Five Steps to Take Good Care of Flower and Fruit Retention in Navel Oranges
Navel oranges have excellent quality, are seedless and juicy, and have bright color; they are an excellent citrus variety cultivated competitively by countries around the world. Navel oranges are rich in nutrients and contain various nutritional components essential to the human body. Navel oranges contain large amounts of vitamin C and carotene, which can inhibit the formation of carcinogens, and can also soften and protect blood vessels, promote blood circulation, lower cholesterol and blood lipids, reduce the possibility of heart disease, and prevent gallbladder disease. Navel oranges have a large number of flowers but poor flower quality, and serious flower and fruit drop. How to carry out flower and fruit retention is one of the important technical measures for obtaining a high yield of navel oranges.
1. Timely pruning and bud removal. After navel oranges bud in spring, they should be thinned and pruned in time. Remove the terminal winter shoots, water sprouts, diseased and insect-damaged branches, and excessively dense branches around the outer canopy, and remove leafless spherical flowers and deformed flowers. Shorten overly long autumn shoots, leaving 3 to 4 flowers, and follow the method of “remove three, keep one; remove five, keep two” to keep the strong and remove the weak. Cut off clustered branches, wipe out the strong spring vegetative shoots at the top and outer part of the canopy and the overly dense short weak spring shoots; for overly long spring shoots, leave only 5 to 7 leaves and pinch or shorten them, and thoroughly wipe out late spring shoots, summer shoots, and early autumn shoots.
2. Flower and fruit retention. During the flower bud stage, flower fading stage, and young fruit stage, spray once each with 0.3% urea plus 0.3% monopotassium phosphate plus 0.2% borax (or boric acid). After 2/3 of the flowers have faded, after the first physiological fruit drop (early to mid-May), and around the second physiological fruit drop (early June), spray the flowers and young fruits once each with 50 mg/kg “920” plus 0.3% imported compound fertilizer solution. In late May, smear the young fruits once with a mixed solution of 250 mg/kg “920”, 0.3% urea, and 0.3% monopotassium phosphate.
3. Preventing navel yellow fruit drop. When 4/5 of navel orange flowers have faded, in combination with flower and fruit retention, spray once with a mixed solution of 70% thiophanate-methyl 800 times and 50 mg/kg “920”. From late April to early May, spray the canopy with foliar fertilizers such as amino acid compound fertilizer 300 times or Greenfinwei No. 2 800 times solution. In early June (after the second physiological fruit drop), spray the canopy with a mixed solution of 50 mg/kg “920”, 0.4% imported compound fertilizer, and 70% thiophanate-methyl 800 times, or smear the navel of the fruit with 200 to 300 mg/kg “920” plus 70% thiophanate-methyl 800 times solution, treating once every 10 to 15 days. From late July to mid-August, smear the navel of the fruit once with yellow-inhibiting ester 600 to 800 times solution, which can inhibit the occurrence of navel yellow.
4. Preventing fruit cracking and fruit drop caused by cracking. In dry seasons, irrigate in time and cover the tree disk; the grass cover thickness should be 10 to 15 cm, and before covering, carry out shallow intertillage loosening of the soil around the tree disk. During the young fruit stage, spray 0.3% monopotassium phosphate. From June to August, especially in early and mid-July, apply additional potassium fertilizer 1 to 2 times; in June after the second physiological fruit drop, use 200 to 250 mg/kg “920” to dot-smear the navel of young fruits; for mildly initially cracked fruits, add 70% thiophanate-methyl 800 times solution to the “920”; and during the fruit expansion period from July to August, continuously spray Greenfinwei No. 1 800 times solution, or 0.3% potassium sulfate compound fertilizer solution, or a mixed solution of 0.3% urea plus 0.2% monopotassium phosphate plus 0.1% quicklime plus 0.1% table salt 2 to 3 times.