Physiological obstacles in the Seedling stage of Cucumber after Root Burning and Root growth

Cucumber seedlings grow fast

1. Stiff seedlings. The growth and development of cucumber seedlings were excessively inhibited, such as short, small leaves, thin leaves, light color, thin stems, small roots, less new roots, abnormal flower bud differentiation, less flowering and easy flower topping after planting. Causes: temperature is too low; long-term cloudy days; lack of water in seedling stage; lack of nutrients, excessive growth control. Prevention and control methods: pay close attention to the temperature of the greenhouse, the ventilation temperature of the greenhouse is 24: 28 ℃ in sunny days, and the vents can be opened less or not in cloudy and rainy days; the seedling beds or nutrition bowls should be fully watered and watered 3-5 days before sowing cucumber seeds; fully mature organic fertilizer is applied to make the seedlings grow rapidly and form strong seedlings; 0.5% urea + 0.4% potassium dihydrogen phosphate solution is sprayed.

2. Rooting. The roots are few and stunted and the color becomes brownish or brown. Cause: due to the use of undermature organic fertilizer or too much fertilizer on the seedling bed, the concentration of salt ion is too high. Control methods: fertilization should be appropriate, not too much; seedling bed soil and fertilizer should be mixed evenly; the organic fertilizer used should be fully mature; the mu of topdressing should not exceed 20 kg, and it should be spread evenly; if root burning occurs, it can be properly watered to alleviate the soil concentration.

3. Grow in vain. The overgrowth of cucumber is a common phenomenon in the seedling stage. The seedlings are slender, the internodes are long, the leaves are large, the leaves are thin and light, the petioles and stems are tender and easy to break, the roots are poorly developed, the number of roots is small, and the roots are small. This kind of seedling is easy to be infected by disease, with weak resistance to freezing and heat, less flower differentiation, easy to turn melon, and low survival rate after planting. Causes: too high temperature, untimely ventilation; lack of light, especially in cloudy and rainy days, grass cover late and early cover; high night temperature; too much nitrogen fertilizer in base fertilizer or nutrient soil; too much moisture; too much density. Prevention and control methods: the air must be released when the temperature reaches 32 ℃; increase the light, remove the cover early and late or add a reflective curtain in the shed; close the doors and windows of the shed when the temperature reaches 24 ℃ in the afternoon, pay attention to the bottom wind; balance fertilization, increase organic fertilizer, pay attention to the combination of nitrogen, phosphorus and potassium, stabilize nitrogen, increase phosphorus, potassium, and apply micro-fertilizer; watering not too often; expand plant spacing, row spacing; inter-seedling and seedling separation, appropriate sparse planting When raising seedlings, it is best to adopt a seedling bowl to raise seedlings, and spray 50 mg / kg paclobutrazol to control growth.

4. Retting root. The root became brown or black, rotted severely, and the aboveground part wilted until death. Causes: improper watering, watering, watering water is too large; ground temperature or air temperature is too low, slow evaporation; poor ventilation; soil sticky weight, poor soil quality. Prevention and control methods: properly watering the seedling bed, not watering the seedling bed; doing a good job of ventilation in the shed, especially in the low temperature period, should grasp the sunny and warm weather ventilation; when the soil quality of the seedling bed is poor, it can be mixed with sand loam in an appropriate proportion, or apply more mature organic matter.

5. Parachute leaves. New leaf tip yellowing, gradually transition to leaf loss of green yellowing, slowly withered, leaf central part of the bulge, around the roll, serious when capped. Causes: greenhouse temperature does not dissipate heat in time, muggy; calcium deficiency in new leaves; cucumber stunting. Preventive measures: pay attention to keep the gas exchange in the greenhouse to promote cucumber leaf transpiration; spray quantitative calcium fertilizer; pay attention to formula fertilization and strengthen management to promote the normal growth of cucumber.