Misc. Gardening - Manufactured vs. Natural Fertilizers

Manufactured VS. Natural Fertilizers

There are many kinds of fertilizers available for the homeowner. For comparison purposes, the products are grouped according to their sources. This document discusses natural organic fertilizers, manufactured organic fertilizers, and manufactured inorganic fertilizers.

Natural organic fertilizers are commonly made from waste products of various sources ranging from chicken feathers and manures 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 fertilizers, being comparatively low in nutrient content will require significantly larger volumes in application. Problems associated with their use include slow response, particularly in cool soils, and homeowners mis-judging application rates due to the larger volume of materials needed. Costs on a per pound of nutrient basis are comparatively high.

Manufactured nitrogen fertilizers are normally made from petroleum or natural gas. Being relatively high in nutrient content, smaller 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 is relatively slow release. 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, application rate on sandy soil must be lighter and more frequent, thus they may have a disadvantage on sandy soils.

No one type of fertilizer stands out as superior for crop growth or the environment. For additional printed information, contact your University of Minnesota Extension Service county office.

Title:	Manufactured VS. Natural Fertilizers	Number:	284
Script writer:	David Whiting	Source:	Univ. of Minnesota Extension Service
Date:	1992/2002	Reviewer:	Bob Mugaas

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