SOIL PREPARATION

CHAPTER 3

FIGURE 3.5: Constant speed hand-operated fixed penetrometer equipped with load cell, monitor and data logger to register and display soil strength quantitatively with depth (Photo: P. Myburgh, ARC Infruitec-Nietvoorbij). Van Huyssteen (1983) employed a portable fixed penetrometer successfully in a series of existing field trials where the soil profiles had been studied previously. He used at least 10 randomly selected positions at each plot to represent a particular treatment. Amongst these field trials was a comparison of five soil preparation methods carried out on a Glenrosa soil of granitic origin at Stellenbosch. Treatments applied in the field trials were as follows: • Diagonal double delved to a depth of 100 cm.

• Wing ploughed to a depth of 100 cm. • Wing ploughed to a depth of 75 cm. • Single-direction delved to a depth of 100 cm. • Shallow ploughed to a depth of 45 cm.

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