Humus composts

Dungerde,/. mold, humus, compost. DUngerfabrik, /. fertilizer factory, diingerfordemd, a. requiring fertilizer. DUnger-salz, n. Dungesalz. -versuch, m. 

Composting is the process of aerobic thermophilic decomposition of organic wastes to a relatively stable humus. Decomposition results from the biological activity of microorganisms which exist in the waste. 

In contrast, composting processes utilize a mixture of solids and yard waste under controlled environmental conditions to produce a disinfected, humus-like product. Three common composting systems are a horizontal agitated reactor, a horizontal nonagitated reactor, and an aerated static pile system (nonproprietary). Compost can be marketed as a soil conditioner in competition with such products as peat, soil, and mulch. Although a large potential market exists, significant effort is required to penetrate this market. Yard waste revenue of 6.50/m (S5/yd ) and product revenue of 2.00/m ( 1.50/yd ) appear to be reasonable market values based on various studies reported on the Web. 

To make sewage sludge compatible with plant life in an environmentally friendly way and also to make it usable as a safe soil conditioner, it is desirable to convert it into living humus by aerobic composting. Irradiation of sludge cake and subsequent composting have revealed the following (see Kawakami et al., 1981) ... 

Soil quality and health play an important role in sustainable agriculture Soil quality assessment provides a basic means to evaluate the sustainability of agricultural and land management systems (Doran and Parkin 1994). Soils that are healthy have homeostatic properties, within broadly set limits (Coleman et al. 1998). The application of compost can results soil quality and health because of the organic matter content and humus-producing properties. 

The European Thematic Strategy on Soil Protection 45% of the EU soils are poor in humus and composted biowaste could be a source of organic matter for the soils. 

Are there preferred degradation products, e.g. methane, compost/humus or CO2 ... 

These results suggest that pure aromatic polyesters may function like the long-lived components in humus and may provide useful properties as a soil additive. Grass sod growing studies using municipal-waste-derived compost in combination with chopped plastic fibers demonstrated improved growing rate and root structure development to accelerate sod production. 

It tends to be richer than garden compost, and the plant foods it contains are more readily available. It is rich in humus, and has good water-holding capacity. These qualities, and the fact that it tends to be available in relatively small quantities, mean that it is usually used more like a concentrated fertilizer than a bulky organic compost (see panel, facing page, for some suggestions). 

In addition to maintaining soil health, microbes are also important in converting manures, crop residues and other organic materials into composts, humus and plant available nutrients (Welbaum ef al. 2004, see also Chapter 2 and Special topic 2), providing biological control of certain pests and diseases (Trejo-Estrada ef al. 1998, Brimner and Boland 2003) and decomposing crop residues in the paddock (Vazquez ef al. 2003). 

These definitions were essentially the same as those put forward by Berzelius. Mulder considered, however, that, besides humus substances, products from the decomposition of organic residues, such as leucine, butyric acid, valeric acid, and formic and ethanoic acids, could exist in soil. These observations are of interest because of the information that has emerged in the past half-century about growth inhibitors and stimulators from low-molecular-weight extracts from SOM and composts. 

Wershaw, R. L, Llaguno, E. C., and Leenheer, J. A. (1996a). Mechanism of formation of humus coatings on mineral surfaces. 3. Composition of adsorbed organic acids from compost leachate on alumina by solid-state 13C NMR. Coll. Surf. A 108, 213-223. 

A managed process that controls the biological decomposition of biodegradable materials into a humus-like substance called compost The aerobic and mesophilic and thermophilic degradation of organic matter to make compost the transformation of biologically decomposable materials through a controlled process of bio-oxidation... 

Compound that proceeds through mesophilic and thermophilic phases and results in the production of carbon dioxide, water, minerals and stabilised organic matter (compost or humus). A base polymer plus plastic additives that are selected to achieve certain desired properties. 

---