Hemoglobina

Australian Journal of E.~perimentalAgricrtlture, 1994,34,529-35

Effects of hydroponic solution composition, electrical conductivity and plant spacing on yield and quality of strawberries
R. A.~a~-ooshi* G. C. ~~.esswell* and
A

NSW Agriculture, Horticultural Research and Advisory Station, PO Box 581, Gosford, NSW 2250, Australia. NSW Agriculture, Biological and Chemical ResearchInstitute, Rydalmere, NSW 21 16, Australia.

Summary. The influence of nutrient solution adjustment and replacement (management), its electrical conductivity (EC) and plant spacing on yield and quality ofstrawbeny fruit (var. Torrey) produced in a recirculating hydroponic system was studied at Gosford, New South Wales. Four ways of managing the nutrient solution were examined: (i) pH and EC adjusteddaily and the solution replaced every 8 weeks (current grower practice); (ii) as above except that a topping up solution with lower potassium to nitrogen (K: N) ratio was used for EC adjustment; (iii) nodaily adjustment of EC or pH and one-third of solution replaced every 2 weeks; and (iv) no daily adjustment of solution volume, EC or pH and full replacement after 8 weeks. Compared with growerpractice, these alternative solution management strategies provided no advantage in yield, fruit number, or in the OBrix, citric acid, sweetness or flavour of fruit. Use of a topping up solutionsupplemented with ammonium nitrate (NH4N03) and calcium nitrate [Ca(N03)2] to reduce the K : N ratio from 1.7 : 1.0 to 1 . 4 : 1.0 had no effect (P>0.05) on yield but Introduction The nutrient film technique(NFT) and channel systems employing rockwool, perlite or gravel as media have all been used for hydroponic strawberry production in Australia (Weir 1987; McCrae 1988). In these systems, the recyclednutrient solution is managed in 1 of 2 ways. In the first, water and nutrients removed by the crop or lost through evaporation are added each day ('topping-up') to maintain a constant electrical...