This study is being conducted in a 15 acre Sauvignon blanc vineyard located on the California State University, Fresno Agricultural Laboratory. The vines are grafted to Freedom rootstock and were planted on a spacing of 8′ x 12′ (vine x row) in 1992. Row direction is north to south with approximately 70 vines per row. The 1996 season represents the second year of data collection for this project. Deficit irrigation scheduling treatments were fully implemented and statistical differences due to treatment were observed. As in 1995, differences were again observed in the management of the irrigation systems. Use of subsurface drip irrigation allowed for reduced application of herbicides. One application of glyphosate to perennial weeds could be avoided because berms were dry. Conversely, use of subsurface drip irrigation required increased efforts for control of gophers. Significant training system effects on yield and fruit composition were observed in 1996. Yields were highest for the open lyre and minimal pruning treatments. Increased yield resulted from higher numbers of clusters per vine. There was an inverse relationship between yield and berry weight or cluster weight, although the number of berries per cluster was not affected. Fruit maturation was delayed significantly for the training systems which had the highest yields. Vines which were minimally pruned showed significantly lower levels of titratable acidity. Irrigation method also had a significant impact on yield and fruit composition in 1996. In general, as irrigation deficit increased, yield level decreased. The number of cluster per vine followed a similar pattern, indicating that this parameter was the most important factor involved in determining yield level. Differences in berry weight and the number of berries per cluster were not statistically significant. Statistically significant differences in soluble solids and pH were observed. Soluble solids were highest in 0.8 Et SDI and lowest in 0.8 Et AGD, even though the amount of water applied was identical for each. There was a trend for increased irrigation deficit to significantly increase pH in the fruit. Training system had a greater impact on vegetative growth than irrigation method during the 1996 season. Shoots per vine was significantly higher for minimally pruned vines. However, total vegetative growth, as indicated by mature nodes per vine, was greatest for GDC vines and lowest for MP vines. There were few treatment effects on vine water relations except at veraison when differences due to irrigation method were detected. Vines with the SDI 0.4 Et treatment had lower stomatal conductance than vines with the SDI 0.8 Et. At this point in the project, significant differences between training systems and irrigation methods have been detected. Further research is needed to determine the reasons for the observed differences.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1996-11-10 14:35:342017-11-10 14:36:13Evaluation of Trellis/Training Systems and Subsurface Drip Irrigation for Wine Grape Production in California