Improvement of Livestock Production in Crop-Animal Systems in ...

Table 3.Human and animal populations, food demand and land use in the two AEZs of Asia.Lowlands Uplands Per cent of Asiain both zonesAmount/No. Per cent of Asia Amount/No. Per cent of AsiaHuman population in 1990 (10 6 ) 960.4 35.1 441.8 16.1 51.2Human population in 2010 (10 6 ) 1264.5 34.4 588.8 16.0 50.4Food demand in 2010 (10 6 tGE) 383.9 35.8 175.5 16.3 52.1Production of food crops (10 6 tGE) 262.7 35.9 167.2 22.8 58.7Production of cash crops (10 6 tGE) 89.7 37.9 62.8 26.5 64.4Cattle population NA NA NA NA 51.0Small ruminant population NA NA NA NA 55.0Agricultural land (10 6 ha) 284.0 29.3 112.6 11.6 40.9Arable land (10 6 ha) 123.4 26.7 73.1 15.8 42.5Rainfed arable land (10 6 ha) 86.1 26.3 55.2 16.9 43.2Permanent cropland (10 6 ha) 17.8 69.7 4.2 16.7 86.4Source: TAC (1992, 1994).NA = not available; tGE = tonnes of grain equivalent.lowlands. Buffaloes are found mainly in the irrigated rice-growing areas, where they play a valuable role inland preparation and haulage. Table 4 shows the value of animal products (meat, milk and eggs) fromruminants and non-ruminants. With the exception of milk, the value of animal products from the lowlandsis approximately twice that from the uplands.Livestock and the environmentOvergrazing by livestock has led to degradation of common property resources in some upland areas.However, erosion and degradation are more often associated with annual cropping on sloping land,particularly in shifting cultivation systems. Although livestock are important in the cycling of nutrients,pollution of water sources with manure from intensive dairy and non-ruminant systems is a problem in someperi-urban areas.Characteristics of the lowlands• The topography is generally flat to gently undulating. In the Philippines, the lowlands are characterisedby slopes from 0–8% (BAR 1989).• Low soil fertility is a major constraint.• The AEZ embraces most of the small-farm systems that support poor and illiterate rural populationsand landless people, often migrating from other areas (Devendra 1983).• Crop growth is dependent on the amount and duration of rainfall, depth and duration of standing water,frequency and time of flooding, soil type and topography.• Rice is the dominant crop. IRRI (1993b) identifies four rice-growing ecosystems, two of which arerelevant to this study (Table 5). Rainfed lowland rice yields range from 1.5 t/ha (Malaysia) to 3.0 t/ha(Indonesia and Myanmar). These compare with 2.5 t/ha (Cambodia) to 5.3 t/ha (Indonesia) for irrigatedrice (IRRI 1993a).• Other cereals and cash crops (pulses and oilseeds) are also grown within intensive cropping systems.• Populations of buffaloes are lower but those of cattle are higher than in the irrigated areas. Limitednumbers of small ruminants are found in the drier areas. Pigs, poultry and ducks in the AEZ utilise riceby-products to great advantage.