Our investigation was carried out in several orchards in Hungary. This study reviews applicability of the different spatial analytical techniques in orchard especially models based on surface relief, such as digital elevation model, digital terrain model, slope and aspect maps. In recent time, the generation of digital elevation model has becom...e a popular examination method. However, the elevation models generated from contour lines or elevation points could be applied to evaluate agro- ecological potential of fruit orchards to some extent. The highest deficiency of these models is the fact that these show the altitude of soil surface only and do not demonstrate landmarks on the surface. Consequently, the calculation of the radiation value results data relating to soil surface. The terrain model generated and applied by our team demonstrates fine surface texture and the landmarks in the orchard, so it is suitable for further examination.
Sap flow rate measurements were carried out during two consecutive ('on' and 'off') years in an apple orchard cv. 'Florina' M.26 to analyse the effects of various crop load on tree water use. Sap flow rate was measured by thermal dissipation method in trunks of nine trees from June to the harvest. Crop load was between 0.2-9.0 fruits • cm ...p>-2 of trunk cross section area (equal to 0.5-35.0 fruits•m-2 of leaf area), trunk diameter varied between 4.7-8.7 cm.
Total leaf area was estimated by leaf counting or using shoot girth and leaf area relationship. In both years, fruit growth rate was determined by measuring diameter of 280 marked fruits with 7 days frequency. Fruit volume calculated as a function of fruit diameter based on a previously determined relationship.
Total leaf area of trees ranged from 4.4 to 19.5 m2 and it was closely related to trunk cross section area. At high crop load the fruit growth rate peaked in August with 0.51.tree-l.day-1 and the leaf area specific total fruit volume reached 61 m2 before the harvest.
There was a linear relationship between total leaf area and daily water use, while the leaf area specific water use was influenced by crop load rate. The relationship was described by piecewise linear regression with the breakpoint at crop load rate of 12 fruits•m2 of leaf area. At low crop load the slope of the fitted regression line was less than at high crop load rate.