Comparative tree growth, phenology and fruit yield of several Japanese plum cultivars in two newly established orchards, organic and conventionally managed

Abstract

The growth, phenology and fruit yield of 14 Japanese plum cultivars (Prunus salicina Lindl) were studied in two newly established experimental orchards under organic and conventional management. The experiment was conducted during 2005-2011 in the province of Seville (SW Spain), an important region of Japanese plum culture. Trunk crosssection areas (TCSA), flowering, yield and tree defoliation before winter dormancy were analysed over several years. After one year, TCSA were larger in the organically managed orchard (OMO) for most of the cultivars, in the next two years they were equal, and from the fourth year, several cultivars showed significantly larger TCSA in the conventionally managed orchard (CMO). Flowering in the conventional orchard started from 2 to 6 days before and lasted for 3 to 5 days more than in the OMO. Several cultivars produced significantly more fruit in the CMO, being the average fruit yield in the organic orchard about 72% of the conventionally managed orchard. Autumn defoliation was significantly advanced in the organic orchard, especially in cultivars highly susceptible to rust (Tranzschelia pruni spinosae), a disease not adequately controlled in the organic orchard.

Carbohydrate and nitrogen reserves in two cultivars of Japanese plum grown under organic and conventional management

“…Under organic management, premature defoliation was observed in both cultivars. These results are in line with what was observed in previous crop years for these cultivars as well as for additional Japanese plum cultivars (Arroyo et al 2013). These differences in time of defoliation are important, since the average number of days between the beginning and the end of defoliation for both managements and cultivars in the period studied was 65.25 days.…”

“…On the other hand, both cultivars showed delayed flowering under; although the differences were not very large, blooming was always delayed under organic management during the period 2007-2014. Twelve other Japanese plum cultivars studied in this period of time showed the same trend (Arroyo et al 2013). Under organic management, premature defoliation was observed in both cultivars.…”

“…We also performed some analyses of reserves in thin roots were in November 2012 and found no differences between the two types of management (data not shown). Moreover, although reserve concentrations were similar under the two types of management, the total amount of reserves under conventional management would be expected to be higher since these trees were taller than those under organic management (Arroyo et al 2013). To our knowledge, there are no previous studies analysing reserve levels in adult fruit trees grown under organic versus conventional managements.…”

“…In previous work with different Japanese plum cultivars, it was found that in organic farming results in significant premature defoliation (García-Galavís et al 2009). Moreover, it has also been observed that trees grown under organic management exhibit reduced vigour, somewhat delayed flowering and lower fruit production than trees grown in conventional agriculture (Arroyo et al 2013). The goal of this study was to analyse whether plum trees reserves are affected by the type of management, i.e., conventional or organic, which employs different fertilization and causes premature defoliation, and to identify whether there is a correlation between tree vigour and carbohydrate and nitrogen reserves.…”

Assessment of Climate Change Impacts on Chilling and Forcing for the Main Fresh Fruit Regions in Portugal

“…For the case of citrus, such as oranges, these plants are usually grown in warmer climates, and exposure to cold temperatures (<5 • C) may result in chilling injuries (Yuen et al, 1995;Santos et al, 2019). When spring arrives, forcing becomes a much stronger driver of tree phenology than chilling (Luedeling et al, 2013), and a period of warm temperatures (heat accumulation) is needed for adequate blooming and fruit ripening (Arroyo et al, 2013;Drepper et al, 2020;Rodriguez et al, 2020;Cho et al, 2021).…”