Growing grass is big business. Most homeowners will agree when they recall their trials and tribulations in getting a turf established and then everlastingly mowing it.
Few realize, however, that the kinds of grass plants used for lawns in America were all introduced into this country instead of being native species naturally adapted to the climate.
Though they may thrive in the moist atmospheric conditions of England or the state of Washington, they still leave much to be desired even in the humid northeastern states.
This may be due mainly to the general practice of close mowing, which permits the intimate action of the sun on their poor unshaded roots, or perhaps the lack of fertilizing and cultivation.
However, new kinds of grasses may be developed or discovered, and there is the prospect of better methods of caring for the established turf.
In the meantime, the establishment of grass on public works programs, following the age-old systems, is running into millions of dollars annually.
It was about the turn of the century when grass for the turf was taken up seriously for the first time in America. This was occasioned in large measure by a new enterprise, the building of golf courses.
Much has been learned in these 50 years, but it now appears that much more remains to be learned.
Grass Problem Discussions
Grass problems are popular topics of discussion at even cocktail hour. At least two in every such group seem to have been on a greens committee of some golf course and are ready to offer an opinion on the merits of a particular strain of bent grass or some profoundly titled new chemical for controlling a bacterial disease of grasses.
With such increasing interest and knowledge, the challenge becomes great for the agricultural experiment stations and agronomists, in general, to point the way to still better turf.
One series of grass problems is closely related to conservation and particularly to the saving of valuable topsoils. This phase of the work has not yet reached the small homeowner, nor even the golf courses, to any appreciable extent.
It is growing up on large development projects such as airfields, highway roadsides, and open areas on the grounds of institutions and industries.
The objectives are far removed from the home lawn, but the problems are fundamental, and their outcome may well reflect turf problems in more intimate surroundings.
A Good Soil Support For Erosion Control
An example of such work is on airfields. The need here is a vegetative cover for erosion control.
This does not have to be a fine, continuous growth of a creeping grass for the sake of appearances, the lie of a golf ball, or resistance to the blows of a number eight iron.
It does have to be continuous enough to keep the surface soil from washing away or being blown into the air to injure the propeller blades or the bearings of the engines.
The soils supporting such growth and the kinds of grasses, sedges, or legumes to endure on these soils are closely related problems.
A practice that has been accepted for many years when building a lawn has been first to put down a layer of good topsoil. This was 2” or 3” inches in depth if topsoil was scarce or 8” or 10” inches deep where topsoil was plentiful or the needs were critical.
If this had been a requirement on each of the airfields of one to 600 acres built during the recent war years, the farms over vast areas of the globe would have been depleted of their topsoil. A different program followed, however.
After the grading was completed, the surface soils were analyzed, some soils were amended to meet the desired consistency, and then a selection of grasses was applied and successfully grown by carefully managed fertilizing, often without any topsoil whatsoever.
Growing grass without topsoil is finding favor in highway construction programs also. Unfortunately, when highways are built in hilly or mountainous countries, it frequently happens that deep cuts are required.
The exposed soils and the fills which are made from these cuts represent soil horizons at depths from 10 to even 50 or more feet below the original surface. All classes of soils are encountered, from sands, clays, and gravel to shales.
With the customary practice of seeding grasses on only soils of good tilth and high organic content, it is difficult to believe that even an erosion-proof type of vegetation could be established and maintained on such an unpromising-looking foundation.
Pioneering Stage
Such work is indeed in a pioneering stage. The new developments are radical departures from practices previously applied, and many answers are still to be secured.
But the present status may be of general interest and, like the developments in atomic power, the work being done today may have far-reaching effects in soil conservation, adding to the supply of topsoil, discovering shortcuts in seeding methods, and reducing the work of turf maintenance.
First, About The Soil
Most research to date has been concentrated on producing plant growth on the kinds of soil which are already known to be able to support plant growth.
The concern lies primarily with their mechanical consistency where inert, sterile soils are involved.
That is a soil composition that comprises those proportions of coarse and fine particles which will accommodate root penetration, have certain amounts of air present, and permit the movement of soil waters in the amounts proper to carry plant foods for the roots to absorb.
This may mean adding sand, clay, silt, or gravel to modify several inches of the surface layer. Soil analyses are critical to determining soil particle gradations, acidity degrees, and plant foods’ presence.
Next, About The Kinds Of Grasses
Research to date seems to have focused on two classes – rank, fast-growing types for forage purposes, and perennial creeping types for lawn effects which are to be frequently mowed.
Not so much is known about grasses or legumes that will grow on soils of low fertility and moisture content.
A new strain of Kentucky bluegrass, known as B-27, has some of these qualities, and fescue called Alta fescue is particularly promising in some sections of the country.
Dwarf Grasses
Dwarf grasses are a further objective of modern research. However, such grasses have undoubtedly been discovered and discarded because of their insignificance for agronomic purposes.
They need to be rediscovered to find those which will make an adequate cover and, at the same time, require one mowing a year or perhaps none.
Buffalo grass, and Buchloe dactyloides, of the western plains were hardy. Two Japanese types of grass, Zoysia japonica and Zoysia matrella have promise in this respect. Others undoubtedly will be found.
Certain varieties or strains of creeping red fescue, such as Olds, Illahee, and Quebec Wild, grow only to a height of 6” or 8” inches.
Their seed heads are less freely produced on well-established plants and need only occasional mowing for appearances or conserving plant energies. Otherwise, the grass leaves are pleasing and reasonably uniform cover at a low level.
Such a growth is not neat enough in appearance for a garden lawn but is wholly adequate for airfields, non-use areas, and highway roadsides which are not closely scrutinized.
Seedbed Preparation
Although seedbed preparation was formerly considered of prime importance, it can often be omitted if specific other provisions are made, such as seeding in mid-winter to take advantage of the honeycomb soil stage in early spring or seeding on freshly graded earth surfaces.
Otherwise, it appears necessary to scarify the soil just enough to break up the thin surface crust.
Mulching with a scattering of soil, sand, stone chips, or even emulsified asphalts will aid germination.
Mulching with a layer of hay, straw, or other organic litter aids in the control of soil erosion before the plants are established, conserves surface moisture, and has numerous other benefits for the culture of grasses, particularly where they are sown on subsoils.
Customary Machine Methods
With these departures from customary practice proving successful, the next interest lies in doing this work by machine methods.
Although several mechanical methods of seeding have been tried, the most promising method is water pressure.
A tank having agitator paddles is filled with water. To this is added lime, fertilizer, and grass seed. The mixture is ejected by a small centrifugal pump and sprayed through a fire hose.
The spray is delivered quite uniformly at a distance of 50′ to 75′ feet from a moving vehicle, and the fertilizing and seeding of an acre of the ground becomes a relatively short job.
A successful method of applying a mulch of hay or straw has been with an ensilage blower. These are primitive tools, but they are undoubtedly the forerunners of much more efficient ones.
Seeding Rate
In many instances, the seeding rate has been reduced from a customary 200 to 309 pounds per acre to about 60, and it may prove successful at 30 pounds or less.
The saving in cost of applying the lime and fertilizer in one operation appears to outweigh the loss of released nitrogen from the fertilizer as previously supposed.
The seeding seems to be sufficiently successful if combined with mulching so that it may be done on any day of the calendar year, regardless of wind, drought, or frozen ground.
Low rates of cereal grains sown before or with the permanent grasses often supplement the benefits of the dry organic mulch, help hold the mulch in place and sometimes replace it altogether as a living mulch.
The Next Important Problem Centers On Plant Foods
On many soils, it appears best to use a mixed commercial fertilizer in the proportion of 10 units of nitrogen, six of phosphorus, and four of potassium at the time of sowing and using rates of application based on the nitrogen content.
The nitrogen carriers would contain about 30% in the form of nitrate nitrogen for prompt availability.
Fifty to 75 pounds of nitrogen per acre are considered a good average. Thus, 500 to 750 pounds of a 10-6-4 fertilizer would be used for an acre when seeding to get the grass started.
For the next 2 or 3 years, about half of this amount of nitrogen alone would be used each year to bring the turf along. After that, subsequent maintenance fertilizing would depend upon the results.
It is surprising to see how soon a dense sod can be created by this method and the inches of topsoil produced in place due in large measure to the millions of roots sloughed off each year from the thrifty plants.
These findings are preliminary and not conclusive. They have, however, been successfully used in a considerable range of soils and climatic zones. They at least indicate a trend that promises to benefit parks, cemeteries, golf courses, and perhaps the owner of the home lawn also.
It is pleasant to anticipate a saving in buying topsoil and avoiding the weary chore of pushing a lawn mower back and forth and back and forth and then doing it all over again.
The use of chemical herbicides to reduce the weed population and perhaps to retard the growth of grass and minimize mowing are other possibilities that may prove practical.
Published by permission of :
Journal of the New York Botanical Garden.
44659 by Nelson M. Wells