Articles
WATER POLLUTION AND THE GREENHOUSE ENVIRONMENTAL COSTS
As matter of fact, the sphere of activity of mankind – civil and industrial settlements, roadway network, agriculture – is continuously reducing the fraction of freshwater in favour of useless water (deep waters, glaciers, oceans). These phenomena come from the increasing use of water for civil and industrial purposes, agriculture representing the highest share.
A lot of these losses are due to runoff phenomena that, as regards greenhouses, are quite limited.
It might seen these worries are excessive, considering the area occupied by protected cultivation.
Taking into account that water is used, other than for irrigation, to prepare agrochemical solutions, to clean greenhouse coverings and floors and mostly to increase air humidity, it can be hypothesised an annual consumption of 5 billion cubic metres.
This amount represents less than 0.2% total irrigation water.
In spite of all that, protected cultivation must contribute towards the protection of total water resources.
After a brief critical description of the interactions between the main protected cultivation systems with the environment, the many aspects related to water as a resource and as a target for greenhouse production processes are discussed.
Then, the main useful actions directed to save water are underlined at strategic, tactical and operational levels following the topics exposed in the previous lectures.
In particular, tools like plant breeding for stress resistance, closed or virtually closed cultivation systems, choice of production mix and plan, irrigation and fertilisation techniques, bioregulation, integrated pest management and so on, are cited.
Finally, the many kinds of environmental costs and the corresponding acceptable thresholds are discussed.
The conclusions point out that a careful management of greenhouse processes can contribute not only to save a significant quantity of water but to strongly reduce runoff and ground water pollution and, more in general, to protect the environment.
At any rate, it is very difficult to develop an environmentally-neutral greenhouse that is profitable.
The solution will be always a compromise, politically balanced in each specific area.