Editing Fertilizer (section)

===Organic fertilizers===
{{Main|Organic fertilizer}}
[[File:HomeComposting Roubaix Fr59.JPG|thumb|Compost bin for small-scale production of organic fertilizer]]
[[File:Krechty kompostarna.jpg|thumb|A large commercial compost operation]]

"[[Organic fertilizer]]s" can describe those fertilizers with a biologic origin—derived from living or formerly living materials. Organic fertilizers can also describe commercially available and frequently packaged products that strive to follow the expectations and restrictions adopted by "[[organic agriculture]]" and "[[environmentally friendly]]" gardening – related systems of food and plant production that significantly limit or strictly avoid the use of synthetic fertilizers and pesticides. The "organic fertilizer" ''products'' typically contain both some organic materials as well as acceptable additives such as nutritive rock powders, ground seashells (crab, oyster, etc.), other prepared products such as seed meal or kelp, and cultivated microorganisms and derivatives.

Fertilizers of an organic origin (the first definition) include [[manure|animal wastes]], plant wastes from agriculture, [[Seaweed fertilizer|seaweed]], [[compost]], and treated [[sewage sludge]] ([[biosolid]]s). Beyond manures, animal sources can include products from the slaughter of animals – [[bloodmeal]], [[bone meal]], [[feather meal]], hides, hoofs, and horns all are typical components.<ref name=Ull>{{Ullmann|doi= 10.1002/14356007.n10_n01 |title= Fertilizers, 2. Types |year=2009 |last1=Dittmar |first1=Heinrich |last2=Drach |first2=Manfred |last3=Vosskamp |first3=Ralf |last4=Trenkel |first4=Martin E. |last5=Gutser |first5=Reinhold |last6=Steffens |first6=Günter}}</ref> Organically derived materials available to industry such as sewage sludge may not be acceptable components of organic farming and gardening, because of factors ranging from residual contaminants to public perception. On the other hand, marketed "organic fertilizers" may include, and promote, processed organics ''because'' the materials have consumer appeal. No matter the definition nor composition, most of these products contain less-concentrated nutrients, and the nutrients are not as easily quantified. They can offer soil-building advantages as well as be appealing to those who are trying to farm / garden more "naturally".<ref>{{Cite journal|last=Haynes, R.J|first=R. Naidu|date=1998|title=Influence of lime, fertilizer and manure applications on soil organic matter content and soil physical conditions: a review.|journal=Nutrient Cycling in Agroecosystems|volume=51|issue=2|pages=123–137|via=Springer Link|doi=10.1023/A:1009738307837|s2cid=20113235}}</ref>

In terms of volume, [[peat]] is the most widely used packaged organic soil amendment. It is an immature form of coal and improves the soil by aeration and absorbing water but confers no nutritional value to the plants. It is therefore not a fertilizer as defined in the beginning of the article, but rather an amendment. [[Coir]], (derived from coconut husks), bark, and sawdust when added to soil all act similarly (but not identically) to peat and are also considered organic soil amendments – or texturizers – because of their limited nutritive inputs. Some organic additives can have a reverse effect on nutrients – fresh sawdust can consume soil nutrients as it breaks down and may lower soil pH – but these same organic texturizers (as well as compost, etc.) may increase the availability of nutrients through improved cation exchange, or through increased growth of microorganisms that in turn increase availability of certain plant nutrients. Organic fertilizers such as composts and manures may be distributed locally without going into industry production, making actual consumption more difficult to quantify.