|Author:||Girona, J. ; Barta, E. ; Marsal, J. ; Arbones, A. ; Mata, M. ; Campos, J. del|
|Book Group Author:||NA|
Midday leaf water potential (Î·md) was monitored for 3 years at a commercial vineyard (cv. Pinot Noir) under four irrigation strategies. Three treatments were established based on irrigating vines with 4-6 mm/day, when daily measured Î·md was more negative than the pre-defined threshold. After the first experimental year, thresholds were adjusted for each treatment as: (1) Control (C), irrigated when Î·md was less than -0.6 MPa at the beginning of the season and gradually fell to -0.8 MPa at about mid-June, after which the threshold was maintained at -0.8 MPa until harvest. (2) Control-Deficit (CD), irrigated as C from bud-break to mid-June (around the middle of Stage II of fruit growth), and from then until harvest when Î·md decreased below -1.2 MPa. (3) Deficit-Deficit (DD), irrigated when Î·md was less than -1.0 from bud break to mid-May (about the middle of fruit growth Stage I), and after that time the Î·md threshold became -1.2 MPa until harvest. A fourth treatment was applied following a soil water budget approach (WB). All treatments were replicated five times but irrigation in the Î·md-based treatments were independently applied to each of the replicate plots, whereas irrigation for WB was applied equally to all replications. The more site-specific information obtained from Î·md thresholds in C provided substantial advantages for yield homogeneity and repeatability of results with respect to WB, thus demonstrating the method's greater ability to account for spatial variability. Average applied water for the 3 years in C, CD, and DD was 374, 250, and 178 mm, respectively, while the yields were 11.8, 9.2, and 6.1 kg/vine, respectively. The CD treatment produced better juice quality than C, and was superior in other quality parameters to both C and DD. However, over the study period, an important carryover effect was observed in the yields and the grape size of CD, which tended to diminish from year to year relative to C.
|Pages:||115 - 127|
fruit growing, vineyards, developmental stages, crop yield,seasonal variation, leaf water potential, wine grapes, Vitis vinifera,irrigated farming, irrigation scheduling, deficit irrigation, Spain