Almond is a stone fruit, from the Rosaceae family, closest to the peach. Originates from the Middle East, where conditions are dry and hot. Almonds spread throughout the entire Mediterranean region and afterwards to the Southwestern USA, Northern Africa, Turkey, Iran, Australia and South Africa. The almond is sensitive to wet conditions, and is therefore not grown in wet climates. The almond is popular in the market due to its dietary properties: Low level of saturated fat, high Vitamin E level and a high level of unsaturated fat.
Almond trees grow to a height of 4-6 m with a diameter of 3-4 m. The almond is hermaphrodite, but male and female blossoms are not in accord, so insect bees are necessary for pollination. Like peaches, the blossoms form around the vegetative buds. They are located on spurs that live 3-4 years, though some blossoms are also formed on new branches.
As opposed to other stone fruit, the pulp does not continue to grow in the third and last period. At the end of the growing season, the pulp dries and opens to expose the seed covering that reaches its final size after about 100 days. The almond tree can live a long time, but the lifetime of a commercial orchard is 30-40 years. Blossoming and fruit-set begin at two years, full fertility at four years, and maximum yield is attained at 7-9 years. Blossoms are light pink. Blossoming occurs in January-March, with fruit ripening in July-August, 5-6 months after blossoming in the northern hemisphere, and in the corresponding months in the southern hemisphere.
Almond best practices
A sub-tropical dry warm climate is optimal. Its growing range is quite wide, between 30°-45° laterals. Almonds do not like excess humidity. This crop is more resistant to dry conditions than other deciduous trees. Almonds can be grown without irrigation with a low yield. It is an accepted policy to add supplementary irrigation, where annual rainfall is less than 500 mm. Almonds require less cold units than other deciduous trees, but vary from one variety to the other. Most varieties require 300-500 cold units. Cold conditions are a serious problem for almonds, which blossom in early spring. Blossoms suffer damage at -2 °C, and vegetative buds at -4 to -6 °C.
Optimal pH is 7.0-8.5
Almonds grow in all types of soil, including chalky and shallow soils.
Main variety: Non-pareil, comprising 50% of global yields
Hard shell varieties: Texas, Buttei
Soft shell varieties: Thompson, Carmel, Rudy
Regular shell varieties: California Mission Neplus, Greek, Marcona, Hanatziv, Um-el-Fahem, Be’eri.
Comment: There are sweet almond and bitter almond varieties.
It is common to graft saplings in the nursery (Like with peaches).
Planting is at the end of the dormant season, before blossoming.
Saplings are planted with roots exposed.
In the past, orchards were not irrigated, and the number of trees per hectares was low - 140 trees/ha, with 7-10 m between rows. Pollinating varieties were planted every fourth row.
Presently row spacing is every 4-6 m with ~400 trees/ ha.
There is also an innovative approach where trees are planted every 2-4 meters due to their short life time.
Trees should be irrigated only to the point where they are sensitive to stress. However, if the quantity of water is insufficient for the tree’s needs, it is necessary to find the right stage where water reduction will do the least harm.
Deficit irrigation – The irrigation strategy can influence not only the current yield, but also the following season’s yield.
It is possible to plan irrigation in orchards for several years. Such a plan should be flexible according to the prevailing conditions. In almonds, it is important to apply full irrigation in the early spring, during kernel filling, and it is also important for the yields in the long run. In early almond varieties and spring varieties, it is possible to seriously reduce water quantities to trees from mid-June for two months. Later varieties can be resistant to stress during the two months preceding harvesting. This method reduces the kernel weight by about 10%, but results in considerable reduction in shell splitting. Renewing irrigation two weeks before harvesting improves shell splitting.
In the northern hemisphere irrigation coefficients (Kc) are as follows:
With drip-irrigated almonds or grown in shallow soil, the irrigation regime after harvesting is critical for the following season. Reduced irrigation after harvesting, results in a reduction in the number of blossoms and in fruit-set in the following year, therefore farmers must retain reserve water for irrigating after harvesting. This must be applied immediately after harvesting. In deep soil or where sprinklers are used for irrigation, it is less important to irrigate immediately after harvesting, and it can be delayed. Early falling off of leaves is a sign of insufficient irrigation. However, irrigating when leaves drop off after harvesting can cause leaves to renew growth, which is not desirable. The approach proposed here improves the tree’s moisture conditions at the critical stage for the following season’s blossom buds. Blossoming at the end of autumn can reduce the following year’s yield. This happens when the leaves renew growth in the autumn, when the climate is cold in October, then turns warm in November. Limiting irrigation during late autumn reduces unwanted blossoming.
Drip irrigation system
Drip irrigation is recommended as follows:
- Older orchards with traditional spacing: 2 laterals per row
- Young orchards: 1-2 laterals per row depending on the soil type
- Recommended distance between drippers: 0.5 m
- Discharge rate: 1.6-2.3 l/h
- Irrigation frequency: Every 2-3 days, according to soil type and development or phenologic stage.
- Uniram As is our universal solution for on surface and SDI applications. Uniram CNL & HCNL are needed if pulse Nutrigation is selected.
During soil preparation: 400-600kg/ha, P2O5 600-700 kg/ha, K2O depending on soil test results.
2kg boron should be added as needed. During years one, two & three 30, 60 & 90 grams N per tree accordingly.
Alphabetically: agrobacterium tumefaciens, brown rot (monilinia sp.), cercospora circumscissa, deplodea sp., nematodes, oak rot (amillaria), polystigma ochraceum, pytophthora, rust on stone fruit (tranzchelia discolor), silver leaf (chondrostereum purpureum), verticilium spp.
Alphabetically: brachycaudus amygdaliana, capnodis tenebonis, cerambyx dux, eccoptogster amygdaly, eurytoma amygdaly, lymantria destituta, lyonetia lerkella, meloidogyne spp, mites, navel orange worm (amyelois transitella), twig borer (anarsia lineatella).
Due to early budding, particularly blossoms, almond trees could easily be harmed by early frost or even by a late seasonal frost. In light of this data, it is recommended that a frost protection system be installed. The recommended system is the use of Super Net micro-sprinklers for every tree. Irrigation rate 3.5 mm/h.
Standard pruning is vase shaped to enable better light and radiation penetration. It is not necessary to thin out blossoms. All the blossoms reach fruit-set and most of them are collected. It is normally recommended not to cultivate the soil. Weeds along the rows should be treated with herbicides, while between the rows they should be mown. Alternatively, it is possible to grow an intermediate crop in this area, mainly legumes.
Buds open at the end of winter - beginning of spring. The flower buds open before the leaf buds. Blossoming time differs slightly according to variety and lasts about two weeks. Fruit develops from mid-July to August. At the end of this period, the green shell opens. The inner shell completes its development 100 days after blossoming. Harvest time is from the middle of August to mid-September. The leaves fall off in October - November and the trees go into dormancy.
After the outer shell of all the fruit has opened.
It is acceptable to use a tree shaker.
Average yields are 2.0-1.0 t/ha.
The annual international yield is 1 million tons.
Comment: In Spain almonds are also used in the wood industry.