What to Do About Calcium Deficiency in Cucumbers? Symptom Identification and Calcium Supplementation Techniques

Insufficient calcium can cause abnormal growth in cucumbers, so vegetable growers should pay attention to identifying the symptoms and supplement calcium fertilizer in a timely manner.

I. Symptoms of Calcium Deficiency in Cucumbers

Calcium has poor mobility within the plant, so calcium deficiency symptoms often appear on new tissues, and generally the calcium content in young leaves is lower than in old leaves. Calcium deficiency can easily cause lesions in the heart leaves, blocked growth at the growing tip, yellowing and curling of leaves, smaller upper leaves, and stunted symptoms, with leaf vines turning brown and dying. If there is continuous low light followed by sudden clear skies and high temperatures, the leaf margins near the growing point curl and die, taking on a parachute shape, the upper leaves show yellowing between the veins, the leaves become smaller, and the roots die.

II. Main Causes of Calcium Deficiency in Cucumbers

1. Insufficient calcium content in the soil. Calcium carbonate and calcium phosphate in the soil are the main sources of calcium, but sandy soil, old vegetable gardens, continuous cropping vegetable gardens, and vegetable gardens with low organic matter content often have problems of insufficient calcium.

2. Low available calcium content in the soil. Soil generally is not lacking in calcium, but ammonium ions, potassium ions, sodium ions, magnesium ions, etc. dissolved in the soil solution can have an antagonistic effect with calcium ions, inhibiting the absorption and utilization of calcium ions by vegetables and showing symptoms of calcium deficiency.

3. Poor calcium absorption capacity of the root system. The absorption of calcium by vegetables is mainly accomplished by the root tips, so if the root system is poor, the absorption capacity is also poor.

4. Poor mobility of calcium within the plant. The main driving force for calcium transport within the plant is the transpiration stream. Calcium is transported through the xylem to vigorously growing organs and basically is not redistributed or reused. Therefore, organs with greater transpiration intensity and longer growth time receive more calcium, resulting in calcium deficiency in upper leaves and fruits.

III. Calcium Supplementation Techniques for Cucumbers

1. Focus on base fertilizer. On the basis of broadly applying decomposed organic fertilizer and phosphorus and potassium fertilizers, sandy soil should be supplemented with calcium-containing fertilizers such as calcium magnesium phosphate, superphosphate, and calcium nitrate; old vegetable gardens and continuous cropping plots should be supplemented with lime, with an annual calcium fertilizer application rate of 1.67-3.33 kg per mu.

2. Foliar fertilization. Add 1-2 kg of superphosphate to every 100 kg of water, stir for half an hour, then soak for a period of time, and take the clear liquid on top for spraying. Amino acid calcium, humic acid calcium, biological calcium fertilizer, etc. can also be selected, and spraying should be carried out during the peak period of calcium absorption by vegetables.

3. Scientifically apply nitrogen and potassium fertilizers. There is an antagonistic effect between ammonium ions and potassium ions and calcium ions. When the content of ammonium ions and potassium ions in the soil is too high, and when the nitrogen-to-calcium ratio is too high, calcium absorption can be inhibited. The use of nitrogen and potassium fertilizers should be appropriately controlled, and scientific fertilization should be carried out to avoid the phenomenon of excessively high nitrogen and potassium fertilizers.

4. Increase the application of organic fertilizer. Organic fertilizer is rich in organic matter and various nutrient elements required by crops. It is a complete fertilizer and has a unique effect on improving soil and building soil fertility.

5. Appropriately supplement boron fertilizer. An appropriate amount of boron can promote the transport of carbohydrates produced by leaves to the roots, stimulate new root growth, and help calcium absorption. An appropriate amount of borax can be mixed in during both soil calcium supplementation and foliar calcium spraying.

Chengde County Agriculture and Animal Husbandry Bureau, Liang Jiujie