Environmental Engineering Reference
In-Depth Information
Fertilization Frequency
Theoretically, it would be most beneficial to apply a very small amount of
fertilizer every day. Obviously, however, this practice is rarely used
because it is impractical and expensive. More feasible is to apply fertil-
izers frequently enough to maintain consistently adequate and balanced
levels of nutrients in the soil. The frequent practice of overloading the soil
with nutrients, then depleting it to the level of deficiency, then over-
loading it again should be avoided. When a fertility programme is
planned, especially in a humid climate, an important factor is intensity
of rainfall. As already mentioned, the most important nutrient, nitrogen,
is the easiest one to lose with rainwater. Several days of intense monsoon
may drain virtually all the soluble nitrogen from the root zone. In this
situation, the fertilization programme should be adjusted.
When fast-release fertilizers are used under relatively stable weather
conditions, high-maintenance turfs such as golf greens should usually be
fertilized once a month (sometimes biweekly), medium-maintenance
turfs such as fairways bimonthly, and home lawns 3-4 times a year. In
the arid or semiarid tropics, intervals will be somewhat longer. In the
humid tropics, especially during the rainy season when slow-release
products are used, fertilizer should be applied only one-third or one-
quarter as often, depending on the type of product used. It is important to
remember that, if slow-release fertilizers are used, rapid changes of
fertilization programme are not possible. Sometimes a rapid and drastic
reduction of nitrogen fertilization is needed, i.e. in response to the sud-
den occurrence of a certain disease or insect pest (see Chapter 11, this
volume). A heavy load of slow-release fertilizer cannot be washed out of
the soil for months, so turf managers are often unwilling to use slow-
release nitrogen carriers on high-value turfs and prefer instead to apply
otherwise less convenient fast-release fertilizers.
