What are the causes of fruit cracking in Shatangju mandarins and what are the control methods
Shatangju is an excellent variety of citrus. Among all citrus varieties, it has an extremely high sugar content and is deeply loved by people, so many people grow it. However, fruit cracking occurs when the fruit is nearly ripe, so why does Shatangju crack? What should be done about fruit cracking? Let's take a look.
I. Causes of fruit cracking in Shatangju mandarins
1. Variety differences
In the same orchard, different varieties also differ in fruit cracking. Uneven peel thickness, especially in varieties with thinner peel at the top of the fruit, makes them most prone to cracking. Be sure to pay attention when choosing varieties.
2. Drought
Sudden rain after long drought or irrigation is the main triggering cause. If there is prolonged drought during the expansion period of Shatangju, the fruit peel contracts, and the flesh absorbs water rapidly and presses against it. The peel has not yet fully grown, and its growth rate is not as fast as that of the flesh, causing the peel to be burst open directly by the flesh. Mechanical fruit cracking occurs.
3. Effect of soil moisture
If there is long-term rainy weather, the soil moisture content is often in a saturated state, causing new roots to suffocate and die, and fruit cracking occurs together when the rain suddenly stops. Earlier waterlogging in the soil will further aggravate the occurrence of fruit cracking.
II. Control methods
1. Keep soil moisture suitable
Maintain a relatively high but moderate moisture content in the soil so that the water supply to the citrus will not fluctuate drastically. Water promptly during drought. Generally, if there has been no rainfall for half a month, irrigate thoroughly once to resist drought. In hot and dry seasons, irrigate once every 10 days. Lay straw on the tree pan to prevent water evaporation. During waterlogging, open ditches promptly for drainage. After heavy rain, shallow plowing should be done promptly to prevent root hypoxia and suffocation.
2. Apply more phosphorus and potassium fertilizer
In July-August, apply 50-70 kg of decomposed human and livestock manure water per plant, plus 0.3 kg of urea and 0.2 kg of potassium chloride, and cover the soil and irrigate promptly after fertilizing. For plants bearing too much fruit, apply more nitrogen fertilizer promptly to enhance peel thickness. During drought, spray different types of foliar fertilizers every 7-10 days, which can both reduce fruit cracking and promote fruit expansion.
3. Balanced growth of peel and flesh
During the expansion period of Shatangju, if there is long drought without rain, Guoguang Lieguobizhi can be used for comprehensive control. The middle and lower parts of the canopy, which are prone to fruit cracking, are the key parts to spray. Spray once a week for three consecutive times, and add one more spray before heavy rain. The control effect is relatively good.
4. Remove promptly
For fruits that have already cracked, remove them promptly to avoid continuing to consume the plant's nutrients and water, and at the same time reduce breeding sites for pathogens.
The above is an introduction to the causes of fruit cracking in Shatangju mandarins and the control methods. I hope it can help you. If you want to learn more related knowledge, please stay tuned to us.