In most cases, climate often plays a leading role in the growth of grapes and the quality of wine, and climate has become the most important and active factor among many factors. Meteorological conditions such as illumination, measurement and precipitation are all necessary conditions for grape growth and fruiting, especially in summer and autumn.
1, lighting
Sunlight is the only energy source of grape photosynthesis, and it is the driving force of grape energy and material circulation. 90%-95% of grape yield and quality comes from photosynthesis. The total energy emitted by the sun into space is 3.7× 1033 erg per second. Outside the earth's atmosphere, if the energy radiated by the sun is 100, the energy reflected back to space through the atmosphere is 37%, and the remaining 63% passes through the atmosphere, of which 20% is caused by atmospheric warming and atmospheric movement, and only 43% reaches the ground. If this 43% is totally absorbed by plants, the photosynthetic effective radiation (PAR wavelength is 380-710 nm (1nm1000 micron), that is, 400-760 nm, is among the sunlight components that chlorophyll absorbs and participates in photochemical reactions when green plants are engaged in photosynthesis. When American scientist R. Emerson and others studied photosynthesis in the 1920s, they found that the quantum utilization efficiency of photosynthesis was only 22.4% in the range of photosynthetic effective radiation of 380-7 10 nm. The reason why the quantum efficiency of photosynthesis is so low shows that plants waste a lot of energy when they absorb light energy and convert it into chemical energy. So in fact, the efficiency of converting solar energy from crops is far from 2%.
Under natural conditions, a lot of solar energy is wasted due to light saturation and other reasons. In many cases, the real solar energy consumed by photosynthesis has not reached 1% of the total solar energy. In China, the solar energy utilization rate of general vineyards is only about 0.5%. Modern science has been pursuing the utilization of solar energy, improving the conversion rate, tapping the potential of increasing production and achieving high yield and high quality. Grapes are light-loving crops and have been erected and pruned for thousands of years. So as to obtain more sufficient and reasonable illumination. In recent years, people still create a more suitable microclimate for grapes through the transformation of scaffolding and pruning, so as to improve the photosynthetic efficiency of each grape leaf and achieve the goal of high quality and high yield.
During the grape growing period, sufficient light makes the flower buds differentiate well and the leaves turn green. Hypertrophy The new buds are stout and the fruits are well colored, especially the European grapes that are particularly sensitive to light. Unlike the European and American hybrids such as Kangke, Kataba and Black Hu Xiang, they can be colored normally only in direct sunlight. In the case of scattered light, bright colors can also be formed. Due to the special demand of grapes for light, the lighting conditions in the grape producing areas are relatively good. However, in the southern provinces where there is no sunny day in China, grapes with good quality cannot be planted, or even cultivated, because in the long-term rainy climate, grape leaves are thin and yellow-green, new shoots are long or thin, petioles are elongated, and flower buds are poorly differentiated, which often leads to small ears and falling flowers and fruits. Due to insufficient light, photosynthetic products are few. Grapes are malnourished, the yield of grapes decreases, the quality is inferior, the new shoots are not fully mature, and the wintering is poor, which is prone to freezing injury. Grape's demand for light is not that the stronger the light, the better. In summer, the high temperature at noon is accompanied by strong light. Under strong light, the surface temperature of fruit can reach above 50℃, and sunburn often occurs on grapes. At noon, when the leaves have the best lighting conditions, there will be a "nap phenomenon". What is the "nap phenomenon"? Under natural conditions, there are two types of diurnal variation curves of plant photosynthesis. One is unimodal, with the strongest photosynthesis and the highest photosynthetic rate at noon; The other is bimodal, with the peak of photosynthesis in the morning and afternoon and the low of photosynthesis at noon, which is called "lunch break" in English. Grapes have obvious "siesta" phenomenon, and the loss caused by "siesta" can account for 30-50% or even more of the total photosynthetic products of some plants. Therefore, we must find ways to reduce or eliminate "siesta" so that precious lighting conditions at noon are not wasted.
Napping is an adaptive protective response of plants to strong light, which is influenced by ecological factors (light, soil, temperature, humidity and carbon dioxide concentration), physiological factors and biochemical factors. At present, it can not be completely explained in theory, nor can it be overcome in production practice.
2. Temperature
Temperature (heat) is the most important meteorological factor affecting the growth and fruit of grapes. Grape is a warm temperate plant. Considerable heat is needed. Active accumulated temperature refers to the sum of daily active temperatures of grapes in a certain growth period, which is widely used. It can not only better reflect the relationship between grape development speed and temperature conditions, but also represent the heat resources in a certain area. The average monthly temperature required during the grape growing period (from budding to fruiting) is 10. The active accumulated temperature above C varies from province to province due to different varieties.
The following table lists the requirements of different grape varieties for effective accumulated temperature.
When planting grapes and regionalizing varieties, grape varieties should be selected according to the annual effective accumulated temperature in each region. Knowing the effective accumulated temperature in a certain area and the requirements of a certain variety for effective accumulated temperature, we can roughly infer the possibility of economic planting of this variety in a certain area. Since the effective accumulated temperature is the average value for many years, the fluctuation range of this average value may be 200℃-300℃. Therefore, the above data should be considered in specific applications.
Temperature also has an important influence on the growth and fruiting process of grapes. When the temperature reaches 7℃- 10 in spring. At point C, the grape roots begin to move. Germination begins at 10℃- 12℃. The suitable temperature for grape shoot growth, flowering, fruiting and flower bud differentiation is 25℃-30℃. If there is low temperature weather (< 15℃) during flowering, the grapes can't bloom normally. The suitable temperature for ripening fresh grapes and dry grapes is 28℃-32℃, and that for wine grapes is 17℃-24℃.
High temperature will do harm to grapes, but the degree is far less than that of low temperature. The harm of low temperature to grapes is a common problem in grape cultivation in the world, and low temperature limits the cultivation area of grapes. Grapes are generally planted in the northern hemisphere between 20-5 1℃ north latitude. The northern boundary of European grape varieties cultivation is the Rhine River basin in Germany. Grapes grow here because the growing period is too short. The temperature is too low and the accumulated temperature is too little. In some years, the vines and fruits of grapes are not mature yet. Therefore, the vineyards here are all facing the sun on the south slope of the north bank of the Rhine River, making full use of the microclimate of the slope and the regulating effect of the Rhine River on the temperature to ensure the ripening of grapes. The southern border of farming extends to India. In the southern hemisphere, grapes are mainly planted at 20-40℃ south latitude. Constraints on the expansion of grape growing areas in Europe to the equator. High temperature, diseases and insufficient low temperature are the causes of grape dormancy. In some parts of India, some European grapes and hybrid grapes can also grow, but there is no real dormancy period. The main limiting factor for the expansion of European grapes to the poles is that the growing season is short, which is not enough to ensure the maturity of fruits and vines and to resist the low temperature in winter.
The harm of low temperature is mainly the severe cold in winter. The cold resistance of Eurasian grapes varies greatly among different varieties, and there are also considerable differences among different tissues and organs. Generally speaking, the cold resistance of American grapes is greater than that of Eurasian grapes. Grape roots have the weakest cold resistance, and most of them are in a 5. C, according to the determination of Shenyang Agricultural University in 1983- 1984, the critical temperatures of root freezing injury of some fresh rootstocks are as follows: Rose fragrance -5.2℃, Kyoho -6.7℃, Kangbaier Zaochang -7.0℃, Harmony -8.0℃ and Freedom -9.0. Gongniang -9.65438 +0℃, Beichun -9.3℃, Pueraria lobata -9.4℃, Binjiang Grape-1.4℃, Peking University-12.6℃. Vitis amurensis× Vitis binjiang hybrid -65438. In order to reduce root freezing injury, it is of great economic value to use Vitis amurensis and Beta as cold-resistant rootstocks to make grapes buried in the ground and planted in colder areas. But cold-resistant rootstocks are not used in most parts of northern China. In some cold years, even in the case of burying soil, the root freeze injury is quite serious. Therefore, it is necessary to do a good job in winter cold protection. It is generally believed that. Grapes can overwinter without mulch when the average minimum temperature for many years is-15℃-14℃, but it must be covered in different degrees below-15℃ to overwinter safely. Even so, the soil temperature 50 cm underground often reaches -5℃. The winter buds of grapes are weak in cold resistance, followed by mature annual branches, and perennial branches and trunks are the most cold-resistant. The bud eye of Eurasian grape can withstand the low temperature of -20℃- 18℃ in winter, but if the maturity of branches is poor and the dormancy period is short, it is-15. At-10℃, the buds will be frozen. At-18℃, if the low temperature lasts for 3-5 days, not only the bud eyes will freeze, but also the branches will freeze.
Low temperature in spring is the harm of late frost. The shoots and young leaves begin to freeze at-65438 0℃, and the inflorescence freezes at 0℃. In autumn, in some years in northern China, early frost appears prematurely, and leaves and grape berries will also be frozen, resulting in discoloration of leaves and softening of berries. At this time, the temperature generally drops to -5℃-3℃.
Step 3 precipitate
Among the agricultural environmental factors, natural precipitation and seasonal distribution of precipitation strongly affect the growth and development of grapes and the yield and quality of grapes. In some areas, the seasonal variation of precipitation of some cultivated varieties is one of the most important climatic factors for grape variety zoning. Due to different climate types in the world, the seasonal variation of precipitation shows significant differences. The seasonal distribution of climate precipitation in the Mediterranean is characterized by drought in summer and autumn and rainy in winter and spring. The climate of the main grape producing areas in China is monsoon climate (except Xinjiang). The seasonal distribution characteristics of this climate decline water are: drought in autumn, winter and spring, and rainy in summer, accounting for 45%-65% of the whole year, which is in sharp contrast with the precipitation characteristics of world-famous grape producing areas.
The grape producing areas in China are all controlled by the high temperature and rainy climate in summer, and the rainy weather in the south in spring increases the difficulty of grape cultivation. Due to the seasonal distribution of precipitation in China, it is suitable for crop growth, but unfavorable to grapes (except Xinjiang), so the phenomenon of "water stress" of grapes is very obvious. The so-called "water stress" refers to insufficient or excessive water. Or untimely, it will hinder the growth and development of crops, so that climate resources such as light and heat can not give full play to their functions, production potential can not be brought into full play, output will drop, and quality will be inferior. For example, grapes grow in soil with more rain, the roots absorb too much water, the new shoots grow rapidly, the cells swell, the cell walls become thinner, and the tissues become brittle and tender. Meiyu in flowering period affects the process of pollination and fertilization, causing serious flower and fruit drop and disease spread. In quite a few years, the grapes suffered more rainfall at maturity, the sugar accumulation in berries was difficult, the new shoots were flourishing, the leaf curtain was closed and the diseases were serious. The scarcity of rain and snow in winter and spring will have a negative impact on the overwintering and the growth of grapes in the next year. Although the "water stress" caused by drought is not as serious as that caused by rainy weather, it should be paid full attention to in production and solved by irrigation.
In grape cultivation, we should not only consider the requirements of grapes for suitable climatic conditions, but also pay attention to avoiding and protecting disastrous climate, such as long drought, flood, severe frost, extreme cold, strong wind and hail. All these may cause great losses to grape production. For example, strong winds in the growing season often break new buds, scrape off fruit ears and even destroy vines. Strong winds in winter will blow away sand and snow and deepen the freezing depth of soil. Hail in summer often damages branches and leaves and ears, which seriously affects the yield and quality of grapes. Therefore, when building a garden, we should consider the frequency and intensity of a certain disaster factor, reasonably choose the garden, determine the appropriate direction, create a protective belt, and have other corresponding protective measures.
Second, the topographical conditions and the quality of wine grapes.
1, latitude and altitude.
Most vineyards in the world are located between 20-52 degrees north latitude and 30-45 degrees south latitude, and most of them are in the northern hemisphere. The altitude is generally 400-600 meters. The altitude of grapes in China varies greatly between 30 and 43 degrees north latitude, about 200-1000 m; The distribution height of Huailai grape in Hebei Province is1100m; Xu Da county is1200m; The altitude of Shannan in Tibet is over1500m. Latitude and altitude are important factors affecting temperature and heat in a large range. In Asia, with the latitude increasing by 65438 0 degrees, the annual average temperature drops by 0.7℃.
2. Slope direction and gradient.
In the case of similar topographic conditions, the microclimate in different slope directions is obviously different. Usually the slopes facing south (including due south, northwest and southeast) receive more light and heat, and the temperature is higher on weekdays. The warming effect of sloping land is closely related to its slope. Generally, every tilt to the south 1 degree is equivalent to advancing 1 latitude (1 12km). The hottest tilt angle is about 20-35 degrees (within 40-50 degrees north latitude). Grape is more suitable for cultivation on sloping land than other fruit trees because it is drought-resistant and barren-resistant, and can develop roots in a relatively small range. However, the greater the slope, the more serious the soil erosion and the more difficult the soil management of the vineyard. Therefore, it is necessary to give priority to the land with a slope below 20-25 degrees when planting grapes.
3. The influence of water surface.
Large waters, such as oceans, lakes, rivers, reservoirs, etc. It absorbs more solar radiation energy and has greater heat capacity, so the temperature in day and summer is lower than that in land, while the temperature in night and winter is higher than that in inland. Therefore, the coastal climate near the water area is mild and the frost-free period is long. The vineyards near the big water surface reflect a lot of blue-violet light and ultraviolet light in the deep water, and the berries are colored and of good quality, so when choosing vineyards, try to be close to big lakes, rivers and oceans.
Third, the soil conditions and the quality of wine grapes.
Grapes can grow in various soils, such as desert, flood plain, saline-alkali land, rocky slope and so on, but different soil conditions have different effects on the growth and fruit of grapes.
1, parent rock core.
In the soil formed by limestone or rich in calcareous core soil, grape roots are developed, sugar accumulation and aromatic substances are more developed, and calcium in the soil has a good influence on the quality of wine. World-famous winemaking areas are located on this land, such as Champagne and Xia Lang de Konnek. But the soil layer is thin, and there is often a gravel layer under it, which is easy to cause water leakage and fertilizer leakage.
2. Soil thickness and mechanical composition.
The greater the thickness of the soil layer, that is, the greater the thickness from the topsoil to the parent rock, the greater the volume of nutrients absorbed by the grape roots, and the stronger the ability of soil to store water. Generally, the soil thickness of vineyards is above 80- 100㎝. The mechanical composition of soil affects soil structure and water, gas and thermal conditions. Sandy soil has strong permeability, strong radiation in summer, large soil temperature difference, high sugar content and good flavor of grapes, but soil organic matter is lacking, and water and fertility are poor. Clay has poor permeability and is easy to harden. Grape has shallow roots, weak yield and poor fruit. Sometimes the output is poor, but the quality is poor. Generally speaking, we should avoid planting grapes on heavy clay. High-quality grapes can be planted on gravelly soil, such as gravelly Gobi soil in Lufan Basin, Xinjiang (gravel and sand are above 80%). After improvement, the grapes grow well. In some large rock slopes such as Fenghuang Mountain in Changli and Daze Mountain in Pingdu, soil improvement measures have been taken, and grape planting has also been very successful.
3. Groundwater level.
Grapes grow in wet soil and produce good fruit. Groundwater level has an influence on soil moisture, and the soil with low groundwater level has poor water storage capacity; The soil with high groundwater level and close to the ground is not suitable for growing grapes. The suitable groundwater level should be below1.5-2m. Under the condition of good drainage, grapes can grow and bear fruit well in the soil where the groundwater level is 0.7- 1 m above the ground.
4. Chemical composition of soil.
This is of great significance to the nutrition of grape plants. Soil organic matter formed by decomposition of plant residues can promote the formation of good soil structure and is the main source of nitrogen supply for plants. Because of the different chemical composition, the pH value of soil is also different. Generally speaking, grapes grow well in a slightly acidic environment with a PH of 6-6.5. In the soil with too strong acidity (PH close to 4), the growth is obviously poor, and in the soil with relatively strong alkalinity (PH 8.3-8.7), yellow leaf disease begins to appear. Therefore, the soil with too large or too small acidity needs to be improved before grapes can be planted. The minerals in the soil are mainly nitrogen, phosphorus, potassium, calcium, magnesium, iron, boron, zinc and manganese. , are important nutrient elements of grapes. These elements can only be absorbed and utilized by roots if they exist in soil solution in the form of inorganic salts. In addition, there are some harmful salts in the soil solution, including sodium carbonate, sodium sulfate, sodium chloride and magnesium chloride. The accumulation of these salts is different, which determines the degree of soil salinization. Grape is a salt-tolerant plant in fruit trees, and it can grow well in places where apple, pear and other fruit trees can't grow.