poster - International Conference of Agricultural Engineering

2. Materials and Methods
2.1 The hybrid
The hybrid used was developed by UENF (UNIVERSIDADE ESTADUAL NORTE
FLUMINENSE) and CALIMAN FARM S/A, in Linhares town- ES resulting from crosses of
'Sunrise Solo 72/12' with the 'JS12'. All characteristics of the hybrid meet the standards
required by the foreign market (RJ-SETEC, 2007).
2.2 Treatments and experimental design
The studied treatments were four water irrigation levels (L1 = 50%, L2 = 75%, L3 =
100% and L4 = 125% of ETo) and the reference evapotranspiration calculated by Penman-
Monteith model standardized by Allen et al. (1998) (Equation 1).
The applied quantities of water (Irrigation + effective Precipitation) in each treatment
during the course studied was 986.7 mm; 1480mm; 1973.4mm and 2466.7 mm, respectively,
for the treatment L1, L2, L3 and L4 as shown in Table 1. In Figure 1 there are a partial view
of irrigation method and papaya cultivation field. The experimental design was randomized
blocks with six replications, each plot consisted of three useful plants.
ETo =
0,48∆(
R
n
⎛ 900U
2 ⎞
− G)
+ γ ⎜ ⎟(
e
⎝ T + 273 ⎠
∆ + γ (1 + 0,34U
)
2
s
− e
a
)
Equation 1
which:
ETo = Reference evapotranspiration (mm day -1 );
Rn = net radiation at the culture surface (MJ m -2 day -1 );
G = heat flow in the soil (MJ m -2 day -1 );
∆= slope of vapor pressure curve versus air temperature (kPa. o C -1 );
U 2 = wind speed measured at two meters in height (m s -1 );
T = temperature ( o C);
e s = saturation pressure of water vapor (kPa);
e a = real pressure of water vapor (kPa);
γ = psychrometric factor (MJ kg -1 ).