Water-efficient zero-emission greenhouse crop production : A preliminary study

Greenhouse cultivations are high input systems with respect to water and fertiliser usage. Worldwide increasing water shortages and competition for freshwater is raising the awareness that water use efficiency is a necessity in greenhouse horticulture. Releasing drain water from the greenhouse into the environment can also compromise surface and ground water quality due to the emissions of fertilisers and plant protection products. In soilless cultivation the nutrient solution can be recirculated; consequently they are highly efficient and sustainable production systems. Dutch growers have to realise zero emission by 2027 due to agreements made with government. However most are hesitant to fully recycle nutrient solutions, despite the many studies that have been conducted to resolve technical (installation) and physiological (growth) problems related to recycling drain water. In this study we demonstrate that with current best practice zero-emission crop production can become a reality. In the first trial (cucumber; July-November 2014) and up to the mid-season evaluation point of the second trial (sweet pepper; Dec-July 2015) no differences in production and fruit quality were found between the zero-emission cultivation and the reference cultivation grown to the agreed emission standards of 2015. Technology and cultivation strategy implemented are described and discussed and compared to common practice.