should not exceed 600 mm per hour.

The upper limit in the Water Infiltration rate is designed high enough to account for the normal on site reduction in Infiltration rate that occurs during the first three to four years due to increases in roots and organic material.

Mix Aeration Porosity.

An acceptable total pore space volume is between 40 and 54 percent. The preferred distribution would be 22 percent capillary and 25 percent non-capillary pore space. Noncapillary pore space should be not less than 15 percent. The measurements are my aid on a root zone mix that has been allowed to percolate water for 8 hours and then is drained at a tension of 400 mm of water.

Mix Water Retention Capacity.

An acceptable laboratory established 400 mm water retention capacity would be between 12 and 25 percent by weight on a 105 to 111C oven dry soil basis.

The available water in the sod is estimated to be that held at a tension of 400 mm of water, which is the approximate distance from resurface to the drain line.

The preferred Water Retention capacity is 18 percent, or 1.5 mm of water held per 10 mm of soil.

Mix Bulk Density.

The preferred root zonemix should have a bulk density of 1.4 grams per cc; with a minimum acceptable bulk density of 1.2 and a maximum of 1.6 g per cc.

pH

The acceptable pH range is 5.5 to 8.0, and the preferred pH range 6.0 to 6.5.

Soil Salinity / Electrical Conductivity.

The acceptable range is less than 4 millimhos per cm, with the preferred range being between zero and one.

Soil Sodium Level.

The acceptable range is an exchangeable sodium percentage (ESP) of less than 15, with the preferred being a minimal sodium level.

Root Zone Mix Analysis.

The starting point in selection of a root zone mix involves obtaining detailed physical and chemical descriptions of the components being considered for a root zone mix and how they respond when n-mixed in various combinations. One or more representative samples of each sand, organic matter, and sandy sore component under consideration for use should be submitted to a reputable physical soil test laboratory. Only a few physical soil testing laboratory's are equipped to conduct these specific Texas-USGA but method tests.  

The primary laboratory physical determinations made of the particle size distribution, bulk density, and the mineral composition. The next laboratory step is to combine serious proportions of the sand, organic matter, and sandy soil, based on physical determinations. These trial mixes are compacted and then evaluated for water infiltration rate, moisture retention, bulk density, and pore space. Mixes are made and tested until one is found that conforms to the standards. Recommendations as to the relative volume of each component to be used are then given.

The crushed stone or gravel for the drainage layer and the coarse intermediate sand also should be tested for particle size diameter to assure that the root zone mix does not washed down and block the drains.

In addition to recommendations concerning the appropriate sand, organic matter, and soil materials and their mix proportions, a description of the chemical properties of each material is needed. Included are the pH, total salts, and levels of P and K.

Submitting Soil Materials for Testing.

A laboratory physical analysis requires a minimum of 8 litres of sand, and 4 litres each of organic matter, soil, intermediate coarse sand and crushed stone or gravel. If there is a choice of sands, organic materials, and sandy soil, send samples of each along with a note indicating a preference based on cost, accessibility, and quantity available. These laboratory will attempt to use the preferred, most cost effective materials in the recommended root zone mix.

Representative samples of the materials must be collected. If the materials are stocked, make sure to compensite several samples dug from within the side or top of the stockpile. Materials near the edge or on a sloping surface may not be representative. Make sure that a prospective vendor will have sufficient stocks of uniform materials over a long period so that if there is a delay of a few months, the materials available at the time of construction will be the same as the original samples tested. All samples should be packaged separately and securely. Strong plastic bags inside cardboard cartons or metal cans are most satisfactory. Use plastic labels inside the package and also to mark the outside of package.

All turf grasses are the same!?  What?   Sure, they are varying shades of green and they all require air, water and minerals to complete their growth cycles.

Every field of turf grass is unique because of the underlying soil.  Every field will take different amounts of Air, Water and Minerals to grow and live because the chemical, biological and physical makeup of the soil will not be c