. We evaluated the effect of the four treatments on canopy volume (CV) during two growing seasons. For 28 days during the second growing season, we evaluated soil moisture content (θ), the soil-moisture depletion factor (p), trunk cumulative growth (TCG), trunk growth rate (TGR) and maximum daily trunk shrinkage (MDS). We found relationships between CV and TCG and between CV and TGR. There were no differences in MDS among the irrigation treatments. We observed significant water stress in plants in the 0.3 ETc treatment (p = 0.47). The highest growth was observed in plants in the 1.3 ETc treatment, which suggests that the crop coefficient (Kc) was underestimated.
Nutrient requirements in young trees increase annually during fruit formation. This study was conducted to determine the effect of fertilisation treatments, using fertigation, on the vegetative and reproductive growth of young cherry trees (Prunus avium) cv.'Brooks' grafted onto 'MaxMa 14' rootstocks in Central Chile. The research was conducted at the La Palma Experimental Station in Quillota on 3-yr-old cherry trees spaced at 5 m x 2 m and trained as central leaders with the Solaxe system over the course of two growing seasons. Few of the measured variables were significantly affected by the treatments. The shoot length was affected only after harvest (November), the node number increased with shorter shoots, and the fruit set decreased with no N application. Fertilisation resulted in some negative effects, such as a lower number of nodes (per m -1 ), decreased fruit set, and increased cracking. Considering the null effect of applying N before harvest and the significant difference in vegetative growth between T 100 and T 200 after harvest, it appears that there are at least two different strategies for the fertilisation of young cherry trees: fertilisation should start either after harvest or a few weeks earlier with N applications higher than 100 but lower than 200 kg-N ha -1 . This amount should be further investigated, and a combined strategy of less than 200 kg-N ha -1 plus accompanying nutrients applied after harvest should be used.
Diameter fluctuations of branches, shoots, or fruits are related to plant transpiration and water potential. In the past, several models have related dendrometric variables and evapotranspiration on a daily scale. However, trunk–branch shrinkage occurs only between dawn and midday, while evapotranspiration occurs most of the day from sunrise to sunset. Previous models have failed to incorporate this key fact. The objective of the present study was to assess the relationship of hourly daily shrinkage (HDS) between dawn and the next 4 h to the hourly reference evapotranspiration (EToh) of the same period in walnut trees and pomegranate plants under different irrigation regimes. Our data show that the relationship between EToh and HDS is much better than several previous models that included maximum daily shrinkage (MDS) and reference evapotranspiration (ETo). The novel slope analysis of the relationship between HDS versus time used here corresponds to the velocity at which the HDS occurs, which depends on the ETo intensity at that moment. This new method of analyzing this type of data calls for a revision of these models and sets a new baseline for future analysis.
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