Onion is one of the most important vegetable crops grown across the world. It is a rich source of vitamins, minerals, and antioxidants, making it a healthy food item. In this article, we will discuss the growth and yellowing of onion crop.
Growth of Onion Crop
Onion crop requires a well-drained soil with a pH range between 6.2 to 6.8. The crop can tolerate a wide range of soil textures, but prefers sandy to loamy soils. Onions grow best in areas with moderate temperatures between 60 and 75°F. The crop requires full sun exposure to grow optimally.
Onions are usually planted from sets, which are small onion bulbs, or from transplants. The planting depth should not exceed 2 inches, and the plant spacing should be around 4-5 inches apart. Onions require adequate water supply during their growing period. Irrigation should be carried out appropriately based on the soil moisture levels to avoid waterlogging, which can lead to yellowing of leaves.
Yellowing of Onion Crop
Yellowing of onion crop can be caused by various factors, including nutrient deficiencies, diseases, and pests. Nitrogen deficiency is one of the common reasons for yellowing of onion leaves. The deficiency causes the mature leaves to turn yellow, starting from the tip and progressing towards the base. The younger leaves may develop a lighter green color than the mature leaves.
Phosphorus deficiency can also lead to yellowing of onion leaves. The deficiency causes the leaves to turn yellowish-green, and they eventually develop purple discoloration on the tips and edges. Potassium deficiency can also cause the tips of the onion leaves to turn yellow.
Onion plants are susceptible to various diseases, including Fusarium basal rot, downy mildew, and white rot. These diseases can cause yellowing of onion leaves and eventually lead to plant death. Pests like onion maggots, thrips, and onion fly larvae can also cause yellowing of onion leaves by damaging the plant tissues.
In conclusion, onion crop growth requires an adequate water supply, moderate temperatures, full sun exposure, and proper planting practices. Yellowing of onion leaves can be caused by various factors, including nutrient deficiencies, diseases, and pests. Proper management practices and preventive measures should be implemented to prevent the occurrence of these problems for a healthy onion harvest.