General Status of Agricultural Plastics
                     By Xu Beilei
Science & Technology Department of the fomer Light Industry
Administration
As is known to all, China is a  big  agricultural  country.
Agriculture is the basis of the national economy and has a
unique position in China.
The Chinese population is 22% of the world population,  but
the cultivated land is only 7% of the world's total.   The
per-capita cultivated land in China is less than one-third
of the world average level.   The  Chinese  population  is
increasing by a net 15 million a year while the cultivated
land is reducing by 467 000 hectares   a  year.   The  per
-capita cultivated land is expected to be reduced from  the
present 0.09 hectare to 0.07 hectare in 2000. The lack  of
land resources is the first constraint to the  development
of agriculture in China. The second constraint is the lack
of fresh water resources. The per-capita  fresh  water  is
only a quarter of the world average level and China is one
of the 12 water-lacking countries in the world. Faced with
these unfavorable factors, China is endeavoring to explore
a way of  agricultural  development  suitable  to  Chinese
conditions. With the advent of  the  plastic  industry  in
China,  various  agricultural  plastic  products  such  as
agricultural film (including canopy film and mulch film) ,
  packing  materials  for  storage  and   preservation   of
agricultural products, water  transmission  pipes,   spray
irrigation  and  trickle  irrigation  devices  and  marine
cultivation devices have been developed. The  agricultural
development has led to the rapid increase in the output of
agricultural plastic products.  Their  proportion  in  the
total output of plastic products has increased year  after
year and reached 18.8% in 1995. Table 1 shows the detail.
Table 1   Output of Plastic Products and Proportion of Agricultural Plastics in China
Year      Total output   Proportion
            ('000 t)              (%)

1958                 21.2       
1970               327.6        10
1975               607.1        10
1980            1 144.0 19
1985            2 482.7 21
1990            3 600.0 16.6
1995            5 300.0 18.8
Canopy Film
China started the research and development of PVC  film  in
1958. Sprout cultivation film was produced  from  domestic
PVC resin in 1963. PVC canopy film started to be used  for
planting of vegetables and cash crops. New  products  were
developed in later years. China  can  now  produce  canopy
film with various functions and uses. Table  2  shows  the
output and coverage of canopy film in China.
Table 2   Output and Coverage of Canopy Film in China
  Year   Raw            Output  Coverage
         material      ('000 t)   ('000 ha.)
                                  
1963   PVC                 0.2         
1965   PVC               12.0
1975   PVC               35.0
1978   PVC, PE 195.0
1980   PVC, PE 217.0             7
1982   PVC, PE 240.0        
1985   PVC, PE 183.8          30
1987   PVC, PE 203.8                  70
1988   PVC, PE 289.4        110
1990   PVC, PE 228.7                120
1992   PVC, PE 300.0        130
1995   PVC, PE 300.0        240
1996   PVC, PE 400.0        330
Major functions of plastic canopy film are as follows:
(1) Plastic canopy film can improve the climate inside  the
canopy and raise the ability of crops to withstand natural
calamities. Canopy planting of vegetables  in  cold  areas
(northeast, north and northwest) of China can increase  the
output of vegetables by 50 - 80%.
(2) One ton of sprout cultivation  film  can  increase  the
output of grain by 5 tons.
(3) The use of agricultural film in the years from 1982  to
1987 generated a direct economic income of 7.1 billion yuan.

Mulch Film
China introduced mulching from Japan in 1979.   Mulch  film
was produced from LDPE resin in China in 1981 and was used
in cultivation of vegetables.  The  use  was  extended  to
cotton and peanuts in 1982 and to more than 40 cash  crops
such as water melon, sugar cane and tobacco in  1983.   It
has now been disseminated in the north and  south  and  in
coastal plains and cold mountainous areas throughout China.
While producing ordinary mulch film, more than a dozen  new
varieties have also been developed.  They  include  silver
reflecting film for cabbage worm prevention, black weeding
film and