What to Do About Forked and Pithy Radishes? Causes and Control Methods
Radish, a biennial or annual herbaceous plant of the genus Raphanus in the Brassicaceae family, has a fleshy taproot that is oblong, spherical or conical, with green, white or red skin; the stem is branched, hairless, and slightly covered with a powdery bloom. The root is eaten as a vegetable; the seeds, fresh roots, dried roots and leaves are all used medicinally: the seeds aid digestion and resolve phlegm; the fresh root quenches thirst and aids digestion, while the dried root promotes urination and bowel movements; the leaves treat the early stages of dysentery and help prevent dysentery; the seeds are pressed for oil for industrial use and for food.
The functions of radish: clears heat and promotes fluid production, cools the blood and stops bleeding.
The nutritional components of radish: the main components of radish include protein, carbohydrates, B vitamins and a large amount of vitamin C, as well as iron, calcium, phosphorus and fiber, mustard oil and amylase. According to measurements, the vitamin C content of radish is nearly 10 times higher than that of fruits such as apples and pears.[1] Radish is cool in nature and pungent and sweet in taste, and has the effects of dispersing accumulated food stagnation, resolving phlegm and clearing heat, directing qi downward and relieving fullness in the middle, and detoxifying. Radish is a genuine health food that can promote metabolism, stimulate appetite and aid digestion, and can dissolve accumulated food stagnation; it is used for food accumulation with distention and fullness, phlegm cough with loss of voice, vomiting of blood, excessive thirst, dysentery, headache, difficult urination and so on; eating radish regularly can lower blood lipids, soften blood vessels and stabilize blood pressure, and can help prevent coronary heart disease, arteriosclerosis, gallstones and other diseases.
The causes and control of forking and pithiness in radish
Undesirable phenomena such as forking, pithiness, cracking and rough skin are relatively common in radish production. These phenomena make the radish poor in appearance and commercial quality and lower in price, causing farmers to increase production without increasing income.
Causes of forking and its prevention
At radish harvest time, you may see a single large radish that has, for no apparent reason, grown another thick fleshy root out of its side, sometimes one and sometimes even two; this phenomenon is called forking. Although forked radishes are still edible and their quality does not become worse, their appearance is deformed, which greatly affects their commercial attractiveness. Under normal circumstances, every field will have some forked radishes. There are many causes of radish forking, mainly the following:
1. Soil quality and tillage: the soil is plowed too shallowly, and the subsoil is too hard. At the same time, during deep plowing, stones, tree roots, tiles and hard plastic objects were not removed. If the subsoil is too hard and not loose, and there are also hard objects blocking it, the main root will inevitably be obstructed, which will promote the development of lateral roots; once the substances produced by photosynthesis accumulate, the main root and lateral roots will thicken at the same time. In addition, if the soil is not turned and dried enough, and there are too many underground pests such as earthworms, white grubs and mole crickets, the main root is damaged and lateral roots naturally form, and forking will also appear later.
2. Fertilizer not fully decomposed: incompletely decomposed fertilizer contains a large amount of uric acid, which on the one hand burns the main root and on the other stimulates lateral roots to grow; if base fertilizer is applied unevenly and not turned deep into the soil layer, it will likewise damage the elongation activity of the main root, and lateral roots will also form. Once substances accumulate and thicken, forking is formed.
3. Excessive planting density: when sowing and thinning radishes, the spacing left is too wide. Summer and autumn radishes fork less, while autumn-winter or winter-spring radishes fork more, because the weather in these seasons is especially favorable for radish growth, photosynthesis is strong and abundant accumulated substances are produced; if planting density is too sparse, the plants grow especially vigorously, the leaves produce especially many photosynthetic products, and naturally more forking appears.
To prevent forking caused by these reasons, farmers must conscientiously carry out deep plowing and careful cultivation of the soil and keep the soil loose, crumbly, soft and expanded. Apply fully decomposed organic fertilizer, and spread this fertilizer evenly into the soil layer. In short, according to the requirements of each variety, plant at a reasonable density.
Causes of pithiness and its prevention
When pulled up, it feels relatively light; when cut open, the flesh is found to be uneven and has white pithy cavities; this phenomenon is called pithiness. Pithy radishes lack sweetness when cooked, have much fiber and little juice, and if cut into pieces and rinsed, they will float on the water surface. Some scholars believe that radish pithiness is a phenomenon of over-maturity. Physiologically speaking, this is because the radish fleshy root has already reached commercial maturity, while the parenchyma cells of the root grow too expanded and rapid, and at this time there is a lack of contents or insufficient contents, resulting in a lack of nutrients in the conducting tissue. Radish pithiness is related to the following factors:
1. Variety relationship: early-maturing varieties show it more often than late-maturing varieties. Varieties with large fleshy-root parenchyma cells have poorer fleshy-root density, and once an adverse phenomenon occurs, pithiness will appear earlier and more often.
2. Cultivation environment relationship: radishes cultivated in light sandy soil will show pithiness earlier than those cultivated in semi-sandy loam or loam. Fertile, loose muddy field soil delays pithiness. Poor soil drainage, uneven application of base fertilizer and topdressing, or topdressing too late, and leaf growth stopping too early, also give more opportunity for pithiness to appear.
3. Improper sowing period: because the sowing period is arranged unreasonably, the growing period often encounters high temperature and drought, which affects the effect of photosynthesis; respiration is often excessive and consumes nutrients, affecting the growth of the radish and the production, transport and accumulation of nutrients as a whole.
4. Unreasonable planting density: if the spacing between radish plants and rows is too large, pithiness will also appear.
5. Improper water supply: if water is even in the early part of the growing period but there is drought later, pithiness will also appear.
Based on the above causes of pithiness, the following measures should be carried out well:
1. Correctly use good varieties: first master the characteristics of each radish variety, especially the characteristic of early or late maturity, and choose to sow in the most suitable season. At the same time, plant according to the most suitable plant and row spacing required by each variety; it is not that the sparser the better, nor that the denser the better.
2. Improve cultivation measures: through careful plowing and careful cultivation and scientific management, create a good cultivation environment, especially through comprehensive measures such as the choice of soil quality, even fertilization and balanced water supply, and timely harvesting, so that radish plants grow normally. If the fleshy root forms under safe and secure conditions, the phenomenon of pithiness will rarely appear.
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Causes of radish cracking and its prevention
When radishes reach the harvest period, irregular cracks appear on the surface of the thick fleshy root. These cracks may be coarse or fine, and may be longitudinal-transverse cracks, transverse cracks or longitudinal cracks. The surface of the fleshy root of a cracked radish is still smooth and not rough, and its edible value is not greatly affected; rough skin means the skin surface is not smooth, with black streaks and even traces of insect bites, but its commercial attractiveness is greatly affected.
Physiologically, the cause of cracking in the fleshy root is considered to be the result of uneven soil water supply during radish growth. Specifically, during the growing period the radish encounters high temperature and drought, soil moisture is insufficient, and the grower does not supplement watering according to actual weather conditions to keep the soil moist and stable; as a result, the tissue of the cortex of the radish fleshy root gradually hardens. In the middle and late stages of radish growth, the temperature is suitable, sunlight is suitable and water is sufficient; under such a good environment, the parenchyma cells of the xylem inside the radish fleshy root divide and expand rapidly, rapidly increasing and swelling transversely toward the cortex, while the hardened cortex cannot grow correspondingly, creating a contradiction; the hardened cortex cannot withstand the force of the inner expansion toward the outside of the skin, and as a result the cortex is split open. In addition, overly sticky or hard soil, or overly coarse sand particles, too high a groundwater table and other environments, as well as underground pests such as the larvae of the yellow-striped flea beetle biting and eating the outer skin of the root, will all leave small marks on the root surface, and with the action of harmful substances, ugly black streaks remain.
How can cracking and rough skin be prevented? Fundamentally, it is still a matter of choosing good soil, plowing carefully and cultivating carefully, always keeping the soil loose, and, according to the weather and the performance of radish growth, supplying water evenly and in a timely manner so that the soil remains moist and breathable; by no means should it be alternately dry and wet or left unwatered for a long time. The most basic method of preventing rough skin is still to choose good soil quality, fully turn and dry it, plow carefully and cultivate carefully, and create a good soil environment. If the radish growth and the fleshy root formation process lack neither water, nor nutrients, nor air, and are not squeezed by the soil, the cortex will not become rough.