Deck 5: Primary Cultural Practices

Question 1

Provide arguments in favor of returning (versus removing) turfgrass clippings during mowing operations.

Answer 1

Clippings refer to the remains, which are left after cutting a turfgrass at the time of a mowing operation. A long-standing debate in lawn culture is whether to remove or grab clippings during mowing.
Arguments given in support of removing clipping include reduced disease resistance, reduced thatching tendency, a generally improved quality of the turfgrass, and reduced injury from heavy deposits of clippings. These clippings can interfere with play has to be eradicated.
On comprehensively cultured golf course fairways with mixed stands of annual bluegrass and creeping bentgrass, the withdrawal of clippings at the time of mowing has resulted in enhanced turf quality. However, clippings are not a concern as long as they are not present as an objectionable clump on the surface.
Mowing at an appropriate frequency and restricting mowing when the grass is wet will generally allow clippings to fall on the turf without affecting turfgrass quality. Converting clippings into small pieces helps in the growth of Pseudomonas species, which in turn promote brisk decomposition of residues.
Clippings are antecedents of plant nutrients and have large a quantity of nitrogen. The nitrogen congregation of dried clippings generally ranges between 3 to 5 percent. In the period of the growing season, this can generate many pounds of nitrogen, and considerable amounts of other nutrients.
Thus, periodic withdrawal of clippings demands the use of additional fertilizer to overcome for the nutrients that have been eradicated. The usage of clippings can be beneficial in returning the organic matter to the soil.

Question 2

List all the major, secondary, and minor nutrients required to support turfgrass growth.

Answer 2

Living plants comprises mainly of water with a considerable few amount of dry matter, that is, about 20 percent composed mainly of organic compounds. The amount of soil-based nutrients necessary for healthy turfgrass development depends upon the cultivar or the species and the particular nutrient.
The critical amount of each nutrient is described as the concentration level in the tissue at which the plant gains about 90 percent of the maximum growth. The mineral nutrients identified as important for plant growth are classified into primary nutrients, secondary nutrients and micronutrients.
The primary nutrients include nitrogen, phosphorus, and potassium. Of these nitrogen is the mineral nutrient, which is required in highest quantities by the turfgrasses. It forms an important part of amino acids, chlorophyll, proteins, enzymes, nucleic acids, and other plant substances.
Phosphorus gives the plant with a means of transferring and holding energy for metabolic processes. After nitrogen, potassium is the second most important nutrient required to help turfgrasses in the development. Its deficiency can result in reduced environmental stress tolerance, increased transpiration and respiration, and increased disease incidence.
The secondary nutrients, which include magnesium, calcium, and sulfur, are absorbed by turfgrasses at levels just below or equal to those of phosphorus. Thus, the secondary and primary nutrients are together referred as the macronutrients. All are components of organic compounds present in the plant.
The term micronutrients do not indicate that these mineral elements are not important. It shows that these nutrients are required at comparatively low quantity. They are also referred as trace elements or tertiary nutrients. Fertilizer use of these nutrients may not be important, especially when a sufficient quantity is present in the soil. It includes, iron, zinc, manganese, copper, boron, chlorine, and molybdenum.

Question 3

Explain the analysis of a fertilizer.

Answer 3

The constitution, by percent of a fertilizer is referred to as the analysis. Conventionally, this has been demonstrated as the percent of the elements nitrogen, potassium determined as soluble potash, and available phosphorus calculated as phosphorus pentoxide. The least guaranteed analysis of a fertilizer is termed as the grade.
The fertilizer grade is demonstrated as a three-numbered sequence specifying the percentages of nitrogen, phosphorus pentoxide, and soluble potash. An example is18-5-9, which is 18 percent nitrogen, 5 percent phosphorus pentoxide, and 9 percent water soluble potash.
In recent times, the fertilizer analysis has also been explained on the basis of the percentage of nitrogen, potassium and phosphorus. Apart from the grade, a packaged fertilizer must be labeled with the manufacturer, with the weight of the material, and the manufacturer's address. Local jurisdictions may also need additional information, such as the acidifying influence of the fertilizer when mixed to the soil.
A complete fertilizer constitutes all the three fertilizer elements, and in the sufficient quantity, to maintain the nutritional requirements of the turfgrasses. For example, a 5-10-5 fertilizer is not generally considered good for fertilizing turfgrasses. In recent times, high analysis fertilizers, having more than 20 percent of the major nutrients are generally used for fertilizing turfgrasses.

Question 4

List the effects of excessive nitrogen fertilization on a turfgrass community.

Question 5

Differentiate between quickly available and slowly available nitrogen carriers with respect to turfgrass response.

Question 6

Explain what is meant by the following terms in relation to slowly available nitrogen carriers: CWSN, CWIN, AI, and 7-day dissolution rate.

Question 7

Illustrate the possible avenues of nitrogen fate in turf.

Question 8

Explain the factors affecting the availability of phosphorus and potassium in turf soils.

Question 9

What would be the likely results from excessive use of micronutrients in a turf fertilization program?

Question 10

Explain the factors influencing the plant-available moisture pool in a turf soil.

Question 11

What equipment and procedures can be used to predict turfgrass irrigation requirements?

Question 12

Provide arguments for and against nighttime irrigation of turf.

Question 13

List and compare the types of mowers typically used in turfgrass culture.

Question 14

Differentiate between precipitation rate and IC, and explain their relevance to turf irrigation.

Question 15

Explain marcelling (provide a geometric analysis as part of your answer).

Question 16

Explain the factors influencing the quality of turf irrigation water.

Question 17

List the measurable differences in turfgrass morphology, physiology, and cultural requirements associated with high versus close mowing of a turfgrass (but well within its mowing tolerance range).

Question 18

What are the important considerations in developing and operating a turf irrigation system?

Question 19

What effects would increased mowing frequency have on turf quality?