(1) Temperature conditions
Apple's various physiological activities, biochemical reactions, growth and development processes must be carried out under certain temperature conditions. Otherwise, its normal growth and development will be suppressed, blocked, victimized or even killed.
Effect of temperature on apple life activities mainly in the following areas:
1) Three base point temperature
The temperature required for apple's life activities and growth and development, in terms of its physiological processes, has the corresponding minimum, optimum and maximum three base temperature. It is generally believed that the minimum temperature of apple is about 5.0 °C, the optimum temperature is 13-25 °C, the maximum temperature is about 40 °C, and the variety, organ, age, growth period, physiological process and temperature changes, and other ecological factors The difference is different. The optimum average temperature for different varieties of growing season is also different.
2) Accumulated
Different varieties, different organs and growth stages of apples require a certain accumulated temperature. The amount of accumulated temperature has an important impact on the growth, development, yield and quality of apples. Therefore, accumulated temperature is often used as an important indicator of variety characteristics, and is an important basis for phenological period prediction, yield 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 flowering period is generally predicted by the effective accumulated temperature of the lowest temperature of 5 °C. According to research, the average accumulated temperature of apples from the temperature of 5 °C to the initial flowering period is higher than 5 °C, and the average accumulated temperature is 160-180 °C. However, the length of the flowering period is affected by the temperature. When the daily average temperature is 7-8 °C, most varieties need to go through 50 days, about 10 days at 10 °C, and only 30 days at 1213. The effective accumulated temperature required for most apple varieties to grow from flowering to flowering is 185 ± 10 ° C, and some years have a difference of 101 ° C. According to relevant reports, the effective accumulated temperature required to grow from flowering to flowering in Xingcheng, Liaoning Province, was about 155.2 °C in 1954 and 253.113 in 1955, a difference of 79.9 °C. The above research results show that the effective accumulated temperature above 5 °C before flowering is used for flowering forecasting, and the accuracy is poor. The accumulated temperature of different varieties or different varieties in different regions and years is different; different topography and microclimate It also has an impact.
4) Flowering temperature
To achieve flowering, apples first need to reach a certain amount of accumulated temperature. Apple flowering is sensitive to temperature. Temperature is an important limiting ecological factor for flowering, pollination, fertilization and fruit setting. Generally, the suitable temperature for apple flowering period is 11.4 to 11.8 ° C, and the optimum temperature is 17 to 18 ° C. From the temperature required for pollinator bee activity, bees usually stop moving outside of 10 °C; between 15 and 29 °C, they gradually become active with increasing temperature, which is conducive to pollination and pollination.
The flowering temperature is an important condition in the process of fertilization of apple pollen and elongation of pollen tube. It has been observed that different varieties require different temperatures, and the suitable temperature for pollen germination is generally between 10 and 25 ° C, and the optimum temperature is 15 to 20 ° C. Above 30 ° C, pollen germination is significantly inhibited.
5) Spring temperature
Low temperature in spring: China's apple producing areas are mostly continental monsoon climates. The spring temperature is unstable and often has low temperature, especially the late frost is more common. In the spring, apples are in the stage of bud, flowering and fruit setting, with low temperature resistance and sensitivity to temperature.
Spring high temperature: Spring temperature is closely related to apple fruit shape and appearance quality. According to the research, when the temperature of the apple is low and the climate is cold after 15 to 16 days of flowering, the vertical axis of the fruit grows faster than the horizontal axis, and it has a long shape and a large fruit shape index. On the contrary, the fruit shape index is small. This is related to the post-anthesis and endogenous hormones of fruit cells during this period.
6) Summer and autumn temperature
Summer and autumn are positive for apple shoots, flower bud differentiation, and fruit ripening. Therefore, summer and autumn temperatures have a great influence on flower bud differentiation, yield formation and quality. According to the survey, the temperature in summer or autumn (June-September) is too high or too low, which is unfavorable to the above-mentioned growth process of apples; it is most suitable for the monthly average temperature variation between 16.5 and 22.85 °C. For example, in the national appraisal, the Marshal Department and the Golden Crown fruit quality have repeatedly ranked among the top Chinese apple quality ecological zones in Sichuan Maoxian, Xiaojin and Gansu Tianshui. The average monthly temperature in the summer varies from 16.2 to 22.7 °C. The temperature is the highest, with an average monthly temperature of 23.5 °C in summer and 16.8-22.3C in Spokane, Washington, USA. If the summer temperature is too high, the ecological response is: the fruit shape index becomes smaller, the coloring is poor, the flesh is easy to be cotton, the maturity consistency is poor, the vitamin content is lowered, and the fruit aroma, flavor and storability are poor.
Summer temperature and flower bud differentiation: According to the research, the suitable temperature for the beginning and the prosperous period of apple flower bud differentiation is 20-27 °C. The morphological differentiation period of Zhu, Marshal and Guoguang flower buds began after a certain number of days when the average temperature stabilized above 20 °C.
7) Winter needs cold amount
It is generally believed that the induction of apple into true dormancy is mainly a low temperature effect, and is not sensitive to conditions such as short daylight and dryness. For the true dormancy of ending buds, many studies believe that the cold weather in winter is also necessary. Cold temperature hours: the number of hours of low temperature below 7.2 °C. The starting point for the cold temperature is 7.2 °C. Scholars in various countries now use 7.2 °C as the accumulated time standard. Apple needs CH values, which vary from breed to breed. As modern cultivation areas expand to lower latitudes, the total value of CH for apples tends to decrease. From the early need of 1400-3684 °C to the recent need of 500-1700 °C.
(2) Moisture conditions
Water is the medium in which apples and the environment adapt to each other, and is the most abundant substance in apple trees. Water plays an important ecological role in the growth, development, physiological and biochemical processes and yield and quality of apples through different forms, quantities and durations. At the same time, it also causes light, heat, Changes in ecological factors such as soil and organisms play an indirect role.
The effect of water on apple growth and development is mainly reflected in the following aspects.
1) precipitation and apple bud, shoot growth and flowering fruit
After the apple is dormant, it requires a certain amount of water to germinate. Insufficient water, often delays germination, or germination is not neat, affecting the growth of new shoots. In the growth period of new shoots, the water is insufficient, the ecological response is weak, the growth is early, the leaves are small, the leaves are easy to fall, the overall nutrient growth of the tree is weak; the water is too much, the branches and leaves of the tree are too prosperous, the tissue is not full, and the storage nutrient level is low. If there is further excess of water, it will cause cockroaches, such as rotten roots, weak tree, early leaves, crowns and tops, leading to dead trees.
When the apple is flowering, the water content is too small, which will shorten the flowering period, affect pollination and fertilization, and the fruit setting rate is obviously reduced. If there is too much precipitation during the flowering period, heavy rain and long-term rainy rain will reduce the secretion of stigma or affect the adhesion and germination of pollen due to scouring, thus affecting pollination and fertilization, resulting in falling flowers and fruit.
In the arid regions of northern China, water is often insufficient in germination and growth and new shoot growth, and should be fully irrigated. In the apple producing areas of southern China, there is often more rainfall, or more rainy days. Therefore, attention should be paid to the choice of gardens, varieties and rootstocks, soil and fertilizer water and flower and fruit management, plastic pruning and pest control.
2) precipitation with apple flower bud and yield
Precipitation has an important influence on apple flower bud differentiation, growth and development, annual yield, and leap year results. According to the research, the initial saplings have less precipitation during flower bud differentiation, which is conducive to the formation of flower buds, which will increase the yield in the next year. The adult result tree is the opposite. The lack of water during the flower bud differentiation period will reduce the yield in the next year. Generally, the distribution of monthly precipitation in the growing season is relatively balanced, which is beneficial to apple growth and development, and is also conducive to the leap year results.
3) Apple fruit development and water demand
As the young fruit grows, the water content increases and the water percentage decreases. When people eat, they feel more ripe fruit than unripe fruit juice, because some of the carbohydrates in the pulp are converted from insoluble to soluble. Fruit growth and development requires a large amount of water supply, especially the rapid expansion of the fruit. If the precipitation is low and the water cannot be poured in time, it will affect the fruit expansion and even fruit drop.
(3) Lighting conditions
The inland area where the apple is native to the sun is a hi-light fruit tree. The annual sunshine hours in the main apple producing areas at home and abroad are more than 2,000 hours, and the average monthly sunshine hours in the three key periods of fruit growth, coloring and maturity are also between 150 and 200 hours.
The effects of light on the growth and development of fruit trees are mainly reflected in the following aspects.
1) Photosynthesis
Early on the day of net photosynthetic rate of apple conducted annual measurement results showed that during the growing season, the light intensity is the most important factor affecting photosynthesis, net photosynthetic products in light condition of the weather, only 25% of sunny days left
The light saturation point and the light compensation point are the two most important physiological and ecological indicators of light. Apple's light compensation points vary due to changes in variety, leaf age, leaf position, leaf area index, carbon dioxide, soil available moisture, and temperature.
2) Yield and quality Photosynthetic products are the basis for fruit setting, fruit growth and quality formation. Within a certain range, the stronger the light, the higher the fruit setting rate, the larger the fruit, the better the coloring and quality.
Quality and light intensity: Experiments with Xu and Marshal Apple showed that in the British Columbia, Canada, 49'44' north latitude, there are three distinct areas of illumination affecting apple quality: FS is more than 60% in the crown area, and the fruit color is best. It is a high-quality light area; 40%-60% FS is a moderately illuminated area, which can produce fruits of normal color; 40% FS or less is under-lighted area, and the fruit is poorly 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 fruit coloration deteriorated, the fruit decreased, the proportion of fruit core increased, and the quality decreased.
3) Effect of light quality
Photosynthesis, photosynthetic products and visible light: In the ecological role of visible light on apples, the most important thing is as an energy source for photosynthesis, most of the spectral segments (generally between 380 and 710 nm) are absorbed. Only green light is rarely absorbed, with blue, violet and red light being the strongest.
Under natural conditions, apples are exposed to different visible spectral components, and the composition of photosynthetic products is also different. Red light is good for carbohydrate formation and blue light is good for protein synthesis. Therefore, it is possible to produce cultivation sites with different topography and lighting conditions, or to use different color films to improve the quality of the fruit.
Vegetative growth and visible light: blue, purple and blue light in visible light have an important dominating effect on cell differentiation, inhibiting elongation growth, controlling vegetative growth, and making the tree body short. Therefore, apple cultivation in alpine areas with more blue and purple light often shows that the tree is dwarfed, the side branches are increased, the short branch rate is increased, the branches are coarse and strong, and the flowering results are good.
The effect of direct and diffuse light: The solar radiation received by the apple tree has two different light and light qualities, such as direct light and diffused light. In fruit cultivation, diffuse light is mainly from the sky, as well as reflections from the ground and other objects. The diffused light has a lower light intensity than the direct light, and the short-wave light in the spectral component is less, and the long-wave red and yellow light is more (up to 50% to 60%), and the utilization rate of photosynthesis is high. Therefore, the diffused light can also reach the light saturation point. Studies on changes in total solar radiation and diffuse radiation in different weathers show that on sunny days, diffuse radiation is about 10% of total solar radiation, showing a relatively stable regular change. On cloudy days, the absolute and relative amounts of diffuse radiation increase, but the total solar radiation decreases. Among them, when the clouds are thick, the two kinds of radiation are almost equal; in the case of less clouds and cirrus clouds, the diffuse radiation is almost twice that of sunny days, which has certain significance for improving apple photosynthesis. The coverage of young orchards is low, which can make full use of the large amount of diffused light reflected from the ground to promote the good growth results of the lower part of the undergrowth. The adult orchard should pay attention to clear the influence of a large number of tall weeds under the tree on the light, and can also use silver gray, aluminum platinum. Reflective film to improve the coloration and quality of the lower part of the crown. The aluminum platinum film has a light reflectance of up to 100%.
Apple fruit coloration, the ecological response to direct light and scattered light varies from species to species. One type is a variety of types that must have direct light to be fully colored, such as marshals, red stars, red crowns, etc.; the other type is under the condition that the direct light is weaker and the diffused light is more than the ordinary type. It can also be a luscious variety, such as the Marshal short-branched red-red variety.
(4) Wind and ice 雹 沂
The apple orchard is suitable for establishment in areas with an average annual wind speed of 3.5 m/s or less. When the wind speed in the flowering period often exceeds 6 m / s, it will lead to a lower fruit setting rate; it is also easy to cause adverse consequences such as partial crown, falling fruit, and even broken branches.
Some apples in China are suitable areas, and there is a regular distribution of hail belts. Before building a garden, you must understand clearly, and do not build gardens in the hail.
Terrain conditions
(1) Plateau and Flatland
The slope is not more than 5°, and the flat terrain is flat, such as plain, plateau, tidal flat, low-lying land, etc. Generally, the soil is fertile, the water source is sufficient, and the climate change is not large. After the garden is built, the apple tree grows well, the tree body is large, and the root system is Deep, and easy to manage, easy to mechanize operation, good transportation conditions, water and soil are not easy to lose. However, the construction of a flat land has its disadvantages. For example, ventilation, light and drainage are not as good as mountains. The quality and storage capacity of the fruit are worse than that of the mountain. The soil in the sea is high in salt content, high in groundwater level, poor in structure, low in fertility, and short in fruit life. It is necessary to improve the soil. Make the fruit trees grow well.
(2) Hill and slope land
Apple is more suitable for cultivation in mountainous and sloping fields. Even in the South, high-quality apples can be produced at high altitudes. In the area of ​​about 1000 meters above sea level in the northwest, apple trees have a slow growth potential, easy flowering, high yield and high quality, and are the best cultivation areas for red apples in China. The mountainous area and the low mountain belt, with a slope of 5°-15° and a height of 200-500 meters, are convenient for transportation and are a good base for the development of apple trees. However, it is impossible to build a garden at the bottom of the mountain valley to avoid frost damage during the flowering period; the middle mountain belt, the slope with a slope of 15°-25° and a height of 500-1000 meters, is difficult to cultivate, the effect is poor, the cost of soil improvement is increased, and the sunshine on the north and south slopes The difference gradually increases, the north slope is colder than the south slope, and the direct light of the east slope and the west slope is gradually reduced; the high mountain belt, the slope with a slope of 25° or more and a height of more than 1000 meters, the garden should be selected to meet the growth and development requirements of the fruit trees. The special location of the park. Otherwise, the soil in this belt contains many rocks, the soil layer is thin, and transportation is difficult. It is generally suitable for planting forests and grasses. Therefore, the orchard should be built on a gentle slope, thick soil layer, to build water and soil conservation projects; in the valley and the lower part of the depression is likely to accumulate cold air, frost damage is serious, it is not appropriate to plant apple trees. The spring temperature rises rapidly on the sunny slope, the fruit matures early, and the quality is good, but the water is not as good as the shady slope, and it is easy to suffer from frost damage and sunburn. The temperature of the shady slope is low, and it is vulnerable to cold damage in winter. It should be considered when building the garden.
Although the hills are also of the mountain type, the terrain is less undulating and smaller than the mountains. The vertical distribution of the climate and the difference in the yin and yang slopes are not as obvious as the mountains. Planting fruit trees in hilly gardens is better than flat land. Generally, hilly land is well drained, air circulation, sufficient sunshine, large temperature difference between day and night, can make fruit trees have long life, early results, high yield, good quality, bright color, and storage resistance. Therefore, hills The land is a good apple orchard.
Due to different slope locations and valleys (valleys), it will cause huge differences in solar irradiation conditions and radiation budgets, resulting in different heat and water conditions, forming different microclimate characteristics and ecological factors, thus producing various ecological effects on apples. effect.
According to the study of Chinese mountain fruit trees, the comprehensive effect law is generally as follows: the south (yang) slope, the leeward slope or the deep mountain, the valley of the east and west valleys (valley) and the north (yin) slope, the windward slope or the north and south valleys The solar radiation is strong, the sunshine is good, the temperature and the soil temperature are high, the temperature is worse, the precipitation is less, the humidity is small, the evaporation is strong, the drying is dry, the vegetation is sparse, and the performance is dry (half), warm, and mostly dry landscape; Apple has a good ecological response. The general pattern is that the tree is strong, the vegetative growth is healthy, the flower bud differentiation and flowering result are good, the fruit surface is smooth and bright, the color is bright, the sugar, acid, vitamin C and other content is high, the sweet and fragrant taste is strong, the quality is good, the pests and diseases Less, the freezing damage is lighter, but the sunburn is often aggravated. Such as Xiaojin, Maoxian, Jinchuan, Danba, Batang, Xiangcheng and other counties of high quality apple orchards, all in the slope to the sun or the valley (valley) to the near east and west, the open width of the valley, Hong (rush) fan , slope skirts, terraces and mountains and other terrain. On the contrary, the north (yin) slope, the windward slope or the north-south ditch (valley), the apple habitat and ecological response are poor.
(3) Altitude
According to the survey, from the perspective of large-scale on-the-spot ecological response, the high-quality areas of the Chinese apple varieties, the Marshals and the Golden Crown, are mostly in the northwest plateau main producing areas, with altitudes above 1,000 meters; the southwest highlands are mostly at 1500-2900. Rice, especially in the range of 2000-2600 meters, especially the fruit of the Sichuan-Yunnan Hengduan Mountains is bright and of good quality. This is because these zones have a relatively low latitude, high altitude, a unique combination of dry and warm valleys in the high mountain gorge (deep valley) or river fault basins, creating a unique habitat with good sunshine and many ultraviolet rays. For example, in the high-quality areas of Sichuan Xiaojin, Maoxian, Yanyuan and Lijiang in Yunnan, the altitude is more than 2000-2600 meters, and the percentage of sunshine is more than 50%. The fruit of the Marshal is full of red and bright colors. The golden crown is golden and bright, and the sunny side is colored red, and many of them occupy 1/3 to 1/2 of the fruit surface. The fruit quality of the Golden Crown, Red Star and Red Crown has repeatedly ranked first in the national appraisal. At the same latitude and low altitude areas, such as the altitude of 400 to 600 meters, the Sichuan Basin area with a percentage of sunshine below 30% is more difficult to color. The coloration of the marshal fruit is not easy to reach 30%, and the coloring index is nearly zero. The golden crown is mostly yellow-green, green-yellow, and less blushing.
Social and economic conditions
The establishment of the apple orchard and the management of the early saplings require a large investment, and there should be sufficient preparation before the establishment of the garden. The address and scale of the garden should be considered based on local geographical location, traffic conditions and economic strength. Specifically, it is mainly whether the reserves of economic power and technical strength can guarantee the establishment and development of the apple orchard. During the period from the completion of the garden and the planting of the apple tree to the flowering of the apple tree, the apple orchard is a period of pure investment and no income. If the economic power is insufficient, it will not be able to successfully pass this period. The establishment and smooth development of the apple orchard and the reserve of technical power are also extremely important.
Soil condition
Type depth water level temperature moisture air nutrient pH salt content
(1) Soil Type
Apple has a strong adaptability to the soil and is cultivated on a variety of soils. However, from the perspective of Apple's own needs and high-quality and high-yield requirements, it is suitable for deep soil, good configuration, appropriate "three-phase" ratio, rich nutrients, and slightly acidic to slightly alkaline. The cultivation of apples in the world and China is dominated by brown soil, cinnamon soil, brown soil, chestnut soil, lime soil and fluvo-aquic soil.
According to the survey, the soil types in China's apple producing areas vary greatly. The main apple producing areas in North China and Northeast China are mainly brown soil, yellow loess, brown yellow soil, cinnamon soil, yellow fluvo-aquic soil and tidal flat soil. The production area is mainly composed of cinnamon soil, loessial soil, black loess soil, light gray calcium soil and silt soil; the main producing areas in Xinjiang are mainly lime soil, brown soil, brown desert soil and oasis soil; The main producing areas are mainly yellow fluvo-aquic soil, fluvo-aquic soil, tidal flat soil and new soil; in the Sichuan Basin, purple soil, purple brown mud, yellow soil and fluvo-aquic soil are the main areas; the main producing areas of the Sichuan and Yunnan Hengduan Mountains are Cinnamon, brown red soil, brown soil, red soil and new soil are the main; southwest plateau, mainly yellow soil, red soil, brown red soil, fluvo-aquic soil and new soil; southern subtropical and tropical regions, with yellow soil, red soil, Red soil and brick red soil; Tibet Plateau producing areas, brown soil, yellow brown soil, cinnamon soil, mountain shrub grassland, fluvo-aquic soil and meadow soil. In general, the soil types in China's apple high-quality areas are mainly cinnamon soil, yellow loess soil, loess soil, gray calcium soil and brown loam. Among them, the area of ​​cinnamon soil, apple quality performance is outstanding.
(2) Soil Depth
The depth of soil directly affects the spatial extent, root composition and ecological stability of apple root distribution, affecting soil moisture, nutrient storage and utilization, thus affecting growth, yield, yield and quality. According to the survey, Guoguang apples have a depth of 3.3 meters and a depth of 0.72 meters, and the length of thousands of weeks, tree height and new shoots are increased by 226%, 220% and 555% respectively, and the output is increased by 5 times; Marshal Apple grew by 147%, 113%, and 211%, respectively, and production increased by 1.5 times. It grows in a golden crown with a gravel layer of soil below 70 cm. The average yield of an 8-year plant is 190.6 kg, while it is found on a gravel layer of soil below 40 cm. The average yield is only 9.4 kg. After deep-turning the soil into this soil, combined with fertilization, the amount of roots in the lower layer increased.
In the tight soil, the growth is blocked, thickened, and branches appear abnormally at the apex. The root tip can have a pressure of 15 to 20 Pa. The response to resistance may be in the root cap. In addition to the pressure reaction, the increase in ethylene can also participate in the regulation. The external use of ethylene can make the root thicker and shorter.
(3) Groundwater level
A 10-year study on the relationship between groundwater level and production showed that the depth of the groundwater level was in the range of 50-120 cm, and the yield increased significantly with the decrease of the groundwater level. Therefore, where there is a high groundwater level, drainage measures must be taken to lower the water table.
(4) Soil temperature
It is generally believed that the optimum temperature for apple root growth is 7-20 °C. Apple roots begin to grow at 5.4 °C, grow at 20 °C fastest, and die at 43.0 °C. According to reports, the optimum temperature for the occurrence of new roots of different rootstocks is different, M1, M2, M3, M9 are 13C, Mt6 is 2512, and M7 is 30 °C. The temperature at which new roots occur is: Mi, M2, M4 is 12.812, M7, M16 and solid anvil are 25 °C.
(5) Soil moisture
Soil moisture is both the most important source of water for apples and a necessary condition for many physical and chemical processes in the soil. The water in the soil complements the air. The change of water and gas directly affects the soil heat, soil biology and microbial status, and affects the temperature and relative humidity of the orchard.
Soil moisture is mainly affected by precipitation, irrigation, soil evaporation, plant transpiration, ground cover and soil porosity, and the content is very unstable. The soil water content when the soil moisture is stopped by gravity is called the field water holding capacity. This is also the water that plants use most easily. When the soil water content drops to make the plant have a persistent wilting state, it is called the coefficient of wilting (wild coefficient). Generally, the apple orchard is suitable to maintain 60% to 80% of the field water holding capacity.
The critical value of apple water demand: that is, in the absence of water; the period that has the greatest impact on its metabolism and yield. It is generally believed that the critical period of water demand of apples is when the new shoots grow rapidly, the leaf curtains form a lot, and the young fruit develops. Some people think that after falling flowers, it is the critical period of water demand.
(6) Soil Air
Soil oxygen concentration: Oxygen in the soil is an essential condition for root and soil microbial life activities. When oxygen in the soil is depleted by roots and microbes, and the accumulation of sulfur dioxide in the soil reaches a certain concentration, the roots are damaged until death. It has been determined that when the temperature is between 20 and 30 ° C, the oxygen consumption of the 0-30 cm soil layer can be as high as 0.5 to 0.7 liter / (square meter? hour). The average air volume in the soil is 33.3%, of which oxygen accounts for 20%. If the air is not ventilated, the oxygen in the soil will be depleted in 12 to 40 hours.
Apple roots need to have a soil oxygen concentration of more than 10% before they can grow normally;
The growth was poor at 3% to 5%, and the root died when 0.1% to 3.0%. When the oxygen concentration is 10% and the carbon dioxide concentration is 5%, the growth of the root system is hindered, and the growth of the shoots is deteriorated. Pot experiments showed that the effect of soil hypoxia on the roots was greater than that of the shoots. When the soil oxygen concentration is about 5%, the growth of the aboveground part is strong, and the root growth is equivalent to 80% to 90% under high concentration of oxygen; under 5%, almost no new root is produced.
Through experiments, it was found that apples grew normally at an oxygen concentration of more than 12%, and the growth was significantly deteriorated at 1,5% to 2%; when 1.5% or less, almost all of the fine roots died. The response of roots to different oxygen concentrations is that 12% of the growth is normal, the fine roots are more, the trunk pores are not obvious; the roots are thin at 2.5% to 11%, and only new roots, straight roots and plant lenticels occur. It is extremely developed; when 1.5% to 2.5%, the roots are accelerated, and the lenticels develop significantly; when 1.5% or less, the fine roots die, the root color is dim, and the viability is weak.
In summary, the soil oxygen concentration in the normal growth of apple roots should be above 10%, and the near-atmospheric oxygen concentration (20.96%) is the best. More than 15% can produce new roots in large quantities, and growth below 5% is inhibited or stopped.
Soil carbon dioxide concentration: Carbon dioxide in the soil is mainly produced by decomposition of organic matter, roots and soil microbial respiration, generally in the range of 0.1% to 4.0%. In the calcareous silt loam orchard, the depth of the 15 cm deep soil layer is 1% to 4%, the depth of the 73 cm deep soil layer is 3% to 7%, and the depth of the 244 cm deep soil layer is 4% to 6%. In the sandy loam and silt loam apple orchard, when the soil depth is 30 cm, the carbon dioxide concentration is below 5%, and the 152 cm deep soil layer is 7% to 8%.
(7) Soil Nutrient
The main nutrients extracted by apples from the soil environment include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and other trace elements and trace elements such as iron, manganese, boron, zinc, copper and molybdenum. The apple tree is large and has a deep root system. It requires both the soil surface layer and the deep soil nutrient rich and well-structured. In the analysis and evaluation of soil nutrients, in addition to attention to large amounts and trace elements, soil organic matter content is of great significance. It not only can decompose and provide a variety of nutrients, but also plays an important role in improving the physical properties of soil and promoting root development. The organic matter is linearly related to apple yield, and the organic matter content of high-yield apple orchards is more than 1%.
(8) Soil pH
It is generally believed that apples are slightly acidic to neutral, and pH 5.5-6.7 is preferred. In alkaline soil, potassium is effective, and the effectiveness of iron, manganese, phosphorus and boron is reduced. In acidic soil, manganese, iron and aluminum are effective, phosphorus and boron are ineffective, and zinc and copper are effective. Reduced sex.
(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 for normal growth is 0.13% to 0.16%, and the damage limit is above 0.28%. When the soil contains 0.117% sodium sulfate, 0.02% sodium chloride, and 0.008% sodium carbonate, the growth is poor.
Barrier conditions
(1) When selecting the garden, avoid the scope of possible pollution hazards
For example, the air contains excessive sulfur dioxide, hydrogen sulfide, hydrogen fluoride, silicon tetrafluoride, chlorine, hydrogen chloride, lead smoke, dust and other harmful gases; or soil, water contains acid compounds, cyanide, arsenic, mercury, cadmium, etc. For hazardous substances, the choice of the garden should avoid the scope of its hazards.
(2) taboo phenomenon
When used as a fruit tree such as grapes, walnuts, pears, peaches, apples, etc., and then successively made apple trees, the growth and results of the apple trees will be inhibited to varying degrees.
It has been reported that bacteria and actinomycetes are reduced and the proportion of fungi is relatively increased in soils where apples are plagued or replanted. When there are many fungi and few bacteria, the dwarf anvil apple tree is seriously damaged by purple plume.
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