By Surinder Sud
Given the rapid surge in the demand for vegetables that is contributing to their high prices, technological interventions that can boost their production and ensure year-round supply are inevitable. One such technology with considerable potential is “protected cultivation”, which involves growing these crops in the controlled environment of greenhouses.
India’s first exposure to truly hi-tech protected farming of vegetables and other high-value horticultural produce came through the Indo-Israel project on greenhouse cultivation, initiated at the New Delhi-based Indian Agricultural Research Institute (IARI) in 1998, shortly after the establishment of diplomatic ties with that country. Though the Israeli experts left India in 2003 at the end of this five-year project, IARI continued to maintain the facility, calling it the Centre for Protected Cultivation Technology (CPCT). It has, in the past 10 years, managed to refine and upscale the system to reduce costs, besides designing greenhouse structures to suit local conditions. New features added to these structures have cut down the requirement of water and energy in such cultivation through novel means like micro irrigation-cum-fertilisation (fertigation) and rainwater harvesting.
A major problem with conventional designs of greenhouses is the concentration of heat within the covered structures, which needs to be either expelled or neutralised through energy-intensive cooling facilities. This problem has been overcome by designing naturally ventilated greenhouses where the temperature can be maintained at the desirable level without consuming any energy.
Significant among other protected cultivation technologies evolved by IARI scientists are an insect-proof net-house for growing healthy plant nurseries; and a walk-in tunnel technology for safe vegetable production during the off-season. These technologies have been found to be of particular value for growing crops like cucumber, capsicum (green and coloured), tomato, bottle gourd, summer squash, French beans, among others. These season-specific vegetables enjoy a good year-round demand, especially in cities — which can be met through greenhouse farming.
According to CPCT head Balraj Singh, the multi-layered cultivation of vegetables under a controlled environment would maximise production and profits per unit area. Integration of rainwater harvesting with greenhouse cultivation can make water available for such farming at lower cost. The rainwater collection tanks constructed at the IARI campus got filled to the brim even this year, although monsoon rainfall in this area was highly erratic and deficient. This water can be supplied to the greenhouse crops efficiently through low-pressure drip irrigation system. Fertigation techniques allow fertilisers to be applied along with irrigation water.
Significantly, CPCT has set up a permanent demonstration unit at the IARI campus where farmers can visit at any time of the year to see this system in operation. IARI also organises training sessions to familiarise farmers with this technique. Nearly 100,000 farmers, including women farm entrepreneurs, have already benefited from these training courses.
IARI is extending technical and other support to various state departments, apart from other interested organisations, to promote this kind of hi-tech farming. In Maharashtra, Karnataka, Tamil Nadu, Andhra Pradesh, Gujarat, Himachal Pradesh, Uttarakhand, Punjab and Haryana, this technology has already made notable headway. Rajasthan, Odisha and some northeastern states are also coming forward. As a result, the total area under protected cultivation is estimated to have expanded in the past one decade to nearly 25,000 hectares.
Though protected cultivation entails the high initial expenditure that comes from putting up the greenhouse structures, farmers do not seem to mind the extra upfront cost as it offers high returns as well. The greenhouses can, in any case, be used by farmers for years to grow and sell vegetables and other high-value commodities during the off-season, when prices are generally high. Moreover, greenhouses help reduce the expenditure on pesticides by warding off insect pests, many of which are carriers of viral and other infections. Meanwhile, consumers will gain access to a sustained supply of seasonal vegetables. There is, therefore, considerable merit to extending the area under this system of cultivation, for the benefit of both producers and consumers.