Development of a novel mechatronic system for mechanical weed ...

Introduction
techniques. It is known that some weeds are able to grow in soil conditions
suboptimal or even unfavourable for crops, so a soil testing is necessary before
the soil nutrient or pH can be improved or the crop selected. The relationship
between soil structure and weed development is similar to that of nutrients,
which means indirect impact. Optimal soil structure will not help the weeding,
but pure structure, compaction and cultivation pans can lead to the spread of
weeds via deep underground stems or roots, or could cause the appearance of
waterlogged soil, preferable for some weed species.
The choice of the crop should be based primarily on the soil type and climate. In
cases where more options in the choice of cultivars exist, most desirable are
species with rapid establishment, vigorous growth, prostrate – leafy types or
long straw cereals. An increase in the sowing rate could result in an
improvement of the crop’s competitiveness effect and provide compensation for
the losses incurred during mechanical weed control (Parish 1990).
Cultivation is of great importance in weed management and it should always be
properly varied depending on needs of different crop and weed populations
(Mohler and Galford 1997). Cultivation also provides many other beneficial
effects far beyond the weeds. It is important for aerating the soil, stimulating
crop root growth, conserving soil moisture and providing insulation with loose,
dry soil mulch. To choose an adequate cultivation mechanism for optimum
weed management, it is important to know the weed history of the field and to
understand their lifecycle (Buhler 1995). Different weed species require different
cultivation procedures. For example one successful method against perennials
is weakening of the weed plant by separation of the above – ground and
underground parts, which leads to exhaustion of the food reserves in the
underground part. The most significant factors of annual weeds are conditions
for their germination. Germination is dependent on the correct levels and
mixture of moisture, oxygen, carbon dioxide, temperature and in some weeds
the presence or absence of light. Combination of these conditions often causes
seeds to have distinct germination periods, so well timed cultivation can
drastically decrease the weed population. Crop seeds are usually larger and
planted deeper then most weed seeds, which provides a possibility to calculate
the cultivation depth, damaging just weed plants. A seedling is most vulnerable
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