Volume 1, Number 1 (2017) pp 10-23 doi 10.20448/818.104.22.168 | Research Articles
Impacts of screen net on water consumption and physiological status of navel orange, Citrus Sinensis, was studied, in order to assess the economic benefits of shaded navel orange trees, reach water use efficiency and gain highest yield quality and quantity. The single span greenhouse was covered by screen net (25% initial shading) as compared to open field. Three irrigation levels (60, 80 and 100%) were adjusted as actual water (ETc) according to lysimeter tank, whereas the crop coefficient (Kc) was determined from the relationship between ETc and reference evapotranspiration (ETo). Water applied at 80% water consumption enhanced fruit growth and quality, but it was not affected in the peak flowering period, creating significant positive effects for other yield parameters as well as water use efficiency (production per unit of water). The interaction, water applied at 80% water consumption under screen net trees save water during the two seasons were 34.4% (1614.4 m3/acre) less than the open field (2458.0 m3/acre). Meanwhile, water use efficiency was higher 29.2% and 26.6% for screen net than the open field 15.1 and 15.3% for both seasons, respectively. The economic assessment of costs and returns from different treatments are calculated. It was found that the average yield were higher under screen net compared to the open field. Gross margin per 720 m2 were analysed using yield data, fruit price structures and production costs. Screen net with 80% irrigation level had the highest gross margin US$ 228.5 and US$ 249.38 (1 US$= 16 Egyptian pound) in the first and second seasons, respectively. The benefit cost analysis (BCA) per 720 m2 were analysed, the screen net with 80% irrigation level had the highest BCA with 3.4 in the first season and 3.6 in the second season.