A novel greenhouse is developed for insect-free Sabbatical Year farming.
By Edward L. Tepper
A special greenhouse designed at Ben-Gurion University of the Negevs Institute for Agriculture & Applied Biology may prove a godsend to Israeli vegetable growers. The greenhouse, initially built to provide a relatively cool environment for desert agriculture, was further modified to solve problems associated with raising crops for Shmita, the Sabbatical year for soil (beginning this October).
The greenhouse-cooling project was initiated by Professor Dov Pasternak, Head of the Institute, with the support of Bertram Loeb of Canada as a continuation of Pasternaks long-standing interest in using renewable energy resources for controlling greenhouse temperatures. Shortly after work on the new cooling system began, Pasternak was asked to find an approach for growing vegetables that conforms with the requirements of Jewish law, according to which the soil in Israel must be allowed to lie fallow every seventh year. .
Taking up the challenge, Prof. Pasternak initiated a think tank that included his long-time partner in greenhouse projects, Dr. Eli Korin of the Department of Chemical Engineering, Shabtai Cohen, a crop-cultivation consultant and Nahum Zamir, a greenhouse engineer. Support for the project was provided by the Rita Altura Trust of California. .
The team designed a greenhouse, built around the "Wall of Drops" cooling system, in which vegetables are grown in long trough-shaped containers suspended from the greenhouse roof. Because the plants are not in contact with the ground and the troughs are filled with coconut shavings (and not soil), growing crops in this manner is not considered to be "tilling the soil" according to Jewish law.
While developing the Shmita greenhouse, the team members modified the cooling system to produce positive air pressure within, thereby preventing insects from entering the greenhouse. With some additional measures, they arrived at an "all-purpose" greenhouse in which it is possible to grow insect- and larvae-free plants without the use of insecticides. Romaine and iceberg lettuce, celery, broccoli, parsley and green onions have all been grown in the new greenhouse. Religious consumers will be especially pleased by the prospect of finding a variety of Shmita-certified, insect- and pesticide-free vegetables in the supermarket. And all Israelis, consumers and farmers alike, will eventually benefit from the availability of produce grown without the use of toxic chemicals.