For a high quality, stress tolerant turf the major factors are:
1) Good soil conditions
(texture, structure, drainage);
2) Using grasses well adapted to the site and use conditions;
3) Good management practices (mowing, fertilization, irrigation, pest management, thatch
control, treatment for compaction);
4) Reasonable use of the turf. Although fertilization is just one of these factors, proper fertilization is essential for maintenance of cool season grasses.
To develop a sound fertilization program one must first understand the growth cycle of cool season grasses and how fertilization, particularly with nitrogen, affects the plant physiologically. Understanding how the plant generates, stores, and utilizes carbohydrates helps understand why it responds to different conditions. While all nutrients are important for good turf, management of nitrogen (N) and potassium (K) have the greatest influence on plant health. A healthy turf is much easier to manage.
Nitrogen management has many important impacts on turf. Among these are:
2) top growth;
3) density – competition with weedy species and recuperative potential after turf
4) wear tolerance;
5) level of carbohydrate reserves;
6) root growth, rhizome and/or
7) susceptibility to diseases,
9) susceptibility to stress conditions(extremes of temperature, moisture, traffic, shade).
I’ve learned much about how potassium plays significant roles in plant health, including influence on:
1) top growth;
2) root growth;
3) carbohydrate synthesis in the plant;
4) cell size and cell wall thickness;
5) how water is stored in the plant;
6) turgor pressure;
7) control of stomatal openings and wilting tendency. The bottom line is that adequate K is
necessary for a healthy, stress tolerant turf.
Turfgrass growth stages can be grouped into several categories during the typical year:early spring, late spring, summer, fall, and late fall. During early spring (April through early May, depending on the year) the typical growth curve begins with the grass breaking dormancy as air temperatures warm. This early growth utilizes carbohydrates stored the previous fall. For this reason, fertilization in the fall is a very important part of a good fertility program. Continued increases in air temperatures result in increasing soil temperatures.
Poa annua (annual bluegrass) comes out of dormancy at a lower temperature than agrostis stoloniferous (creeping bentgrass) which makes it more competitive in the early spring. With spring rains turfgrass growth increases rapidly. Heavy rates of N in the early spring contribute to rapid growth resulting in increased mowing. The growth enhances turf density and competition with weeds.