How do I prevent fruit cracking and improve fruit set in longan?

Fruit cracking and heavy fruit drop in longan, like in litchi, are mostly linked to uneven moisture, sudden rain after a dry spell, calcium and boron nutrition, and weather stress during fruit development. To reduce them, keep soil moisture steady during fruit growth through mulching and regular irrigation rather than letting the soil dry out and then flooding it, which is the classic cause of cracking. Maintain balanced nutrition with adequate calcium and micronutrients as per a local schedule, since deficiencies weaken the skin. Some flower and fruit drop is natural, but severe drop can come from poor pollination, water stress or pests, so ensure good conditions at flowering and control fruit borer near harvest. Irregular flowering some years is part of the crop's nature, helped by a cool dry spell before bloom. Avoid heavy nitrogen late, which encourages soft growth. Confirm a moisture, nutrition and spray schedule with your KVK, and treat steady moisture as the single biggest factor against cracking.