Growers know that in the process of planting plants, including vegetables, fruit trees, flowers, medicine plants and other crops, they want to achieve good economic benefits. If they do not know the technology, are not serious, and do not try their best, they will not be able to go smoothly and think about things. Therefore, in view of the changes in environmental factors encountered in the cultivation of crops (including medicine plants), the loss of control in management techniques will affect the harvest of economic products. Answers to difficult problems that may be encountered in production are provided for reference only.
Symptoms of abundance and lack of nutrients(1)
1. Symptoms of nitrogen(N) deficiency: when nitrogen is lacking, plants grow short, with few branches and tillers, small and thin leaves, few flowers and fruits and easy to fall off; when nitrogen deficiency affects the synthesis of chlorophyll, the branches and leaves turn yellow, the leaves become premature, and even Withered, resulting in lower yield; because of the high mobility of nitrogen in the plant, the nitrogen in the old leaves can be transported to the young tissues for reuse after decomposition, so the leaves will turn yellow when there is a lack of nitrogen, and gradually start from the lower leaves.
Symptoms of excessive nitrogen(N): the vegetative body is elongated, the leaf area is enlarged, the leaf color is dark green, and the leaves are draped; the stem is weak, and the resistance to diseases and insects is poor;
Measures to solve nitrogen(N) deficiency: ① apply quick-acting nitrogen fertilizer, such as urea mixed with water, the concentration is 1%; ② spray foliar fertilizer outside the roots, spray with urea mixed with water, the concentration is 0.2-0.3%.
Measures to solve the problem of excessive nitrogen(N) nutrition: ① Apply less nitrogen fertilizer, arrange the plants with excessive growth of branches and leaves, first cut off the middle and lower leaves of the thick leaves, or thin out part of the dense growth of branches and leaves, and carry out the treatment of the branches with weak growth. Pruning to promote the balance of carbon/nitrogen ratio, so that the plant will gradually return to normal growth.
2. Phosphorus(P) deficiency symptoms: growth stagnation, thin plants, reduced tillers and branches, stagnant growth of young shoots and young leaves, slender stems and roots, short plants, shedding of flowers and fruits, and delayed maturity; leaves are dark green or purple-red, dull , The leaves show abnormal dark green or purple-red; when phosphorus is deficient, most of the phosphorus in the old leaves can be transferred to the growing young tissues. Therefore, the symptoms of phosphorus deficiency first appear in the lower old leaves and gradually progress upward.
Symptoms of excessive phosphorus(P): stem and leaf growth is inhibited, causing premature plant senescence; thick and dense leaves, premature development of reproductive organs; hindering the absorption of silicon, rice is prone to "rice blast"; symptoms caused by excessive phosphorus, often It is manifested by chlorosis such as zinc deficiency, iron deficiency, and magnesium deficiency.
Measures to solve phosphorus(P) deficiency: ①Apply quick-acting phosphate fertilizers, such as calcium-magnesium phosphate fertilizers mixed with water, with a concentration of 0.5-1%; ②Spray foliar fertilizer outside the roots, spray with potassium dihydrogen phosphate mixed with water, with a concentration of 0.5-1% 0.2%.
Measures to solve excess phosphorus(P): The method to prevent excess phosphorus is simple, just reduce the amount of phosphate fertilizer. Pay attention to the scientific application of phosphate fertilizer, and improve fertilizer efficiency while reducing the amount of phosphate fertilizer. If the soil is acidic, phosphorus is insoluble.
3. Symptoms of potassium(K) deficiency: decreased resistance. When potassium is lacking, the stems of the plants are weak, easy to lodging, drought and cold resistance are reduced; the tips and edges of the old leaves begin to turn yellow, and then gradually wither, and the leaves appear small spots, and then dry or scorched, and finally the veins The mesophyll in the middle is also dry, and brown spots and patches appear on the leaf surface. The growth is slow, but because the middle part of the leaf grows faster, the whole leaf will form a cup-shaped bend or shrink; some crop leaves are bronze. , Curled downwards, the mesophyll tissue on the surface of the leaf is raised, and the veins are sunken; the old leaves show symptoms first. Potassium is also an element that is easy to move and can be reused, so nutrient deficiency symptoms first appear in the lower old leaves.
Symptoms of excessive potassium(K): Generally, there is no excess potassium, which is mainly caused by excessive potassium fertilizer. Excessive potassium hinders the plant's absorption of magnesium, manganese, and zinc, resulting in magnesium, manganese, and zinc deficiency symptoms.
Measures to solve potassium deficiency(K): ① Apply quick-acting potassium fertilizers, such as potassium sulfate or potassium nitrate mixed with water, with a concentration of 0.5-0.6%; ② Spray foliar fertilizer outside the roots, spray with potassium dihydrogen phosphate mixed with water, The concentration is 0.2%.
Measures to solve excessive potassium(K): Generally, there will be no excess potassium. If there is too much potassium, the frequency of potassium fertilizer application should be reduced. It is advisable to adopt the method of "eat less and more meals" to apply potassium.
4. Calcium(Ca) deficiency symptoms: plant growth is hindered, internodes are shortened, and plants are short; the meristems such as the top buds, lateral buds, and root tips of the plant are easy to rot and die, and the young leaves are curled and deformed; the growth of the fruit is poor (due to the small transpiration of the fruit , It is easier to have symptoms on the fruit when calcium is deficient), such as: tomato and pepper navel rot, apple bitter disease, water core disease, grape shrinkage and fruit cracking.
Symptoms of excessive calcium(Ca): When calcium is too much, the soil tends to be neutral or alkaline, causing a lack of trace elements such as iron, zinc, and manganese.
Measures to solve calcium(Ca) deficiency: ① Apply calcium-containing fertilizers, such as lime powder mixed with water to water the roots, with a concentration of 2-3%; ② Or use calcium magnesium phosphate or superphosphate mixed with water, with a concentration of 0.5-1% .
Measures to solve excessive calcium(Ca): soil with excessive calcium carbonate is generally called calcareous soil or alkaline soil. Therefore, less calcium-containing fertilizers, such as calcium-magnesium phosphate, superphosphate, and calcium nitrate, should be applied to alkaline soils.gh phosphorus exists in the soil, it cannot be absorbed. Therefore, moderately improving soil acidity can improve fertilizer efficiency. The application of pile manure prevents phosphorus from directly contacting the soil, and can reduce the binding of iron or aluminum, which is very helpful for the sound development of roots and the absorption of phosphorus.
After going through all the above steps, watch to make sure that the problems start to clear up within a few days to a week or so. The problems (brown spots, unhealthy lower leaves, red/purple stems, etc) will stop appearing on new leaves, usually within a week.
Please note that leaves which have been damaged will probably never recover or turn green, so you want to pay attention to other leaves for signs of recovery.
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