Since the early eighties, research aimed at lowering production costs for wild blueberries has resulted in new technologies like flail mowing and mechanized harvesting.

These technologies are considered efficient, as long as the results of their use compares favourably with that of older techniques like burning and manual harvesting.

In addition to the cost of the new technologies, it is field conditions (such as the presence of stumps, stones, hummocks and knolls) which have limited the ability to mechanize. It is these factors that land levelling seeks to address.

• Facilitate work with machinery and to minimize mechanical breakdowns.
• Ensure a more uniform spread of pesticides and fertilizer.
• Improve the working speed of agricultural operations.
• Prepare the ground for the mechanization of pruning and harvest.
• Diminish production costs.
• Improve profitability of the farm business.
• Solve the problems of labour shortages in certain regions.
• Consolidate fields.

Removing stumps whose location and size interfere with operations;

• Removing rocks, stones and stone walls;
• Enlever les roches de surface et les gros cailloux;
• Flattening knolls and filling in the ruts and hollows which interrupt a uniform flow of machinery over the land;
• Flattening the embankments formed during the construction of firebreaks.

• Levelling of wild blueberry fields should always be done when the plants are approaching dormancy, that is, around the first autumn frosts or before regrowth in the spring. This will of course depend on the degree of levelling which needs to be done.
• Land levelling should be limited to relatively moist field conditions, since drought periods will cause the damaged or disturbed rhizomes to dry out.
• Land levelling should be avoided under wet conditions, since this will lead to soil compaction. In addition, the passage of heavy machinery could result in significant damage to the field.
• Land levelling should be done in such a fashion as to minimize the impact on the density of plants and the percentage of field cover.
• It is best to wait a few years after clearing operations before levelling land. If not, the removal of fresh stumps will cause damage to too large an area around the stumps. Two crop cycles would be a suitable amount of time, and this would also give enough time to control the hardwood regrowth, which would make the stumps easier to pull.
• In order to avoid soil erosion, steep slopes should not be left bare by land levelling.
• Once levelling work has begun in a field, it is very important to complete the work in the same year. Spreading the work over a too long period will stress the plants and diminish their performance.
• When using bulldozers & excavators, it is important to avoid sharp turns, in order to avoid breaking the soil surface unnecessarily. Sharp turns should be limited to roads and fire-breaks.
• Levelling can sometimes leave rhizomes exposed. It is therefore advisable to prune (by mowing or burning) prior to land levelling. Mowing the field prior to levelling will also help to reveal the stumps, and irregularities and contours in the terrain.

Bulldozers:

This type of machinery is not recommended, since the damage to plants is generally severe. Its use should be limited to pulling other pieces of equipment like rollers or for the removal of large stumps (e.g., white pine).

Backhoe:

Backhoes and track hoes are useful for removing stumps and rocks, filling holes and levelling small bumps. Excellent work of this type can be done without too much damage to the field, but the work is slow because of the time required to adjust the stabilizers.

Excavators:

Excavators are the preferred method of land levelling in the rolling country of southern New Brunswick and Nova Scotia. They are used primarily to level the knolls and hollows, and remove the stones in old farm fields. The technique consists of plunging the bucket under the knolls, spreading out the soil underneath, and tramping the surface level. Some operators have added thumbs to the bucket, to assist in extracting rocks. An experienced operator will do approximately 1 acre per day, depending on the nature of the field. Some acres will take twice this time, while others may take half.

An experienced operator can level a rough field without resorting to filling the holes where rocks and stumps were removed. If the work is well done, there will be minimal damage to the plants. This piece of machinery does work more rapidly than a backhoe and can work in a range of 360o. In very rough fields with deep soils, this is the most appropriate method. In the northeastern part of New Brunswick, the method is sometimes used to remove stumps. In these circumstances, a bucket with teeth is required to avoid excessive damage to the blueberry plants. It is a good method if the density of stumps is not too high. A video demonstrating this technology is available from the New Brunswick Department of Agriculture & Rural Development.

Farm tractors equipped with a stump remover and a bucket:

This is a commonly used method on young fields for the removal of small stumps and the filling of holes. Many of the fields in northeastern N.B. were developed using this method. Once the stumps are taken out, the sod is put back in place and the stumps are removed from the field.

Rototillers:

Some growers in northeastern N.B. have used this method to untangle rhizomes in order to facilitate levelling. The method is used mostly in situations in which a small portion of the field is covered with knolls and hollows. The technique is acceptable as long as the rhizomes are not pulverized, and this situation is improved by removing teeth from the tiller. This technology is destructive and should be limited to small areas with deep soils, and performed late in the season. The soil should be moist, and rolled after the treatment.

Discing, dragging and rolling:

This technique was used for years in southern N.B., but has been displaced by excavator technology. The method consists of discing the field in order to loosen the soil, and then dragging and rolling the field level. It may actually spread the stand, if the initial coverage is poor. The technology is destructive, however, and fields characteristically take two or more cycles to recover. In a couple of instances, this method has been observed to diminish the survival of bunchberry, by breaking up the plant and/or by making it more susceptible to herbicide action.

H-beam:

Several northern growers have used this method to finish levelling. It is acceptable for this purpose, and will allow for the removal of small stumps which may not have been reached by other methods. Extensive use of this technique will result in a lot of damage to plants, because several passes with an H-beam scrapes the organic matter layer and exposes rhizomes to dry summer air and the intense cold of winter.

Rollers:

Rolling is useful for flattening fields which have been disturbed by other levelling activities, but is not useful unless the stand has been disturbed by another means. The use of vibrating rollers falls into this category and can be time-consuming and costly. In southern New Brunswick, fall levelled fields are often rolled the next spring. This helps to compensate for the heaving which usually occurs over the winter months. Excessive rolling will compact a soil, as evidenced by the short plants which emerge after frequent rolling. Rolling should be limited to a maximum of two cycles after levelling.

Flail mowers:

Some growers in northeastern N.B. use flail mowers to level their fields. The danger in excessive use of this method is that it can damage rhizomes if the blades enter too deeply and disturb the plants. The use of flail mowers should be limited to pruning.

Root rakes:

Root rakes are normally used to remove debris and stumps during agricultural land clearing. In wild blueberry fields, they can be useful for wind-rowing the larger pieces of debris which might interfere during mowing and harvesting. The root rake can be of some use in finishing off land work.

This factsheet has covered the most common methods of land levelling. There may be others. The most common error in land levelling is not the choice of machinery, but rather misuse of the machinery.

It is important to keep in mind that proper land levelling should make mechanization possible, while causing minimal damage to the wild blueberry plants. Any significant reduction in plant density may take several cycles to recover and the crop may be severely compromised. The field does not need to look like a table top following levelling, as machinery adjusts very well to moderate undulations in the terrain.

For more information, and to discuss suitable alternatives for particular fields, please contact the personnel of the New Brunswick Department of Agriculture, Fisheries and Aquaculture.