Page 513 - Biosystems Engineering

Agricultur e Management 485

interrow cultivators. With improvements in planting equipment, it
becomes less necessary to do secondary tillage after primary tillage.
Crop residue can sometimes create a problem with secondary tillage
if there is not a good residue flow through the tillage machine.
Sowing and Planting Equipment
The basic objective of sowing is to put the seeds in the soil at a desired
depth and seed-to-seed spacing, to cover the seeds with soil, and to
provide proper compaction over the seed. The recommended row-to-
row spacing, seed rate, seed-to-seed spacing, and depth of seed place-
ment vary from crop to crop and for different agroclimatic conditions
3
to achieve optimum yields. Different crops have different methods
of sowing, depending on the size of the seed and other crop factors.
Seed Drills Seed drills are generally used for sowing small-size seeds
at a depth where seeds can get proper moisture.

Planters Planters deposit seeds at equal distances in the row at spec-
ified depth and cover the seeds with soil. Unlike with the seed drill,
plant-to-plant distance is maintained in the planter. They are used for
row crops such as maize, cotton, beans, and potatoes, which require
accurate placement of seeds for obtaining good yields, and to permit
intercultivation operations.
Transplanters have been used to plant seedlings. Transplanters
need considerably less time and less labor than manual transplant-
ing. They are used with rice and some vegetables (e.g., cabbages and
lettuce).
Intercultivation and Plant-Protection Equipment
Intercultivation operations like weeding and hoeing, and plant-
protection measures such as spraying have to be carried out to main-
tain a healthy crop.
Intercultivation Operations Intercultivation operations are carried out
to nourish the plant. They provide favorable conditions to the plants
for promoting plant growth. These operations include weeding, har-
rowing, and hoeing.

Plant Protection Plant protection includes using chemicals as spray-
ers and dusters. The main function of a sprayer is to break suspension
(pesticides in solvent) into droplets of effective size and distribute
them uniformly over the surface to be protected. Another function is
to regulate the amount of herbicide or pesticide to avoid excessive
application that might prove harmful or wasteful. 3

17.2.5 Manure and Vermicomposting
Recently, there has been a great increase in food production due to the
use of fertilizers to maintain soil fertility and control pests. Chemical