Mixed Systems

Mixed systems are defined as farming systems conducted by households or by enterprises where crop cultivation and livestock rearing are more or less integrated components of one single farming system. The more integrated systems are characterised by interdependency between crop and livestock activities. They are basically resource driven aiming at an optimal circulation of locally available nutrients (nutrient circulation systems): e.g. ecological farming and some, but not all, Low External Input Agriculture (LEIA) systems. The less integrated systems are those where crop and livestock activities can make use of, but not rely on each other. In general one or both activities are demand driven, supported by external inputs (nutrient throughput systems): e.g. High External Input Agriculture (HEIA) systems. For more details see Degree of Integration.

Mixed farming is practised in nearly all Agro Ecological Zones: from rainforests to oases in arid zones, but the environment impacts are more closely related to the source of the feed than to the difference between zones.

The principal objectives of farmers engaged in mixed farming are:

- complementary benefit from an optimum mixture of crops and livestock farming
- spreading income and risks over both crops (primary) and livestock (secondary) production
- scope to adjust crop / livestock ratio to social and economic needs and opportunities

In general there are more opportunities to mitigate the negative and enhance the positive impacts of livestock on the environment in mixed systems than in specialised systems. Still, the most remarkable aspects of Livestock – Environment interactions and the degrees in which they play a role will depend on the production objectives for livestock, the feed resource base in use, the land / livestock ratio, the livestock / cropland ratio , and the species involved.

Based on the principal feed resource base in use and feeding practices the following sub-systems and their general environmental benefits and risk have been identified:

Sub-systems within the Mixed Production System

Sub-system | Benefits | Risks
Mixed, communal grazing | Permanent crop cultivation enhanced | Overgrazing and decline in soil fertility of communal areas
Mixed, crop residues | Permanent crop cultivation on nearby fields enhanced | Decline in soil fertility of crop fields if manure not returned
Mixed, cut and carry | Import of local plant nutrients, permanent crop cultivation enhanced | Decline in soil fertility of communal areas
Mixed, feed from farm | Permanent crop cultivation enhanced | Decline in soil fertility if manure returned
Mixed, external feed | Import of external plant nutrients, increase nutrient availability on farm | Decline in soil fertility in area of feed origin Fossil fuel requirements

The sub systems are selected from the many sub systems to cover a wide range of possibilities. The mixed communal grazing system can be regarded as an evolution from pure grazing systems while the external feed systems can evolve into an industrial system. Development trends may cause systems to move between the different classifications and the prevalence of the various systems may change in response to a range of driving forces.

Organic Production
Increasingly, the production of livestock by Organic or Ecological farming methods is becoming important. This is due to an increasing consumer demand for Organic / Ecological products and an increasing rejection by consumers of products that include pecticides, anti-biotics, chemical additives and that are seen as being produced through the use of "unethical" production methods. Many of the problems referred to under Mixed Systems are also relevant to Organic and Ecological Farming methods. However, a major difference between them is the extent to which Organic farming in particular has adopted certain techniques that respect natural ecological balances. These make it possible to avoid methods which are contrary to the principal aims of Organic farming and in general result in farming systems that are more environmentally sustainable. Mixed Systems in particular are ideally suited to Organic farming methods.

Low-Cost Food Production ?
Modern farming techniques have resulted in food in abundance and at low cost, especially within the industrialised world. Or has it? Recent analysis indicates that this low cost is an illusion. A new analysis of British farming (reported in New Scientist 18 December 1999) suggests that the external costs of farming are far greater than have previously been thought. These external costs are those that result from the present farming systems but which are not borne by individual farmers (and are therefore not passed on to consumers). These include short term effects such as such as: the costs of cleaning up pollution of the water supply, damage to habitats, and the health effects of air pollution. Longer term effects include the impact of greenhouse gas emissions and resulting global warming.

For, example, in Britain, water supply companies spent £214 million in 1996 removing pesticides, nitrates and farm pathogens from drinking water. The annual UK costs resulting from greenhouse gas emissions are estimated at £1.1 billion.

These findings strongly suggest that pricing and cost-recovery policies for environmental services need to be adopted whereby producers internalise their environmental costs (the "polluter pays" principle). Similarly, there is also is a case for transitional subsidies to encourage the adoption of less environmentally damaging methods, for example organic farming (see Regulatory Policies, Standards, Charges and Subsidies).

[Livestock & Environment Toolbox Home]