Climatic conditions
Temperature, humidity, light, wind and hail
(1) temperature condition
All kinds of physiological activities, biochemical reactions, growth and development of apples must be carried out under certain temperature conditions. Otherwise, its normal growth and development will be inhibited, hindered, hurt or even die.
The influence of temperature on apple life activities is mainly manifested in the following aspects:
1) Three base point temperatures
As far as physiological process is concerned, there are three corresponding minimum, optimum and maximum basic points for the temperature required for apple life activities and growth and development. Generally speaking, the minimum temperature of apples is about 5.0℃, the optimum temperature is 13-25℃, and the maximum temperature is about 40℃, which varies with varieties, organs, ages, growth periods, physiological processes and temperature changes, as well as other ecological factors. The optimum average temperature of different varieties in growth period is also different.
2) Accumulated temperature
Different varieties, different organs and different growth stages of apples need a certain accumulated temperature. Accumulated temperature has an important influence on the growth, yield and quality of apples. Therefore, accumulated temperature is often regarded as an important indicator of variety characteristics, and it is an important basis for phenological prediction, yield and quality research, ecological analysis and zoning.
3) Accumulated temperature and flowering period
Calculating the accumulated temperature before flowering can predict the flowering period of apples. In temperate regions, the effective accumulated temperature of 5℃, the lowest temperature of tree growth, is generally used to predict flowering period. According to the research, the average effective accumulated temperature of apples above 5℃ is 160 ~ 180℃ from the temperature of 5℃ to the early flowering stage, and there is little change among varieties. But the length of flowering period is affected by temperature. When the daily average temperature is 7-8℃, most varieties need about 50 days, 10℃ needs about 40 days, and 12 13 only needs 30 days. The effective accumulated temperature of most apple varieties from the beginning of growth to flowering is 185 10℃, and the annual temperature difference is 10 1℃. According to relevant reports, the effective accumulated temperature of Guoguang apple in Xingcheng, Liaoning Province from the beginning of growth to flowering, 1954 is about 155.2℃, and 1955 is as high as 253.438+05438+03, with a difference of 79.9℃. The above results show that it is not accurate to use the effective accumulated temperature which is stable above 5℃ before flowering as the florescence prediction; Different varieties, or the same variety in different regions and different years, need different accumulated temperatures; Different topography and microclimate also have influences.
4) Flowering temperature
In order for apples to blossom, they need to reach a certain accumulated temperature first. The flowering period of apples is very sensitive to temperature. Temperature is an important limiting ecological factor for successful flowering, pollination, fertilization and fruit setting. Generally, the suitable temperature for apple flowering is11.4 ~1.8℃, and the optimum temperature is 17 ~ 18℃. Judging from the temperature required for pollinator activity, bees generally stop going out below 10℃; 15-29℃, gradually active with the increase of temperature, which is beneficial to pollination.
Flowering temperature is an important condition for apple pollen germination and pollen tube elongation to complete fertilization. It was observed that different varieties have different requirements on the suitable temperature. Generally, the suitable temperature for pollen germination is between 10 ~ 25℃, and the optimum temperature is 15 ~ 20℃. When the temperature is higher than 30℃, pollen germination is obviously inhibited.
5) The temperature in spring
Low temperature in spring: The apple producing areas in China are mostly continental monsoon climate, with unstable temperature and frequent low temperature in spring, especially late frost. Apple is in the stage of germination, flowering and fruit setting in spring, which is weak in low temperature tolerance and sensitive to temperature response.
High temperature in spring: The temperature in spring is closely related to the shape and appearance quality of apples. The results showed that the vertical axis of apple was longer than the horizontal axis and the fruit shape index was larger when the temperature was low and the climate was cold from15 to16 days after flowering. On the contrary, the fruit shape index is small. This is related to post-anthesis division of fruit cells and endogenous hormones.
6) Temperature in summer and autumn
Summer and autumn are the time when apple shoots stop growing, flower buds differentiate and fruits mature. Therefore, the temperature in summer and autumn has a great influence on flower bud differentiation, yield formation and quality. According to the investigation, the temperature in summer and autumn (June-September) is too high or too low, which is unfavorable to the above growth process of apples. The monthly average temperature range is 16.5 ~ 22.85℃. For example, in the national appraisal, the average monthly temperature in China apple quality ecological zones such as Maoxian County, Xiaojin County and Tianshui City, Gansu Province, which are among the best in fruit quality, is 16.2-22.7℃ in summer, the highest in Tongchuan, Shaanxi Province, 23.5℃ in summer, and 16.8-22.3℃ in Spokane, Washington, USA. If the temperature is too high in summer, its ecological reaction is: the fruit shape index becomes smaller, the color difference, the pulp is easy to fluff, the maturity consistency is poor, the vitamin content is reduced, and the fruit aroma, flavor and storage resistance are poor.
Summer temperature and flower bud differentiation: it is pointed out that the suitable temperature for the initial stage of apple flower bud differentiation is 20-27℃. The flower bud morphological differentiation period of Zhu, Marshal and Guoguang began after the average temperature stabilized above 20℃ for a certain number of days.
7) Cold demand in winter
Generally speaking, it is believed that inducing apples to enter real dormancy is mainly due to low temperature and insensitivity to short sunshine and drying conditions. In order to end the true dormancy of buds, many studies believe that a cold climate in winter is also necessary. Low temperature hours: that is, the hours of experiencing low temperature below 7.2℃. The starting point of low temperature is 7.2℃. At present, scholars all over the world take 7.2℃ as the standard of accumulated hours. The required CH value of apples varies greatly from variety to variety. With the expansion of modern cultivation areas to low latitudes, the CH requirement of apples tends to decrease gradually. From 1400-3684℃ needed in the early stage.
It needs 500- 1700℃ in the near future.
(2) Humidity conditions
Water is the medium of mutual adaptation and unification between apple and environment, and it is the most abundant substance in apple trees. Water plays an important ecological role in the growth and development, physiological and biochemical processes, yield and quality formation of apples through the changes of different forms, quantities and durations. At the same time, it also plays an indirect role by causing changes in ecological factors such as light, heat, soil and biology.
The influence of water on apple growth and development is mainly manifested in the following aspects.
1) precipitation and apple germination, shoot growth, flowering and fruit setting
After dormancy, apples need a certain amount of water to germinate. Lack of water often delays germination or causes irregular germination, which affects the growth of new shoots. During the growth period of new shoots, the water is insufficient, and the ecological response is that the branches are weak, the growth stops early, the leaves are small, the leaves are easy to fall, and the overall vegetative growth of the tree is weak; Too much water, the branches and leaves of the tree grow too vigorously, the tissue is not full, and the level of nutrient storage is low; Further excess water will cause waterlogging, such as rotten roots, weak trees, early deciduous leaves, dead crowns, etc., which will cause trees to die.
Too little water in the flowering and fruit-setting stage of apple will shorten the flowering period, affect pollination and fertilization, and obviously reduce the fruit-setting rate. If there is too much precipitation during flowering, heavy rain and long-term rain will reduce stigma secretion or affect pollen attachment and germination due to erosion, thus affecting pollination and fertilization, resulting in falling flowers and fruits.
In the arid areas of northern China, water is often insufficient during germination, flowering and new shoot growth, so it should be fully irrigated. In the southern apple producing areas of China, there is often too much rainfall or rainy days. Therefore, we should pay attention to the selection of garden, variety and rootstock, the management of soil, fertilizer, water, flowers and fruits, the regulation of pruning, pest control and other supporting technologies according to local conditions.
2) Precipitation and Apple Flower Bud Differentiation and Yield
Precipitation has an important influence on apple flower bud differentiation, growth and development, yield in the current year and fruit in the next year. According to the research, young trees with early fruiting have less precipitation during flower bud differentiation, which is beneficial to the formation of flower buds and the improvement of the second yield. Adult fruit trees, on the other hand, lack of water during flower bud differentiation will lead to yield reduction in the following year. Generally speaking, the monthly precipitation distribution in the growing season of the previous year is relatively balanced, which is beneficial to the growth and development of apples and the fruits of the next year.
3) apple fruit development and water requirement
With the growth of young fruits, the water content increased continuously, while the percentage of water content decreased continuously. People feel more mature juice than immature juice when eating, because some carbohydrates in the pulp are converted from insoluble substances to soluble substances. The growth and development of fruits need a lot of water supply, especially in the period of rapid fruit expansion. If there is less precipitation and irrigation is not timely, it will affect the fruit expansion and even fruit drop.
(3) Lighting conditions
Apple originated in the inland areas with strong sunshine, and it is a kind of light-loving fruit tree. The annual sunshine hours in the main apple producing areas at home and abroad are mostly around 2000 hours, and the average monthly sunshine hours in the three key periods of fruit growth, development, coloring and ripening are also between 150 ~ 200 hours.
The influence of light on the growth and development of fruit trees is mainly manifested in the following aspects.
+0) Photosynthesis
The daily net photosynthetic rate of apples was measured every year in the early years. The results show that light intensity is the most important factor affecting photosynthesis in the growing season, and the net photosynthetic products in weak weather are only about 25% of those in sunny days.
Light saturation point and light compensation point are the two most important physiological and ecological indexes of light. The light compensation point of apple varies with variety, leaf age, leaf position, leaf area index, carbon dioxide, soil available water and temperature.
2) Photosynthetic products of yield and quality are the basis of fruit setting, fruit growth and quality formation. In a certain range, the stronger the light, the higher the fruit setting rate, the larger the fruit, and the better the coloring and quality.
Quality and light intensity: The experiment of Marshal Xu He's apple shows that there are three obvious light areas that affect the quality of apple in British Columbia, Canada, at 49' 44' north latitude: the canopy area with FS above 60% is the best fruit coloring area, which is a high-quality light area; 40%-60% FS is in moderate light area, which can produce fruits with normal color; Below 40% fs is the area with insufficient light, and the fruit is seriously colored.
Light affects the synthesis of anthocyanins by affecting photosynthesis. The results of artificial shading treatment showed that with the increase of shading degree, the color change of fruit became worse, the large fruit decreased, the proportion of stone increased and the quality decreased.
3) the influence of light quality
Photosynthesis, photosynthetic products and visible light: In the ecological function of apple, visible light is the most important energy source for photosynthesis, and most spectral bands (generally between 380-7 10 nm) are absorbed. Only green light is rarely absorbed, and blue, purple and red light are the strongest.
Under natural conditions, apples are irradiated by different visible spectrum components, and the components that form photosynthetic products are also different. Red light is beneficial to the formation of carbohydrates, while blue light is beneficial to the synthesis of protein. Therefore, in production, we can choose different cultivation sites with different topography and lighting conditions, or use different color films to improve fruit quality.
Vegetative growth and visible light: Blue, violet and cyan light in visible light play an important role in cell differentiation, which can inhibit elongation growth, control vegetative growth and make trees shorter. Therefore, when planting apples in mountainous areas with more blue and purple light, the trees tend to be dwarfed, with more lateral branches, higher branching rate, stronger branches and better flowers and fruits.
The function of direct light and diffuse light: the solar radiation received by apple trees includes direct light and diffuse light with different intensity and quality. In fruit tree cultivation, diffuse light mainly comes from the sky, but also from the ground and other objects. Diffuse light has lower intensity than direct light, less short-wave light and more long-wave red and yellow light (up to 50%-60%) in spectral components, and the absorption and utilization rate of photosynthesis is high. So diffuse light can also reach the light saturation point. The research on the variation of total solar radiation and diffuse solar radiation in different weather shows that the diffuse solar radiation in sunny days accounts for about 10% of the total solar radiation, showing a relatively stable and regular variation. On cloudy days, the absolute and relative amount of diffuse radiation increases, but the total solar radiation decreases. Among them, when it is cloudy, the two kinds of radiation are almost equal; When it is partly cloudy and cirrus, the diffuse radiation is almost twice that of sunny days, which is of certain significance to improve the photosynthesis of apples. The coverage rate of young orchards is low, which can make full use of a large amount of diffuse light reflected from the ground and promote the good growth and fruiting of skirt branches under the crown; Adult orchards should pay attention to removing the influence of a large number of tall weeds under trees on light, and can also use reflective films such as silver ash and aluminum platinum to improve the coloring and quality of fruits under the crown. The light reflectivity of Al-Pt film can reach 100%.
The ecological response of apple fruit coloring to direct light and scattered light varies with varieties. One is the variety type that must have direct light to be full-colored, such as Marshal, Red Star and Red Crown. The other is that under the condition of weaker direct light and more diffuse light than ordinary varieties, you can also wear lewd varieties, such as Marshal short branch and thick red variety.
(4) Wind and hail
Apple orchards are suitable to be built in areas where the annual average wind speed is below 3.5 m/s, and when the wind speed often exceeds 6 m/s during flowering, the fruit setting rate will decrease; It is also easy to cause adverse consequences such as crown deviation, falling fruit and damaging leaves, and even breaking branches.
In some areas suitable for apple growth in China, there are regular hail zones, so we must know clearly before building a garden, and don't build a garden in the hail zone.
terrain condition
(1) Plateau and Pingdi
Plain, plateau, beach, low-lying land and other flat land with a slope less than 5 generally have fertile soil, abundant water resources and little climate change. After the garden is built, the apple trees grow well, with deep roots, convenient management, mechanized operation, good traffic conditions and no easy soil erosion. However, building a garden on the ground also has its disadvantages. For example, ventilation, lighting and drainage are not as good as those in mountainous areas, and the quality and storage capacity of fruits are worse than those in mountainous areas; The beach soil has high salt content, high groundwater level, poor structure, low fertility and short life span of fruit trees. Only by improving the soil can fruit trees grow well.
(2) Hills and slopes
Apples are more suitable for planting in mountainous areas and slopes. Even in the south, high-altitude areas can produce high-quality apples. Northwest elevation 1000m, apple trees have moderate growth potential, easy flowering, high yield and high quality, which is the best cultivation area of red apples in China. Hills and low mountains, with a slope of 5 ~ 15 and a height of 200 ~ 500m, are good bases for developing apple trees. However, you can't build a garden at the foot of the mountain to avoid freezing injury during flowering; In the middle mountain zone, the slope 15 ~ 25, the height is 500 ~ 1000m, the cultivation is difficult, the effect is poor, the cost of soil improvement increases, the sunshine difference between the north and south slopes increases gradually, the north slope is colder than the south slope, and the direct light on the east and west slopes decreases gradually; High mountain area, the slope is greater than 25, and the height is greater than1000 m. The garden should be built in a special area that can meet the growth and development requirements of fruit trees. Otherwise, the soil in this area is stony, thin and difficult to transport, which is generally suitable for planting trees and grass. Therefore, orchards should be built on gentle slopes and thick soil layers, and soil and water conservation projects should be built; Cold air is easy to accumulate in the lower part of the valley depression, and the freezing damage is serious, which is not suitable for planting apple trees. The temperature in sunny slope rises rapidly in spring, and the fruit ripens early and has good quality, but the moisture is not as good as that in shady slope, so it is vulnerable to frost and sunburn. Shady slopes are prone to cold in winter because of the low temperature, which should be taken into account when building gardens.
Although hills also belong to mountain type, their ups and downs and amplitude are smaller than those of mountains, and the vertical distribution of climate and the illumination difference between yin and yang slopes are not obvious. Planting fruit trees in hilly land has advantages over flat land. Generally, hilly land has good drainage, good air circulation, sufficient illumination and large temperature difference between day and night, which can make fruit trees have long life, early fruit bearing, high yield, good quality, bright color and storage resistance. Therefore, the hilly land is a good apple orchard.
Because of the different slope direction and gully (valley) direction, there will be great differences in solar radiation conditions and radiation budget, different heat and water conditions, different microclimate characteristics and ecological factors, thus producing various ecological effects on apples.
According to the study of fruit trees in mountainous areas in China, the comprehensive effects are generally as follows: compared with the north (shady) slope, windward slope or north-south valley direction, the valley has strong solar radiation, good sunshine, high air temperature and soil temperature, large daily temperature difference, less precipitation, low humidity, strong evaporation, dryness and sparse vegetation. Apple has a good ecological response. The general rule is that the tree is strong, the nutrition grows vigorously, the flower buds are well differentiated and firm, the fruit surface is bright and clean, the color is gorgeous, the sugar, acid, vitamin C and other contents are high, the fragrance is sweet, the quality is good, the pests and diseases are few, and the freezing injury is light, but the sunburn is often aggravated. Such as Xiaojin, Maoxian, Jinchuan, Danba, Batang and Xiangcheng. , all in the open valley, diluvial fan, slope skirt, terrace, foothills and other topography, sunny in the slope or near the east and west in the ditch (valley). On the contrary, in the north (shady) slope, windward slope or north-south gully (valley) direction, the habitat and ecological response of apples are poor.
(3) altitude
According to the investigation, from the large-scale field ecological response, the high-quality areas of Yuan Shuai and Jinguan, the main apple varieties in China, are in the main producing areas of the northwest plateau, mostly in areas above sea level 1000 meters; The southwest highlands are mostly at the altitude of 1500 ~ 2900 meters, especially in the range of 2000 ~ 2600 meters, especially in the Hengduan mountainous area of Sichuan and Yunnan, with bright color and excellent quality. This is because these zones are relatively low in latitude and high in altitude, and the unique combination of dry and warm valleys or river fault basins in alpine valleys (deep valleys) has created a unique habitat with good sunshine and many ultraviolet rays. For example, the altitude of Xiaojin, Maoxian, Yanyuan and Lijiang in Yunnan in high-quality areas is 2000 ~ 2600 meters, and the sunshine percentage is more than 50%. The fruit surface and two depressions of the Marshal system are full red, bright in color, golden in crown, sunny, and flushed to the sunny side, accounting for more than 1/3 ~ 1/. The fruit quality of Jinguan, Hongxing and Hongguan has been among the best in the national appraisal for many times. However, in low-altitude areas of the same latitude, such as Sichuan Basin, where the altitude is about 400 ~ 600 meters and the sunshine percentage is below 30%, it is difficult to color. The surface coloring degree of marshal fruit is not easy to reach 30%, and the coloring index is almost zero. Golden crowns are mostly yellow-green, green-yellow, and rarely blush.
Socioeconomic conditions
The establishment of apple orchard and the early management of young trees need a lot of investment, so we should be fully prepared before establishing the orchard. The address and scale of the park should be comprehensively considered according to the local geographical location, traffic conditions and economic strength. Specifically, it is mainly whether the reserve of economic strength and technical strength can ensure the establishment and development of apple orchards. From the establishment of apple orchards, the planting of saplings to the flowering and fruiting of apple trees, it is a period of pure investment and no income, and it cannot be successfully spent without sufficient economic strength. The establishment and smooth development of apple orchard, the reserve of technical force is also extremely important.
edaphic condition
Type depth, water level, temperature, humidity, air nutrients, pH value and salt content.
(1) soil type
Apples have strong adaptability to soil, and are cultivated and distributed in various soils. However, from the needs of apples and the requirements of high quality and high yield, it is suitable to have deep soil, good configuration, suitable proportion of three phases, rich nutrition and slightly acidic to slightly alkaline. The distribution of apple planting in the world and China is mainly brown soil, cinnamon soil, brown calcium soil, chestnut soil, calcareous soil and fluvo-aquic soil.
According to the investigation and study, the soil types of apple producing areas in China are quite different in different regions. The main apple producing areas in North China and Southeast China are brown soil, yellow soil, brown yellow soil, cinnamon soil, yellow tide soil and tidal yellow soil. The main producing areas of the Loess Plateau in northwest China are cinnamon soil, loessial soil, black loessial soil, lime-lime soil and irrigated silt soil. The main producing areas in Xinjiang are mainly lime soil, brown lime soil, brown desert soil and oasis soil. The main producing areas in the Central Plains mainly include yellow fluvo-aquic soil, fluvo-aquic soil, fluvo-aquic soil loessial soil and neoaccumulation soil. Sichuan basin is dominated by purple soil, purple brown soil, yellow soil and tidal soil; The main producing areas in Hengduan mountain area of Sichuan and Yunnan mainly include cinnamon soil, brown red soil, brown soil, red soil and newly accumulated soil. The southwest plateau is dominated by yellow soil, red soil, brown red soil, fluvo-aquic soil and newly accumulated soil; There are yellow soil, red soil, lateritic soil and latosol in subtropical and tropical areas of South China. There are brown soil, yellow brown soil, cinnamon soil, mountain shrub grassland soil, tidal soil and meadow soil in Tibet Plateau. Generally speaking, the soil types in high-quality apple areas in China mainly include cinnamon soil, loess, loessial soil, calcareous soil and brown soil. Among them, the quality of apples is particularly prominent in cinnamon soil areas.
(2) Soil depth
Soil depth directly affects the spatial range, root composition and ecological stability of apple root system, and affects the storage and utilization of soil moisture and nutrients, thus affecting growth, fruit, yield and quality. According to the survey, compared with the soil depth of 3.3 meters and 0.72 meters, the thousand weeks, tree height and new shoot length of Guoguang apple increased by 226%, 220% and 555% respectively, and the yield increased by five times. Marshal apple increased by 147%, 1 13% and 21%respectively, and the yield increased by 1.5 times. The average yield per plant of Golden Crown grown in sandy soil below 70 cm was 190.6 kg, while the average yield per plant of Golden Crown grown in sandy soil below 40 cm was only 9.4 kg. After deep ploughing and fertilization, the root amount of the lower layer increased.
The growth of roots in compact soil is blocked, thickened and the top is abnormally branched. The young root tip may have a pressure of 15 ~ 20 Pa. The antagonistic reaction may be in the root cap. In addition to pressure reaction, the increase of ethylene can also participate in the regulation of root resistance, and external use of ethylene can make the root system thicker and shorter.
(3) Groundwater level
The investigation on the relationship between groundwater level and output in 10 year shows that the output increases significantly with the decrease of groundwater level in the range of 50- 120 cm. Therefore, in places with high groundwater level, drainage measures must be taken to reduce the groundwater level.
(4) Soil temperature
It is generally believed that the optimum temperature for apple root growth is 7 ~ 20℃. Apple roots begin to grow at 5.4℃, the fastest at 20℃, and will be injured and die at 43.0℃. It is reported that the optimum temperature for new roots of different rootstocks is different, with M 1, M2, M3 and M9 as 13C, Mt6 as 25 12 and M7 as 30℃. The optimum temperature for new roots of Oryza sativa, Oryza sativa and Oryza sativa is 12.8 12, and the optimum temperature for M7, M 16 and seedling rootstock is 25℃.
(5) Soil moisture
Soil moisture is not only the main source of water needed by apples, but also the necessary condition for many physical, chemical and biological processes in soil. The moisture in soil and air is complementary to each other. The change of moisture directly affects soil heat, soil organisms and microorganisms, and affects the change of air temperature and relative humidity in orchard.
Soil moisture is mainly affected by precipitation, irrigation, soil evaporation, plant transpiration, land cover and soil porosity, and its content is very unstable. Generally, the soil water content when it stops moving under the action of gravity is called field water capacity. This is also the easiest water for plants to use. Wilting coefficient (wilting coefficient) is called when the soil water content drops to the point where plants are permanently wilted. Generally, 60% ~ 80% field capacity is suitable for apple orchards.
Critical value of apple water requirement: that is, under the condition of water shortage; The period that has the greatest influence on its metabolism and yield formation. It is generally believed that the critical period of apple water demand is the time when new shoots grow rapidly, a large number of leaf curtains form and young fruits develop. Some people think that the critical period of water demand is after flowering.
(6) Soil air
Soil oxygen concentration: oxygen in soil is a necessary condition for the life activities of roots and soil microorganisms. When the oxygen in the soil is exhausted by the respiration of roots and microorganisms, and the accumulation of sulfur dioxide in the soil reaches a certain concentration, the roots will be damaged until death. According to the determination, when the temperature is 20-30℃, the oxygen consumption of 0-30 cm soil layer can be as high as 0.5-0.7 L/(m2? Hours). Assume that the average air capacity in the soil is 33.3%, of which oxygen accounts for 20%. Without ventilation, the oxygen in the soil will be exhausted within 12 ~ 40 hours.
Apple roots can grow normally only when the soil oxygen concentration is above 10%.
3% ~ 5% growth is poor, and 0. 1% ~ 3.0% root system dies. When the oxygen concentration is 10% and the carbon dioxide concentration is 5%, the root growth is blocked and the shoot growth becomes worse. Through pot experiment, it was found that the effect of soil hypoxia on root system was greater than that on shoot. When the soil oxygen concentration is about 5%, the aboveground growth is vigorous, and the root growth is equivalent to 80%-90% under high oxygen concentration; Below 5%, almost no new roots are sent.
According to the test, the apple grows normally when the oxygen concentration is higher than 1.2%, but it grows obviously worse when 1.5%-2%. Below 1.5%, almost all the fine roots died. The response of root system to different oxygen concentrations is that 12% seems to grow normally, with thin roots and no obvious trunk lenticels; From 2.5% to 1 1%, the roots are thin, only some new roots appear, and the straight roots and plant lenticels are extremely developed; When 1.5%-2.5%, the root cork accelerates and the lenticels develop significantly? When it is lower than 1.5%, the fine roots die, and the thick roots are dull in color and weak in vitality.
To sum up, the soil oxygen concentration for normal growth of apple roots should be above 10%, preferably close to the atmospheric oxygen concentration (20.96%). More than 0/5% of/kloc-can produce a large number of new roots, and the growth below 5% is inhibited or stopped.
Carbon dioxide concentration in soil: Carbon dioxide in soil is mainly produced by decomposition of organic matter and respiration of roots and soil microorganisms, with a general concentration of 0. 1%-4.0%. Determine in calcareous silty loam orchard,
1.5 cm deep soil layer is 1% ~ 4%, 73 cm deep soil layer is 3% ~ 7%, and 244 cm deep soil layer is 4% ~ 6%. In sandy loam and silty loam apple orchards, when the soil depth is 30 cm, the carbon dioxide concentration is
Below 5%, the depth of 152 cm is 7%-8%.
(7) Soil nutrients
The main nutrients absorbed by apples from soil environment are nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and trace elements such as iron, manganese, boron, zinc, copper and molybdenum. Apple trees are large in size and deep in roots, which requires that the surface soil and deep soil should be rich in nutrients and well configured. In the analysis and evaluation of soil nutrients, in addition to macro and trace elements, the content of soil organic matter is of great significance. It can not only decompose and provide various nutrients, but also play an important role in improving soil physical properties and promoting root development. There is a linear correlation between organic matter and apple yield, and the organic matter content in high-yield apple orchard is greater than 1%.
(8) Soil pH value
Generally speaking, apples like to be slightly acidic to neutral, and the suitable pH value is 5.5-6.7. In alkaline soil, the availability of potassium is better, while the availability of iron, manganese, phosphorus and boron is lower. In acidic soil, the availability of manganese, iron and aluminum is better, phosphorus and boron become ineffective, and the availability of zinc and copper decreases.
(9) Soil salt content
The salt tolerance of apples is weaker than that of main fruit trees such as grapes, dates, apricots and pears. The total salt content of normal growth is 0. 13% ~ 0. 16%, and the damage limit is above 0.28%. When the soil contains 0. 1 17% sodium sulfate, 0.02% sodium chloride and 0.008% sodium carbonate respectively, the growth is poor.
Obstacle condition
(1) When choosing a garden, the range where pollution hazards may occur should be avoided.
For example, the air contains excessive harmful gases such as sulfur dioxide, hydrogen sulfide, hydrogen fluoride, silicon tetrafluoride, chlorine, hydrogen chloride, lead smoke and dust smoke; Or the soil and water system contain harmful substances such as acidic compounds, cyanide, arsenic, mercury and cadmium. And avoid the scope of harm when choosing a garden.
(2) Taboo phenomenon
When used as grape, walnut, pear, peach, apple and other fruit trees, the growth and fruit of apple trees will be inhibited to varying degrees.
It is reported that bacteria and actinomycetes decreased and the proportion of fungi increased in apple taboo areas or soil with replantation obstacles. When there are more fungi and less bacteria, the purple feather of dwarf rootstock apple tree is seriously harmful.