Maintaining and optimizing soil quality in the tree nursery sector in the Netherlands, Denmark, Sweden, United Kingdom and the north of Germany. The past decennia the soils in agriculture, and also in the Hardy Nursery Stock sector and in the cultivation of bulbs , has decreased in quality. In all the nurseries chemical fertilizers were used and large amounts of herbicides.  Recent scientific studies show that by the use of these products complete chains of soil life are destroyed.  Organic matter levels dropped down to very low levels of 1,5 till 2 %.  Organic material is however the base for good soil life like fungi, bacteria, protozoa and nematodes.

Specifically this means that the amount of organic matter in these soils is less than optimal for plant growth. The soil life is often out of balance and is less present. The soils often lack different nutrients and trace minerals which are important for plant growth. Because of the  lacking balance in the soil, there are more problems with all kind of diseases and soil bound diseases. Problems with  other diseases and  pests can also be the result of this lacking balance. Scientific research showed that a good balance in the soil of nutrients is very important for healthy growing plants.

Organic matter content is also very important in absorption of water. Water and nutrients don’t flush to the ground water so fast when the percentage organic matter in the soil is higher.   

Last two-five years some Dutch tree nurseries, which are ahead of the other tree nurseries in this area (the precursors), work more and more on optimizing the soil, actively increasing the organic matter and soil life.   This group of nurseries is growing, but is still small. Also bulb growers in the West and north of the Netherlands face the problems with the soils and the challenge to increase the organic matter levels.  Growers in, United Kingdom, Denmark and Sweden talk about this development just recently.  That is why we like to start this project in these countries.

Another important reason to start this project is the development of good compost in the countries mentioned. In the Netherlands  there are some companies which produce good compost. To improve the soils and increase soil life and the percentage of organic matter, the application of good quality compost is important. In Denmark, Sweden but also in the United Kingdom  a defined quality compost to improve the soil is not or almost not available in larger amounts. But starting material is available to develop this compost. Compost produced in ex Denmark is often made by adding slurry from wastewater cleaning stations. The pH is very high and content of potassium and phosphor can be very high like some of the heavy metals. The microflora composition is not helpful in bringing a soil back into a wanted balance. There is a need for initiation of a marked for quality compost that can be used in optimizing soil   and other purposes like growing trees in urban areas and substituting peat in with compost in container growing of trees and bushes.

Looking at the carbon emission the following results can be seen:

• Less transport for getting the compost on the right location.
• Using compost increases the organic matter in de soil very slowly. In this process CO₂ is bound in the soil.
• Plants needs  CO₂ as nutrient.   Good healthy plant growth will increase the uptake of  CO₂
• Production of compost delivers a small amount of Co2 to the air. 

Water rich Countries and legislation

All countries around the North Sea have to take the legislation for Water management  of ground and surface water into account: The Waterframe Work.  This project will play an important role in reducing the use of chemical fertilization and the use of chemical crop protection and the flushing of these products to the ground- and surface water.  The big challenge is the same for all the participating countries.

Green waste of communities

For the communities green waste can be made profitable and renewable by using it in the process of compost development.  As a result of this project local communities and  nurseries will work together. 

Central aim 

Main problem is that the quality of soils in agriculture contain less organic matter. Over the years organic matter percentages decreased.  Because of the intensive cultivation on the same fields and the use of chemical fertilization soils are worn out.  Developing processes with amenities (local sources of green material), potential compost firms and the end users to develop good quality compost to solve the problem mentioned above, is the main objective.   Maintaining and optimizing soil quality and organic matters in the tree nursery sector in the Netherlands, Denmark, Sweden and UK results in healthy soils, resilient plants with few diseases and in a sustainable production  method.  It will be possible to use  less pesticides in growing trees and plants because the plants protect themselves much better, when they are in good condition.

Other objectives:

• Leaching of  nitrogen, phosphorus and other minerals to the groundwater, pools and lakes, will be diminished by decreased  use of industrial fertilizers and pesticides
• Helping the different countries in developing good compost and  solve eventually problems in the soil in nurseries and amenities  areas in towns and cities and generally to improve the soil quality.  Compost is a very important part of this improvement strategy. 

At the end this project:

• Tree nurseries and bulb growers as well as communities are aware that a soil is  a sustainable production factor which needs to be kept in quality and often must be optimized.  Good soils can help in a sustainable cultivation of trees and bulbs with resilient plants. Less pesticides are needed. Also the use of chemical fertilisation can be reduced.  They are also aware that application of good quality compost can help in optimizing the soil and bringing up the organic matter levels.  Awareness arises by the organization of large practical days (one a year) were the results of the tests and pilots are presented. Also sending e-mail newsletters and writing articles leads to this awareness.
• In pilots tree nurseries have used the different developed quality compost and gained experience with using these composts.
• Local amenities and local potential compost firms in the different countries developed the process for making certified and a constant quality of compost and produced already this compost according to this certified process
• Research centres and universities gained information in different scientific tests about the effect of compost on different aspects of the soil: existence of soil life and balance between harmful  organism and predators , structure of the soil, nutrients, permeability of the soil.  Research centres will carry out also practical tests at some of the nurseries.

  Reduces carbon emission

• By delivery of high quality plants the results of plantings in for example urban areas will be more successful, and this leads the end consumer and governments buying plant material  to be more satisfied and gives an incitement to buy more plants. A growth in sales helps more employment in the green sector for the communities.
• Availability of specific defined composts with different purposes for the use in different growing regimes will increase the marked for compost products.

A website will be developed which is the place where al reports and information about the project is found. 

We are in contact with a lot of organisations for this project.  Not every potential member has given the definitive answer and we are still talking to them:

• Wageningen University (costal provinces) : company with knowledge about scientific research in  tree nurseries, flowerbulb cultivation and concerning diseases and soils.
•  Wageningen University part of which brings in knowledge about existing and stimulating soil life, knowledge about soil structure en soil fertility Will develop and work on a 3-4 year test with application of different kinds of compost and the effect on de development of organic matter, existence of soil life, influence on soil structure.
• Network of tree nurseries  and flower bulb growers for whom the information and experiences of the project are very important. They will apply the new methods and use the compost developed within the project.
• DLV Plant (Hazerswoude):
• Contacts with the tree nurseries and flower bulb growers
• Application of new practices and methods on the tree nurseries

Denmark:

1. Gartneri Radgivning (HortiAdvice Scandinavia A/S): Anne and Bent

1. 1. Contacts with the tree nurseries in Denmark for whom the information and experiences from the project are important.
   2. Application of new practices and methods on the tree nurseries, for container cultivation (Anne) and open ground (Bent)
   3. Organizing local meetings with tree nurseries. For example visiting the tests at the university with the tree nurseries.
   4. Planning and conducting the trials on the use of the specific compost in nursery tree production in relation to investigation of the plant quality, and res

1. Danske Planteskoler Danish  Nurserystock Association
   1. Network of tree nurseries in Denmark. Tree nurseries will join the local and international meetings about soil optimization and the use of compost.
2. University of Copenhagen:

• Knowledge about soil life and soil food web. Knowledge about nematodes and soil bound diseases
• Working on local tests with application of composts and the effect on soil life, soil structure and plant growth.
• Fundamentals of soil organic matter decomposition and nutrient turnover
• Land use and soil quality
• Recycling of nutrients from organic waste!
• Environmental impacts of agriculture

Denmark and Sweden: two potential compost firms

United Kingdom

1. Advisory organisation of tree nurseries

1. Compost firms Netherlands: bringing in knowledge about good quality compost and the processes to become this compost.
2.  Laboratory in Denmark, the Netherlands and UK : testing composts on composition
3. Communities with substancial amount of  green material als potetial material for compost   

United Kingdom:

* Research Centre for soil bound diseases, and knwoledge about soils and soil characteristics.