Food deficit and farm productivity
By Dr Sardar Riaz A.
Khan
GROWING population and declining water resource have created
food deficit. The cereal deficit alone may increase to 25
per cent by 2025, while China will enjoy a surplus of over
three per cent despite having population, several times
higher than ours.
One
of the reasons of higher crop production in China is the use
of drip irrigation system which while enhancing crop yields
also saves irrigation water by 60 per cent, enabling more
area under cultivation. China has extended its drip
irrigation system to major crops like cereals, cotton,
peanuts, fruits and vegetables etc. Thus, average crop
yields are much higher than those obtained through
conventional gravity flow irrigation system.
This scribe during mid-80s had warned the then federal and
the provincial governments that due to over-mining of
groundwater in Balochistan, the resources may exhaust for
which adoption of drip irrigation was sought at the
earliest, while subsequently extending it to other
provinces.
A study on drip irrigation in orchards by the FAO in
Balochistan has proved that it not only saves irrigation
water by 60 per cent but also helps in boosting fruit yields
by 20 per cent. Due to over-mining, several basins
comprising 30 per cent of the geographic area were exhausted
by late 90s. More area would have been exhausted by now.
This practice in other provinces is also diminishing the
water-table which may further enhance water shortage.
About 40-60 per cent of canal water never reaches fields due
to faulty designed and poorly maintained water courses,
uneven fields and inefficient conventional irrigation
system. The decreasing water resource base and
politicisation of the construction of new dams have produced
water shortage which may proportionally amplify with the
rising population and more food and fibre needs. The common
man is already suffering from burgeoning inflation in food
prices.
Under such circumstance drip irrigation is the best option
for increasing water use efficiency. The technique keeps
evaporation losses at an efficiency rate of 95 per cent and
reduces water use by 40-60 per cent depending upon crop and
soil conditions as compared to conventional gravity flow
irrigation system. It is now extensively followed all over
the world.
The government in the Budget 2005-06 provided Rs1 billion
for the introduction of drip irrigation and sprinklers.
Sprinkler irrigation can be applied to all crops except rice
and jute. The advantage of both the systems is direct
utilisation of water equivalent to crop needs at root zone
by saving up to 60 per cent of extra water requisite in
conventional gravity flow irrigation system. Had drip
irrigation been initiated in mid-80s, the situation today
would have been quite different.
The government in 2006 signed an agreement with the National
Centre for Efficient Irrigation Engineering and Technology
Research – Xingjiang, China, according to which drip
irrigation demonstration sites will be established on 2,500
acres in Pakistan with 1,000 acres in Punjab and 500 acres
each in Sindh, Balochistan and the NWFP, along with holding
fourth International Training Course on efficient irrigation
technology in Pakistan.
Sharing of research results and information will be made
available. Likewise, exchange of experts for transfer of
technology and knowledge to Pakistan is also in the deal.
Furthermore, technical assistance for adoption of Chinese
drip irrigation technology under local conditions through
acquisition, pilot testing, indigenisation, demonstration
and up-scaling is also to be undertaken.
The government will provide Rs156.5 million for
demonstration sites to be established with the Chinese
assistance, besides up-scaling drip irrigation on 225,000
acres under the PSDP-funded pipeline project.
Accordingly, nine experts - six from Punjab and three from
Sindh with four farmers, two each from these provinces went
to China to participate in the Third International Training
Course. This appeared a good beginning and experts and
farmers from Balochistan and the NWFP should also have been
included.
Policy makers should realise that the people living in
nearly 10.6 million hectares of our neglected and
underdeveloped sandy deserts too have equal rights for
development of their area. Rainfall is limited in desert
regions. Although, sweet water lenses exist at few places
but the major source is groundwater which is mostly brackish
and can be used for irrigation on soils with good drainage.
Fortunately, the sandy desert soils provide excellent strata
for quick percolation of water through sand. The salt
tolerant plants growing on such soils are well aerated as
sand offers more space between its particles. Chloride,
sodium and magnesium components of saline water are easily
washed down to deeper layers of sandy soils without
adversely affecting plant’s root system.
The harmful sodium ions are not adsorbed in sand particles
unlike their easy adsorption on the surface of clay
particles. Use of gypsum and sulphuric acid through acid
generator further improves the prospect of saline water
agriculture in our sandy deserts.
Since much of the limited groundwater, if applied through
conventional will be wasted through percolation in sandy
soils, therefore, drip irrigation has great potential where
water is applied directly to root system of salt tolerant
crops like fruits, vegetables, forest trees, range species
etc., as is being successfully done in the sandy deserts of
Abu Dhabi, Israel, the US, Australia, India, and China.
The government should also establish drip irrigation
demonstration sites with the Chinese help in our sandy
deserts of Thal and Cholistan in Punjab; Thar in Sindh;
Chagi-Kharan in Balochistan; and desert tracts of southern
NWFP. It should also consider adopting well established
Chinese high mountain irrigation technology which has great
potential of bringing a large cultivable area along the high
banks of streams and rivers in the mountain areas in North
and North-West of the country.
Other areas where Pakistan can benefit is the use of Chinese
wheel type combine grain planter which does sowing of seed,
fertilization and soil pressing in one operation thus
reducing cultivation cost. This technology can be used on
medium and large farms, while two-wheel hand-driven diesel
Chinese tractor commanding 12 hectares can be used on small
farms. It reduces the cost of cultivation by land
preparation and sowing of crop in one operation by
increasing the yield by 20 per cent.
Courtesy: The DAWN
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