Appropriate use of local resources in integrated farming as a strategy for sustainable agriculture in central Vietnam
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Date
1996
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Publisher
Swedish University of Agricultural Sciences
Abstract
The research was conducted from February 1995 to February 1996 in the Socialist Republic
of Vietnam . Located in the Asia-Pacific region, Vietnani has an area of 329,560 km2 and its
population is over 70 million people. The overall objective was to devise ways of making better
use of the local resources, especially the livestock, in order to improve the well being of the
people.
The first study was carried out in two villages in a rain-led hilly region in Central Vietnam
(Paper I). The original idea of evaluating an intervention based on restricted milking of the local
cattle was abandoned in the light of the insistence of the farmers that the expected benefits vvere
too long term and they had other more immediate pnonties. In contrast, discussions about the
potential benefits from introducing low-cost biodigestcr technology were enthusiastically
received, especially by the women.
The traditional diet fbr pigs in the region is lacking in protein. Conventional protein suppknK ui.5
are expensive and their availability is low. Biodigesters produce nitrogen-nch effluent and arc
a logical source of the required nutrients fbr growing aquatic plants such as duck weed as a local
source of protein. Thus there was a potential connection between the biodigcsters (being installed
primarily as a source of fuel) and the need to improve the diet of the pigs.
It became apparent during the development of the "duck weed" project that tiiere were many
factors which influenced duck weed production, some controllable and others determined by
climatic conditions (flooding!). Management was found to be the most important factor —eg. the
levels of eflfluent to be used, water exchange and the need to renovate the seed. Very little was
known in the use of the biodigester effluent to produce duck weed in such conditions, so this
aspect was a logical subject fbr ,,on-stationH research (Paper II)
In Paper II the hypotheses to be evaluated were that: effluent from biodigesters would be an
effective source of nutrients with which to grow duck weed of high protein content; and the
protein level in the duck weed would be a function of the amount of effluent added to the pond
water. Six ponds were used, each lined with polyethylene film (0.2mm thickness) having 9.4 m2
area and 15 cm water depth. The two treatments were 32 and 4.5 kg eSluent/m3 pond water
which were estimated to support N concentrations in pond water of 73 and 10.3mg N/litre
respectively. The effluent was from plastic tube continuous flow biodigesters, charged with pig
manure, and contained 6.5% of solids and 3.41% of N in the solids. 200 g of duck weed/m2 were
added to each pond and the total biomass was harvested at 3 day intervals over a period of 9
days. Biomass yield and protein (N*6.25) in the duck weed dry matter were linearly related with
the N concentration in the pond water and negatively related with root length of the duck weed.
Optimum levels ofN in pond water were in the range 40-60mg N/litre. Duck weed of more than35% protein had a root length less than 10mm. Duck weed biomass yield at optimum pond N
levels was of the order of 100 g fresh biomass/m2/day with 6% dry matter and 30-40% protein
(N*6.25) in the dry matter.
As a result of the project activities in the village and based on fanners expectations, research to
document the local breeds became a pnonty. A survey was done to get some baseline data. These
observations at village level about the efficiency of the Mong Cai breed in the use of local
resources were the basis to carry out an ,;on-station experiment" to explore the digestion
parameters and N metabolism of Mong Cai and exotic breeds and their crosses (Paper III).
The hypotheses to be evaluated in paper III were: (i) Mong Cai pigs would eat greater amounts
of duck weed (Lenina minor) and use it more efficiently than exotic pigs such as those of the
Large White breed, and (ii) duck weed grown in ponds fertilized with biodigester effluent would
be a satisfactory source of supplementary protein in a low protein basal diet of sugar cane juice.
Four Mong Cai male piglets (5-10 kg) were obtained from the local market; four Large White
male piglets (12-17 kg) from a nearby State farm and four Mong Cai*Large White piglets (2
male and 2 female) (9-14 kg) from a litter (Mong Cai mother; LW sire) bom at the farm. They
were housed in metabolism cages made from bamboo and wood (floor area 70*70 cm) with
freedom to move around
Relationships between tlic percentage of diet dry matter consumed as duck weed (X) and
apparent cbgestibilin/ (DM and N) and N metabolism (retention as % of intake and digested N)
v-ere denied lor the combined data for the 2 breed groups (8 pigs) and expressed as linear
the regression coefficients of which were all significantly different from zero.
Thee: were no significant diflcrenccs between Mong Cai and Mong Cai*Large White crosses
for -
of
parameters and the results indicated that the nutritive value of duck weed is high
/h
to indigenous pigs and their crosses as a supplement in a basal diet of sugar cane juice.
Fifty percent of the pigs were able to consume fresh duck weed in proportions sufficient to
provide a diet with more than 10% of protein in the dry matter. Purebred exotic pigs (Large
White) appeared to be less adapted to consume the duck weed.
Key words: Sustainability^; Vietnam; Women; On farm research; Extension; Mi/k
production; Low cost plastic biodigester; Effluent; Duck weed; Lemna; Integration;
Ponds; Nitrogen; Protein; Pigs; Indigenous breeds; Animal welfare; Mong Cai:
Energy; Sugar cane juice; Digestibility; N balance; Biodiversity.
Description
Dissertation
Keywords
Local knowledge, Animal welfare, Duck weed production, Integration, Indigenous breeds