impact of urban areas on farming
TRANSCRIPT
IMPACT OF URBAN AREAS ON FARMING
Dr. N. Sai Bhaskar Reddy
Urbanisation is possible only with the surplus production by the farmers. The global urban
population is already more than 50% and in some of the states in India, the urban population soon
exceeds the rural population. The rivers flowing out of urban areas loaded with domestic sewage
and industrial pollutants are the source of water for irrigation by farmers. If crops are irrigated by
polluted water the crops cultivated are also polluted. Especially the periurban areas and areas close
to urban areas are high intensive agriculture areas, especially farmers cultivating perishable crops
and diary. The crops include mainly leafy vegetables, vegetables, grass as fodder for milch animals,
etc. In the recent years the small rivers or they could be best called sewerages have become
perennial and the total flows have tremendously increased. The farmers in the periurban areas are
cultivating throughout the year i.e., harvesting 3 to 4 crops in a year. The heavy metal contaminants
from the polluted waters are reaching the consumers through the food chain. Especially in the leafy
vegetables the heavy metal contaminants and biological pathogens are finding their way. As the
domestic sewage systems has heavy loads of phosphates and nitrogen apart from other nutrients
the farmers need to invest very little on the fertilizer inputs. The overall yield of some of the crops
grown is very high. Some grasses are highly adapted to these polluted waters, but loaded with pollutants affecting the quality of milk and other products.
The rainfall in the perurban areas is sometimes higher, due to air pollutants (particulate matter),
acting as nuclei for the cloud seeding. But the acid rains are very common in the perurban areas as
there are many acidic polluted air (such as sulphur, CO2, NOx, et.). The acidic rains and the
pollutants affect the crops.
The natural drainage systems are affected due to the urban infrastructure and construction
activities. The outer ring roads which are elevated has impacted the natural drainage systems,
especially the every years recharging and filling of the tanks. Most of the tanks in the per-urban
areas are not being filled. If “the tank bunds are roads – why not roads as tank bunds”, say around
Hyderabad there are two ring roads, Outer ring road 158 kms (almost completed) and 290 kms
(proposed regional ring road), the same elevated ring roads could be used for creating at last 100
tanks which could harvest all the waters from the urban areas and useful to the farmers in the per-
urban areas for irrigation. The urban areas could also use for urban greenery, recharge and reuse of the waters.
The overall ground water in the peri-urban areas is highly depleted due to urbanisation. The demand
for water in the urban areas is very high. The farmers dependent on the groundwater are having
great difficulty in having water. The ground water as they go deeper is saline, the saline waters when applied to the fields over a period increase the alkalinity of the soils.
The leachates from the solid waste dump yard sites are polluting the ground water. In the recent
past people are producing compost from the city waste. The city waste compost has highest number
of the pollutants including the plastics which cause cancer. Some farmers buy these materials for
soil amendment / grown regulator for very high yield of the crops. But these pollutants find their
way into the food chain and finally in the products consumed by people. There are no regulatory
mechanisms.
Sewagigation and floatigation are the two methods for urban greenery are partially meeting the food security needs from less polluted water sources.
At least 20% of the urban green spaces should be used for growing plants whose products could be
consumed by the people. Urban greenery is a waste of resources and funds, incase of a calamity
none of the plants in urban areas could be consumed. Many plants are poisonous and exotic. If they don’t even support the local life like animals, birds and insects.
Instead of seeing the urban areas affecting the agriculture, there is a need to explore the possibilities of how urban areas could also support the farmers.