Preparing Land for Planting

The mechanical processing or preparation of the soil is also referred to in agricultural terms as the process of tilling, pre-planting herbicide control, fertilising, and seedbed preparation.

Tilling soil

 

Tillage in agricultural terms refers to the preparation of soil (seedbed) for planting and the cultivation of soil after planting. Cultivation refers to the loosening and breaking up (tilling) of the soil. The soil around existing plants is cultivated by machine using a cultivator to destroy weeds and promote plant growth by increasing soil aeration and water infiltration. Soil being prepared for the planting of a crop is cultivated by a harrow or plough.

 

Some Tilling Implements

Equipment used to break and loosen soil for a depth of 15-90 cm is called primary tillage equipment. These implements include the plough, disk, rotary, chisel, and subsoil ploughs.

Plough: The plough has been the most important agricultural implement since the beginning of commercial crop production. The plough is used to break up the soil, turn the topsoil upside down, bury crop residues and also to control weeds.

Types of ploughs:

There are different types of Ploughs available to match various types of soil structures. These different types are listed below:

• Mouldboard plough.
• Disc.
• Rotary plough.
• Chisel or sub-surface plough.
• Sub soiler plough.

Mouldboard plough

The mouldboard version cut the furrow slices into pulverised form. The main use of this tool is to cover vegetables and green manure crops. It is also used for inverting grass into the soil after rainfall.

Disc plough

The name “disk” resembles the structure of this implement. It is in the form of a disc i.e., DISK (concave shape). The disc is used to till the soil and is also used to chop up unwanted weeds or crop remainder. The disc plough is used as the first step in seedbed preparation.

Rotary plough

The rotary hoe is very popular nowadays due to its specific use in seedbed preparation. The cutting of soil is done by steel tines or blades.

 Rigid tiller

 

The ridged or spring-loaded tiller as tooth implement is used for seedbed preparation. In the modern times of precision farming and zero tillage, these tooth implements are very popular and used as the only implement to loosen the seedbed before planting.

Ripper

The ripper is a primary tillage implement used to loosen the subsoil for better water and root penetration. The ripper is designed to break up soil compaction while leaving a smoother soil profile and retaining as much residue as possible for soil conservation practices.

 

Planters and Fertiliser Spreaders

A. Mechanical Seed Drill

Mechanical seed drill

The mechanical seed drill is used to plant the seeds of various types of autumn or winter cereals (e.g., mainly wheat, oilseed rape, barley, soya bean, and so on) in parallel furrows. This type of seed drill incorporates a mechanical seed distribution system. It essentially comprises a load-bearing frame equipped with a hopper containing the seeds to be sown, a seed distributor with a series of delivery elements that direct the seed toward the soil, and furrowing elements equipped with seed-covering devices which open small furrows in the soil, into which the seeds are deposited. The mechanical seed drill is hitched to the tractor and is powered mechanically by the drive wheels: it is connected, via a quick-fit coupling, to a power harrow or a rotary tiller. Combining soil preparation and seeding makes it possible to perform two operations in a single work phase, drastically reducing fuel consumption and saving time for the operator while at the same time preventing excessive soil compaction caused by repeated passes of the tractor.

B. Pneumatic Planter or Monosem Planter

This planter works much the same as the drill except instead of air to transport the seed, it uses the opposite, a vacuum system. The seed is sucked from a large hopper to individual hoppers for each row. Then a vacuum sucks the seed into a disc that has holes for one maize seed. As the disc goes around, it drops one seed into the ground in precisely measured increments. The depth can be increased or decreased much like the drill. This planter can also regulate the distance from seed to seed in a row which makes the planter more precise. Much like the drill, some discs open the soil and make a furrow to deposit the seed into. This planter has two discs mounted in sort of a V-configuration. And then finally, there is a furrow closer much like the drill.

 

 

 

C. Special-Designed No-Till Planters

South African commercial farmers over the past decade imported zero-tillage equipment and planters mostly from Brazil and Argentina, as their products seemed to be the best for local conditions. No-till planters are today available from most of the so-called big brand tractor and implement manufacturers.

Zero tillage planter in-field

 

Calibrating the Planter

The ongoing development of agricultural technology has made the use of machinery for planting purposes more popular. Since these machines do the whole operation, they need to be set to the correct depth and spacing if a good stand, high yield, and quality are the main concerns.

A. Planting Depth

In deciding on planting depth, the development of the seedling, especially the lengthening of the mesocotyl, must be considered. Where planting is early, the low temperature of the soil must be considered, and the seed must be planted shallower. Soil depth also determines the planting depth and as a rule, planting will be shallower in heavier soils than in lighter soils. For example, in sandy soil 7.5-10 cm and a maximum of 5 cm in clay soil. Since damper conditions are required for germination, the seed must be planted at a depth where these conditions prevail for long enough. The soil must not dry out too rapidly at the level where the seed has been placed.

B. Plant Population

The two components, row width and spacing within the row indicate what plant density is. The term plant density concerns the number of plants per area unit, that is the so-called plant population per hectare. A successful plant population must be able to produce a good yield under both favourable and unfavourable conditions and it should therefore be planned or set with great care. The 100-cm row width and the 150-cm row widths will both be suitable, but rows as wide as 200 cm apart will be impractical since the spacing in the row is too close together. The general practice is to plant 100 cm rows where the rainfall, plant population and yield are high and for the following reasons:

• Rows 100 cm apart with wider spacing in the row result in better distribution of plants over the land area.
• A moisture-use pattern in a wider spacing is impractical under conditions of high rainfall.

The row widths and spacings in the row at different plant populations are given in the Table below.

Row widths and spacings in the row at different plant populations.

Plant Population/ha	Row Width (cm)
	75	90	100	150	225
	Spacing (cm)
10 000	133	111	100	67	44
15 000	89	74	67	44	30
20 000	67	56	50	33	22
25 000	53	44	40	27	28
30 000	44	37	33	22	15
35 000	38	32	29	19	–
40 000	33	28	25	17	–
45 000	30	25	22	15	–
50 000	27	22	20	–	–
55 000	24	20	18	–	–
60 000	22	19	17	–	–

 

It is therefore important that the farmer selects plant spacing that best suits the environmental condition.

Plant spacing in and between rows:

It is important to plan the plant population per hectare. This will be done according to the climate and soil conditions of the area as well as the expected and planned yield. One (1) hectare = 100 meters x 100 meters = 10 000 square meters.

Plant spacing in and between rows.

Row width:

If the row spacing needs to be 1.2 meters in between rows, this means that on 1 hectare, there can only be 83 rows. 100 meters divided by 1.2 meters = 83 rows. If 83 rows per hectare are required, then, the row width will be 1.2 meters (100 meters divided by 83 rows = 1.2-meter row width).

Planter calibration:

Seed spacing: To calibrate the planter accordingly, the row width and the spacing of the distance between the seeds in the rows need to be set.