We are going to dedicate this article to the walnut tree in Spain and how we should control irrigation with sensors to improve the quality and quantity of walnuts.
Walnut irrigation problems in Spain
- The lack of water causes a shortening in the life of the tree, lowering the quality and production. In addition, with evaporation, salts accumulate on the surface that in the next irrigation can be too much for the proper absorption of the roots and damage the tree.
- Excess water impairs the aeration of the roots and diminishes oxygen with the appearance of diseases.
The fact that three sensors are installed, as seen in the images, is to control the depth of the humidity.
- The line planting must have an isolation from tree to tree of about 7 × 7 or 12 × 12 meters to favor aeration. Walnut in its development has a wide crown.
Controlled irrigation
Control the water you need at each time of the year with moisture, soil temperature and conductivity sensors .
Measure the humidity in the soil to offer the walnut a distribution of irrigation more or less away from the trunk depending on the growth of the roots.
Avoid puddles.
Maintain a balance between the needs of the walnut and the supply of water so that it does not suffer from water stress.
Monitor the accumulation of salts.
Control at all times prevents diseases such as anthracnose and bacteriosis from appearing.
The wet bulbs depend on the type of soil, these would be sandy-loam. The irrigation system moves around the walnut tree and adapted to its growth.
Other times, as the drawing illustrates, the depth of the sensor is adapted to the age of the walnut, because the depth of the roots varies as the tree grows.
It is estimated that in a very few years production will double according to (MAP). At present, the "nuts of Spain" brand has been created to publicize the brand nationally and internationally. Our nuts surpass in quality and in flavor the Californian and the Chilean ones.
Climatic conditions for walnut cultivation in Spain
- A large number of hot hours between May and September.
- A number of cold hours per year.
- In dry weather it needs irrigation. An irrigation control in spring and summer is very important.
In the north of Spain you do not need irrigation. - Very sensitive to late frosts because they affect flowering and autumn frosts that can cause fungus to the fruit. It is affected by sudden changes in temperature.
- Productions vary within each community. Usually because of irrigation problems.
In areas where there was not much production, it is increasing with intensive and aligned crops, prepared to collect mechanically if irrigation allows it.
This is the case of Valnut-Valladolid, where Plantae will control drip irrigation with humidity sensors.
Another plantation with sensors is that of Cortijo Calonge in Córdoba.
Type of terrain
In clay soils the small roots die easily and this impairs the absorption of nutrients. In the silty we can plant but the production will be less.
Walnut pruning
El nogal necesita cuatro tipos de poda:
- The first training session . Prune developing a central axis. The first four years the tree has to form.
- The second production . Side branches are thinned out to allow the tree to air out.
- The third renewal . As the walnut becomes adult, the branches that we observe are not very productive are pruned.
- The fourth control pruning . Better in winter, especially in December, branches that grow poorly located.
Walnut varieties.
Walnut in Spain at an intensive level is a recent crop. The non-intensive has a less commercial production.
In the new walnut plantations, the varieties stand out:
- Chandler, one of the most cultivated.
The depths are 20/40/70 cm. In this way we measure the humidity of the wet bulb .
- Howard, good for intensive
- Forde, good for intensive.
- Lara, very adapted to intensive.
- Serr, early maturing.
- Franquette, a variety of the first imported.
- Hartley.
- Sunland.
- Vina.
- Tulare.
- Pedro.
As a «regal» rootstock.
Walnut wood in Spain
Walnut wood in Spain is one of the most appreciated and expensive on the market, due to its grain and its hardness.
There are several types of walnut trees to produce quality wood, all with high water needs:
- Common walnut or Spanish, called Juglans regia .
- Juglans nigra or American black
- Hybrid , combination of several species among others with American black walnut.
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