Staged harvesting and improvement in quality.

摘要

The quality of tubers harvested in one operation or in two stages (grubbing and allowing the tubers to dry on the soil surface followed by lifting) and the operational advantages of 1- or 2-stage harvesting were compared. Depending on the weather the tubers were left on the soil surface from 10 minutes to some hours. The labour (person hours) required to harvest potatoes (50 t/ha) in 1 stage, 2 rows at a time required 20.38 h/ha, compared with 18.17 h/ha for 2-stage harvesting 2 rows at a time and11.01 h/ha for 2-stage harvesting 4 rows at a time. Compared with 1-stage harvesting, 2-stage harvesting reduced the spread of Erwinia carotovora in the field. This was partly due to the shorter distance travelled by tubers through grubbers than throughsingle-stage harvesters and partly due to tuber drying on the soil surface, which killed the bacteria. Tuber drying in the field also reduced the incidence of Rhizoctonia solani in storage. However, harvesting in 2 stages in very sunny conditions could cause tuber scorching (black flecks on the tubers), and if wetted by rain the tubers would need to dry out completely before lifting.