Trials of sugar beet seed pressing with different type pressure rollers

Abstract

Pressure rollers are mounted behind the seeder coulters as it improves the contact between sugar beet seeds and the soil and furthermore it improves seed germination ability. But pressure rollers of conventional sugar beet seeders used for sowing into tilled and cultivated soils cannot always be used for seed pressing in non-ploughed and uncultivated soils. The main design parameters of the pressure rollers of sugar beet seeds are: diameter, width, the number of rollers and fingers, mass, etc. The even seed pressing, the profile of the furrow bed, its hardness, seed damage and gravity, etc. depend on the above mentioned parameters. This paper presents the investigation of the technological process of operation of special type sugar beet seed pressure rollers and the experimental trial results of the tests carried out in the Hohenheim University in various soils. The theoretical investigations proved that the pressure rollers should be mounted on the seeder unit with the help of hinges and their pressure force onto the soil would depend on the gravitational force when the sugar beet seeds were sown in non-ploughed soils. The diameter of the pressure rollers should be not less than 180 mm in order to press the seeds into the soil into the depth of about 3 mm, and ensure their good contact with the soil. The experimental trials revealed that the narrow disc pressure roller of 220 mm diameter and 15 mm width introduces the seeds of sugar beet into the hard soil of 0.4 and 0.9 MPa and satisfies the conditions of good seed and soil contact. Disc pressure roller with fingers is made of two discs and every disc with 17 fingers introduces sugar beet seeds by 2 mm shallower than the narrow one and forms the waves in the furrow bottom. When the finger type pressure roller has been pulled through 0.4 - 0.9 MPa hardness soil the force used should be from 0.004 to 0.011 kN greater than using the narrow pressure roller.