What are biodigesters?

A biodigester system utilizes organic waste, particularly animal and human excreta, to produce fertilizer and biogas. A biodigester consists of an airtight, high-density polyethylene container within which excreta diluted in water flow continuously and are fermented by microorganisms present in the waste. The fermentation process is anaerobic, i.e., it takes place without oxygen, and the bacteria responsible for decomposition are methanogenic (i.e., they produce methane, also known as biogas).

Organic agriculture is a production system which avoids or largely excludes the use of synthetic fertilisers, pesticides and growth regulators. It can sequester carbon using crop rotations, crop residues, animal manure, legumes, green manure, and off-farm organic waste (Lampkin et al., 1999). It can also reduce carbon emissions by avoiding the use of fossil fuels used in the manufacture of the chemicals used to make synthetic materials.

The introduction of new cultivated species and improved varieties of crop is a technology aimed at enhancing plant productivity, quality, health and nutritional value and/or building crop resilience to diseases, pest organisms and environmental stresses. Crop diversification refers to the addition of new crops or cropping systems to agricultural production on a particular farm taking into account the different returns from value-added crops with complementary marketing opportunities. Major driving forces for crop diversification include:

Description

Crop rotation consists in sequentially producing plant species in a given location by alternating crops every year, every two years or every three years. This diversified production system prevents the build-up of pests and diseases as well as the exhaustion of the soil that usually occur with production of a single crop (or crops of a single family) in successive agricultural cycles.

Soil is a fundamental requirement for crop production as it provides plants with anchorage, water and nutrients. A certain supply of mineral and organic nutrient sources is present in soils, but these often have to be supplemented with external applications, or fertilisers, for better plant growth. Fertilisers enhance soil fertility and are applied to promote plant growth, improve crop yields and support agricultural intensification.