Articles containing the keyword 'aura'

Five ploughed research areas from Finnish Norther Karelia were selected for comparison studies of plough ridges and untouched soil. Measurements were made at a depth of 10 cm in sample plots on both mineral and paludified mineral soil and peatland parts of these areas. In summer 1987 daily soil water matric potential was measured using tensiometers, and volumetric soil moisture content and density were determined from soil samples at two dates during the summer. Water characteristics of the core samples were also determined. On paludified mineral and peat soils the water table depth from the soil surface was measured.

The results indicated that in plough ridges matric potential was lowest. Plough ridges were also seen to dry and wet faster and to a greater degree than untouched soils. In untouched soils, soil water relations and aeration were not affected by the distance to the furrow. The effect of the plough ridge was smallest on peatland, where there was a good capillary connection from plough ridge to the ground water, if the ditches were not very effective. The soil in the ridges did not dry too much to restrict seedling growth. The untouched surface soil in poorly drained peat and paludified minear soil was, at least in a rainy growing season, often and also for long times so wet that 10% minimum air space required for good seedling root growth was not available.

The PDF includes an abstract in English.

• Mannerkoski, E-mail: hm@mm.unknown
• Möttönen, E-mail: vm@mm.unknown

The study deals with the interaction of various soil preparation and reforestation methods. The most favourable time of the year for broadcast sowing and the effect of stabilization after soil preparation on restocking were studied as special problems.

Prescribed burning, scalping and disc ploughing made a better combination with sowing than planting, and ploughing better combination with planting than sowing. The longer the period was between sowing and germination the fewer seedlings emerged. The best stocking was clearly resulted with sowing in June. Stabilization of soil after preparation had a negative effect on reforestation results.

The PDF includes a summary in English.

• Pohtila, E-mail: ep@mm.unknown
• Pohjola, E-mail: tp@mm.unknown

The objective of the study was to compare different reforestation methods on ploughed areas in Finnish Lapland. Four species were compared: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), silver birch (Betula pendula Roth) and Siberian larch (Larix sibirica Ledeb.). The experiments were established in different parts of Lapland on different types of sites in 1970–72.

In Scots pine there was a difference of 15 percentage points in survival of seedlings between the best and worst methods of regeneration. Containerized seedlings and paper pot seedlings had the best survival rates. In Norway spruce the respective difference between sowing and planting was about 20 percentage points. In favour of planting. The survival rate can be increased by about 20 percentage points by selecting the right tree species. The average height varied from 25 cm (the sowed Norway spruce) to 179 cm (the planted silver birch) after 10 growing seasons. The birch was planted at the most fertile sites only. The longer time passed from the afforestation the clearer was the effect of the local growing conditions on the development of the seedlings. The elevation of the site was one factor seemed to influence the success of the seedlings.

The PDF includes a summary in English.

• Pohtila, E-mail: ep@mm.unknown
• Pohjola, E-mail: tp@mm.unknown

The areas of soil cultivation in regeneration sites using different methods in 1976–1979 and the cultivation units in use in Finland in 1979 were studied by means of a questionnaire. Application of soil cultivation methods appears to have become strongly polarized: in Southern Finland disc plowing with wheel tractors are used, whilst in Northern Finland wing plowing with crawler tractors is the most popular method, each being practically the only alternative in the respective area.

The PDF includes a summary in English.

• Kaila, E-mail: sk@mm.unknown
• Päivänen, E-mail: jp@mm.unknown

The changed in size and shape of ditches made by draining plows and tractor diggers were followed over a one-year period after the draining in four different peatland types. The material consists of 51 ditches made with each method in dwarf-shrub pine bog, herb-rich spruce swamp, in herb-rich sedge bog and sedge pine bog. The measurements were made immediately after the digging, and one month and a year later.

Ditches made by plowing and surrounded by peat became shallower quickly during the first 2–3 days after plowing due to the pressure of the surrounding peat. Ditches made with tractor diggers did not become shallower as fast, and their bottom did not widen to the same extent than plown ditched. During the first year, machine-made ditches change in a same way as handmade ditches, especially when compared to ditches made by tractor digger.

Immediately after digging the ditches made by tractor digger were 10 cm deeper and 0.13 m³ larger than plown ditches. One year later the values were 7,5 cm and 0.09 m³, respectively. Plown ditches made in the peat were 14.4 cm deeper than ditches that penetrated into the subsoil, for tractor digger the value was 13.2 cm. Ditches made with a tractor digger were deeper than plown ditches both in soils with deep and shallow peat layer.

The changes were largest and fastest in the wettest peatland type herb-rich sedge bog. In herb-rich spruce swamps, which have a shallow peat layer, the shallower plown ditches kept their form better than ditches dug by tractor digger.

The PDF includes a summary in English.

• Timonen, E-mail: et@mm.unknown