Saline Soil improvement
Northern China mostly alkaline soil and water, although some areas are built green space in fertile ground, underground saline water for irrigation, can also cause secondary saline soil. Saline area green building, improve the survival rate is a priority, and basic water and soil is a major obstacle to cause trees to die, and some excessive application of compound fertilizer in salinity green, these “chemical salts” will increase the soil salinization. The current 143 million hectares worldwide are saline, 5.2 million mu of China, Shandong 1620 acres, 500 acres of the Yellow River. Our inland saline-alkali soil mainly in the northeast, north, northwest, and other places, including Hebei, Shandong, Heilongjiang, Jilin, Liaoning, Jiangsu, Xinjiang, Inner Mongolia, Gansu and other provinces. Mainly in the coastal saline 1800 km coastline, especially in Tianjin, Liaoning, Shandong, Jiangsu, Zhejiang, Fujian and other places in coastal areas. City saline areas, mainly the city of Tianjin, Dongying, Binzhou, Dezhou, Liaocheng, Cangzhou, Huanghua Renqiu, Daqing, Panjin.
Saline-alkali soil is a result of excessive salt content or strongly alkaline, and “sick” of the soil. Saline grade indicators are as follows: mild soil salinization, soil salinity 0.1-0.2%; moderate soil salinization, soil salinity 0.2-0.4%; severe soil salinization, soil salinity 0.4-0.6%; ( Another indicator of majority to 30 cm topsoil to calculate the salt content.) is a measure of saline pH, namely PH value, generally 7.5 is neutral, 7.5 is slightly alkaline.
Salts with bases saline improved coexistence determines the complexity of the same species, in the same salt content, because different ions exhibit differences in the degree of tolerance. The same species, the degree of tolerance saplings and trees sometimes double the difference.
Although the country has introduced a modified base fertilizer, but the improvement effect of moderate saline is often unsatisfactory, so often troubled Green saline. Therefore, comprehensive management, local conditions, the use of construction techniques, in order to achieve a multiplier effect. Alkali soil soil greening biggest dilemma is the source of tension, with Tianjin as an example, earthwork salinity TEDA traded around 0.5 percent, and adopt comprehensive measures to ameliorate and salt reduction a reality of great significance.
Saline green common foreign soil improvement model has green construction, improved construction of the original soil saline-alkali soil and fertilizer salt balance improvements. 🙁 Green construction techniques with new soil for heavy, moderate saline)
Big hole with new soil + spacer layer of salt: salt selection generally separated materials are gravel, pebbles, ashes, sawdust, bark, straw, wheat straw, wheat bran, vermiculite, perlite, garbage, broken grass. Thickness of 20 centimeters, and some kind of big ginkgo spread 50 cm grit, wheat straw, rice straw virtual shop 50 cm.
Foreign soil + separated salt bags: new soil before backfilling, tree hole or green is surrounded with plastic sheeting and the surrounding earth isolation, plastic sheeting bottom and separated salt layers together, most of the salt drainage pipe application is no sand cement PVC drain pipes and arms markings, simple use of effective, low cost, salt drainage pipe interval 5-10 meters, its gradient is not less than 0.3%. Salt drainage pipe generally separated salt layers together, the water collected in a timely manner to the discharge pipe to drain away the salt through salt water seepage hole discharge tube, there are leftover material of the unit can be designed to automatically strong emission devices. Separated salt is made using 0.02 mm polyethylene bags, according to pool size tree, a variety of points, usually the height of 0.8 meters, the bottom of the playing several sieve (aperture pitch 0.5 cm to 5 cm).
Salt drainage ditch blind design: The small green area, you can position the exhaust tube filled with salt stones, sand, construction refuse, for the media, groundwater import natural trench drain away, longitudinal slope is generally more than 0.5%, salt drainage ditch salt layer and the spacer can be set together. Soil testing and water testing: The focus garden project should be measured soil salinity, take soil is 0-10 cm, 10-30 cm, 30-60 cm, calculate the average content of salt, with a weighted average. In addition to the total amount of salt soil tests, but also analyze the soil eight ions, referring CO3, HCO3-, CL-, SO4-, Ca ++, Mg ++, K +, Na + content for comparison. Actual greening greening projects SMEs often only measured 40 cm planting layer salinity and PH value. Irrigation water must be measured salinity, PH value.
Construction technology improvement of the original soil saline-alkali soil moderately saline 🙁 applicable)
Freshwater wash salt: for higher ground, good drainage area.
Salt biological change: planting halophytes and salt plants, promote soil desalination, desalination rate is amorpha, tamarisk, white thorn, Limonium like. Further planting green manure plants, not only when the soil desalination, and can increase soil organic matter to improve soil fertility. Increase soil particle structure, promote microbial activity, further improve soil physical and chemical properties, to lay the foundation for the next green. Salt part Jiana balance fertilizer salts adsorption equilibrium conversion unadsorbed
🙁 Fat salt balance improved method for the improvement of mild saline).
Use special fertilizer, effectively improve moderate to mild saline gardens, the fertilizer is converted by ion adsorption salt, fat salt balance of force to reduce the salt content, lower PH value, within the sodium ion adsorbent, humic acid, fulvic acid, allyl soil composition suck salt down the best base polymer. Moderately saline with a large number of fertilizer application bran Stuttgart species, will have better results. Specialty fertilizers on salt adsorption amount Rendering: potassium and sodium balance 14%; 18% fat salt balance; transforming 8%; 20% adsorption; salt unadsorbed fraction 40%.
Sodic silvicultural techniques
First afforestation saline survived, forest, timber, followed by the benefits. This is only in the salt content of the soil is not too heavy conditions can be achieved. Therefore, we must first take steps to improve saline improved site conditions, to conform to the requirements of afforestation.
First, the improved saline measures
1. The groove drainage, construction of an irrigation ditch Jota
Suitable for low-lying inland saline drainage in poor, shallow groundwater, salinity, heavy soil salinity, waterlogging double threat of land affected by salt. Rule change would be to the excavation dry, branch, bucket, hair groove drainage system, and to make an irrigation ditch Jota. So you can quickly exclude floods during the rainy season, and the natural leaching by rain, to play the role of platoon alkali salt down, to be reached afforestation soil salinity requirements, re-forestation. When freshwater irrigation conditions, should pay attention to fix the irrigation system at the same time, in order to use artificial irrigation wash salt, accelerate the transformation of heavy saline. If the water table is too high, heavy clay soil heavy saline closed, construction field drainage ditches can not guarantee the rainy and dry seasons when the salt does not return, would need to raise the ground trenching, the construction of an irrigation ditch station fields, the following fields to be reduced accordingly station water level. In the coastal saline areas, should be established embankment to prevent seawater intrusion. Meanwhile, the construction of a dry, branch, Mao ditch drainage system. The removed soil trenching ditch strip sprinkled on the field, so Jota ground elevation around Jota have a ridge, so that rainwater accumulated fresh water, fresh water infiltration process, according to the salt with water to the truth, the salt is pressed into Jota ditch. Such as Jiangsu Province, state-run forest farms Jota width 50m, length of about 100m, Jota Jota perimeter ditch deepened over 1.5m, branched Goushen of 3m or more, and there are gangou, drainage channels to match.
2. irrigation wash salt, transform heavy saline
Irrigation saline wash salt can accelerate the transformation of heavy, especially the case with the drainage system, citing fresh water to dissolve the salt in the soil, and through gutters drain away the salt, can receive immediate results. Xinjiang Production and Construction Corps Nong Bashi thirty group were angustifolia Afforestation Experiment, mainly for heavy sulphate saline soil, salt wash after three times, at an interval of seven days, a significant decline in soil salinity, afforestation survival rate of 94 %; wash salt without land, afforestation failed.
1, wash the salt season
Should be rich in water resources, the water table is low, a small amount of evaporation, high temperature season. Because the water table is low, irrigation wash salt leaching surface salinity down too deep; small evaporation, washed without strong return in salt; the temperature is high, the salt easy to dissolve.
① autumn wash
Xinken saline, or re-forestation program next spring saline, can wash salt in autumn to early winter irrigation. At this relatively abundant water, low water table, to be frozen after washing, small soil evaporation desalination is better, but the fall of the drainage outlet must be washed, otherwise they will wash the salt increase the groundwater level, causing early spring back to salt.
② spring cleaning
After autumn plowing sun mattress of land, a good spring cleaning effect. Immediately after thawing in the soil irrigation wash salt, light
Afforestation of arable farming. After also afforestation, combined with irrigation were washed salt. After washing the salt evaporation spring growing strongly, we should seize the loose soil.
③ volts wash
Newly reclaimed weight saline, before the rainy season in the land, on the basis of salt on the rain-volt seize abundant water, favorable conditions for the water temperature, the conduct underlying quaternary salt wash, accelerated soil desalination.
(2) wash the salt water
Under normal circumstances, a small amount of water to wash salt water good majority. But if the water is too large, not only a waste of water, can also cause the water table is high, a lot of side effects such as loss of soil nutrients. Generally dominated sulphate soils can be larger, mainly soil containing chloride may be relatively small. Usually salt wash 2-3 times, each time water 80-100m3, total water consumption 200-300m3 can.
3. The ground around the Dam
Land leveling, soil improvement is a basic work, the horizon can reduce runoff, improve irrigation volt rain washed salt and salt effect; at the same time to prevent depression flooded, high return salt, salt is also effective measures to eliminate plaque. If the floor height is too large, influential for leveling land can be made small plot leveling, the implementation of border irrigation. Reclamation Dam, is in leveling the land, based on the ridge Dam built in the Land four weeks. Its role is to facilitate irrigation water evenly covered ground, enhance the effect of washing salt. Dam construction ridge must be compacted to prevent running water. In some places in Shandong Province in Taiwan Tian week plus water ridge, supplemented by artificial irrigation freshwater wash primer Yanpai salt better.
4. organic fertilizer, planting green manure
Lack of organic matter, oxygen levels low, is characteristic of saline. Increasing organic fertilizer or planting green manure, on the one hand to increase soil nutrients, on the other hand can improve soil structure and beneficial to desalination. According to the experience of Jiangsu Province, three years after the saline-alkali soil vetch seed, soil salinity increased from 0.18% down to 0.038%, organic matter from 0.9% to 1.23%, becoming the desalination of soil. Soil salinity 0.3% -0.5% of the saline-alkali soil, the first 2 years of Tian Qing species to improve soil, then planted amorpha 3–5 years, the soil salinity can be reduced to about 0.25 percent, to planting salt trees. Up 0.2% on heavy coastal saline, prior to the introduction of fresh water in summer, planting salty plants, rice straw, fine Ophelia, combined with fish, two years after the soil salinity can be reduced to 0.02%.
4. alkaline soils chemically modified
Due to soil particles exchangeable sodium ions, soil solution of sodium carbonate and sodium bicarbonate, which leads to soil alkaline (PH value up to 9 above), the soil produce adverse physical traits. The so-called chemically modified, is aimed at the chemical properties of alkaline soil, to be modified by chemical methods. Chemically modified approach, the first is to increase the calcium in the soil, in order to displace the sodium ions on the soil adhesive force; second is subjected to acidic chemicals to hydrogen ion substitution exchangeable sodium ions and neutralize the alkaline soil. Commonly used modifiers include: soluble calcium salts, acids and chemicals into acids, soluble calcium salts have CaCL. 2H O, CaSO. 2H O and low solubility of limestone; acids and chemical substances into acids S (sulfur), H SO, FeSO. 7H O, Al (SO). 18H O, CaS (lime sulfur) and the like. As well as some industrial byproducts, such as by-product phosphogypsum phosphorous fertilizer manufacturing, coal gangue and other areas.
Treatment of saline and landscaping methods
Abstract: The physical and chemical properties of saline-alkali soil for tree growth caused by physiological disorders, difficult to form plant communities, planning and construction of urban ecological garden in serious difficulties. The saline-alkali soil improvement measures and make gardening closely, both to create a landscaping colorful landscape view, but also to achieve the purpose of soil improvement treatment salt, making it the landscaping, greening, ecological, economic, etc. improved respect, to promote and accelerate the landscaping business to contribute to salinization of land area. Keywords: saline environment, saline-alkali soil, landscaping, improvement measures
I. Introduction
The nature of the soil acidity is affected by climate, rock and soil inorganic and organic ingredients, not more terrain, groundwater and plants affected by factors. Generally speaking, in the arid and hot climate, neutral and alkaline soils more; in cold or warm hot humid rainy places where acidic soil based; rock such as granite-like, compared with acidic soil, limestone When compared to alkaline soil; topography and water as cold as the low humidity place is often acidic soil; groundwater rich calcareous component as compared to alkaline soil; in the same way according to their different soil depths and different seasons on soil acidity will change; in addition, such as long-term administration of some inorganic fertilizers, can gradually change the acidity of the soil.
In accordance with the 1978 standard, CAS Nanjing Institute of Soil Science, the pH of the soil can be divided into five, namely strong acid to PH <5.0, acidity is PH5.0-6.5, neutral 6.5-7.5, basic as PH7.5 -8.5, strongly alkaline to PH> 8.5. Saline land area due to the high salt content, mostly barren, the urgent need to improve the appearance of a green environment. Therefore, based on the discharge of salt, with shrubs and herbaceous plants form communities, to form a new ecosystem. Effectively reduce evaporation of surface water, inhibited the migration and accumulation of salinity. Meanwhile strong roots, shrub, grass formed, absorbs moisture carried transpiration, played a lower water table, to avoid the biological role of underground drainage backwater effectively prevent soil salinization students to form a good ecological cycle.
Plants and the environment is a unified whole, both in turn to a significant impact on the environment by environmental constraints, and. On heavy clay soil, the high salt content, high water table of saline, should select hi water wet, salt tolerance of trees and flowers. Such as hair ash, willow, pine, Sophora japonica, tamarisk and so on. These species in life activities, requires a lot of water, but also in the management of a large number of watering, the water except for some is absorbed by plants consumed in transpiration, the vast majority will be the gravitational water, carrying saline seep into the soil through a branch or discharge pipe outside the soil, the soil desalination. While plants in their life activities, with its well-developed root system, releasing large amounts of carbon dioxide and organic acids, thereby reducing soil pH, soil replacement of sodium ions adsorbed on the surface, other than the soil with water from the soil of chemical and physical properties have been improved.
Second, saline Profile
In the Earth’s surface, saline environment is having a significant macro-dominant geographical factors. The so-called saline environment means a higher salinity in water, soil, ground, air and various macro or micro environment. Earth’s total area of ​​510 million square kilometers, with the sea as the representative body of saline water environment occupies 71 WTB3〗 〖WT〗 〖Earth’s surface% or more, which accounted for 361 million square kilometers of marine area, representing 149 million square kilometers of land area. In land area of ​​051 million square kilometers of barren land accounts for the world, only 015 million square kilometers of arable land, while the saline area of ​​about 010 million square kilometers, inland brackish waters (lakes) area of ​​about 0.008223 one hundred million square kilometers of surface salinity The total area of ​​about 371,800,000 square kilometers environment (see Table 1), as well as widely distributed underground salt, brine and salt layer. Saline environment is a broad field, with a global scale trial production continuity. This continuity not only in the ocean and over the border with the land, but also in the global distribution of land salinity environment. Widely distributed in arid and semi-arid inland areas large saline desert, secondary saline, saline groundwater brackish lakes and land at different levels, brine and salt mines, development, an important natural and geographical features. This inland saline environments often with a variety of desert and Gobi desert as well as irrigated agriculture accompanied by students.
A very large area of ​​saline soil types complex, the various types of saline-alkali soil total area of ​​148,700 hectares, distributed in 23 provinces and autonomous regions, including more than 100 cities, of which 55400 acres of soil salinization, residual salinization The soil is 67300 acres, potential soil salinization of 26,000 hectares, the soil surface salinity over 0.6% 〖〗 〖WT〗 WTB3, the big
Most plants are not able to grow. Soil soluble salt content exceeds 1.0% 〖〗 〖WT〗 WTB3 only a few special plants adapted to saline soil to grow. This leads to a vast area of ​​saline environment not suitable for growing plants in landscaping needs, thereby limiting their geographical distribution, so landscaping is difficult to meet the needs of contemporary urban economic and ecological economic development. Therefore, saline-alkali soil improvement and utilization, the protection of the ecological environment, the city’s economic development is an extremely important issue.
(A) harm saline due to the accumulation of soil a lot of salt, causing the deterioration of a series of soil physical properties: the structure of the viscous, ventilation is poor, high bulk density, soil temperature rises slowly, the soil aerobic microbial activity, poor differential release slow , low permeability, strong capillary action, but also lead to increased surface soil salinization. Salinization of harm plants in the following aspects:
1. cause physiological drought halophytes contained excessive soluble salts, can improve soil solution osmotic pressure, causing physiological drought plants, so plant roots and seeds can not absorb enough water from the soil germination, and even lead to Moisture from the root cell extravasation, so plant wilting and even death.
2. Plant tissue damage soil salinity is too high, especially in the dry season, salt accumulation of topsoil often hurt hypocotyl class, its ability to harm sodium carbonate, potassium carbonate, is maximum. At high PH value, but also cause direct damage hydroxide ions on plants. Some plants gather too much salt, leaving victims protoplasm, protein synthesis has been seriously hampered, leading to the accumulation of intermediate metabolites of nitrogen, resulting in cell damage.
3. Impact of Plant Nutrition normal sodium ions due to competition, so that the plant absorption of potassium, phosphorus and other nutrients is reduced, the transfer of phosphorus will be suppressed, thus affecting the nutritional status of the plant.
4. Effect of plant stomata closed at high salt concentrations effect, stomatal guard cells forming starch hampered, resulting in cells can not be closed, so the drought withered plants easily.
Third, saline improvement
(A), saline modified the traditional method of saline soil in soluble salts harmful to plants sodium carbonate as the most powerful, followed by potassium chloride, magnesium sulfate, magnesium chloride, magnesium chloride, potassium chloride and second, sodium bicarbonate , sodium poison lighter. It is necessary to remove them from the soil prior to landscaping projects.
1. Physical improvements (1), flat ground. Stay a certain slope, digging drainage ditches, irrigation to wash salt. (2), deep plowing sun mattress. Where heavy clay texture, poor, poor permeability structure of the land, especially the original station saline wasteland, plowing before the rainy season, can enhance the permeability of loose topsoil to prevent rising water and salt. (3) timely scarification, scarification can maintain good moisture resistance, control soil salinity increases. (4), back style foreign soil elevation and ground floor flowerpot raise new soil type ground. (5), micro soil improvement, big hole site preparation. When planting the first plastic film bags set isolated tree hole in Tim with new soil. Sometimes a tree cavity separated salt layer spread by laying grit, furnace ash, sawdust, shredded bark, horse manure or wheat bran, etc. then filled with new soil.
2. CONSERVANCY improved (1), the pressure build light salt. Deposit precipitation in saline soil around the building, prompting the soil desalination. (2), irrigation wash salt. Precipitation in areas with better conditions, in the field of irrigation wash salt can accelerate soil desalination speed. (3), big hole with new soil, the lower spacer layer disposed exhaust pipe and infiltration salt. It divided into two forms, one with cement leakage leaking pipe or plastic pipe, buried deep underground suitable dissolved salt to drain away. Second row salt digging culverts, ditch Xianpu pebbles, then sand and gravel or paved cover not burn through rice bran shell ash, then filling.
3. chemically modified (1) by applying a chemical to the saline-alkali soil acidic wastes superphosphate, can reduce the PH value, while phosphorus can increase the resistance of trees. Facilities into proper mineral fertilizer, supplemental content of nitrogen, phosphorus, potassium, iron and other elements of the soil, there is a significant effect of soil improvement. (2), applying a lot of organic matter, such as: leaf mold, pine needles, sawdust, bark, manure, peat, vinegar residue and organic garbage.
4. Biological improved planting green manure and pasture salt, such as Sesbania, sweet clover, alfalfa, has a positive effect on the saline soil improvement. Green reduce costs, accelerate afforestation rate, improve landscaping effect, is the main indicator evaluate the effect of saline areas greening projects. In which biological change base investment minimum, but effective slow, poor landscaping; back style with new soil and ground elevation ground floor of measures to raise new soil pots style, although effective,