Radishes often cause various physiological diseases under adverse natural and cultivation conditions, which seriously affect their yield and quality. Common physiological diseases and effective control measures are as follows. 1, lack of disease. (1) Nitrogen deficiency: The plants grow slowly, the leaves are narrow and thin, the leaves are yellow, the stems are thin, and the roots are stunted. They are fine and small, more lignified, and spicy. (2) Phosphorus deficiency: The back of the leaves is purple, and the leaves are small and shrinking. (3) Potassium deficiency: dark green leaves, curled leaves, pale yellow to brown, lower leaves and stems appear dark yellow to bronze, thickened leaves, the roots do not expand normally. 2, deformed roots. In the early stages of radish development, the main root growth point is damaged and hindered, resulting in lateral root hypertrophy. The fleshy root diverges or forms various types of deformities. According to the survey, where there is too much rain or irrigation, soil compaction; use of unfamiliar organic fertilizers or uneven fertilization; soil plough layer is too shallow or hard stone under the roots; underground pests, seedling roots were bitten, are It is easy to form deformed roots. 3, rooting. The weather was prolonged and the soil was too dry. The growth of the roots was temporarily halted. Afterwards, heavy rain or water poured suddenly, and the roots grew rapidly and prone to cracking. 4, hearty. The heart is a kind of physiological disease caused by the rapid enlargement of the straight root and the lack of boron in the middle of the delivery tissue. It has also been reported that potassium deficiency occurs in the soil during cultivation, and excessive nitrogen fertilizer is applied at the later growth stage. 5, black skin (heart). The soil is hard, compacted, and poorly ventilated. Fresh manure is applied. The microbial activity in the soil is intense and the oxygen consumption is excessive. As a result, root suffocation is caused, and part of the tissues appear black or black due to lack of oxygen. In addition, radish infection black rot, will also cause black heart. 6, spicy. The radish contains mustard oil. When its content is moderate, the radish flavor is good. If the content is too much, the pungency will be aggravated. When the climate is hot, the drought or the organic fertilizer is insufficient, the mustard oil content of the radish is easily increased. 7, bitter. During the growth process of radish, the weather is hot or the application of nitrogen fertilizer is too much and the phosphorus and potassium fertilizers are insufficient. In the roots of the meat, a kind of nitrogen-containing alkaline compound, momordicin, is easily produced, which makes the radish appear bitter. Prevention and control measures: (1) The selection of fine varieties is generally not suitable for the occurrence of malformed roots in shallowly-inoculated varieties; the white or green varieties are lighter in taste and bitterness. (2) Select a thick plot of land for planting and deep plowing to loosen the soil. (3) For scientific fertilization, the applied organic fertilizer must be fully decomposed and seasoned. Phosphorus and potash fertilizers should be added appropriately. For land that has been debilitated year after year, when the soil is prepared, 0.5-1 kg of boric acid or borax will be applied per mu, and the roots will be inflated. Spray with 0.2-0.5% borax or boric acid solution, spray once every 5-7 days, spray 3-4 times in total. (4) Reasonably water to prevent it from drying out or being too wet and dry.
NINGXIA KOFOLON INTERNATIONAL CO.,LTD. , http://www.kofolon.com