Complying with Society’s Demands - Solving the Emission Problem Caused by Irrigation Surplus in Greenhouses

Irrigation surplus is a commonly used strategy in soil grown crops in greenhouses in the European Union. This leads to emissions of both nutrients and plant protection agents, resulting in problems with the quality of ground and surface water. New European regulations will be implemented, limiting the amount of nutrients and plant protection agents to be released in the environment. These developments pose a serious challenge – or threat – to commercial growers in Europe. We develop innovative solutions that aim at social, economic and environmental sustainable production systems. These solutions can only be implemented successfully when all stakeholders are involved in the process and show their commitment. An overview of our strategy, actions and projects is presented. INTRODUCTION For several decades research of Wageningen UR has dedicated considerable scientific effort to the study of plant nutrition and crop protection. After World War II, Western society simply asked for products, and our efforts contributed to an increase in both yield and product quality. We studied nutrient uptake of various greenhouse flower and food crops, learned about nutrient deficiencies, introduced substrates as a rooting medium for some crops, developed good agricultural practices for plant nutrition, improved yields, and gradually understood the trade-off between yield and quality in greenhouse production systems. Over the years many scientific and popular papers were published, which were recently summarized by Sonneveld and Voogt (2009). Also, crop protection systems were developed and refined over the years, resulting in biological pest control and integrated pest management (e.g. De Buck and Beerling, 2006; Van der Lans et al., 2008). Over the recent years, society’s demands are changing. People are increasingly aware of the impact that agricultural production systems have on the natural environment. More recently, European Union regulations such as the water framework directive (European Union, 2000) and nitrate directive (European Union, 1991) that aim at safe and good water quality were developed and imposed. As a result, local initiatives are now emerging in which new coalitions cooperate towards the common goal of sustainable production (e.g. Thoenes, 2009). Especially soil grown greenhouse crops require high fertilisation rates. Overirrigation is common practice to prevent any shortness for uptake at minimal costs. Also, it induces salinity stress for quality improvement and as a result, leaching of nutrients (N and P) occurs. Both nutrients and plant protection agents follow the water flow, and the reduction of waste water is becoming an issue in dense greenhouse areas like in the Netherlands. This waste water is discharged to municipal waste water systems and into surface water, containing high concentrations of both nutrients (Balthus and VolkersVerboom, 2005; Wunderink, 1996; Boers, 1996) and residues of plant protection agents (Teunissen, 2005). Even in closed irrigation systems with cultivation on substrates, drain is sometimes inevitable. The regional collection and purification of drain water to a [email protected] Proc. 6 IS on Irrigation of Hort. Crops Eds.: S. Ortega-Farias and G. Selles Acta Hort. 889, ISHS 2011 54 irrigation water has been proposed (Van der Velde et al., 2008), but an alternative solution could be the redesign of production systems with no-emission as a primary design rule. This, however, requires a transition towards new sustainable agricultural production systems. Therefore, we started an integrated research project to develop such social, economic and environmental sustainable production systems. These systems can only be successfully implemented when all stakeholders are involved in the innovation process and show their commitment. We work on solutions by bringing different stakeholders together. An overview of our strategy, actions and projects is presented here. A comparison is made with transition processes in agriculture and with the current energy transition in the Dutch greenhouse industry. TRANSITION PROCESSES IN AGRICULTURE Transitions can be defined as planned structural societal changes towards sustainability (Poppe et al., 2009). Transition processes in agriculture towards sustainable production systems are well documented (Wijnands and Vogelezang, 2009; Vogelezang and Wijnands, 2009). Their strategy consists of six actions, viz., (1) Inspire stakeholders through identification of opportunities and shared future scenarios; (2) Identify trends and critical transition points with stakeholders; (3) Innovate through the generation of new insights and proof-of-principle projects; (4) Connect people by organizing workshops, innovation café’s and coalitions for innovation; (5) Stimulate innovators through individual coaching and networks of early adopters, and finally (6) Broaden the initiatives by the construction of demonstrators, organizing excursions and sharing the knowledge in virtual and physical knowledge centers. A typical feature in the innovation process is the cooperation with stakeholders to identify trends and transition points in an “innovation agenda” (Fig. 1). After such a platform is created, specific research can be carried out. Through a process of analysis and design, ‘innovation projects” with pioneering growers (Fig. 1, stars in the right hand arrow) can be set up. The “networks of early adopting growers” (Fig. 1, left hand arrow) may both contribute to and learn from these innovation projects. The successful elements from these innovation projects can be directly used by the participants at their own companies. Through the formation of networks of early adopting growers, experience and knowledge can be shared and spread. Gradually, early adopting growers may become pioneers themselves. THE ENERGY TRANSITION Over the recent years, a transition is taking place in the Dutch greenhouse industry from energy consuming towards energy production (Roza, 2006). This has resulted in a joint innovation agenda and research programme “Kas als Energiebron” (The Greenhouse as Energy Source) which generated enthusiasm und confidence among stakeholders, initiated numerous initiatives and created a vast body of new knowledge (see website Kas als Energiebron, 2009). It also lead to innovation projects with pioneering growers such as Greenport Glasshouse in Venlo (Verkerke and Vermeulen, 2008) and the Energy Producing Greenhouse in Bergerden (De Zwart et al., 2008). These innovation projects showed that a reduction of the use of fossil energy was really possible and also allowed growers to learn by doing, generating enthusiastic responses from stakeholders. Networks of early adopting growers, either national or local have played a role the transfer of knowledge to early adopting growers, stimulating them to use innovative technology (Verkerke, 2008). The elements of the innovation process from Figure 1, viz., “innovation agenda”, “innovation projects” and “networks of early adopting growers” are thus clearly discernible in this energy transition. We participated and learned from this transition, and now try to set up a transition towards emission free greenhouses. THE START OF AN EMISSION TRANSITION With support by the System Innovation programme of the Dutch Ministry of Agriculture and SenterNovem, we started an integrated research project. One of our first actions was the organisation of a series of workshops with all relevant stakeholders to