Methods and timing of harrowing potatoes

When planting potatoes in a small area, the grower has the opportunity to closely monitor the shoots, weed out weeds and periodically loosen the ground with a rake. If the potato plantation occupies more than 2-3 acres, then it is better to mechanize both the planting of tubers and the subsequent processing. An analogue of a rake in this case is a harrow, which is hung on a walk-behind tractor or on a tractor.

Purposes of harrowing potatoes:

  1. Rapid weed control over large areas. The harrow’s teeth pull out the weeds that have not yet taken root, and it dries up, additionally fertilizing the soil.
  2. Providing planted bushes with oxygen. The better the soil surface is loosened, the more air will enter into the depths. If the bed is covered with a crust, as is often the case after rain, the tubers will begin to suffocate, which subsequently will have a bad effect on the harvest.
  3. Saturation of potatoes with moisture. The spring sun dries up the land quickly. In the soil in the garden, capillaries form – paths along which water circulates. During harrowing, the capillaries in the upper layer are destroyed, and moisture is trapped at a depth of 5–8 cm.

Types of harrows for processing potatoes

Three main types of harrows are used for harrowing potatoes:

  • tooth – teeth are attached to a metal frame (Fig. 1);
  • mesh – a kind of tooth harrows. The teeth are set to a light and flexible wire mesh stretched over the frame (Fig. 2);
  • rotary – disks with welded-on teeth are put on a metal axle (needle rotary harrow-hoe – fig. 3). A variety of rotary harrows – hedgehogs: cones of several discs of different diameters with welded-on teeth (Fig. 4). Hedgehog harrows are convenient to use as hillers.

Fig. 1. Tooth harrowphoto of harrowFig. 2 Harrowphoto of rotary harrowFig. 3. Rotary harrow (needle)Rotary harrow-hedgehog photoFig. 4. Rotary harrow-hedgehog

Preplant harrowing of the site

The area intended for potatoes is usually plowed in the fall. In early spring the field is harrowed. For loamy soils, heavy tine harrows are often used, for sandy and sandy loamy soils – needle rotary harrows.

With the help of tine harrows, it is convenient to distribute (pull) manure over the site. To make the field smoother and the soil evenly fertilized, the walk-behind tractor or tractor with a harrow is first led at an angle of 45 Β° to the future beds (plowing lines). When the entire field has been passed, the soil is re-harrowed at an angle of 135 Β° to the plowing lines.

Harrowing potatoes after planting

The harrow will do well with weeds as long as they are in a threadlike state. Therefore, the potato plantation is harrowed 5–6 days after planting, and if it rains during this time, then immediately after the crust has formed. It is best to harrow during the day, so that the weeds pulled out by the roots dry out in the sun. This treatment is carried out every 7-10 days until the emergence of shoots.

If potatoes are planted using a potato planter, then the tubers are not germinated first, and seedlings appear 20-25 days after planting. Accordingly, in the pre-emergence period, the site is harrowed 2-3 times. Sprouted tubers sprout in 12-15 days, therefore, 1-2 harrows will be needed.

The choice of harrow depends on the grower’s preference. The only exception: from tooth harrows for cultivation of potato plantations, mainly light models are used, in the case of clay soils – medium-weight harrows. The depth of planting in the furrows (under the plow) must be at least 15 cm, otherwise the teeth can pull out or damage the tubers.

Harrowing potatoes is most effective when the land is slightly damp. If the soil is dry, the rotary harrow can handle the weeds better than the tine harrow. In order for the tine harrow to loosen the soil well and pull out the weeds, a tractor or walk-behind tractor is driven on dry soil at a higher speed than on wet soil.

Theorists of organic farming argue that the best result is obtained by pre-emergence harrowing of potatoes with rotary harrows: their teeth dig into the ground, and when pulled out, a “mini-explosion” occurs, due to which the soil is saturated not only with oxygen, but also with nitrogen. With this treatment of the site, nitrogen fertilizers are required much less than usual.

If the tubers are planted in ridges, then the beds are most conveniently harrowed with hedgehogs. However, light tine harrows or harrows can also be used. In this case, the two frames are attached parallel to each other and at an angle to the soil surface in such a way that the teeth “comb” the ridge on both sides, but do not flatten it.

Post-emergence harrowing of potatoes

After the emergence of shoots, it is allowed to carry out another 1-2 harrowing until the potato sprouts reach a height of 15 cm. But the tooth or mesh harrow can be used only when the first shoots are still breaking through and their height is no more than 1-2 cm. The sprouted potatoes are treated with rotary hedgehog harrows: this way there is less danger of damaging the bushes.

Harrowing potatoes is such a convenient way to get rid of weeds that the owners of large plots even make certain sacrifices: during mechanized cultivation, 0,5-1% of the bushes die. But this damage pays off in the speed and efficiency of weeding.

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Anna Evans

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