TheImprovement ofTropical and Subtropical Rangelands

RBIlAB1LITATION TBOlINIQU1l8 167
• Swath width and rate of eeediDg vary with speed of travel
and the speed of the Ipinner. In most of theee machines, there ill no
mechanism to control the speed of the drive motor.
• Seed ill not spread as evenly as from a drill box. The amount
of seed is greatest near the center of the swath.
• Where seed mixtures are used in Ipreaders without agitators,
seed. ill segregated by weight and applications are uneven.
Seeder Demll of the DrlD-Llke or lertUlIer-Spreader TJpe In
these broadcasters, a fluted or force gear-feed mechanism letsleed
fall out of the bottom of the box onto the ground. The seed box
ill mounted on equipment such as brushland plOWl or brush cutters.
In general, the seeder-box type of broadcuter distributes seed more
uniformly than does the rotary type.
Drlbblers A recent adaptation of this type ofbroadcuter ill the
-seed dribbler.· The dribbler was designed to be mounted on the
right and left lide of the deck of a crawler tractor. It has a direct
drive from a rubber-tired wheel riding on the tracks of the tractor
and utilizes either fluted-force-feed or Ipoke-and-thimble metering
mechanisms. The seed il metered onto the track pad just as it breakl
over the front idler. It dropi off the pad in front of the track and ill
embedded in the soil as the tracks pUl over. The seed box units of
the browae seeder (flgure 7-9) can be adapted for use u dribblers.
Units With Airstream Seed Dllpenal The seed ill metered from
a hopper either by gravity or forced gear into an airstream. Blower
spreaders are available that broadcut both fluffy and slick seed, or
fluffy seed only. The airstream can be created either by exhaust
from equipment motors or by a fan designed for this purpoee. Seed
distribution ill poor when wind velocities are high, and uncovered
broadcast seed iIIlubject to movement by wind and water.
MmmaI Bqutpmmt This method ill as old as civilisation. Many
small areas are ltill seeded by a sower throwing seed from a sack
lUlpended at a person'l side with a Ihoulder Itrap. An experienced
person can maintain a good distribution ofseed by thill method.
An adaptation of manual seeding is the Whirlwind seeder. This
hand implement conlists of a canvas seed container with a controlled
feed that drope seed on a Ipinner. A crank ill turned by the lOWer
as he walkl. The crank gear turns the spinner. The spinning action
scatters the seed. Many hundreds of hectarel are still seeded in this
manner each year.