Fertilizer - Manufactured vs. Natural (5007)

The environmental movement has stimulated interest in the use of organic fertilizers for lawn care. This has spurred debates on the qualities of natural vs. manufactured materials. Unfortunately, misconceptions confuse the issues for people selecting fertilizer.

Primary considerations in selection include release rate and cost. Fertilizers with fast release rates will stimulate quick growth, particularly in cool soils, and are also more prone to cause leaching of the nitrates into the ground water, as well as burning when over-applied.

There are many kinds of fertilizers available for the homeowner. For comparison purposes, the products will be grouped according to their sources. We will discuss "natural organic" fertilizer, manufactured organic fertilizers, and manufactured inorganic fertilizers.

Natural organic fertilizers are commonly made from waste products of various sources ranging from chicken feathers and manure to treated sewage sludge. These materials have very slow release rates, requiring soil bacterial action to convert the organic matter into forms usable by plants. Nutrient release will be excessively slow when cool soil temperatures reduce bacterial activity. Higher application rates may safely be applied, and the fertilizer will last over a longer period of time.

Natural organic fertilizer, being comparatively low in nutrient content and lightweight per volume, will require significantly larger volumes in application. Problems associated with their use include slow response, particularly in cool soils, and homeowners misjudging application rates due to the larger volume of materials needed. Costs are comparatively high.

Manufactured nitrogen fertilizers are normally made from petroleum or natural gas. Being relatively high in nutrient content, small volumes are required, and the fertilizer can burn if over-applied.

Phosphate and potash fertilizers are mined from the earth. Manufactured organic fertilizers vary in release rate depending on the product. For example, urea is moderately fast in release, while sulfur-coated urea releases relatively slowly. Costs range from inexpensive to moderate.

Manufactured inorganic fertilizer includes common products like ammonium nitrate and ammonium sulfate. These products are quick-acting, even in cool soils, and they are inexpensive. Being prone to leaching, their application rate on sandy soil must be very light and more frequent, thus they have a disadvantage on sandy soils.

In summary, no one type of fertilizer stands out as superior for crop growth or the environment.

For more information on this subject, Please visit the College of Agricultural Sciences Publications Web site.

Feel free to forward, post or reprint any of the "Solutions" in their entirely, but please credit http://www.solutions.psu.edu/ as the original source of information, and please do not change the content.