ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
FOUR SEASONS OF SUSTAINED DEFICIT IRRIGATION: IMPACTS ON CHARDONNAY AND SHIRAZ VINES GRAFTED TO FIVE ROOTSTOCKS |
| Authors: | J.M. Pech, R.M. Stevens, P.R. Nicholas |
| Keywords: | irrigation water use index, clothesline effect, oasis effect, nutrition |
| Abstract:
Increasing extractions of water from the Murray-Darling river system have led to cutbacks in irrigation. We investigated whether grapevines grafted to a range of rootstocks (Ramsey, 140 Ruggeri, 1103 Paulsen, 110 Richter, K51-40 and Schwarzmann) vary in their tolerance to irrigation cutback. Sustained deficit irrigations (~5 versus ~8 ML/(ha.y)) were applied to Chardonnay and Shiraz grapevines grafted to one of five different rootstocks. The two trials were located at different sites within the same climatic zone. Deficit irrigation reduced yield in Chardonnay by 9% and in Shiraz by 31%. Chardonnay vines grafted to Ramsey and Shiraz grafted to Schwarzmann yielded highest (32.2 and 13.2 kg/vine, respectively). Rootstock performance at both sites was not affected by irrigation treatment. Sustained deficit irrigation increased the value of the irrigation water use index (IWUI), that is yield/irrigation, of Chardonnay vines by 40%, but did not affect the value in Shiraz. We suggest that the different effects which irrigation cutback had on IWUI at the sites were due to the between-site differences in conditions affecting evaporative demand, the water use of a well watered vine, and vine nutrition. Irrigation cutback increased IWUI where the amount of applied water was close to estimates of the amount used by a well-watered vine, but where the amount of applied water was substantially below such estimates, irrigation cutback had no effect on IWUI. Based on an absence of irrigation by rootstock interactions on yield and IWUI at both sites, we conclude that the rootstocks in these trials had equivalent tolerance to irrigation cutback. | |
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