The pistachio crop, known as green gold, is produced in many countries, first and foremost the United States and Iran, but also in Italy, Spain, Turkey, China and Greece.

Let’s find out together how best to cultivate it.

Pistachio: characteristics

Native to the Middle East, the pistachio tree (Pistacia vera) is a plant that can grow up to 11-12 metres and reach the age of 300 years. The fruit is a thin, hard-shelled drupe containing the ‘real’ pistachio, the green-coloured fruit. In Italy it is mainly cultivated in Sicily but pistachio groves are growing also in Basilicata, Calabria, Apulia and Sardinia.

Soil and climate

The pistachio is a plant that is resistant to drought and temperature changes. The plant requires a cold winter and a dry summer to grow at its best. The cold winter exponentially increases flowering after the winter dormant period while the summer with high temperatures and low humidity helps us to control the spread of fungal growth and diseases on the plant. The pistachio tree is a fan of poor, well-drained soils.

Plant development is determined by soil type and roots. These are usually formed by a main root (taproot) and a deeper root system useful for the plant to find water and minerals.

Florescence

The shrub is a dioecious species and has only female or male flowers. This must be taken into account especially when arranging the plants within the installation. Flowering usually occurs between mid-April and early May and pollination is anemophilous, i.e. wind-driven.

Fruits

Pistachio fruits are small, elongated, oval-shaped drupes in clusters. The fruit is covered with a reddish-green outer husk.

The recommended planting layout is 5x5m if not 6x7m, i.e. 5 or 6 metres distance between plants and rows. It is recommended to plant the plants between the end of February and the end of March, alternating male and female plants. The flowering of the pistachios takes place in April, while harvesting takes place between September and October.

Under certain conditions, the pistachio produces fruit every two years, and this is the case of the Bronte pistachio, which is grown in extremely dry conditions and highly variable temperatures. Many irrigation methods can be used on pistachios, but localised irrigation is considered one of the best.

Pistachio precision irrigation

Water availability is crucial, especially in young plants where it is advisable to irrigate from the first warmth (plants up to 8 years old have a water requirement of 1200-1800 litres of water per year) to ensure greater plant development.

Attention must be paid not to give too much water, otherwise we will harvest large fruits but with less flavour. Pistachios are drought-tolerant, but it is better to provide a drip irrigation system to avoid major droughts.

During the first few years it is recommended to mulch, which is also useful if you have limited possibilities to irrigate, to keep the soil moist.

Benefits of localized irrigation on pistachio

• proper irrigation allows us to balance the supply of water and minerals correctly, thus managing to evenly develop pistachio production year after year;
• uniform growth of the drupes on the plants with an even better quality;
• yield and quality are increased by a continuous nutrients supply;
• the root system grows rapidly, reducing sensitivity to climate change.

The first harvest of pistachios is approximately done 6 years after sowing, while the full harvest is reached after 12-15 years. Water requirements are crucial in the early years for a correct and complete development and in the following years for a production capacity at maximum efficiency. It is estimated that in July, given the current climatic conditions in the Mediterranean basin, the plant needs about 6mm of water per day.

Precision irrigation

By mentioning precision irrigation, we refer to micro-irrigation and drip irrigation: water is delivered to the plant at low pressure and up to 95% efficiency.

Let’s analyse together the main solutions to irrigate pistachio:

• micro-sprinklers: a system that is little subject to clogging and irrigates a large area, it is recommended to place the dripper between two plants taking care that it does not wet the leaves. The downside of this system is that it retains moisture with the risk of disease for our plants;
• Sub-irrigation: it is a good irrigation method to irrigate roots directly, reducing losses. The system requires to be buried underground in the winter with considerable work and investment both pre- and during the season in case there’s any damage;
• Drip irrigation: best irrigation system for pistachios given its efficiency and also the possibility of combining it with fertigation. Given the recommended planting layout and the plant’s demand for water, it is recommended to place two lines in each row. Regarding the distance between the drippers, it all depends on the type of soil, a distance of 30-50cm with a flow rate of 2l/h is recommended. A low flow rate will facilitate the gradual dispersion of water to the roots. This system, it turns out, is the best in relation to the other two.

Which is the best system to choose?

First consideration to be made is the soil, second the water by examining the location of the source, availability and quality of it, which can adversely affect the whole system.

Given the fact that every project differs from another, there is no perfect system that can be chosen in advance, but once the various aspects have been analysed together with the possibility of investment, we recommend drip irrigation.

Irrigation efficiency of 95%, possibility of using fertigation and increased production capacity are just some of the advantages we can count in favour of this technique that also requires a fair investment in the renovation of the system.

The system can be structured with drip lines, which allows us to keep it active for several years without having to renew the system every year and guarantees continuous efficiency. This efficient solution for the first few years of life when plants need large amounts of water also gives us the opportunity to optimise the layout of our pistachio grove.

Valducci offers its customers a choice of different lengths, colours and characteristics of drip lines, available for direct purchase on our e-commerce.

Here our drip lines, with immediate availability –> drip lines in Valducci