What causes the alternate bearing phenomenon in fruit trees?
When it comes to alternate bearing, many people are familiar with it, especially in fruit trees, which often show a pattern of a heavy crop one year and a light crop the next. If a tree produces a high yield this year, it may produce a low yield or no fruit the following year. If this phenomenon is not controlled in time, it can form a vicious cycle, greatly shorten the lifespan of the fruit tree, and seriously affect the grower's economic returns. So what causes alternate bearing in fruit trees? Let's find out together.
1. Extreme climate
During the growth and development of fruit trees, when normally fruiting trees encounter harsh weather such as extreme drought, excessive rainfall, abnormal freezing damage, hail, and late spring cold, the tree vigor weakens the following year, the number of flowers and fruits is severely reduced, or a large-scale flower and fruit drop occurs, causing reduced yield and resulting in an off year. After an off year, the number of fruits is small and nutrient consumption is relatively low, so the tree accumulates more nutrients and bears larger fruits the next year, thus producing an on year.
2. Tree load
Many fruit growers believe that the more flowers and fruits a fruit tree bears and the more it overwinters, the higher the later yield will be, so they are unwilling to thin flowers and fruits at the young fruit stage. This is also the main cause of normal alternate bearing. When a fruit tree has too many flowers and set fruits, it consumes a large amount of tree nutrients, causing an imbalance between vegetative growth and reproductive growth. This reduces the nutrients available for branch growth, and flower bud differentiation of the fruit tree is inhibited, which leads to a decrease in the number of flowers and fruits the following year and results in an off year. An off year is then closely followed by an on year.
3. Improper pruning
Fruit growers do not pay attention to pruning methods when pruning, for example, an unreasonable ratio of vegetative branches to fruiting branches, or repeatedly light pruning and delayed pruning or heavy pruning of fruiting trees year after year. Pruning methods like these can all cause alternate bearing.
4. Variety characteristics
Different varieties of fruit trees have different growth characteristics, so the probability of alternate bearing also differs. For example, early-maturing and mid-maturing varieties have a lower probability of alternate bearing, while late-maturing varieties have a relatively higher probability of alternate bearing. Mature and old fruit trees experience more severe alternate bearing than young fruit trees. Common pear trees, persimmon trees, as well as stone fruit and small berry fruit trees in our daily lives have milder alternate bearing, but grapes, peaches, jujubes, pomegranates, and other fruit trees are highly prone to alternate bearing, so attention should be paid when planting.
The above is an introduction to the causes of alternate bearing in fruit trees. We hope it helps you. To learn more related knowledge, please follow us.