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Peas are among the oldest cultivated plants in the world, with the earliest finds dating back to the Stone Age. They are still a popular food and feedstuff in Austria. In recent years, however, farmers have had to contend with new challenges and a significant drop in yields. Due to the changed climate, aphids feel particularly at home and can act as carriers of a nanovirus that damages the pea and leads to yield losses.
Usage
In Austrian cuisine, peas are popular as a side dish, in soups, salads, stews or with rice in risi-bisi.
Fresh peas can be frozen, canned or dried. The latter must be soaked for about 12 hours before cooking. The so-called sugar snap peas are harvested before they are actually ripe, when the pods are still flat and the peas are still quite small. They can be eaten raw or lightly steamed.
Peas are characterized by their high protein content and are rich in vitamins, minerals and trace elements.
Peas are also used in cattle, pig and poultry feed as protein feed.
Botany
The cultivated or garden pea(Pisum sativum L.) belongs to the legume family.
The annual, summer annual or perennial plant grows its relatively thin stem into a climbing or prostrate plant. Its paired pinnate leaves run out into a branched winding tendril. The individual leaflets may be ovate to broadly elliptic or reshaped into tendrils.
The relatively large and long-stalked butterfly flowers arise from the leaf axils, which have two broad stipules. The elongated legume contains 4-10 seeds, also called peas.
The pea is divided into three subspecies. The most commonly used cultivated form is Pisum sativum subsp. sativum L.. Depending on the use, four further subspecies are distinguished:
- Forage or field pea has pink to purple flowers and dark brown seeds, which are often spotted or dotted. Mainly used as fodder, the ground, ripe peas of this subspecies are also used as green fodder and green manure.
- The pal/shell/drooping or grain pe a has white flowers and yellow or green peas. It is particularly starchy and is therefore well suited for drying (dry pea) and subsequent cooking.
- The seeds of the marrow or wrinkled pe a appear shriveled when ripe. Their sugar content makes them taste sweet and they are usually preserved as canned or frozen products.
- In the case of sweet peas or sugar snap peas, it is mainly the whole, fleshy, sweet pods with the still undeveloped seeds that are used for edible purposes.
Agricultural aspects
In Austria, grain peas were cultivated on 6,366 ha in 2022, 6% more than in 2021, with the majority being grown in Lower Austria, Vienna and Burgenland. Statistics Austria reports a production volume of 9,600 t of green peas for 2022.
Peas are rather undemanding when it comes to climate. Germination of peas already occurs at temperatures of 1 to 2 °C. The frost sensitivity or winter hardiness of the young plants ranges from -4 to -10 °C, depending on the variety; in general, winter peas are less sensitive than summer peas. A good water supply is important, especially at flowering time, otherwise there will be yield losses due to drought stress-induced flower drop. Sites with less than 500 mm annual precipitation should therefore be avoided for cultivation if too little winter moisture - stored as soil reserves - is available.
Peas prefer medium-heavy, deep, well-drained soils without compaction and waterlogging. For optimal nodulation, the soil pH should be above 6.2.
Since peas are not self-tolerant, cultivation breaks of at least 6 years must be observed. Due to a possible occurrence of ascochyta, sclerotinia and botrytis (gray mold), other legume species, as well as canola, flax and sunflower, are also ruled out as main or catch crops. One should choose a preceding crop with good weed suppression properties to facilitate later weed control. Pea itself is considered a good preceding crop for winter cereals or summer crops such as corn and sugar beets.
As with many legumes, nitrogen fertilization is not necessary.
Field peas are harvested when the entire crop is mature and dry, the pods are light brown and the kernels are hard. Pith peas are harvested while still fresh, as soon as the seeds are fully formed and close together in the pod. Sugar snap peas are harvested before or shortly after the pea seeds form, when the pods are still flat.
Grain yields are highly dependent on rainfall or water availability, and decrease during pronounced drought conditions during the growing season. Disease, pest and virus infestations can also significantly reduce yield levels.
Development of resistant varieties
Pea cultivation in Austria has declined in recent decades, as the aphid-borne Pea Necrotic Yellow Dwarf Virus (PNYDV) has led to significant yield losses.
In our research projects, we have investigated which plants are affected, which aphid species act as vectors and which pea varieties are particularly resistant to the virus.
Last updated: 12.07.2023
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