Numbers and Units

Numbers and units are useful in many aspects of golf and sports turf management. Numbers and units assist in planning and specifying maintenance resources (labor, finances, materials) and in designing golf and sports turf areas, e.g., different sports have different rules and requirements on the size and shape of play areas. Environmental concerns demand the use of numbers and units in the calibration of field applications (fertilizers and pesticides) and in measuring the fate of nontarget pollution from turf areas.

This exercise is designed to outline the major uses of numbers in golf and sports turf management, and to emphasize the uses of numbers that are most specific or unusual. The purpose of this exercise is to take a different look at golf and sports turf management.

What is a number?

A number is a concept for describing a collection of units such as objects and occurrences. Early people probably developed numbers to describe occurrences that could not be readily seen, such as the days of the year, and as a means of divination with the spiritual forces.

Modern uses of numbers are based on a decimal or ten-base system that had an old origin in the number of fingers on two hands. However, for many thousands of years there was no constant use of a system of tens, therefore other systems such as systems of twelve and sixty were used as well. We can still see the vestiges of these systems in our way of counting time, for example, 60 minutes per hour.

As a consequence of no consistent methods for accounting for larger and smaller numbers, the use of numbers was limited until the 600s A.D. At that time the Moslem cultural expansion carried from India the concept of cyph, or zero, which made it much easier to work with large numbers, as well as fractions. The ways that modern numbers are used include multiplication and division.

What is a unit?

A unit is an entity such as a single thing or a person, which can be counted with numbers. While units can sometimes be subdivided conceptually and still maintain the essential concept of the unit, there is usually an integrity which is lost. Measurement units consist of concepts with no physical existence, so they can normally always be subdivided. Traditional units were used to measure qualities of products that were traded, based on the containers in which they were carried, e.g., bushels of wheat, barrels of wine, and hogsheads of beer. Other traditional units were distances traveled by foot, or measurements made with body parts.

For example, the cubit, based on the length of the human forearm, was used to measure fabric size, and the inch, based on the width of the human thumb, was used to measure smaller objects. The furlong was the distance of a furrow, and an acre was a plowed or sown field. In virtually all cases the primitive units of measurements predated the Moslem introduction of the decimal system, therefore they were not intended to be counted as tens. Therefore the traditional units were subdivided according to fractions other than ten. For example, a fortnight consists of 14 days, a bushel consist of four pecks, a foot contains twelve inches, a chain contains 66 feet or 100 links, and an acre contains ten square chains, and a pint's a pound the world around.

As international trade developed it became increasingly difficult to maintain consistency, because different cultures had developed different units of measurement. The metric system was developed beginning in 1791 by the French Academy of Sciences to serve as a logical basis of measurement. It was based on the metre, a unit of length which was 1/10,000,000 of a quadrant of a great circle of Earth, measured around the poles of the longitudinal meridian passing through Paris, or about 39.37 inches. Added later was the other basic unit, the gram, and other units followed. Widely promulgated by Napoleon Bonaparte, the metric system has spread to common usage in virtually all countries of the earth, with the notable exception of the United States. It is also known today as the Si, or Système internationale and is maintained on the basis of international treaties by the Bureau International des Poids et Mesures (BIPM) http://www.bipm.fr/enus/welcome.html

Practical uses of numbers and units

1. Area-based field applications
1. Fertilizer and pesticide applications
2. Irrigation
2. Pump pressure and flow
3. Growth responses
1. Propagation
2. Herbicide effects
4. Pesticide mobility and persistence

Special cases of using numbers and units

How long does it take to grow-in a field of grass?

How soon can one overseed an area treated with preemergence herbicide?

How can we tell the flow and pressure based on knowing the horsepower of a pump?

How do we know whether we applied the right amount of pesticide?

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