Response of red roomy grapevines to sprayof orthophosphoric acid and copper sulphate

In a private vineyard located at Aga district, Dakahlia Governorate, forty two head trained Red Roomy grapevines 17 years old to study the effect of four sprays of orthophosphoric acid and /or copper sulphate each at 0.1 or 0 .2 % on yield and quality of Red Roomy grapes during 2018 and 2019 seasons. Results showed that single or combined application of such two fertilizers was very effective in improving berry set, yield as well as physical and chemical properties of the berries. Meaningless effect on such parameters was observed due to raising their concentrations from 0.1 to 0.2 %. Spraying orthophosphoric acid surpassed the application of copper sulphate on improving the productivity of the vines. For obtaining the highest economical yield and improving quality of berries, it is recommended to spray Red Roomy grapevines with orthophosphoric acid plus copper sulphate four times at 0.1 % per each. The relative increases in yield/vine were about 89.6 and 123.0% for spraying orthophosphoric acid with copper sulphate each at 0.1% than unsprayed vines in the 2018 and 2019 seasons, respectively.