Published 11/05/2015

Dutch suppliers in African demo project

In the summer of 2014, the demonstration project ‘climate management in East African greenhouses’ was put into practice at two rose farms in Naivasha. With this project, leading Dutch suppliers, amongst others Ludvig Svensson, Hoogendoorn and Bosman Van Zaal, aim to demonstrate that greenhouse climate optimization results into higher yields with better quality and less use of pesticides and water. Mrs. Jane Ngige, CEO of the Kenyan Flower Council, participated in the official opening on January 20.

Hortfresh-May-june2015-650x396Now that greenhouses in Kenya are increasingly being used to protect crops against the negative impact of the outside environment, it is time to optimize the inside growing conditions. In July 2014 the Dutch Green Farming consortium set up the project ‘Climate management in East African greenhouses’ to demonstrate the advantages of screening. The project aims to convince the East African horticultural sector that movable screening systems are an affordable and environmental-friendly solution to counter climate extremes while improving crop production. 

Challenges in a high altitude growing area

The demonstration project has been implemented by two rose farms in Naivasha, Kenya: Maridiadi flowers and Kreative Roses. Since these growers are located in a high-altitude growing area, they struggle with humid conditions in the greenhouse, especially during the early morning hours and in the rainy season. As a result, they experience high levels of infection, such as mildew and very high yield losses. With the use of climate screens both growers expect to improve this. They also trust that screening will have a positive impact on the color of the roses and growth, such as the length and thickness of the stem and the amount of stems per m2. 

Movable, light-diffusing shade screen

 In both plastic-covered greenhouses a white HARMONY screen with an open structure for enhanced light diffusions and shading has been supplied by Ludvig Svensson,world leader in climate screens. Hugo Plaisier, senior consultant of Svensson comments: “Our screens are used all over the world to improve the growing climate in the greenhouse. Both light, humidity and temperature can be optimized by a proper screen selection and use. For this trial we have selected a 30% shade screen with open structure to allow for enough air exchange. With the use of a movable system, growers only apply shade when needed, which prevents excessive shading and consequent drops in production. At the same time, the screen can be used during the night to keep the crop temperature somewhat higher, reducing wet-leaf situations drastically.”

Automated climate control

In both greenhouses the screen is linked to a process computer that registers and manages all parameters on greenhouse climate, irrigation and screening. The Hoogendoorn iSii process computer, used at Maridadi Flowers, and installed by partner Bosman van Zaal, makes use of local weather forecast. Based on weather data and climate measurements in the greenhouse, the screen will be (partially) closed or opened and irrigation cycles will be adjusted to the plant’s needs. Hoogendoorn partner Bosman Van Zaal provides local support, which includes advice, installation and maintenance service.

Expected results

During 2014 and part of 2015, all results are gathered, processed and shared with the horticulture sector in East Africa by the Green Farming consortium. “With this demonstration project we expect an increase in production and quality of 20% at lower water and pesticide use per stem. The first results are already promising”, Hugo Plaisier comments. These positive results are confirmed by Bas Smit, general manager of Kreative Roses who stated: “The retractable screen has given us a reduction in drain of around 70% and the plants seem much more comfortable. The quality has improved a lot.”

Roll out to vegetables

The use of climate screens is not only very beneficial to the production results in flowers, but also in the vegetable production. Growing vegetables in greenhouses providesgood opportunities to support food security and food safety conditions. Screening systems add to production increase, water use efficiency and quality by making the growing climate more favorable for the plant. Hugo Plaisier:”Vegetable production levels are very temperaturedepending. Our screens really help to optimize this; on top of this we prevent sun-burning of fruits and water stress at the same time.”

Official opening

At 20 January the project was officially opened during a seminar at Kreative Roses (Kordes). Guest speaker Mrs. Jane Ngige, CEO of the Kenyan Flower Council, reflected upon current horticultural developments and the impact of demonstrated technology on the sector. Harm Maters, Chairman of Green Farming, and members Svensson and Hoogendoorn presented the results of the realized projects. The seminar was attended by several representatives of public authorities, such as Marnix Sanders, assistant Agriculture of the Dutch Embassy in Kenya.

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