Document Type : Research Paper
Abstract
The high cost of direct planters is a limitation in the development of no-till planting for row crops.
Attaching appropriate coulters to conventional row crop planters can adapt existing tilled soil planters for a
no-till system. In this study, two types of commonly-used disk coulters for no-till planters (plain and fluted
(waved) were tested for installation at the front of a common vacuum planter with runner openers. The
performance of the coulters was first compared under different vertical loads and forward speeds and for
two soil moisture contents (dry and moist). The results showed that the plain coulters cut the residues, but
could not produce a strip of fine soil wide enough for the runner openers at an appropriate depth. However,
the fluted coulter in dry soil cut the residues properly as well as loosening a strip of soil 25-34 mm wide to
a depth of 24-40 mm. Thus, in dry soil at a forward speed of less than 1.35 m/s, applying a vertical load
equal to one-fourth the weight of a conventional vacuum row planter on a fluted coulter created a 31 mm
wide strip of fine soil to a depth of 35 mm. The installation of four fluted coulters on the tool bar of a four
row vacuum planter (in front of each planting unit) sufficiently distributed the machine weight on the drive
wheels and coulters to create the vertical load required for both soil-wheel contact and penetration of the
coulters into hard soil. This allowed adequate uniform placement of seeds at the desired depth. Maintaining
a forward speed of 1.35 m/s guaranteed 95% soil coverage for an emergence rate of 83%. In moist soil, the
fluted soil threw the soil outside the planting strip and, thus, is not recommended.
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