Degree of Crop-Livestock Integration

Mixing of crops and livestock occurs in different degrees and forms. The classification adopted by this toolbox uses a distinction based on kind and degrees of external input use and plant nutrient cycling on the farm. The degree of input use is essentially related to the outfield / infield ratio, i.e., the area of land available for grazing outside the farm (outfield) in relation to the feed requirements for animal production (draught, dung, milk, meat, etc.) and manure requirements for crop cultivation on the farm (in field). | Mixed systems making use of communal grazing Mixed, Crop Residues Mixed, Cut and Carry Mixed Feed from Farm Mixed External Feed References

Mixed systems making use of communal grazing have a high outfield / infield ratio. The area of outfield required to supply enough manure for one hectare of cropland is known to be around 20 – 40 ha. In cases where these pastures are available, it is often neither economic to harvest and conserve fibrous crop residues nor to improve housing for manure collection. In general crop residues are left in the field to be grazed and animals are gathered in corrals or night pens. Manure so collected can be used to sustain crop cultivation. The so formed crop-livestock integration can be within one mixed farming system as well as between specialised livestock and specialised crop farming systems. The system is characterized by throughput of nutrients with a low level of output in terms of animal products such as milk or meat.

Mixed, crop residues

An expansion of area under crop cultivation in general is at the cost of pastureland, having a double impact on the outfield / infield ratio: less pasture land (less outfield) and more cropland (more infield). The reduced availability of outfield implies an increased need to keep and recycle resources on farm. Crop residues become more important and mixed systems emerge where crop residues are the principal feed resource base. The function of animals changes from the collection of nutrients from outfields to cycling of nutrients on infields. This requires different ways of keeping animals: stall feeding instead of grazing; more limitations in the number of animals that can be kept; selection of specific animal types, draught animals or cow calf production; placing of surplus stock in grazing systems; etc. Mix farming increasingly takes place at on-farm level, and traditional forms of exchange of services between crop and livestock farmers start to break down.

Mixed, cut and carry

Further increase in land use for crop cultivation often results in restrictions on the free grazing of animals. Tethering and the collection of feed from roadside, other communal land and neighbouring farms then replace grazing on communal land and mixed systems based on cut and carry appear. In short, human labour (men, women and children) replaces the energy used by grazing animals to collect their feed. Consequently, labour availability on the farm can become a major constraint for the number of animals that can be kept. The cut and carry systems therefore are, in general applied by households with access to little land and no better alternative income generation for their labour. Through the collection of feed from the limited outfield areas there is still some import of nutrients on the farm. The high labour cost for collection will stimulate that the feed resources on farm are intensively used. Therefore the system is characterized by external input through feed from a limited area of outfields and an intensive cycling of feed on farm.

Mixed feed from farm

Farms with access to more land relative to outfield can reduce labour costs by growing more fodder crops on their land. They then can evolve in mixed system with feed from farm. The cultivation of fodder crops on farm can in addition contribute to:

- prevent erosion (soil cover, boarder vegetation);
- fix Nitrogen (legume plants shrubs and trees);
- mobilise nutrients from the soil (catch crops);
- improve soil structure (organic matter content);
- provide by-products (fuel and construction wood, flowers for bees);
- more variation in crop rotation scheme

In general it is the combination of benefits that makes farmers decide to plant fodder crops. The primary reason even has not always to be for livestock. The system is characterized by intensive cycling of plant nutrients on farm (infield). However, the lack of outfield in relation to infield will eventually threaten the sustainability of even very efficient recycling systems. Inevitable losses of nutrients from even efficient recycling systems imply a development trajectory of increased mining and decreased outputs. Eventually therefore the throughput needs to be re-established i.e. through inputs from external feed and / or fertilisers. The mixed systems may so evolve into systems using external feed.

Mixed external feed

The mixed external feed system can evolve from any other mixed system but is characterized by input of plant nutrients through external feed for livestock. As such it is a throughput system. The principal differences with the earlier throughput systems mixed communal grazing and cut and carry systems are that the feed is of high quality and that it originates from distant outfields, whereas the other systems rely on feed of moderate to poor quality from local outfields.

Specialisation and expansion in livestock production can easily result in low utilisation of resources on farm (feed quality inferior to requirements), a poor utilisation of manure (dumping instead on fields instead of application to crops) and surplus of manure (not enough land to put manure on). Such developments may create opportunities for a comeback of associations between specialised farms, i.e. one farm specialises on dairy providing manure to another farming specialised in crops or vegetables, while receiving crop residues in return.

Some of the characteristics of the different modes of mixing are summarised in Table 1 and Table 2. In the system "mixed, external feed" a distinction has been made between ruminants (dairy) and mono gastrics (pigs and poultry). Each of the tables can be further refined. For example it is possible to distinguish between different fluxes from local fodder, crop residues, feed from farm and external concentrates. Also, the validity of the details can be different depending on the situation. However, the Tables may provide a tool for analysis and characterization of the systems under study.

Table 1. Nutrient flows in livestock production on mixed system

System | External input | Cycling of nutrients on farm | Output animal products*
| Local outfields | Distant outfields
Communal grazing | High |  | Low | Low
Crop residues | Low |  | High | Low
Cut and carry | High |  | High | Low
Feed from farm | Low |  | High | Low
External Feed: Dairy Pig and poultry |  | High High | High Low | High High

- Not included are indirect products such as security, saving value, effect on nutrient dynamics, diversification of income and cropping pattern, etc.

Mixed farming includes crop cultivation and livestock. The contribution of manure from external feed by livestock, the use of external inputs for crop cultivation, the area under crop cultivation, the intensity of land use and the types of crop grown determine largely whether the farm will have a positive of negative nutrient balance. In Table 2. an estimate is made of expected nutrient balance on farm by system. Considered are situations with a low (or no) or a high external input in the form of fertilisers for crop (and fodder) cultivation.

Table 2. Nutrient balance on mixed farms with low or high fertilizer input.

System | External input | Nutrient Cycling On farm | Expected on farm nutrient balance *
| Through Livestock | Fertilizers
Communal grazing | High High | Low High | Low Low | + +
Crop residues | Low Low | Low High | High High | -- +
Cut and carry | High High | Low High | High High | + +
Feed from farm | Low Low | Low High | High High | - +
External Feed: Ruminant Mono-gastric | High High High High | Low High Low High | High High Low Low | + ++ + ++

- expected nutrient balance: -- = strong nutrient deficit; - = nutrient deficit; + = around nutrient balance; + = nutrient surplus; ++ = strong nutrient surplus.

A similar pattern emerges when the area under cultivation is related with the number of animals on the farm, see livestock / cropland ratio.

References

Schiere, J.B., G.J. Oomen and M.N.M. Ibrahim, 1997. Mixed crop-livestock farming: different systems and their trade-offs. Invited paper at the annual workshop of the South African Society of Animal Sciences, University of Zululand, Faculty of Agriculture, Empangeni, October 1997, South Africa.

Schiere, J.B. and De Wit, J. 1995. Livestock and farming systems research II:development and classifications. pp. 39 - 61 in J.B.Schiere, Cattle, straw and systems control. Royal Tropical Institute. Amsterdam. 216 pp.

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