Walnut: Description, Varieties, Ecology, Uses, Cultivation, Chemical Composition and much more

             Walnuts                                    

Introduction

The generic name of this species "Juglans" comes from the Latin "Iovos glans" which means "Jupiter's acorn", which is what the Romans called walnuts. The specific name "Regia" also comes from Latin and means "royal" alluding to its splendid and majestic bearing.

The walnut (Juglans regia) is a fruit tree belonging to the family of the yuglandáceas and native to Persia (Himalayan region), according to some authors, or from China and Japan, according to others; it was transported to Greece and then to Italy and the other countries of Europe. 

The official cultivated species are the following: European walnut, ashen walnut, black walnut, and California walnut.

It is a very long-lived tree that exceeds 500 years of life.

The farming of walnut cannot occur if there is no least rainfall, which is around 700mm, or effective artificial irrigation. In addition, the walnut is a tree that does not stand late spring colds or too high temperatures without adequate moisture. This type of temperature can cause damage to the walnut fruit: the walnut.

Regarding the land needed to grow a walnut tree, we will say that it is a very neutral and flexible tree in this sense, although the soils preferred by this tree are deep and loose soils.

Description

Plant: The walnut is a very tall deciduous tree that can reach 30 or 40 meters in height and has a trunk with nothing more and nothing less than 2 meters in thickness, although some varieties of 5 meters in diameter have been found. 

It is a resistant trunk with a color that turns greyish and from which the abundant and vigorous branches grow that will form an enormous rounded crown and that have a reddish color when they are still young, and later turn brown.

The branches of the walnut tree are full of huge leaves up to 35 cm in length.  Young branches are thick and knotty, with the medulla typically empty and divided by transverse spacers.

                                                                

Deciduous leaves, alternate odd-pinnate, large, compound, with 5 or 9 leaflets. The end of the blade is larger than the sides. The edge is quite smooth.

The walnut loses its leaves in winter and in spring they come out again at the same time as the flowers, of which there are male and female, the former being the ones that house the largest number of flowers. The leaves have a long petiole with a veneer at the tip and 2-3 pairs on the sides; when they come out they have a reddish color but when they mature they turn green.

Each female flower has an ovary that is already a small nut where the upper end is the calyx and two horns emerge from the middle, which are the stigmas (the flower crowns the fruit). The male ones come out of the log from the previous year below the female ones in the form of bouquets. The male flower is a catkin. It is pollinated by the wind.

The walnut is the fruit of the walnut and is a drupe or trima that houses a seed composed of 2 wrinkled cotyledons that are separated by a perpendicular partition.

They consist of a thin, glandular, and glabrous fleshy layer, green in color, which turns black and cracks when ripe. 

Inside it is the nut, formed by a hardcover that opens in two parts, the welding lines of which do not coincide with the welding of the carpels, but with the middle nerves of these. In addition, it has 2 or 4 false partitions incomplete. It houses a seed with four lobes, rich in oils. It begins to bear fruit around 10 years of age.

CHEMICAL COMPOSITION OF THE COMMON WALNUT

It is a very nutritious food, with a high caloric value, 662.5-688kcal / 100g and among the vitamins present in walnuts, the most important are those of group B, among which folic acid stands out.          

- Water 4%
- Carbohydrates 15% (fiber 5%)
- Proteins 15%
- Lipids 60% (linoleic acid 30%)
- Sodium 4 mg / 100 g
- Potassium 500 mg / 100 g
- Calcium 80 mg / 100 g
- Phosphorus 400 mg / 100 g
- Iron 2 mg / 100 g
- Vitamin B1 0.3 mg / 100 g
- Vitamin B2 0.1 mg / 100 g

Ecology and cultivation

It lives in loose, deep, and fertile soils, between approximately 200 and 1,500 meters of altitude, which have an average annual rainfall of 400 to 700 mm. It also adapts well to limestone soils.

It needs humidity both in the environment and in the soil, and it is well resistant to annual temperature fluctuations and late frosts. It is a heliophilic tree, typical of a temperate climate, which almost always appears quite scattered to take advantage of the available resources. It is sometimes mixed with other hardwood species.

Walnut trees are found in southeastern Europe and western Asia. From northern Greece to the Himalayas, passing through the Balkans. Its presence in China, Iran, Armenia (wild), and North America (especially California) stands out. Generally, in temperate zones.

Cultivation: It is easy to grow and care for it. To reproduce this tree, it can be done through seeds in autumn, the seeds being the fruit of the tree. It does not require large amounts of water and is very resistant to cold. In addition, the soil needs to be finely drained.

Temperatures: Places, where spring temperatures can drop below 1.1ºC, should be avoided, as they can cause frost damage to male inflorescences, new shoots, and small fruits.

Walnut is very sensitive to spring frosts, which will substantially reduce the harvest, but also to early autumn frosts that interfere very negatively with the formation of the first years; During this juvenile period, the entire aerial part of the seedling may die.

If there are temperatures above 38ºC accompanied by low humidity, it is possible that sunburn may occur on the most exposed nuts.

If this occurs early in the season, the nuts will be empty, but if it is later, the seeds may furrow, deepen, or attach to the inside of the shell.

In very temperate climates and in low situations, affected by dry and warm winds from the south, in addition to causing premature leaf fall, it is difficult for the harvest to be saved by the laying of the lepidopterous Cydia pomonella, which causes the watering of the fruit.
Rainfall: Despite its rusticity, it is very sensitive to drought, being unfit to be cultivated in drylands and dry nature.
For farming to be possible, it needs the least rainfall of 700 mm, being 1,000-1,200 mm for intensive operations.
If the rainfall is insufficient or is unevenly distributed, it will be necessary to resort to irrigation to achieve a normal development of the trees and good production of walnuts.
Soils:
It is a tree that adapts very well to very different soils, although it prefers deep, permeable, loose soils with good fertility. The drainage will be determined by subsoils made of broken limestone, rocks, etc.

For good water retention, soils with an organic matter content between 1.2 and 2% and 18 -25% clay are required.

Walnut grows in soils with a neutral pH (6.5 - 7.5).

Depending on the characteristics of the soils, different types of patterns will be used, highlighting J. nigra for acid soils and J. Regia for the more limestone ones.

Traditionally there were isolated trees around country houses or in villages that did not correspond to any specific variety, since they often come from sexual reproduction through the planting of walnuts. Extensive cultivation began in California with the large-caliber American varieties. French varieties with better organoleptic qualities, but smaller, are also grown.

The problem with this crop is one band that takes many years to start bearing fruit and the other is a species highly affected by bacteriosis. The late spring frosts if they coincide with the flowering can leave the tree without harvest, since the flowers do not support beyond a degree below zero. Only high temperatures in summer give thick sizes that are preferred by the market, despite the fact that the small varieties have better taste. Intensive plantations are always irrigated.

Varieties of walnuts
The varieties cultivated in Europe for the fruit belong to the species Juglans regia. Early sprouting varieties and late sprouting varieties are distinguished.

Within each group they are in turn divided into varieties with soft shell fruits and varieties with hardshell fruits, distinguishing them into subclasses according to whether they produce edible fruits or extract oil.
Late budding varieties are preferred, taking into account the rapidity of development and fruiting of the plant, such as the taste of almonds.
The most oil-rich walnuts are the least appreciated for dessert and have a very hard and full shell.
For dessert, nuts that have a tender or semi-tender shell, with a certain appearance and rather thick, are preferred.
There are varieties in which the male flowers (protandria) develop first; others, the feminine ones (protogyny), and others at the same time both (homogymous).
They can also be classified as soft-shelled (mollars) or hard-shelled. The latter are better resistant to fungal infections.
SOFTSHELL WALNUT
Mollar.
Early ripening.
Moyet (French).
Barthere (French).
Franquette (French).
Of the birds.
HARD-SHELLED WALNUT
Common.
Parisienne (French).
Partridge beak.
Late.
Precocious.
Early ripening.
Bijoux (French).
Other varieties of walnuts
Payne (USA).
Meylannaise (French).
Marmot (French).
Fernor (French).
Corne (French).
Gourlande (French).
Brantome (French).
Ashley (USA).
Concord (French).
Ehrhardt (USA).
Waterloo (USA).
Chandler (USA).

 

Industrial Uses

Walnut wood is hard, homogeneous, very heavy, and easy to work, polish, and varnish, which is why it is highly valued in cabinet making and hardware.

Its color is grayish brown, often broadly veined, with grayish or blackish bands, which give it a characteristic appearance.

It is used naturally, stained, waxed, or varnished. It is also an industrial wood, as it is used for butts of shotguns and luxury rifles. It is also used in fine carpentry, for stair ramps, cast-iron models, etc.

In times of tobacco scarcity, dried and shredded leaves were used for smoking. Nuts are edible, very nutritious, and rich in oils that have vermifuge properties.

Pharmacological uses of walnut

Walnut is one of the best trees that exist since all its components are very good and are used for various functions.

The wood of the walnut is very demand in the woodwork, it is a strong wood.

The leaves of the walnut have healing properties and are collected in June.

 The infusion of walnut leaves is good against digestive disorders such as constipation, purifies the blood, and is good against diabetes. Mouthwashes help against gum and throat conditions.

The fruit The walnut is the fruit of the walnut, rounded or ovoid in shape, with a hard and rough shell of a reddish-brown color. 

The eatable part of its inner has a specific sweet flavor.
In the market there are shelled, chopped or ground walnuts and products made with them.

Normally, the nut is consumed raw as a snack or dessert, either alone or combined with another food. It is used as an ingredient in many dishes, sauces, and ice cream. In the market can be found whole walnuts, chopped or ground as more or less fine flour.

 In addition to being one of the most appreciated nuts for its pleasant taste, it is one of the richest in oil, which is why they are used to obtain it. Walnut oil has a pleasant sweet taste. The young fruit is used to make the juice known as Ratafía. The nut is edible and very nutritious. It is worth it for the heart, for circulation, to decrease cholesterol, and against hair fall. It also has Vitamin E and Vitamin C, omega 3, and omega 6.

Walnut leaves have large amounts of gallic and ellagic tannins. Naphthoquinone is also present, mainly juglone, which crystallizes orange in color and has a bitter taste. Specifically, it is 5-hydroxy-1,4-naphthoquinone. Inositol, flavonic derivatives, and vitamin C are also present as active principles. The leaves and walnut (green walnut shells) contain abundant tannins that give it its important astringent property.

It is known for its effects as an antidiarrheal due to the astringent effect of tannins and as a dermatological astringent also due to the effect of these same tannins on the skin. The uses approved by Commission E of the German Ministry of Health are exclusively for nonspecific dermatitis. Other recognized traditional uses are in the treatment of acute diarrhea, whether of the bacterial origin or not, and, above all, to cure intestinal parasitic infections. Other more traditional uses are for skin conditions such as burns, skin ulcers, or itching.

Medicinal uses of walnut

Internal employment

The leaves and the green rind and bark have astringent properties. From the latter, a varnish known by the name walnut is obtained, which is used to stain other woods. Likewise, the oil from the seed is deworming and is reputed to cause the expulsion of tapeworms (intestinal parasites). The leaves are hypoglycemic and are taken as an infusion to combat diabetes.

Diarrhea: leaves, due to their tannin content, are astringent and can be used to fight diarrhea. The decoction of a teaspoon of dried leaves made crumbled per glass of water for ten minutes. You have to drink two glasses a day.

Hypothyroidism: walnuts, particularly green walnuts, have components that stimulate the production of thyroid hormones. The decoction of four eggs per liter of water is suitable for twenty minutes. Take 2 cups of water. Eat fresh walnuts or use crude walnut oil in salads.

Sweat: the preceding preparation can also be used to treat excess sweat.

Tapeworms: walnut oil is used to expel these parasites from the intestine. For dinner, dress a plate of boiled potatoes with sixty grams of walnut oil.

 

Outside employment

The astringent, antifungal, and aseptic properties exercised by the juglones of the leaves and the covers of the walnuts, are used as disinfectants and vulnerable.

External treatment of the skin. Ten percent infusion of dried leaves in one liter of water. Apply wet compresses on the affected area. Also, add a handful of dried leaves to the bathwater. For the treatment of scabies, a handful of walnut shells should be cooked in a liter of water until such time as the water reduces to fifty percent. Wash with this water.

Prevention of hair loss. An application of the preceding infusion on the hair will help to prevent its fall. The extract of the pericardium is also proposed.

Treatment of vaginal infections. A wash with this infusion will help to suppress the microorganisms of the vaginal discharge.

Conditions in the respiratory system. The astringent and disinfectant properties can be used for gargling to treat respiratory tract conditions such as pharyngitis and tonsillitis.

Prevention of tartar on teeth. Make rinses with the previously explained infusion.

Other uses

Juglones form a natural colorant used to make hair dyes, widely used in the cosmetics industry, called walnut. Walnut wood is considered the most appreciated and appreciated of European woods. In cabinetmaking objects such as pianos or shotgun, butts are made. E n times is grown only by wood without interest nuts and in these cases can be done in colder lands. It gives good firewood and good lignite.

the nuts

Walnuts stand out for their content in polyunsaturated vegetable oils. Walnut oil with multiple uses is commercially obtained from walnuts. Although the oil contains oleic acid (monounsaturated) such as olive oil, the proven cholesterol-lowering effect is due to its richness in alpha-linolenic and linoleic acid (polyunsaturated). These last two oils also make it useful in the prevention of diseases in the circulatory circuit. The frequent intake of new ones reduces the risk of suffering diseases such as myocardial infarction or angina pectoris by up to fifty percent, therefore they can be considered antianginal.

In addition to this, these oils increase arterial elasticity, prevent clot formation and reduce tension. This ability to promote blood circulation is due to the transformation of alpha-linolenic acid into prostaglandins responsible for avoiding the onset of atherosclerosis.

Eating about five nuts five times a week, instead of other animal sources such as lard or animal meat, is a good way to take care of your heart. However, it must be remembered that walnuts, like most dried fruits, provide a high amount of calories.

They are a good source of fat-soluble vitamin E and calcium, they also provide a small amount of vitamin C and B, and zinc, they are a natural antianginal.

Walnut cultivation
Vegetative propagation of walnuts:
Walnut trees are propagated in nurseries by spike grafting and budding.

Bud grafting on black walnut is done so that a small piece of trunk rests on the black walnut, which decreases the hazard of sunburn and access of root fungi.

When the trunk is about 2.5 cm high, it is removed with a hoe about 5 to 10 cm and the spike is grafted onto the foot below ground level.
It is tied well, covered with asphalt emulsion and this region is covered with earth again.

The plants thus grafted in the nursery are kept for another year forming a central axis, without sides, which is tied to a stake 2.5 to 5 cm by 2.4 m high.

Patch grafting can be used on one-year-old, fast-growing nursery plants. It is advisable to pre-mature the buds, removing the leaves from the branch, leaving the rachis attached, 10 days before removing the buds.

Plastic or rubber bands can be used to tie the bud firmly to the foot.
Propagation by the seed of walnut trees:
Although it is not widely used, walnuts are chosen from a tree well known for their adaptability to the region in which it is grown and for the quality of its product.

From the nuts, the ones that have matured the first are chosen and once the coconut is stripped, they are stratified in the sand, to later marinate them and the shell opens.

Two to three seeds per hole will be placed in nurseries for two years until the appearance of the foot.

Pests
- Carpocapsa or walnut worm ( Cydia pomonella).
- Zeuzera ( Zeuzera pyrina ).
- Cossus (woodworm).
- Aphids ( Callaphis juglandis, Chromaphis juglandicola ).
- Erinosis.
- Cacoecia.

Diseases
- Walnut ink or black bad ( Phytophthora cinnamomi ).
- Rot ( Armillaria mellea ).
- Bacteriosis or badly dried walnut ( Xanthomonas juglandis ).
- Walnut anthracnose ( Gnomonia leptsostyla ).

HOW TO RECOGNIZE IT?

Walnut is characterized by having a straight and thick trunk and has a smooth bark that is silvery-gray, or grayish-brown, which superficially cracks with age and is rich in resins and tannins.

The little abundant twigs are thick, gnarled, and greyish. Those of the year are hairless, shiny, and with clear lenticels. The buds appear in groups of three and are blackish brown, scaly, and little apparent before their development.

The leaves, decayed and alternate, are compound, have between five and nine lanceolate or elliptical leaflets, with entire or wavy edges, and have a pale green color with some hairiness in the axils of the lower veins. They exhale, like the green mesocarp of the fruit, an intense aromatic odor.

Walnut flowering takes place in specimens that are over fifteen years old and is similar to oak and hazelnut trees.

As a dioecious species, male and female flowers appear in separate groups but are present on the same tree. Male catkins are greenish, long, and hanging. The female flowers, isolated or in groups of two to four, are found at the end of the young twigs of the year.

The male flower appears welded to an underdeveloped bract and consists of a perianth of five or six divisions and between six and thirty-six stamens (usually twelve to twenty) of short and connective filament. The female flower consists of a short perigonium, of three to four lacinia, surrounded in turn by an involucre composed of between three and five lobes, or teeth, which is formed by a bract and several welded bracteoles.

The ovary is inferior, unilocular, and uniovulate, it is composed of two welded carpels and is topped by two very short styles, with two feathery stigmas.