A split-plot design with three replications was used with irrigation methods as main
plots and irrigation levels as subplots. Each subplot had six rows with 4.2 m width and
10.0 m length (42 m2). The rows were 0.70 m apart from each other. The medium-early
potato cultivar ‘Marfona’ was planted with 0.25 m row spacing and 0.10 m depth by hand
on 13 March (72nd Julian days) in 2000 and 4 February (35th Julian days) in 2002
(Table 2). Plots were fertilized with 90 kg N, P, K per ha before planting and an additional
nitrogen dose of 60 kg per ha was side-dressed at the beginning of tuber bulking.
Subsurface drip lateral lines were installed 0.15 m below the soil surface (Camp, 1988)
in each row at preplant. Surface drip irrigation lines were installed after emergence.
Surface drip irrigation laterals were 16 mm in diameter. The drippers were inline type and
placed 0.25 mapart from each other and had 4 l/h flow rate at 1.0 atm pressure. Flow rate of the subsurface drip irrigation was 1000 l/h per 100 m of hose at 1.0 atm pressure. Drippers
were 0.20 m apart from each other in the subsurface drip method. One drip line for each
crop line was used in the experiments.