Turnips

As I announced yesterday, starting from the post on the most famous Halloween story I intend to structure all the posts until October 31st. Well, in the last update I told you that Mr. Jack was eating a turnip. Turnips are common in Ireland, and the question I would like to answer is: why?

The turnip is the large, fleshy root of the plant Brassica rapa L., which belongs to the brassicaceae family. Rich in vitamin C, B and folic acid, it is useful for its detoxifying and antioxidant properties. I don't know how many of you play Animal Crossing: New Horizons, but surely among the younger readers there is someone who learned about this tuber from buying and selling turnips in that game.

https://animalcrossing.fandom.com/wiki/White_turnip

"Turnip grows best in a moderately deep loam, fertile and slightly acid soil. Turnip does not do well in soils that are of high clay texture, wet or poorly drained. For good root growth turnip needs a loose, well aerated soil." (D.J. Undersander et Al.)

Cultivating turnips requires relatively little care and can usually be harvested after 5-10 weeks by taking both the vegetable root and the green part. You start with the seeds and plan to grow turnips in spring or autumn. Turnips thrive in colder temperatures, so you should plant them when the soil temperature is still quite low. For spring turnips, plant the seeds outdoors three weeks before the last expected frost. For autumn turnips, plant the seeds in the middle of summer, about two months before the first expected winter frost. The soil temperature must average at least 4°C for the seeds to germinate, but temperatures between 10 and 21°C encourage faster growth. Turnips grown in autumn are generally sweeter than spring turnips and are also less likely to attract root worms.

These are the real reasons why turnips are widespread in Ireland. But what is the condition for having this type of soil suitable for their cultivation?

Acidic soils are considered to be those in which the pH is lowered to values that compromise the mineral nutrition of the plants. In general, a slight acidity is tolerable, up to the pH 6 limit; below this pH the anomaly intensifies, but it clearly manifests itself below pH 5-5.5, values below which most agricultural species find it difficult, if not even prohibitive conditions, which affect their cultivation. The acidity of a soil can have several origins, often combined. The one that I can tell you more about is the one that depends on the mother rock from which the soil is born. Lithologically, the acidity is due to a high silica content of the rocks that have originated the soil. Acidic soils are generally the offspring of granitoid and porphyritic rocks. The acidity is also accentuated by the systematic runoff of the bases in rainy climates and the accumulation of humic acids due to moderately low temperatures and rainy weather. All these characteristics are indeed found in Ireland.

https://landscaperpro.it/ciclo-azoto/

Granites are coarse-grained acidic plutonic rocks consisting of quartz (20-60%), alkaline feldspars, plagioclase and mafia minerals such as biotite (the most common), hornblende. Other minerals that may be present in particular cases are: pyroxenes, andalusite, muscovite, garnet, corundum, tourmaline. Rocks with a percentage of quartz between 20% and 60% but with a different alkaline feldspar/plagioclase ratio are called granitoid rocks and take different names according to the alkaline feldspar/plagioclase ratio.

http://storiadellageologia.blogspot.com/2014/08/il-mistero-del-granito-ii-la-nascita.html

In petrography, porphyry is a generic term used to indicate filonian eruptive rocks (corresponding to granites or syenites) or paleovulcanic effusive rocks (corresponding to liparitis and trachytes, neovulcanic), with a distinctly porphyric structure, very hard. Because of their resistance to abrasion and compression, thanks to their smoothness, these rocks are used, in the form of rough cubes, for road paving and in the form of polished slabs for floors, stairs and as ornamental material.

https://it.wikipedia.org/wiki/Porfido

This is as far as the best soil for turnip cultivation is concerned. If you would like to intervene with some advice on cultivation, leave a comment to the post so that everyone can see your opinion.