Effects of alternate partial root-zone drip irrigation on growth of root and shoot of Cabernet Sauvignon grape seedlings

Abstract: On the basis of its own subsurface drip irrigation with tank system, effects of alternate partial root-zone drip irrigation on grape seedling growth were explored, and the best drip irrigation mode and method was selected that was suitable for wine grape production in arid and semiarid areas of China. The experiment used Vitis vinifera L.'Cabernet Sauvignon' as materials and used conventional drip irrigation (DI) and subsurface drip irrigation with tank system(SDI) (independent design) as the basis of engineering technology .Under bag control experimental condition, four kinds of partial-root zone alternative controlled drip irrigation methods were designed as follows: SDI-DI (SDI was on the left side, DI was on the right side) SDI-SDI (both sides were SDI), DI-SDI (DI was on the left side, SDI was on the right side), DI-DI (both sides were DI).Effects of alternate partial root-zone drip irrigation on shoot biomass, root distribution, root vigor and leaf physiological function of Cabernet Sauvignon seedling were discussed. The ratio of root to shoot was at optimum level (1-1.3) and shoot biomass accumulation were not significantly affected by SDI-SDI、DI-SDI、DI-SDI under the same irrigation conditions . The ratio of root and shoot was increased, plant experienced drought stress more intense and plant growth was limited by DI-DI. Horizontal root number on the left and right of DI-SDI and SDI-DI had great differences, and root number on the right was 13.3%、10.5%、14.0%、22.1% more than that on the left ,while horizontal root number on both sides of DI-DI and SDI-SDI had small differences. Root penetration was promoted and root activity in the depth of soil layer 20-60 cm was improved by SDI-DI and DI-SDI. In the depth of soil layer 0-20 cm ,Root average diameter on the left side of SDI-DI and SDI-SDI were significantly higher than that of DI-DI and DI-SDI, and root surface area, root volume on the left side of SDI-DI and SDI-SDI were lower than DI-DI and DI-SDI treatment. In the depth of soil layer 0-10 cm, root average diameter on the right of SDI-SDI was the highest, but there was a little difference with DI-SDI. Ratio of root surface area, root volume on the right side of SDI-SDI and DI-SDI in the depth of soil layer of 20-40 cm were the most, root surface area of the two irrigation methods accounted for 48.8% and 49.2% respectively of the total surface area of the root on the right side, root volume accounted for 47.5% and 46.3% of the total volume of the root on the right side. The two irrigation methods maintained leaf photosynthetic performance stability and the leaf instantaneous water use efficiency (WUE) at a high level. The study on relation between root and shoot of plant showed that net photosynthetic leaf photosynthetic rate and transpiration rate were improved by reducing root biomass of surface and increasing root biomass of deep zone. The root activity significantly affected the photosynthetic characteristics of leaves of above-ground part, which was a key factor influencing on physiological characteristics. Under alternate partial root-zone drip irrigation, effects of SDI-DI and DI-SDI on the growth of root and shoot in Cabernet Sauvignon grape seedlings were better than DI-DI, and were the same as SDI-SDI. Considering the production cost, the field operation and difference on growth of root to shoot, SDI-DI and DI-SDI were the best drip irrigation mode and method under the condition of this experiment.