Revista Temes Rurals núm. 1

Orchard design and management
The agricultural sector must adapt to climate change through new
choices related to crops (species and varieties), the cultural vocation,
orchard design and its management. To try to adapt to
climate change, during orchard design it is important to choose
the correct species, rootstock and variety in accordance with the
environment.
The choice of rootstock
During the last years dwarfing rootstocks have been widely
used in high density orchard systems. Nevertheless, these particular
rootstocks develop a superficial root system, without
reaching the deep layers of the soil and exploring a very limited
soil volume: for these reasons the soil explored by roots is a
small container for water storage. These rootstocks are very
sensitive to water scarcity. In periods of high evapotranspiration
demand on the environment they need a daily irrigation
supply. Their choice is often made to contain the development
of plants, increasing the number of plants per hectare. However,
in the next few years it will be necessary to choose rootstocks
tolerant to drought. In the past years, the introduction of
“dwarfing” cherry rootstocks in semi-arid environments with
scarce water availability caused high damages and economic
losses. Replacing them with more vigorous rootstocks was the
only possible solution.
The choice of correct species,
variety and planting density
The choice of species has to be directed towards those that
are drought and pest tolerant. Yield stability, yield performance
and tolerance to biotic and abiotic stresses are the most important
parameters to consider in the choice of varieties in order
to reduce risks in regard to climate change (Macholdt and
Honermeier, 2016). Increasing crop water productivity (WP)
and drought tolerance by genetic improvement and physiological
regulation may be the means to achieve efficient and
effective use of water. In addition, in order to increase soil volume
explored by roots and the timing between two irrigation
events, the reduction of plant number/hectar is needed.
The timing of phenological events such as flowering are often
related to environmental variables such as temperature
(Parmesan and Yohe, 2003). Temperate perennial crops that
are growing in seasonally restricted temperate regions have
chilling requirements that should be satisfied in order to initiate
growth and flowering in spring. Failure to receive sufficient
chilling can lead to serious consequences including reduction
of flower quality, abscission of flower buds, protraction of the
flowering process and reduced fruit set (Melke 2015). Extreme
events like spring frost are often more frequent and they could
damage flowers and fruits, in particular for early blooming varieties.
Late blooming is often a main selection criterion in breeding
programs. Nowadays, breeding programs have to focus
on selecting the most frost tolerant cultivars, with low chilling
requirement and high heat requirement, in order to postpone
the bud-break and avoid spring frost damage.
Worldwide, many crops rely on insect pollination. Insufficient
pollination can reduce fruit and seed set by reducing pollen
deposition (Chautá-Mellizo et al., 2012). Considering that,
self-incompatible varieties need cross pollination and, given
that artificial pollination has high costs, self-compatible varieties
have to be preferred
Paisatge i ecosistemes
Fruit orchard management: How can we adapt to/face climate change?
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