| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4479553 | Agricultural Water Management | 2011 | 7 Pages |
Using a correlation between trunk diameter fluctuation (TDF) and stem water potential (SWP) it appears possible to determine water deficit threshold values (WDTV) for young cherry trees. This correlation must be based on a significant effect between SWP and at least one variable associated with the vegetative or reproductive growth of the trees. The objectives of this study are: (1) to determine the effect of several irrigation treatments on vegetative and reproductive growth and the SWP of young cherry trees; (2) to determine the correlation between TDF and SWP, and; (3) to propose a first approximation of SWP and TDF water deficit threshold values for young cherry tree plants. The experiment was carried out between September and April of the 2005–2006 and 2006–2007 seasons, in Quillota, in the Valparaiso region, central Chile. The irrigation treatments consisted of applications of 50% (T50), 100% (T100) and 150% (T150) of potential evapotranspiration (ET0) over the two growing seasons, using a randomized complete block design (RCB). The effect of irrigation scheduling was observed on: apical shoot growth rate (GRAS), branch cross-sectional area (BCSA), canopy volume (CV), annual length of accumulated growth (ALAG) and productivity. This effect showed that the T50 treatment caused lower SWP (measured pre-dawn), vegetative growth and productivity. The fruit quality variables (cracking and size) were not affected by the different treatments. Combining the vegetative growth, productivity and SWP results shows that the water deficit threshold value, as a first approximation, is between 50% and 100% of ET0, and therefore the critical SWP for defining irrigation frequency should be close to −0.5 MPa. Upon applying a post-harvest drought period (14 days without irrigation), a linear correlation was determined both between SWP and maximum daily trunk shrinkage, MDS (R2 = 0.69) and between SWP and trunk growth rate, TGR (R2 = 0.57). Using these correlations and the SWP reference value, reference values were obtained for MDS (165 μm) and TGR (83 μm day−1), which would permit automated control of water status in young cherry trees.
Research highlights▶ Use trunk diameter fluctuation to determine water threshold in young cherry trees. ▶ Based on significant relation of SWP and vegetative or reproductive growth of the trees. ▶ 50% water application caused lower pre-dawn SWP and vegetative growth and productivity. ▶ Observed Irrigation effect apical shoot growth rate, branch cross-sectional area. ▶ Using correlations and reference SWP critical values were obtained for MDS and TGR.
