Fertilizing rainfed wine grapes (Mavro, Carignane noir and Lefkas) with nitrogen, phosphorus and potassium in highly calcareous soils.
1998
Orphanos, P.I. (Agricultural Res. Inst. (Cyprus))
In Cyprus wine grapes are grown mainly in the south-west flanks (elevation 400 to 800 m) of the Troodos massif on highly calcareous (30 to 80 CaCO3) on igneous soils. Winter fainfall is normally above 500 mm in most of these areas. In all areas the soils are low in N (about 0.1 total N)and available (Olsen) P (4ppm). Ingeous soils are also low in available K (exchangeable + soluble + K150 ppm), but calcareous soils are well supplied with available K (150 to 300 ppm). Fertilizer experiments were carried out with the variety Mavro testing N rates (up to 150 kg N/ha) in combination with P (35 kg P/ha) and K (up to 150 kg/ha). In addition to Mavro, two other new to Cyprus varieties, i.e. Carignane noir and Lefkas, were tested. It was shown that, with a relatively high yield of 15 t/ha, an amount of N,P, and K (30, 4.5 and 48 kg/ha, respectively) was removed. There is evidence to support that vineyards that have been sufficiently supplied with N for a few years continue to produce at their potential level even when N application is discontinued. Soil P content of about 9ppm should be considered sufficient. Available soil P increased relatively fast with P application in highly calcareous soils and remained available for fairly long. Therefore, analysing the soil at relativey wide intervals can safely guide P fertilizing. Likewise, application of K did not influence yield, but it significanlty increased available soil K. Carignane noir produced the highest yields and Lefkas the lowest, with Mavro intermediate. The second half of the experimental period was exceptionally dry. This appreciably decreased yields of Carignane noir and, particularly, Lefkas but not of Mavro, which produced 10 to 12 t/ha throughtout the experimental period.
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