Mechanisation: A short guide for new farmers

planter

Any new farmer should consider a number of aspects before deciding on a mechanisation package. Expert advice should be sought on soil conditions and the operations needed to plant a successful crop in that specific area.

If a farmer knows which operations are needed on his land, he then knows which implements he will need. This collection of implements, together with the tractors needed to draw them, is known as the mechanisation package.

Mechanisation planning is also necessary to determine how many of which implements and tractors are needed to execute the task for a specific crop timeously, under specific conditions.

THE MECHANISATION SYSTEM

The question that needs to be answered here is which operations, if any, are needed to be carried out on the soil so that it can provide for optimum growth of the crop.

Our forefathers did not necessarily do the right things, so a critical evaluation of current methods should be done by experts. It should also be borne in mind that decreasing input costs (fewer operations) should be pursued in order to maximise profits.

If there are compacted layers in the soil profile, the soil will need to be ripped with a ripper  to break down the layers. The depth of ripping will depend on the depth of the compacted layer.

Compacted layers serve as barriers through which water cannot penetrate into the soil profile. Only rip when these layers are present, otherwise unnecessary costs can be incurred.

Chisel ploughs are used to loosen soil without inverting it. Inverting the soil causes the dry upper soil to be deposited deeper into the soil profile and the wet deeper soil to be deposited on the surface.

The net effect is that soil moisture is lost. On the other hand, chisel ploughs tend to leave about 60% of the crop cover residue still on the surface of the soil. This residue acts as isolation to limit the evaporation of soil moisture.

It also serves as a barrier to limit raindrop damage to the soil surface and slows down water run-off. The resulting effect is that more water penetrates the soil and less is lost through erosion.

Mouldboard ploughs are used to loosen the top 250 mm of the soil and to invert it and so bury weeds, which is its biggest advantage and main aim. In modern agriculture, the mouldboard plough is losing favour for a number of reasons, including that the inversion of the soil causes excessive soil moisture loss.

It also bares the soil surface and leaves it at the mercy of wind and water. Using the mouldboard plough necessitates the use of other implements to counteract some of its effects. Extended use of the mouldboard plough causes ploughpan (compacted layer) formation.

This has to be remedied by ripping. The use of a mouldboard plough also necessitates the use of a disc harrow or field cultivator to prepare a finer seedbed or to break clods before planting.

Disc harrows are used to cut up crop residue, prepare finer seedbeds and to control weeds. The disadvantage of disc harrows, especially at high speeds, is that they break down the soil structure.

Prolonged and careless use of the disc harrow will create soil without structure that will need even more loosening than previously.

Field cultivators are used to control weeds before planting, to loosen the top soil, to prepare finer seed beds and to break the crust of topsoil. The field cultivator is normally worked at a depth of 65 mm.

Drills and planters are used to sow seeds in rows and to plant seeds at specific intervals in rows, respectively.

The planter is probably the most important implement and a whole article in a previous issue explained the use and choice of planters.

Row crop cultivators are used to control weeds between the rows of a crop. Some row crop cultivators are equipped to apply additional fertiliser while weeding, during the growing season of the crop.

Boom sprayers are used to combat pests and weeds chemically. The boom sprayer is extensively used in minimum tilling scenarios, to combat weeds.

PLANTERS, SPRAYERS AND HARVESTERS

In a no-till system, the only implements in the mechanisation package will be planters, sprayers and harvesters. Harvesters are needed and there the beginner farmer should look at single or double row trailed harvesters.

Once the farmer has decided, together with the soil scientist or agronomist, which operations need to be executed to cultivate a successful crop, the mechanisation system is defined. The implements needed to use this mechanisation system can now be listed.

Also read: Machinery to improve production for small-scale crop farmers

It is also important that the agronomist or soil scientist assist in defining the starting and finishing dates of the different operations. Ripping, for instance, can only start after the harvesting of the previous crop and must end before the soil becomes too dry during winter.

There is a definite starting date and an estimated date to complete ripping. The same must be done for each operation.

THE MECHANISATION PACKAGE

The farmer now knows what should be done and which implements are needed for those operations.

What is needed now is to determine how many of which implements he needs, and with how many tractors, to complete the operations as quickly and effectively as possible. These calculations are made, based on the conditions that exist on the specific farm.

A farmer has a very big influence on the size and cost of the mechanisation package, in the same way that operations and people need to be managed on a farm.

Without going into too much detail about mechanisation planning, the following important factors should be noted:

1. Effective time spent working with the tractor:

If the tractor operator works a 10-hour shift, this does not mean that those hours will effectively be spent doing the needed operation.

One will typically find that the operator leaves for the field 30 minutes after signing on, travels for 30 minutes to the field, spends 30 minutes during the day on stoppages and breaks to relieve himself, spends 60 minutes on a lunch break, travels for 30 minutes back to the farmyard and spends another 30 minutes on refuelling and other maintenance.

This comes down to a time loss of 3 hours during the day and one can only rely on the driver actually sitting and working on the tractor for 7 hours a day.

This can be worse if not managed properly. Time is also lost as a result of breakages to implements and the tractor if the machinery is not well maintained. Good management can do a lot to achieve better operational rates and therefore less machinery needed to do the same job.

2. Good tractor/implement combination:

Tractors have different power capabilities and implements have different power requirements, depending on soil conditions, speed of operation and implement width. The object is to choose the implement size that will make use of the full capacity of the tractor, or choose a tractor that will just be able to pull the implement depending on which one was chosen first.

Buying a 1-share plough cheaply at an auction and putting it behind a tractor that is capable of pulling a 3-share plough does not make economic sense, because the savings in the cost of the plough will be offset by an increase in the cost of the operation, as it can work at a third of the speed.

Also read: Keep every machine in good working order!

  • This article was written by Johan van Gass and first appeared in Farming SA.

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