Production Practices and Quality Assessment of Food Crops. Vol. 1

136 S. Pereira-Lorenzo and A. M. Ramos-Cabrer
nut production will be delay for some years while the trunk and crown is
forming.
There are two possibilities in producing quality timber. The most interesting,
according with the higher prices obtained in the timber market is forming a long
trunk up to 7 m free of branches. It will take at least 40 years to cut a good
trunk, more than 40 cm width. But in Galicia, the best qualities, more than 70 cm
width are obtained after 80 to 90 years. The advantage of this system is the
addition of annual production of nuts. Such system is used in Galicia, Spain, with
Garrida and Loura cultivars and in Cuneo, Italy, with cultivars ‘marron type’
(Figure 13).
Other possibility is forming a trunk 2 to 3 m long and pruning over that point
to obtain 4 to 6 vertical branches (Figure 14). After 20 years we can obtain more
than 20-cm width logs. And when the tree is removed part of the stump can also
be used. Such poles are often used for vineyard trellis, hops trellis, fences, charcol
making or, in general, as outdoor timber without any treatment.
6.2. Management of ground
Four systems are used: (1) In humid areas pasture is the most common since it
can be used for animals. (2) In drier areas, pasture could not be maintained without
irrigation, which limit its use as intensive orchards (Figure 15). In some situations
farmers grow wheat or rye during spring as a complementary crop which will help
to limit weeds and incorporating organic matter. A first ploughing is made before
sowing the spring crop and one before collecting the nuts. Though spring crops
are no being any more, growers continue ploughing the ground, which increase
soil erosion. (3) The use of herbicides can be a possibility but the ecological importance
of chestnut growing must prevent its excessive use. In intensive orchards
herbicides are recommended on the inter-lines. But for this system it is only useful
when the orchard is irrigated. (4) The last alternative is to use minimum inputs by
natural grass cover the ground and two mows must practice to control the vegetation,
avoid fires and facilitate the harvest.
6.3. Fertilisation
The best suggestion for fertilizer input can be found in Breisch, 1995. Average values
for macro- and micronutrients in leaves can be found in Table 13.
The lack of copper is related with granite soils, extremely poor in nutritive
elements, and produce symptoms of reddish-brown in the secondary veins top of the
leave (Breisch, 1995). In South Korea, the lack of Boron is related with the early
fall of young burs after flowering and in France, necrotic parts of the bark after
hard pruning in orchards located in poor soils areas.
Chestnut can be found in soils of high acidity, as much as pH 4,5, but soils
with a pH higher than 6 it is recommended to rectified with calcium magnesium
carbonate.
For soil amendments to get a minimum level of fertility with recommendation
given by Breisch (1995) are quantities of 200 to 300 kg/ha of P 2O 5, 150 to 300 kg/ha