EXPERIENCE WITH APPLICATION OF TABLETTED SILVAMIX® FERTILIZER IN FOREST STANDS OF THE FOREST OFFICE OF THE TOWN OF JACHYMOV
(A contribution presented at the Czech-Polish Silvicultural Workshop about the Application of Ecological SILVAMIXÂ® Fertilizers in Forestry by Dipl. Ing. J. Capek. Komorni Lhotka, 1996)
The Forest Office of the town of Jachymov manages 3,660 hectares of forests situated in the western part of the Krusne hory Mountains which are considerably affected by immissions. These stands are mostly situated on a plateau and in the neighbourhood of the Klinovec peak (altitude 1,244 m). As far as the classification of forest types is concerned, the sites are mostly acid and poor but the area of waterlogged sites is also important (gleys, waterlogged soils, moors).
The seventh and the eight vegetation degrees are the most frequent. The immission load is the highest in these localities. About 85% of the forest area of the town of Jachymov is situated in the zones A and B of immission danger. From the viewpoint of economic measures it is therefore necessary to supply seedlings immediately after re-planting with such a necessary amount of nutrients which could enable their adaptation to the new environment in the best possible way.
The application of tabletted SILVAMIX? fertilizer started in 1992 and since that time all newly planted stands of both deciduous and coniferous woody species are regularly fertilized year by year. At first, the fertilizer was applied in accordance with recommendations of the manufacturer (ECOLAB ZNOJMO, Ltd.). In 1993, newly planted seedlings of Picea excelsa with naked roots were experimentally fertilized and this resulted in an increased uptake of this fertilizer (by ca 80%) so that the colour of needles was markedly changed. Seedlings receiving nutrients from the supplementary fertilizer showed a beautiful and deep coloration and differed from the neighbouring natural regeneration differed only in the structure of aboveground parts and planting into a hole. Seedlings which were not supplementary fertilized and did not accept the applied fertilizer showed a traditional yellowing of needles and inhibition of growth. In the following year, practically all dressed seedlings showed a deep green colour of needles. The use of fertilizer immediately after re-planting supports the development and growth of the root system on the one hand and prevents an exaggerated withdrawal of nutrients from the plant organism.
Since 1995, and partly also in 1994, all stand areas have been fertilized immediately after planting because we wanted to adapt the seedlings to their new environment as quickly as possible and, at the same time, to reduce the percentage of losses in the course of afforestation. Developmental trends in unsuccessful planting indicated that this idea was correct. So, for instance, in 1992 the failure represented 52 hectares, in 1993 only 26 hectares and in 1994 and 1995 24 and 18 hectares, respectively. Supplementary fertilization is currently applied on all stand areas situated in exposure zones A and B with the exception of waterlogged sites. In the zone C, this supplementary fertilization is only of marginal nature. In the zone A, fertilization of stand areas was repeated after three years due to their considerable immission load and forest soil typology (BM - poor, BZ - lithosol) and it was decided that in case of necessity this supplementary fertilization should be repeated once more.
An individual application of SILVAMIX? fertilizers was approved also by representatives of the Ministry of Environmental Protection; it can be used even in the nature preserve ?Bozidarske raseliniste? peat bog which represents a significant part of the complex of suburban forests.
When using this fertilizer, it is important to apply directly it into the surface layer of the soil. If there is a lack of labour, it is very useful to do it either directly in the course of planting or immediately after the end of afforestation works. This principle is valid also in case of limited numbers of forest workers and for that reason the Forest Office was forced to apply this fertilizer after the end of planting because there is a chronic lack of forest workers in the northern part of the Karlovy Vary district.
It is quite unsuitable to apply this fertilizer on forest areas overgrown with weeds without a thorough chemical weed damage. Satisfying results can be obtained only with those herbicides which kill completely weeds in the neighbourhood of the seedling because they also use the nutrients. Basing on this experience, the Forest Office of the Town of Jachymov decided to apply SILVAMIX? tablets directly in to the holes to prevent wasting with nutrients.
Recommendations of the manufacturer must be observed, especially as far as the distribution of tablets into the hole or around the crown perimeter and their application into the soil are concerned. We use 4 to 5 tablets, i.e. 40 to 50 grams of fertilizer. Tablets are pressed into the soil to enable their gradual decomposition and to prevent their wash off during intensive rainfalls which are quite common in the Krusne hory Mountains. Application of tablets on the soil surface was unsuccessful.
At present we try to solve the problem of supplementary fertilization on waterlogged stand areas because they represent approximately one seventh of the total acreage of managed forests. To be successful in the process of afforestation, it is necessary to pile up small heaps of soil in these stand. Outside the nature preserve ?Bozidarska raseliniste? peat bog it is possible to use an excavator for this purpose while inside it is necessary to do it by hand. All waterlogged stand areas are situated in the exposure zone B and the forest soil types involve BT - waterlogged soils, BG - gleys and BR - peat bogs. A supplementary fertilization of seedlings must be done also on these sites. The size of heaps piled up by an excavator is sufficient and it is relatively easy to apply the tablets into the soil. Inside the nature preserve, where the heaps are piled up by hand, it is necessary to apply the tablets either before or at the moment of plantation because later on there is a danger of erosion.
Basing on a long-term experience with the application of SILVAMIX® fertilizers the Forest Office Jachymov plans to use them also in future because the obtained results are good and the preparation helps to afforest those areas which are destroyed by immissions in the Krusne hory Mountains.