The definition of soil salinization定义
Soil salinization refers to the process of salt accumulation in the surface soil after the salt
from the bottom soil or groundwater rises to the surface with the capillary water. In brief, it refers to the accumulation of soluble salt in the surface of the soil phenomenon or process,
also known as salinization.
土壤盐渍化（soil salinization）是指土壤底层或地下水的盐分随毛管水上升到地表，水分蒸发后，使盐分积累在表层土壤中的过程。简而言之，是指易溶性盐分在土壤表层积累的现象或过程。
High incidence’s region of salinization
Soil salinization mainly occurs in arid and semi-arid areas, with poor retention and drainage
of surface runoff and underground runoff and high groundwater level, except in coastal areas where salinization occurs due to the influence of seawater immersion. Due to the dry climate and the intense evaporation, the salt contained in soil parent material and groundwater accumulates on the surface with the rise of soil capillary water. In addition, in extremely arid regions, even with deep groundwater, the salinity carried by highly mineralized surface runoff can salinize the soil.
除在滨海地区，由于受海水浸渍影响而发生盐碱化外，一般的土壤盐渍化主要发生在干旱和半干旱地带，地表径流和地下径流滞留排泄不畅且地下水位较高地区。由于气候干旱，地面蒸发作用强烈，土壤母质和地下水中所含盐分，随着土壤毛细管水上升而积聚于地表。此外，在极干旱地区，即使地下水很深，高矿化地表径流携带的盐分，也能使土壤发生盐渍化。
Geographical distribution
China is also a country with a wide distribution of saline soil. According to a rough
calculation when compiling the distribution map of saline soil in China, the area of saline soil in China is about 100 million ha, of which modern saline soil accounts for about 37%, residual saline soil accounts for about 45%, and potential saline soil accounts for about 18%. China’s saline soil is distributed in 19 provinces and regions, including Liaoning, Jilin, Hei, Hebei, Lu, Henan, Jin, Xin, Shaanxi, Gansu, Ning, Qing, Su, Zhejiang, Anhui, Fujian, Guangdong, Inner Mongolia and Tibet.
中国也是盐渍土分布广泛的国家，编制中国盐渍土分布图时粗略计算，中国的盐渍土面积约为1亿ha，其中现代盐渍土约占37%，残积盐渍土约占45%，潜在盐渍土约占18%。中国盐渍土分布于辽、吉、黑、冀、鲁、豫、 晋、新、陕、甘、宁、青、苏、浙、皖、闽、粤、内蒙古及西藏等19个省区。
Influence factor
1.Climatic factor
The process of soil salinization is the gradual accumulation of soluble salt in the soil surface, and the process of surface evaporation and infiltration is an important driving force of salt migration and movement in the soil, which directly controls the distribution and existence of salt in the soil. Climatic environment plays an important role in the migration, accumulation and transformation of soil elements, and is one of the influencing factors for the formation of subgrade soil salinization. Dry climate is the main external factor of soil salinization, and
dryness and the ratio of evaporation to precipitation are closely related to soil salinization.
Soil freezing aggravated the process of soil salinization. Under the influence of geothermal gradient, soil water moves from the bottom to the freezing front, and the salt migrates
upward. When the local temperature gradient is large or the groundwater level is high, the
amount of water and salt migration increases. When the soil contains salt, the freezing
depth decreases correspondingly, and the water and salt are lifted up near the surface,
which is the incubation period of potential salt evolution.
土壤盐碱化过程是易溶性盐分在土壤表层逐步积累的过程，地表蒸发、入渗过程是盐分在土体中迁移运动的重要驱动力，直接控制着盐分在土体中分布、存在状态。气候环境对土壤元素的迁移、聚集、转化有重要的作用，是其路基土盐渍化形成的影响因素之一。干燥气候是发生土壤盐渍化的主要外界因子，干燥度和地面蒸发与降水比值与土壤的盐渍化关系十分密切。土壤冻结加剧了土壤盐渍化进程。在地温梯度影响下，土壤水从下向冻结锋面移动，盐分随之向上迁移。当地温梯度较大或地下水位较高时，水分和盐分的迁移量随之增大当土壤含盐时，冻结深度相应减小，水盐被抬升靠近地表，是潜在盐演化的孕育期。
2.Topographic and geomorphic factor
Topography and landforms directly affect surface and groundwater runoff. From the foothills to the reflux basin, the water-salt movement can be roughly divided into four types:
mountain Infiltration-horizontal sports slow slope low land mostly upward, downward
infiltration-horizontalsports depression mostly downward infiltration - vertical sports
depression edge may also appear reverse horizontal – upward type. In the process of surface water and groundwater runoff, the salt in the upper soil and formation is dissolved, and the total dissolved solid is increased. Therefore, the degree of soil salinization shows a trend
of increasing gradually from high to low and from upstream to downstream with the terrain. In the same basin, due to the difference of micro-topography, the degree of soil salt
evolution will be different. On the relatively high micro-topography, due to the moisture
difference in vertical and horizontal directions, the water migrates from the low to the high, and the evaporation and concentration result in more salt accumulation.
地形和地貌直接影响地表水和地下水的径流。从山麓到回流盆地，水盐运动大致可分为4种类型山地为下渗--水平运动型缓斜低平地多为上升、下渗--水平运动型洼地多属下渗--上升交替垂直运动型洼地边缘也可能出现逆向水平--上升型。地表水和地下水径流途中，溶解了上壤和地层中盐分，加之蒸发浓缩，溶解性总固体不断增高。因此，土壤盐渍化程度表现为随地形从高到低、从上游到下游逐渐加剧的趋势。同样在盆地内，由于微地形的差异，土壤盐演化程度也会出现较大不同。相对高起的微地形上，由于同时存在纵横方向的湿度差，水分由低处向高处运移，加之蒸发浓缩，积盐多。
3.Subsurface diving position and water quality factor
4.Halophyte factor
In arid and semi-arid areas, there are meadow plants and desert plants, such as reed grass,
ice grass, flower seedlings, turniflora, salt grab, salt lock, alcamel thorns and tamarisk, etc.
Most of them have deep roots and special physiological characteristics of salt resistance.
They are called halophytes, with salt content up to 10% ~ 45%, and absorb water and salt
from the bottom through strong roots. It remains on the ground in the form of residues,
and the calcium and sodium salts formed by the decomposition of plant residues return to
the soil, contributing to the salt evolution of the soil.
干旱和半干旱地区生长着草甸植物和荒漠的植物，诸如芦草、冰草、花花秧、罗布麻、盐抓抓、盐琐锁、骆驼刺和红柳等，大都具有根深根茂和特殊的杭盐生理特性，称之为盐生植物，含盐量可达10%～45%，通过强大的根系从底层吸收水分和盐分，并以残落物的形式留存地面，植物残核被分解而形成的钙盐和钠盐返回土壤中，对土壤的盐演化起到推波助澜的作用。
Soil salinization improvement土壤盐渍化改良
1.Chemical improvement measures
Chemical improvement measures are the methods of improving saline soil by applying
chemical amendments and mineral fertilizers. Commonly used chemical amendments are
organic or inorganic fertilizers, mineral fertilizers, calcium sulfite, desulfurized gypsum,
phosphogypsum, ferrous sulfate, polymer amendments and soil comprehensive
amendments. The principle is to improve the physical and chemical properties of soil and
inhibit the occurrence of salinization through acid-base neutralization. The soil structure in
salin-alkali land is poor. Organic fertilizer can decompose microorganisms and form
humus to promote the formation of soil aggregates, increase soil aeration and permeability,and enhance soil buffering capacity, and form sodium humate with NaCO3 to reduce soil
alkalinity. Meanwhile, sodium humate can stimulate plant growth and enhance salt resistance. Decomposition of organic matter in humus fertilizer will form organic acids, which can
not only neutralize soil alkalinity, but also enhance the decomposition of nutrients and
increase the availability of phosphorus. Therefore, rational application of organic fertilizer
plays an important role in improving saline soil and enhancing soil fertility.
化学改良措施是通过施用化学改良剂及矿质化肥改良盐渍土的方法。常用的化学改良剂有有机或无机肥料、矿质化肥、亚硫酸钙、脱硫石膏、磷石膏、硫酸亚铁、高聚物改良剂及土壤综合改良剂等。其原理是通过酸碱中和，改良土壤理化性质，抑制盐渍化的发生。盐碱地土壤结构差，有机肥通过分解微生物、形成腐殖质，促进土壤团粒形成，增加土壤通气透水性，提升土壤缓冲能力，并和NaCO3，作用形成腐殖酸钠，从而降低土壤碱性，同时腐殖酸钠还具有刺激植物生长的作用，增强其抗盐性。腐殖质肥料中有机质分解会形成有机酸，不仅能中和土壤碱性，还能加强养分的分解，増强磷的有效性·所以，合理施用有机肥对于改良盐渍土，增强土壤肥力有着重要作用。
2.Bioimprovement measures
The above-ground growing part of plants has a shielding effect, which can reduce the
evaporation of soil water and the rate of salt accumulation on the surface. The salt
absorption of plants can reduce the salt content of soil. The penetration of plant roots into
the soil can change the physical properties of soil and promote soil desalination. As for
physical and chemical improvement measures, biological measures have low cost,
environmental protection and effective, and can produce economic benefits, which is
popular with farmers.
植物地上生长部分具有遮蔽作用，能够降低土壤水分蒸发，减弱地表积盐速度植物吸收盐分能降低土壤盐含量植物根系穿插土壤中能改变土壤物理性质，促进土壤脱盐且植物根系的生化作用还能改善土壤养分及化学性质，抑制土壤盐碱化的发生。同物理、化学改良措施而言，生物措施成本低，环保有效，同时可以产生经济效益，颇受广大农民的喜爱。
3.Comprehensive improvement measures
Physical measures are effective, but the engineering amount is large, the cost is high, is not permanent, and is limited by water resources, it is not easy to promote chemical measures
are effective, but if used improperly, it is easy to cause secondary pollution to the
environment, and a large amount of water is needed after the application of amendments, which is difficult to apply and the economic cost is expensive biological measures can
reduce soil salt. But it can not completely solve the problem of salinization. After many years of practice, it is found that soil salt evolution is a complicated process, and only one control measure can not achieve the best effect of improvement. In recent years, in arid and
semi-arid areas, comprehensive treatment measures such as washing and desalting, deep
tilling and extensive planting of salt-tolerant plants have been used to solve the problem of
soil salinization.
物理措施成效快，但工程量大，成本较高，不具有长久性，而且受水资源的限制，不易推广化学措施见效快，但若使用不当，易对环境造成二次污染，且施用改良剂后需要大量的水冲洗，应用起来较困难且经济成本昂贵生物措施能减少土壤盐分，但不能完全解决盐渍化问题。经多年实践发现，土壤盐演化是个比较复杂的过程，仅用某一种防治措施并不能达到改良的最佳效果。近年来，干旱、半干旱地区多使用淋洗脱盐、深翻松耕及广泛栽植耐盐植物等综合治理措施解决土壤盐渍化问题。
Harm
1.Salinization affects soil physical and chemical properties盐碱化影响土壤物理化学性状
In saline-alkali soils dominated by Na+ and Cl-, a layer of white salt crust will appear on the
surface of the soil in spring, with fine particles, especially in temperate areas. In addition, the soil’s aggregate structure and porosity are also changing. With the increase of particle density, soil is more prone to compaction and porosity decreases, which leads to the decrease of soil permeability and the increase of surface runoff and soil erosion. At the same time, soil
chemistry is changing. The ion concentration in soil solution increases, the pH value
increases, the ratio of conductivity to exchangeable sodium increases, the salinity of carbon and nitrogen decreases, and the enzyme activity in soil is inhibited, thus affecting the
activity of soil microorganisms and the transformation of organic matter, and reducing the
utilization rate of soil nutrients, organic matter content and soil fertility.
在以Na+、Cl-为主的盐碱土中，春季土壤表层会出现一层白色盐结皮，颗粒细密，尤其在温带地区非常明显。此外，土壤的团粒结构和孔隙度也在变化。随着微粒密度的加大，土壤更容易板结，孔隙度减小，导致土壤的透水透气性降低，发生地表径流和水土流失的可能性增加。同时，土壤的化学性状也在改变。土壤溶液中离子浓度增大，酸碱值升高，电导率与可交换性钠比率提高，碳、氮的矿化度下降，土壤中酶活性受抑制，进而影响土壤微生物的活动和有机质的转化，使土壤养分利用率、有机质含量和土壤肥力下降。
2. Salinization affects engineering facilities and land盐碱化影响工程设施和用地
Because salinization changes the physical and chemical properties of the original soil, there are even phenomena such as land subsidence and salt swelling in some areas, which not
only causes adverse effects on engineering construction, but also makes industrial land can not be used effectively, resulting in huge economic losses. In addition, the high salt and
high alkali environment will aggravate the corrosion damage of engineering facilities.
由于盐碱化改变了原先土壤的理化特性，部分地区甚至存在土地溶陷、盐胀等现象，不仅对工程施工造成不良影响，还会使工业用地不能有效地利用，造成巨大的经济损失。此外，高盐高碱的环境还会加剧工程设施的腐蚀损坏。
3. Salinization affects the normal growth of plants盐碱化影响植物的正常生长
Under the action of high concentration of salt, the formation of starch in stomatal guard
cells is hindered, resulting in stomata can not be closed, and plants are prone to drought
and wilt. High concentration of salt environment can increase the osmotic pressure of soil s
olution, cause physiological drought of plants, and in serious cases, it will lead to water seepage from root cells, so that plants wilting or even death. In addition, due to the competition of Na+, the absorption of potassium, phosphorus and other nutrient elements by plants is
reduced, and the transfer of phosphorus will also be inhibited, thus affecting the nutritional status of plants, and thus inhibiting the normal vegetative growth and reproduction of
plants.
在高浓度盐分作用下，气孔保卫细胞内的淀粉形成受到阻碍，导致气孔不能关闭，植物易干旱枯萎。高浓度的盐分环境可提高土壤溶液的渗透压，引起植物生理干旱，情况严重时还会导致水分从根细胞外渗，使植物萎蔫甚至是死亡。此外，由于Na+的竞争，植物对钾、磷和其他营养元素吸收减少，磷的转移也会受到抑制，从而影响植物的营养状况，进而抑制植物正常的营养生长和繁殖。
4. Salinization affects crop yield and quality盐碱化影响作物产量和品质
Soil salinization can also affect crop yield and quality. According to research, the higher
content of chloride ions in soil will make the burning property of tobacco worse and the
quality decreased. Proper amount of chloride ions in soil can promote the improvement of grape yield and quality, but when the content of chloride ions in soil exceeds a certain
amount, the yield and quality of grapes will decrease.
土壤盐渍化还能使农作物的产量和品质受到影响。据研究， 土壤中氯离子 含量较高时将使烟草的燃烧性变差，品质下降。土壤中适量的氯离子能促进葡萄产量和品质的提高，而当土壤中的氯离子含量超过一定量时就会使葡萄的产量和品质下降。