Research for the Dutch Organic Glasshouse Sector
Some 100 hectares is currently used for cultivating organic greenhouse vegetables in the Netherlands. Over 75% (74 ha) of this area is dedicated to tomatoes, sweet peppers and cucumbers, as well as aubergines. Most of these vegetables are exported. The most important customers are Germany, UK, Italy, Austria, Scandinavia, Switzerland and the USA.
Measures are necessary to reduce the consumption of fossil fuels. Organic growers are faced with specific problems in a closed greenhouse however, such as climate control and removal of undesirable gases.
The Dutch interpretation of the EU rules is that organic cultivation under glass should take place in the soil. The demand to recognize substrate cultivation as organic is increasing and has led to intensive discussions with the government and various organisations at home and abroad.
Many years of intensive cultivation of greenhouse vegetables in the same soil causes production to drop off and soil infections and infestations to increase. An increasing occurrence of root-knot nematodes and/or soil fungi such as Verticillium means the problem needs to be tackled now.
Crop rotation is a well-established strategy to prevent the occurrence of soil-associated infections and infestations. Suppressive soils are an underutilized resource for the control of soil-borne pathogens, but considerable progress is being made.
