Livestock Advisor, Agriculture and Natural Resource Department, World Bank

LEAD Livestock, Environment and Development initiative

U.S. Sheep Experiment Station, Dubois, Idaho,USA

Mixed farming systems are the largest animal production systems in terms of animal numbers, productivity and the people they service. Moving across agro-ecosystems and phases of human socio-economic development the intensity of technology and the type of livestock-environmental interaction changes dramatically. Mixed systems have the capacity to change rapidly as markets, infrastructure and income grow. In many instances these systems serve as a bridge between the grazing and industrial systems.

Mixed farming systems encompass about 2.5 billion ha land, of which 1.1 billion ha arable rainfed land, 0.2 billion ha irrigated land and 1.2 billion ha grassland. Mixed farming systems produce 92% of the worlds milk supply, all buffalo meat and approximately 70% of the sheep and goat meat (Figure 1). About half of the meat and milk produced in this system is produced in the OECD, Eastern Europe and the CIS, the remainder comes from the developing world. Over the last decade, meat production from this system grew at a rate of about 2 percent per year, which is greater than the one percent output growth of the grazing areas, but remains behind global growth in demand.

Figure 1. Percent of global production produced by mixed farms

Figure 1

Evolution of the mixed farming system

As rural population pressure increases and less land becomes available, both crop and livestock farmers need to intensify. McIntire et al (1992) showed that as population pressure increases, the two activities often integrate. The soil protection techniques, and in particular the long fallow (rest) periods under traditional cropping systems, which allow soil nutrients to regenerate and soils to be protected from erosion (Kjekshus, 1977) are not sufficient anymore.

If farmers can not resort to external inputs, the integration of livestock and crop activities represent their main avenue for intensification. Mixed farming has thus constituted the basis for modern agriculture. Mixed farming systems provide farmers with an opportunity to diversify risk from single crop production, to use labor more efficiently, to have a source of cash for purchasing farm inputs and to add value to crop or crop by-products. Blending crops and livestock has the potential to maintain ecosystem function and health and help prevent agricultural systems from becoming too brittle, or over connected, by promoting greater bio-diversity, and therefore increased capability to absorb shocks to the natural resource base (Hollings, 1995).

Environmentally, mixed farming systems:

  1. maintain soil fertility by recycling soil nutrients and by allowing the introduction and use of rotations between various crops, forage legumes and trees or land to remain fallow whereby grasses and shrubs become re-established;

  2. maintain soil bio-diversity and minimize soil erosion, water conservation and provide suitable habitats for birds;

  3. provide the best of using crop residues. If the stalks are incorporated directly into the soil, they act as a nitrogen trap, exacerbating deficiencies. Burning, the other alternative, increases carbon dioxide emissions.

If pressure increases further, the crop-livestock systems can decompose into specialized crop or livestock activities. If there are no improved market opportunities, such as the case in many developing countries, and as human population pressures builds further, increased rates of nutrient depletion (and therefore reduced flora and fauna bio-diversity) and erosion easily follow in the arable land part of the system. This can in turn lead to an involution or downward spiral of mono-culture with lower quality food crops, increased under-nutrition and famine (Cleaver and Schreiber, 1994).

However, if urban incomes rise, more market opportunities open up and farmers become more integrated into the market economy, specialization, allowing farmers to take advantage of economies of scale and develop greater levels of expertise, normally occurs. Finally, under very strong demand, and with high input or price subsidies, as such exist in many developed countries and in the fast growing economies of East Asia, excessive importation of nutrients can lead to soil and water tables being overloaded with nitrogen or phosphorus, as was see in Brittany, France (de Haan et al., 1997).

The challenge for the mixed farm sector will therefore be to maintain a nutrient and energy equilibrium through crop-livestock integration and at the same time allow sustainable productivity growth. While the mixed farming system, more than in any other production system, operates under a wide range of environmental and economic conditions, requiring regional solutions and practices, there is one overriding criteria in determining the size and nature of the system's impact on the environment. This is the nutrient balance. This balance is determined by the nutrients (N, P and K) brought into the farming systems by in-organic fertilizer, feed, Nitrogen fixed by leguminous plants, transfer from - mostly common - grazing areas outside the farm, and the amounts exported in animal products or lost from the land in the air or ground water. A positive balance will have completely different effect (and will require different measures) than a nutrient deficient system. In this analysis, the mixed farming systems will therefore be classified in nutrient deficient systems, mostly occurring in the developing world, and of nutrient surplus systems, mostly found in the industrialized world and increasingly in the fast growing economies of East Asia.

Driving forces in the mixed farming systems.

Developing Country, Nutrient Deficit Systems: Like in the grazing systems, human population pressure, poverty and poor infrastructure are the most important fundamental driving forces affecting the environmental impact of mixed farming systems in the developing world. And in that respect, the mixed farming systems are entering a dynamic period of growth and change, as they cover some of the countries with the highest birth rate in the world (e.g., Uganda, Sahel, Ethiopia, Nepal, Bangladesh). Human population pressure affects the critical nutrient balance. In many systems in Africa and the mountainous areas of Asia and Latin America, this balance is being maintained with - at best - small inputs from outside, as poverty and poor infrastructure often preclude this balance to be maintained with outside feeds and fertilizer. The balance then depends mostly on the ratio between crop and non-arable land. In the case of Nepal, it was determined that 3 ha of forest land with livestock are needed to maintain 1 ha of arable land, without causing deterioration of the forest. In West Africa, the ratio was about 10 – 40 ha of dry season grazing and 3 – 10 ha of wet season grazing to provide adequate nutrients for one ha of millet crop land (Williams, 1995).

However, with increasing population pressure more and more grazing land is converted into crop land, the crop/grazing land ratio narrows, and the nutrient flow into cropland decreases. For example, cropland increased in the Machacos area of Kenya from 35 percent of the higher potential area in 1948 to 81 percent now. In Northern Mali, the rate of increase of the arable cropping area was the same as the 2.6 percent rate of annual population growth over the last twenty years (Powell, 1995). This can lead to increased competition for land and grazing on the open rangelands, which in turn, can lead to privatization of crop residues and rangelands. For example, the common property lands in India, decreased since 1960 by 50 percent, so that in 1992 they constituted only 15 percent of the total area (Jodha, 1993). Population pressure causes farmers to push cultivation out into more resource limited areas, causing soil erosion.

Mabbutt (1989) reports, for example, in Niger millet fields are appearing 100 km north of the recommended limit to cultivation, increasing the risk of crop failure and leaving soil exposed and erodible, and as a result livestock have been moved to the most marginal areas. With even further deteriorating crop/grazing land ratios and without adequate substitution of soil fertility by other sources, fertility gaps arise. This is typically the case of many mixed farming systems in the tropics. Reported losses range from about 15 kg N/ha/year in Mali, to more than 100 kg N/ha/year in the highlands of Ethiopia. Downward spirals of declining soil fertility, overgrazing, increased erosion and losses in soil micro flora and fauna are the result and will ultimately cause significant decreases in agricultural productivity and political stability. Events in Rwanda underscores the need for a balance between crop activities, animal inputs and human population pressure, to avoid the involution (or maybe even implosion) of farming systems, impoverishment and even civil war (de Haan et al.,1997).

In irrigated mixed farming system, grazing is more contained on the farm. In these areas, the type of feed supply will shift increasingly from non-arable grazing to grazing crop-aftermath and utilization of fallow land. Soil nutrient deficits are covered in these areas by inorganic fertilizer. The main feature of the irrigated areas has been the dramatic intensification of crop production as a result of the Green Revolution. With the introduction of improved “dwarf” varieties, the quality and quantity of crop residues decreased, but cereal production and total farm income increased. This has decreased the amount of feed available for ruminants, but increased the supply of cereals, which could be used for intensive production. Moreover, the rising incomes from the Green Revolution increased demand for livestock products. The two trends together promoted the development of intensive industrial units in these areas. This, combined with the high fertilizer use, leads to increasing concerns for nutrient loading.

Pressure is also on the use of draught power, the other link between crops and livestock production. Off-farm employment increases labor cost and if the time available to prepare land becomes shorter, tractorization becomes more important, decreasing buffalo and cattle populations for traction. For example, in India the number of bullocks used for animal power decreased from 85 million in 1960 to 60 million now, at the same time the number of tractors increased from 30,000 to 1.4 million. Only about 30 percent of the total arable area is cultivated by animal power (World Bank, 1995).

Developed Country, Nutrient Surplus Systems: Soil erosion increases with increasing levels of grazing pressure and cropping intensity. Reynolds et al. (1995) reported how variable soil erosion can be observed under different grazing pressures. Soil loss on lands with good ground grass cover was estimated at 1 ton/ha; this increased dramatically on overgrazed pastures to a level of 53 tons/ha. If grazing pressure is in balance with the forage resource being produced, livestock's interaction can encourage more stable land-use practices. Pimental et al. (1995) discussed how in the United States in order to increase farm size, grass strips and shelter belts were removed, thus increasing the erosion rate. In the past, livestock provided a rationale for grass strips and shelter belts, but with the disaggregation of crop and livestock systems in OECD countries the rationale for utilizing land resources in such a way has decreased.

Nutrient surpluses cause the main pressure on the quality of land and water. These surpluses come from a combination of inorganic and organic fertilizers. Inorganic fertilizer is used, in spite of the fact that the system could be balanced based on the nutrients supplied by the manure produced in the systems. For example, in the case of Brittany, the organic manure produced by the intensive industrial and mixed farms of the region would adequately balance the regional nutrient balance, but large surpluses emerge because of the additional importation of large quantities (between 35 and 100 kg N/ha per year) of inorganic fertilizers. The inorganic fertilizer is said to be necessary because of the readily available nutrients and its easy transport, as in the case of pure intensive grazing systems. The preparation of nutrient balances (inorganic and organic) on a regional basis is therefore a critical element in identifying land conservation and fertilizer policies.

For a large part, the heavy import protection of most animal products, especially beef and milk, and the wide array of producer subsidies, especially on feed imports, have led to the wide use of feed concentrates and the surplus nutrient situations.

Technology and policy options

A fundamental requirement to achieve environmental sustainability of the natural resource base is to incorporate change and flexibility into the respective production systems and overall landscape (Levin, 1995). Agriculture and particular crop agriculture seeks to stabilize production and environmental change, causing a loss in ecosystem flexibility. But the vibrancy of any ecosystem which supports the production of food, can be enhanced through the integration of livestock as a mechanism to promote system flexibility. Mixed farming, with careful attention to the nutrient balance to prevent system involution, is probably therefore the environmentally most desirable system, and should be the prime focus of agricultural planners and decision makers. The challenge will be to identify the technologies and policies, which generate the sustained and accelerated growth needed to satisfy the world's sky-rocketing demand for meat and milk. This challenge will be enormous. Past global growth of the meat and milk output of the mixed system has remained behind the increase in global demand. Will the growth in demand levels continue to rise beyond the capacity of mixed farm systems to meet national demands and therefore result in an immediate transition to highly intensive industrial systems? This study argues that, while for environmental reasons establishing the appropriate enabling environment for mixed farming is critical, mixed farming should make an important contribution to meeting global demand, it might not be enough, and industrial production growth will be essential.

The key enabling factor seems to be access to inputs and attractive markets, as illustrated by the Machacos case study in Kenya. Here, a dynamic market and access to inputs led to sustainable development of a resource poor area, of which the population had quintupled over the last sixty years. Use of livestock in such intensive situations includes a shift in species from cattle to sheep and/or goats. Driving this option would be the access to markets and the infrastructure necessary to process milk. Farmers with more difficult access to markets would be more inclined to raise small ruminants (Cleaver and Schreiber, 1994). This path has the biggest potential in the highlands areas of Latin America and the semi-arid and highlands of sub-Saharan Africa, where the land to human ratio is already rather high and integrated crop-livestock systems have an immense potential to contribute to the required growth in productivity.

The second development path could lead to specialization in either crop or livestock production. Controlling this path will be existing infrastructure, and relative price ratios between the different inputs and outputs and economies of scale, which will determine the comparative advantage in one enterprise versus another. This is to a large extent the development path in the developed world and East Asia and will be discussed separately below.


In mixed farming systems, there are exciting opportunities for introducing technologies. Applied research and extension are of critical importance to maintain the environmentally friendly factors of the system, although McIntire et al (1992) strongly make the point that African farmers are well aware of the technologies involved. The challenge will be to convince farmers about technology's utility. In the nutrient deficient systems of the developing world, the emphasis would be on control of soil erosion and improving nutrient recycling. Some examples are:

  1. Improvement of soil cover through the use of alternative crops for mulching, and introduce soil management techniques such as conservation tillage, bench terracing, strip cropping, contour farming, etc.;

  2. Improvement of feed production and quality to reduce the pressure on the grazing areas, and improve internal nutrient transfers. Technologies to do so include:

  3. Reduce nutrient losses from manure and improve the efficiency of their application by:

  4. Increase production efficiency, and thereby farm income, resulting in improved purchasing power for soil improvement and conservation methods. They include:

In the developed world, strong regulatory frameworks are being introduced, restricting the emission of nutrients in the case of point-source pollution, and stocking rate restrictions (“manure quota”) in the case of non-point source polluters. A cross-section of current legislation in some of the developed and developing world is provided in Table 1. As can be seen, they include a variety of restrictions on stocking rate, level of fertilizer, manure storage, application techniques and times, along with government subsidies on manure processing and management.

There are a variety of incentive instruments to reduce nutrient surpluses in nutrient surplus areas. These include:

Technologies to reduce nutrient surpluses are also described under the industrial systems. But of particular importance to mixed systems are the following:

In addition, over the last decade, there has been a considerable interest in promoting low-input mixed farming systems, as sustainable, and environmentally friendly systems. In the USA, the Rodale Institute in Pennsylvania, and the LISA (Low Input Sustainable Agriculture) movement, strongly promoted by USDA has been in the forefront. In Europe, the ILEA (Institute for Low External Input Agriculture) has been one of the prime movers. The mixed farming system, with its rather closed character, is especially suitable for this type of production. Some of the main technologies, which can be used on the livestock side are:

Table 1. A cross section of manure management regulations.

CountryN - EmissionP - Emissions
European UnionMaximum stocking rate: 2.0 cows, equivalent to 170 kg N per year in manure Nitrate level in drinking water: MAC1 50 mg NO3/lP2O3 in drinking water: 5,000 microgram/lt.
NetherlandsSame water standards as EU. Reduction of NH3 emission by 50–75 percent, through low ammonia emission techniques: injection techniques, bans on autumn and winter applications, covered manure storage. Cost sharing for manure drying and transport to manure deficient regions.Max. amount of P2O5 in animal manure allowed to be added to the soil to decline as follows
with levies for every kg of phosphate produced per hectare of farm-owned land in excess of a tax-free amount of 55 kg P per ha. The tax of US $ 0.40 per kg of P2 O5 is doubled for production over 87 kg. per ha.
GermanyVaries according to the State. Maximum fertilizer rate at 240 kg N per ha, and in some states maximum stocking rates of 3.5–4.5 cows (or manure equivalent) per ha. Manure application (winter) and storage restrictions. Mineral record keeping required.UnlikeNetherlands,most attention is on Nitrogen
USAVaries according to the State. Manure management plans required for all farms (with federal and state cost sharing in the implementation) and permits required for concentrated animal feeding operations (CAFO's), and bans on the direct discharge on surface water.

1 Maximum Allowable Concentration

On the crop side, this has to be accompanied by environmentally friendly low-input techniques, such as no-till, manuring and composting, integrated pest management (IPM) etc. The opportunity to employ precession agriculture concepts, due to the information available concerning the resources base and the economic incentive, to minimize production costs provides a mechanism to keep soil nutrients balanced as well as mosaics across a landscape.

Such low-input, environmentally safe farming can have a special attraction to consumers with products under green labels, eco-farming, organic farming, etc.. It needs to be accompanied by clear and strict quality standards (especially regarding residues) and be supervised by reliable quality control systems. Prices of such organic food products are still between 20 and 50 percent higher than the normally produced foods. The low and stagnant share (2–5 percent of the market in the EU), and the consequently high transport costs and lack of economies of scale are main factors in this much higher product price. Green label eggs (free range production) is one of the most wide-spread products and now have a market share of five to ten percent in the EU.


Mixed farming systems, with crops and livestock on the same farm, will be a dynamic element (although a potentially transient one) of the growing livestock sector. Across ecoregions the time frame in which within-one-farm mixed systems will develop, flourish and recede will be closely tied to overall economic growth and development.

In the future, mixed farming systems will be subjected to a more open market economy. Structural adjustment reforms will continue, resulting in less distortions in exchange rates and input pricing. The global trade reform initiated under GATT and the World Trade Agreements will cause import barriers to be lowered. In all these discussions, it is critical to assess, where the particular system is located in terms of its regional nutrient balance and the infrastructure linkages. The strict regulation on manure production and emission are expected to be further strengthened in the OECD countries and should become increasingly important in the mid-income level countries of Latin America and East Asia.

Mixed farming systems have a capacity to absorb and mitigate the negative environmental impacts when environmental costs are internalized and markets are liberalized. Furthermore, these systems have the largest capacity to benefit from technological innovation. These two factors combined should help these types of systems grow in size and importance as environmental costs force a decapitialization of industrial systems. However, if significant industrial systems are developed there will still be opportunities to continue producing in a mixed farming context, integrating industrial, land-detached units and arable farms in a “regional mixed farm”.


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