Ploughing

Disadvantages

The ploughing has however like disadvantage of creating a " Sole of ploughing " , to make disappear the surface layer of Humus, argilo-humic complex , to expose the ground to the erosion (which can be very important on the fragile grounds such as Lœss), dehydration and with the solar Ultraviolet S, strongly to decrease the quality and the quantity of the organic matter on the surface, and to hide the vegetable residues of surface and the organic soil conditioners, thus supporting their anaerobic decomposition , while harming the useful Champignon S of the ground (those all are aerobic) and by supporting the acidification of the ground, of the Nématode S which can Parasite R roots and some Bacterium S anaerobes which mineralizes too quickly the Organic matter (what results in a loss of Nitrate S (very water soluble) and an expensive need for Engrai S, with the risk to pollute the Ground water). The ploughing disturbs also the work of the Vers of ground in the exhibitors with the Pesticide S, and in them incentive to go up each night on the surface more, since they find the organic matter hidden. Their work of ventilation of the ground thus is decreased or stopped on the surface. The reduction in the biomass in ground worms, associated with the disappearance of the humus decrease quickly and strongly the capacity of the ground to infiltrate and retain water.

With the current method of ploughing, the grounds erode of a millimetre per annum. However, to reconstitute this tiny thickness, it takes ten years.

The ploughing is for these reasons increasingly called into question, in particular on the fragile grounds, dry or exposed to the tropical climates, for its consequences on the degradation or sterilization of the grounds and for the reduction in the outputs which it involves, compared to the cultures without ploughing, which are however technically more demanding, delicate and complex.

Alternatives

For this reason, the farming technical simplified and TSL ( Work of the ground without ploughing ), generally with direct Semis under vegetable cover were developed like alternatives to the ploughing, in particular in France in the zones at the already high erosive risk (slopes, floodplains, grounds exposed to the rains and strong winds), by agronomists such as Claude Bourguignon, specialist in microbiology of the grounds. The direct Semis is applicable on all the grounds and preserves much best fauna and the auxiliaries, especially if there is no use of weeding chemical, but sowings on thatch of the cultures of the previous year, or on cereals with strong development racinaire, but which will freeze in winter.

These techniques seem to provide to be adapted to all the types of ground. On the degraded grounds, the outputs can often double and allow a resistance to the Sécheresse and a ecological Résilience very improved and always are very improved.

Theoretical aspects

Under the effect of advance, the working parts of the plow practice two cuttings, a vertical carried out by the coulter and horizontal realized by the plowshare the strip of land thus detached, said band of ploughing, parallelepipedic section, is involved on the mould board, which raises it and turns over it in the line created at the time of the preceding passage. This reversal causes a fragmentation of the band of ploughing in mounds.

The operation creates a formed furrow of an open line and a band of ploughing turned over. The line is delimited by a vertical wall, the wall, and a horizontal bottom of line, which result from the cuts carried out. The opposed side, marked by a more or less irregular peak of ploughing, is delimited by the band which has just been turned over. This furrow will be filled by the reversal of another band at the time of the following passage. The first furrow, called framing, leaves a band turned over on the ground not plowed, forming a relief. The last traced furrow will remain open forming in limit of piece or board of ploughing a “water-furrow” which will be levelled later on by surface farming ways.

The relationship between the bandwidth (difference between two successive walls) and the depth of the furrow (height of the wall) varies in general from 1 (major ploughing) to 1,6 (surface ploughing). For ploughings of average depth, up to 30 cm, this report/ratio is generally equal to 1,4. In this case, the band is turned over by a rotation of approximately 135° and lie down with 45° on the tape turned over at the time of the preceding passage.

The degree of crumbling of the band of ploughing depends on several factors, of which most determining are the following:

the width-depth ratio: the bands proportionally broader are subjected to stronger mechanical requests because of increase in the angle of reversal;
the shape of the mould board: a helicoid mould board accompanies the band by ploughing in its movement of reversal while a cylindrical mould board causes a more brutal swing and thus a stronger fragmentation;
rate of advance: the requests increase with speed;
the texture of the ground: it determines its cohesion, this one is weaker for the sandy grounds and stronger for the clay soils. In the borderline case of a sandy ground, with incoherent structure, the ploughing will do only one simple work of mixture without reversal. In the grounds provided well in Clay, the degree of crumbling depends on moisture.
plastic State of the colloidal grounds (related to moisture): a dry ground, with strong cohesion, undergoes a low level of crumbling and it is formed rather large mounds. Beyond a certain water content, the band of ploughing tends to being moulded by the mould board without disaggregating. On an intermediate level of moisture, one obtains a certain degree of crumbling.

Types of ploughing

According to its unfolding in plan and the type of plow used, the ploughing can be done in two manners:

ploughing flat, strips of land being always Rejected on the same side. It requires the use of a reversible plow in order to be able to reverse the direction of discharge at the time of an outward journey and return;
ploughing in boards or balks. It is the only realizable one with a general-purpose plow which turns around the piece, and it can be done either while splitting, the bands being rejected towards the outside of the board (leaving in the center of the board a “water-furrow”), or while leaning, bands being rejected towards the axis of the board (leaving in the center of the board a “banked-up bed”).

One can distinguish according to the depth from work:

from 10 to 15 cm, of the light ploughings, carried out in particular for the resumption of ploughings in spring,
from 15 to 30 cm of the average ploughings, most spread, in particular for the culture of cereals,
from 30 to 40 cm of the major ploughings, for cultures with major rooting (beet, alfalfas, etc),
beyond that, of the ploughings of breaking up, in particular carried out to allow the setting in culture of new grounds or to prepare the plantation of Orchard S.

One can distinguish according to the slope from the bands:

drawn up ploughing,
laid down ploughing,
flat ploughing.

Conditions of realization of the ploughing

The ploughing carried out depends mainly on two series of factors: the type of ground and its state, primarily its percentage of moisture on the one hand, adjustments of the material on the other hand.

A good ploughing, allowing a good fragmentation of the ground, must be carried out under variable optimal conditions of moisture according to its characteristics.

In too wet conditions, the weight of the tractor whose file of wheels generally rolls in bottom of line packs the ground and can cause the formation of a “sole of ploughing”, which creates an obstacle with the development of the roots.

Fallow

Practiced periodically within the rotation of crops, the Jachère formerly allowed the grounds plowed to reconstitute a richer layer humic and a more resilient ground with the climatic risks and the ploughing, but since the advent of manures, one often believed to be able to do some while cultivating with more artificial fertilizers and more powerful tractors, which finally led to an increased degradation of quality biological and structural of the grounds. The European Union had within the framework of the first CAP, initially imposed a minimum rate of fallow, but under pressure of certain representatives of the agricultural world relayed by the Ministers for the Agriculture of the Member States, the fallow known as energy or huntings were accepted, which do not allow any more the rest of the ground.

Quotation

“ Tilling and pasture are the two udders whose France is fed and the true mines and treasures of Peru ”. Sully, in royal Economies .

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