1. Factors affecting fruit setting rate and uniformity of grapes
1, temperature and humidity influence
When the temperature is above 10℃, the grape leaf buds begin to germinate, but if the temperature is below 10℃, the grape new shoots will not grow normally, which will affect the normal differentiation of flower buds. At flowering stage, the most suitable temperature for grape growth is 26~28℃. Too high or too low temperature will affect the development of grape flower organs. When the temperature is lower than 15℃, the flowering period is stunted; If the temperature exceeds 35℃, it will also lead to flower necrosis in closed vineyards.
Humidity is also the main factor affecting the fruit setting rate and uniformity of grapes. Both moisture and drought will affect flowering and pollination. The optimum air relative humidity at flowering stage is 60%~65%, which is beneficial to anther cracking and pollen spread.
2, the influence of light and ventilation
Light intensity is also an important condition that affects the fruit setting rate and uniformity of grapes. Adequate light can make plants synthesize more nutrients for the development of flower organs, while insufficient light will lead to poor development of flower organs. In addition, if the vineyard is poorly ventilated and too closed, it will lead to the lack of pollination media and affect the normal pollination of flower organs.
3, the influence of water and fertilizer
Grapes need more water and nutrients because of the large amount of flowers at flowering stage. At flowering stage, if the supply of water and fertilizer is insufficient, especially phosphorus, potassium and boron, the pollination ability will be weakened; However, if there is too much water and fertilizer, the stems and leaves will grow in vain, resulting in a large number of new branches, which will make the vegetative growth and reproductive growth unbalanced and lead to falling flowers and fruits.
The result is too few branches and leaves.
For vines with weak growth, if there are too few fruiting branches and leaves, especially less than 4, it will affect the normal flowering and fruiting of inflorescences.
5. It is unreasonable to thin flowers and fruits.
Thousands of 800 buds can grow on an inflorescence of grapes, and a bunch of grapes will eventually form dozens of fruit grains. Therefore, if they are allowed to grow freely without thinning flowers and fruits, it is easy to cause a lot of waste of nutrients, affect the growth and development of trees, and cause flowers and fruits to fall.
Second, management measures to promote the fruit setting rate and uniformity of grapes
After analyzing the factors affecting the fruit setting rate and uniformity of grapes, reasonable management measures can be formulated according to these factors. To sum up, there are mainly the following aspects:
1, do a good job of temperature and humidity management in the flower and fruit period.
Adjust the temperature and humidity according to the requirements of different growth stages of grapes.
Inflorescence separation period: the most suitable temperature for growth is 20~28℃ during the day and 15~ 18℃ at night. During the inflorescence separation period, the relative humidity of air was controlled at about 50%. Flowering period: The most suitable daytime temperature for flowering period is 25~30℃, and the nighttime temperature is 15~20℃. The relative humidity of air should be strictly controlled at about 60%~65%. Berry growth period: the suitable temperature for berry growth period is 25~28℃ during the day and 18~20℃ at night. The relative humidity of air should be controlled at 50%~60%. 2. Prebud fertilization
After the grapes are unearthed, they can crawl on the ground for about 10 days, and can be applied with farmyard manure 10~ 15 kg/plant and ammonium bicarbonate of about 40 kg/mu, and can be tied on the shelf after the bud eyes germinate evenly.
3. Bud management
Before the leaf buds spread out, the nutrient consumption of trees comes from their own storage, so early bud wiping can reduce nutrient consumption. The principle of bud wiping is to erase the heavy buds, crooked buds, weak buds and pests on the main stem, leaving full and strong buds.
4. Pruning management
When the new shoots grow to more than 20 cm, pruning management should be carried out, mainly in the following four aspects:
Sparse: the principle of sparseness is to leave the weak and the strong, and to leave the small and the big. Tie the tender branches: Tie the vigorous branches to the bracket, so that the other branches can spread evenly, ensuring sufficient nursing space. Picking: for the branches with strong growth, leave 7 leaves and pick the core, and the branches with weak growth will pick the core 2~3 days before flowering. Leaf clamping: The leaves around the inflorescence should be removed from the closed trees in the orchard to ensure good light transmission. 5. Comb flower
When combing inflorescences, the principles to be followed are pinching shoulders, removing tips and leaving the middle part.
Shoulder pinching is to pinch off the branches that are too scattered at the base of inflorescence; Tickle is to remove the branches at the top of inflorescence. Because of the limited nutrient supply of these branches, they are easy to blossom and bear fruit or soften the fruit in the later stage. Leaving the middle part is to keep the strong branches in the middle part of the inflorescence. Generally, an inflorescence maintains about 15 branches.
6. Pollination management at flowering stage
The mixed solution of 0.2% urea and 0.1%borax can be sprayed 1~2 times during the flowering period of grapes. By foliar spraying, the stigma of female flowers can become moist and the adsorption capacity of pollen can be enhanced. In addition, boron can improve the activity of stigma, while urea can supplement nutrients for trees, thus ultimately improving the quality of pollination and fertilization and fruit setting rate.
7. Pick the core and remove the auxiliary tip and tendrils.
When the grapes are about to bloom or just open, the fruiting branches should also be pitted. The inflorescence of vigorous bearing branches should have 6-8 leaves, the inflorescence of medium bearing branches should have 4-5 leaves, and the inflorescence of weak bearing branches should have 2-3 leaves. At the same time of coring, all the secondary branches below the inflorescence should be erased, leaving only 1~2 secondary branches above the inflorescence at the top, and the rest should be removed. The tendrils that grow out should also be removed in time, and the branches should be bound once every 35 cm.
8. Water and fertilizer management in berry period
During the berry period, the fruit expands rapidly, and there is more demand for nutrients at this time. At this stage, attention should be paid to the application of phosphorus and potassium fertilizers. Phosphorus can promote the expansion and maturity of fruit grains, which plays an important role in improving the uniformity and quality of grapes, while potassium has an important influence on the sugar content and color of grapes. Generally, water once a week during the berry season, and fertilization should be carried out at the same time with the water. Fertilization amount is suggested to be combined with soil testing formula.
9. Fruit thinning management
2~4 weeks after fruit setting, thinning management should be carried out to remove abnormal fruits, pests and dense fruits, and fruit grains should be kept in combination with the target yield.
In order to improve the fruit setting rate and uniformity of grapes, it is necessary to carry out scientific and reasonable management, especially the management of fruit period and flowering period of grapes, which has the characteristics of many technical measures and strong professionalism. But as long as we manage scientifically and reasonably, we will improve the fruit setting rate and uniformity and lay a good foundation for high yield.