| Front page | | Contents | | Previous
| | Next |
Cleaner Technology Projects in Denmark 1997
Jorddækning som alternativ til kemisk ukrudtskontrol
Miljørapport nr. 359, 1997, Miljøstyrelsen
This report is concerned with soil cover methods to control unwanted vegetation in greenery and forest growth areas. Cover
materials should be considered as an alternative to chemical control. In the introductory
passages, known materials and establishment methods are described with regards to effect,
consequence and economy. This information is illustrated in figure 3 and appendix 2.
Chips of different qualities and plant covers might be interesting methods in small,
scattered stands, but they are too expensive in big stands.
When the project was established straw seemed to be very promising but already in the
preliminary phase of the project it proved to be unsuitable. However, the price of straw
covering is moderate and the effect reasonable, but the insulating effect of the material
increases the risk of spring night frosts significantly, which is not acceptable for e.g.
Nordmann’s fir (in addition, mice are attracted to straw which causes dramatic
damages in other stands).
On the basis of the above it was decided to ignore straw as a possibility in the
further work. Instead tests were carried out with a number of plastic materials, which
were not as environmentally attractive as straw but less damaging than the soil herbicides
that have been used so far. Later the test plan was complemented with straw covering
around the plant rows. The revised test plan can be found on page 30.
The test was carried out at Vordingborg on light as well as heavy soil and in both
cases in Nordmann’s fir stands.
The first year, the tests showed a good effect of all the tested treatments against
weed. Already in the second growth season the weed grew through the plant holes in the
cover materials. The problem was particularly large with Fibertex
and UCO-Agrotekstil.
In certain periods the temperature was measured 10 cm above the surface of the
treatments in question. The black cover materials caused increased temperatures, which
again caused an early bursting; especially in 1992. In situations with quiet clear whether
in the spring period, it was observed that the temperatures above the plastic and both
types of cloth corresponded to the temperatures above effective chemical control. The
temperatures above the untreated were 1-3°C below this. And the temperatures above the
straw were (-3°C below the untreated. However, spring night frost damages were not found
in the straw covered plots in the test, which is probably due to the mild location and the
fact that only covering in rows was used.
Damages that occurred in the tests were estimated on the basis of a scale, which is
normally used in connection with chemical control. Fibeztex and UCO-Agrotekstil can be
penetrated by precipitation and was applied in approx. 4m wide rows. It turned out that
the wind could make the cloth move because of the wide rows and, consequently, some of the
small plants were covered or partially ruined. Chemical control resulted in scattered
plant loss in connection with a moist spring followed by a dry summer in I994.
Soil covered with plastic and cloth has higher moisture content in dry periods than
soil that has been treated with chemical control, which again has higher moisture content
than untreated.
Based on the high growth of the stand, it seems that the treatments have had no effect
on the stand. However, straw cover seems to have had a positive effect on the growth but
the test has very limited security on this point.
Concerning prevention of wear damages on Christmas trees, only
chemical control was completely satisfactory. Plastic cover complemented with chemical
control showed an acceptable result.
The test showed that UV-stabilised black 100m , thick
plastic applied in rows with subsequent planting though the plastic is still the only
technically and economically realistic alternative to chemical weed control within the
group of soil cover. In Christmas tree and greenery stands the method should be
complemented with mechanical or chemical control or use of over plants to prevent wear
damages and shade.
Author/ institution
Lars Kjærbølling, Forskningscenteret for Skov og Landskab
This report is subsidised by the National Council for Recycling and Cleaner Production
ISSN no. 0908-9195
ISBN no. 87-7810-782-2
| Front page | | Contents | | Previous
| | Next | | Top | |