Although integrated farming systems have long been practised and are widespread in South-East Asia, their importance and potential contribution to sustainable development has been inadequately appreciated. Also, there are few systems that have been able to consistently demonstrate sustainable production and economic benefits. There are several reasons for this, among which is the fact that there has been very little research aimed at understanding the nature and functions of the systems or measuring their productivity and economic benefits. This is reflected in poor documentation of the value of these systems and their development. Another reason is associated with the notion of a subsistence operation which is dependent on meagre and often diminishing scarce resources on small farms. There are also the various types of constraints to production on small farms (Chapter 6) that further affect integrated systems.
Additionally, integrated systems demand more initiative, inter-sectoral effort and inter-disciplinary approaches, greater resourcefulness and commitment, willingness to be innovative and access to information and technical know-how, all of which can be serious deterrents. The only exception to this is the pig-fish-duck-vegetable system (see Chapter 7).
For these reasons, the development of integrated systems has been hampered by inadequate national and donor support in the past. The situation is however changing and there is increasing appreciation of and support for such systems, in view of their wider benefits in terms of efficiency of natural resource use, nutrient recycling, environmental protection and sustainable development. Such efforts need to be accelerated, especially in South-East Asia where the potential for such development is obvious and where there has been a tradition of using such systems on small farms.
INTEGRATED PIG-DUCKS-FISH-VEGETABLE SYSTEMS
With specific reference to fish, integration with pigs, ducks and vegetables is a time-honoured practice in which meagre resources are effectively used interactively to maximize protein production. In recent years, recognition of the importance of ruminants, both in terms of production and the value of their manure, has led to efforts to explore the integration of other systems with fish production. The potential benefits are increased efficiency of use of the existing crop and animal resources, reduced dependence on purchased concentrates for feeding fish and a concurrent reduction in costs of feeding and production. The efficiency of nitrogen utilization for fish biomass production is relatively higher in systems where concentrates are used but the use of nitrogenous manure from animals causes less pollution.
These systems have been widely practised in China. Vietnam and Cambodia but, surprisingly, the different systems, individual components, interactions between them and the effects on the environment, economic analysis, socio-economic benefits on farm households and issues of sustainability do not appear to have been studied and documented.
INTEGRATED SYSTEMS INVOLVING VARIOUS ANIMALS
Unlike the traditional integrated system involving pigs, ducks, fish and vegetables that is more widely known, the inclusion of ruminants into such systems is relatively new. There are several reasons for this, chief of which is the fact that ruminants, unlike pigs and ducks, are not normally reared adjacent to ponds but rather in extensive grazing systems. Secondly, and related to this, extensive systems do not enable easy concentration and collection of dung from animals in sizeable amounts for use in fish ponds, unless the animals are maintained in stall-fed systems. Thirdly, feedlots that provide a large supply of dung for use by fish are relatively uncommon in South-East Asia, which has also not encouraged the development of integrated systems combining fish and animals.
These limitations are also reflected in the very limited research into such systems and, associated with this, the failure to develop suitable methodology to promote such enterprises. Figure 10 illustrates the integration of animals (ruminants and non-ruminants) with crops, pigs and fish. The crops referred to are mainly annual crops like cassava, maize, groundnuts, rice and sweet potatoes.
It is not surprising therefore that results from such integrated systems, and the effects of interactions of the components (crops, fish and individual animal species) are scarce. This has also prevented the identification of which animal species fits best into such integrated systems.
One of the few studies of this type concerns the integration of goats and ducks with fish in Malaysia. A 30–40% increase in growth rate has been reported in this system in which the performance of grass carp was also superior to that of big head carp (Mukherjee, 1985).
In the ponds, several water weeds are invariably present, a very good example of which is water hyacinth (Eichhornia crassipes) which has been used for feeding both pigs and ruminants (Devendra, 1988). The special features of this type of integrated system are:
The complementary role of ruminants to utilize non-marketable crop residues in situ, the manure production being used by fish, whereby the meagre resources are put to more effective use.
Figure 10. Relationships between crop-animal interactions and fish production.
THE SIGNIFICANCE OF MANURE FROM ANIMALS
The quality and amount of manure produced from animals influences the development as well as the efficiency of integrated systems. The amount of manure produced by individual animal species, and hence the nitrogen contribution, is mainly a function of type of species, size, age, sex, feeding regime and also health of the animals. Table 8.1 provides an indication of the relative contribution by individual species on the assumption that these are only meat producing animals and that they are stall-fed.
|Species||Adult live weight (kg)||Dung production (kg DM)||N content (%)*||N production (g)*||N production/year (kg)*|
* On dry matter basis
** In mg
It is clear that there are distinct qualitative and quantitative difference between the manures produced by individual species (Mueller, 1980). In particular, attention is drawn to differences in the N content in the faeces. With ruminants in general, the distribution of N in facces and urine is approximately the same but, with non-ruminants, the percentage of N is higher in urine. Smith, Calvert and Menear (1973) reported for instance that pigs and poultry had 33–67% total N in faeces and 25–75% in urine. Additionally, there is also the issue of differential rates of N breakdown between different types of faeces. Goat manure for example has contains biuret from which ammonia is more slowly released (Devendra, 1983).
PRODUCTIVITY OF FISH
Nitrogenous manure inputs clearly influence the productivity of fish in ponds. Quantitative studies on this are limited and in any case usually restricted to the involvement of individual animal species.
In an effort to overcome the difficulties of comparing data from various workers, Edwards (1983) attempted to estimate the number of pigs, dairy cows and buffaloes required to produce a mean yield of 174.7 kg of fish/200m2/year from the manure of 26.7 ducks (equivalent to an extrapolated yield of 8735 kg/ha/year from 1335 ducks). The number of animals required to produce this quantity of fish per 200m2/year was approximately 8 pigs, 1 dairy cow and 2 swamp buffaloes. Table 8.2 presents the details of this calculation.
|Livestock||Manure production (kg DM/animal/year)||N content (%)||Livestock (no./200m2 pond/year)||Livestock (no/ha/year)|
FUTURE OF INTEGRATED SYSTEMS INVOLVING PONDS
The future of integrated systems is dependent on the following:
INTEGRATED SMALL RUMINANTS-TREE CROPPING SYSTEMS
The importance of small ruminants in integrated systems is becoming increasing recognition in several countries in South-East Asia (see Chapter 7). However, the process of integration and the methodology for this remain to be fully developed. There are also issues of the effects on the parent crop and also the effects of crops on animals that need to be analyzed.
Effects of animal integration on the parent crop
A wide variety of issues must be considered in this complex interaction. The following are not listed in any particular order of priority but refer to a number of important examples. It is by no means an exhaustive list.
Effects of primary crop management on small ruminants
The following issues are relevant to the effects of primary crop management on the animals. These issues merit continuous monitoring and research.
Most of the animal-related issues are common to other intensive, mixed crop-livestock farms. However, the following are unique to the tree crop-livestock association.
INTEGRATED SYSTEM BASED ON SUGAR CANE
Elsewhere, in Colombia, an example of an integrated farming system is based on sugar cane and forage trees, fractionated to provide feed for pigs and poultry (the juice and tree leaves), sheep (the cane tops and tree leaves), fuel for the family (bagasse and firewood) and litter for sheep and earthworms (bagasse), with recycling of excreta through biodigesters to provide fuel (biogas) and fertilizer (the effluent) for water plants in ponds and for crops (Preston, 1990). Figure 11 illustrates the model. The system has considerable merit especially in situations where biomass production from sugar cane is high such as in the Philippines, Vietnam and Malaysia.
Figure 11. Integrated system based on sugarcane (Presfon 1990)
IMPLICATIONS FOR RESEARCH AND DEVELOPMENT
Given the paucity of knowledge on the subject of integrated systems and, since the development of such systems is especially consistent with sustainability, efficient management of natural resources and environmental protection, a high priority needs to be accorded to the formulation of research and development on this subject, backed by institutional and government support for such programmes. The following are some of the areas that merit attention: