Combination Impacts of Irrigation Regimes and N&K-Humate Rates on Sunflower Productivity and Water Use Efficiency in Sandy Soil

TWO field experiments were carried out under sprinkler irrigation
system at the agricultural research station (ARC), Ismailia
Governorate, Egypt in two successive summer seasons (2009 and
2010) to study the combination effects of irrigation regimes and N&Khumate
rates on some soil properties, yield quantity, yield components,
oil yield, crop water requirements as well as nitrogen use efficiency
(NUE) and water use efficiency (WUE) of sunflower crop in sandy
soil. A split- plot design with four replications was used. Two
irrigation regimes (25% from the available soil moisture depletion
(ASMD) and 50% ASMD) and four levels of N&K-humate combined
(F0: control treatment, F1: 15 kg N + 2.0 kg k-humate /fed, F2: 30 kg
N + 4.0 kg k-humate /fed, F3: 45 kg N + 6.0 kg k-humate /fed). The
results indicated that the application rates of N&K-humate fertilizers
and irrigation scheduling treatments significantly affected soil
hydrophysics properties, yield and yield components. Therefore, an
an increase in total porosity (TP), field capacity (FC) and wilting point
(WP), meanwhile, small decrease in soil bulk density and hydraulic
conductivity was obtained. The average values of actual
evapotranspiration (ETa) were 383.6, 362.6, 352.3 and 330.2 mm, for
25% ASMD irrigation treatments, respectively. Meanwhile, those were
321.6, 310.2, 301.4 and 295.9 mm for 50% ASMD irrigation
treatments, respectively. Also, the chosen treatments were affected on
seed yield and yield components. The highest averages of plant height,
head diameter, head weight, seed weight/head and 100 seed weight,
seeds yield/fed and seed oil/fed, in the two seasons, were obtained from
the highest application level of N&K-humate fertilizers and under the
irrigation regime of 25% ASMD. The highest value of WUE was
obtained under the highest level of N&K-humate (F3) and at 25%
ASMD irrigation treatment. On the other hand, the highest value of
NUE was obtained under the lowest level of N&K-humate (F1) and at
25% ASMD irrigation treatment.