Plant growth promotion improvement method for salinized soil in Hexi region

Abstract

The invention discloses an improvement method for promoting growth of plants in salinized soil in Hexi region. The improvement method is realized by two steps of preparation of a soil conditioner and planting of salt-tolerant plants. The soil alkali-hydrolyzable nitrogen content of other plants except T2 is 1.2-2.5 times of the soil alkali-hydrolyzable nitrogen content of T0, the soil available phosphorus content of other plants except T5 and T6 is reduced by 12.9%-62.8%, and the reduction amplitude of the soil available phosphorus of T1 and T9 is maximum. The content of rapidly available potassium in soil is reduced by 28.8%-77.6% by planting plants, and the reduction amplitude of rapidly available potassium in T4 soil is maximum. After plants are planted, the salt content of plough layer soil is reduced by 27.8%-33.6%, and the reduction effect of T5 is the maximum; by means of planting of the salt-tolerant plants, the salt content of the soil of the 30-60 cm soil layer is reduced by 17.0%-37.3%, and T2 is reduced most obviously. The method has the advantages that obvious desalting effects can be realized during planting of the plants, the desalting rates of the plough layer soil can reach 13.3%-20.3%, and T5, T2, T3 and T1 are 20.3%, 16.2%, 15.5% and 15.1% respectively.

Description

Technical Field

[0001] The invention belongs to the technical field of soil improvement, and particularly relates to a method for promoting plant growth in saline soil in Hexi region. Background Art

[0002] Saline soil is a special type of soil, including various saline soils, alkaline soils and other salinized and alkaline soils of varying degrees. Its notable characteristics are high content of saline and alkali components in the soil and poor physical and chemical properties. Soil salinization is common in arid and semi-arid areas of my country, especially in the northern part of the Hexi region. About 10% of the total plain area and about 60% of the total cultivated land area in the Hexi region are affected by salinization, resulting in a grain loss of more than 1.0×10 per year. 8 kg. The soil salinization area in the Shule River, Shiyang River and Heihe River basins reached 9.0×10 5 hm 2 , 7.4×10 5 hm 2 and 4.4×10 5 hm 2 Soil salinization has become a strategic issue for the sustainable development and improvement of environmental quality in the Hexi Corridor. Improving the salinized soil in the Hexi Corridor is of great significance to farmland security, food security, ecological construction and high-quality regional development.

[0003] According to the existing literature search, the Chinese patent application with the publication number CN110105961A and the publication date of August 9, 2019, discloses a saline soil conditioner and a method for improving saline soil, including composting, plowing saline soil, mixing to prepare the conditioner, and covering the saline soil with the conditioner and mixing. Although the patent application increases soil nutrients and plant biomass, the desalination effect of plant cultivation is poor, and the reduction of sodium adsorption in the tillage layer soil is not significant. Summary of the invention

[0004] The object of the present invention is to provide a method for promoting plant growth and improving saline soil in the Hexi region, which has good plant planting and desalination effect and significantly reduces sodium adsorption in the cultivated layer soil.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0006] A method for promoting plant growth in saline soil in Hexi region, comprising the following steps:

[0007] 1) Preparation of soil conditioner: garden waste compost, flue gas desulfurization gypsum, ammonium bicarbonate, sludge compost, polyether polyol, sodium lauryl sulfate, wherein the weight parts of each substance are respectively:

[0008] 90-100 copies of garden waste compost;

[0009] 20-26 parts of flue gas desulfurization gypsum;

[0010] 8-10 parts of ammonium bicarbonate;

[0011] 30-35 parts of sludge compost;

[0012] 10-12 parts of polyether polyol;

[0013] 3-6 parts of sodium lauryl sulfate;

[0014] 2) Planting of salt-tolerant plants: Based on the types of salt-tolerant plants, soil conditioners are turned into the soil, and the seeds of salt-tolerant plants are sown into the soil at a depth of 0.3 to 5 cm. The sowing time is early May, and tillage and weeding are carried out during the growth period.

[0015] Furthermore, the soil conditioner in step 1) is composed of the following raw materials in parts by weight: 92-98 parts of garden waste compost; 22-24 parts of flue gas desulfurization gypsum; 9-10 parts of ammonium bicarbonate; 31-33 parts of sludge compost; 11-12 parts of polyether polyol; and 4-6 parts of sodium dodecyl sulfate.

[0016] Furthermore, the soil conditioner in step 1) is composed of the following raw materials in parts by weight: 95 parts of garden waste compost; 23 parts of flue gas desulfurization gypsum; 9 parts of ammonium bicarbonate; 33 parts of sludge compost; 11 parts of polyether polyol; and 4 parts of sodium dodecyl sulfate.

[0017] Preferably, the salt-tolerant plant is selected from one of white-stemmed halophyte, alkali grass, alfalfa, hairy vetch or arrow pea.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) In the present invention, the biological salt excretion of plants is T1>T2>T7>other treatments, and T1, T2 and T7 are 1.9 to 47.6 times that of other treatments; the biological salt excretion of T6 is significantly lower than that of other treatments.

[0020] 2) The soil alkaline nitrogen content of plants other than T2 in the present invention is 1.2 to 2.5 times that of T0, and the soil available phosphorus content of plants other than T5 and T6 is reduced by 12.9% to 62.8%, and the reduction of soil available phosphorus in T1 and T9 is the largest. Plant planting reduces the soil available potassium content by 28.8% to 77.6%, and the reduction of soil available potassium in T4 is the largest.

[0021] 3) After planting plants in the present invention, the salt content of the cultivated soil was reduced by 27.8% to 33.6%, among which T5 had the greatest reducing effect; the planting of salt-tolerant plants reduced the soil salt content of the 30-60 cm soil layer by 17.0% to 37.3%, and the reduction of T2 was the most obvious. Planting of plants has a significant desalination effect, and the desalination rate of the cultivated soil reached 13.3% to 20.3%, and T5, T2, T3 and T1 were 20.3%, 16.2%, 15.5% and 15.1% respectively.

[0022] 4) Planting of the test plants of the present invention reduced the alkalinity of the topsoil. After planting the plants, the sodium adsorption ratio of the topsoil was reduced by 81.5% to 90.9%, and the reducing effects of T2 and T5 were the most significant. Planting of salt-tolerant plants significantly reduced the pH of the topsoil by 1.0% to 4.3%, among which the reducing effects of T4 and T5 were significantly better than those of other treatments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the emergence rate and survival rate of the plant of the present invention.

[0024] Figure 2 Schematic diagram of the salt content of the aboveground and underground parts of different plants of the present invention.

[0025] Figure 3 It is a schematic diagram of the salt accumulation in the aboveground parts of different plants of the present invention.

[0026] Figure 4 It is a schematic diagram of the alkaline nitrogen content of the soil in the 0-30 cm soil layer of the present invention.

[0027] Figure 5 It is a schematic diagram of the available phosphorus content in the soil layer of 0-30cm of the present invention.

[0028] Figure 6 It is a schematic diagram of the available potassium content in the soil layer of 0-30cm according to the present invention.

[0029] Figure 7 It is a schematic diagram of the sodium adsorption ratio of the soil in the 0-30 cm soil layer of the present invention.

[0030] Figure 8 It is a schematic diagram of soil desalination rate of 0-60cm soil layer of the present invention. DETAILED DESCRIPTION

[0031] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. Those skilled in the art can obtain alternative technical solutions from the following description without departing from the spirit and scope of the present invention.

[0032] Example 1

[0033] A method for promoting plant growth in saline soil in Hexi region, comprising the following steps:

[0034] 1) Preparation of soil conditioner: garden waste compost, flue gas desulfurization gypsum, ammonium bicarbonate, sludge compost, polyether polyol, sodium lauryl sulfate, wherein the weight parts of each substance are respectively:

[0035] 90 portions of garden waste compost;

[0036] 20 parts of flue gas desulfurization gypsum;

[0037] 8 parts of ammonium bicarbonate;

[0038] 30 parts of sewage sludge compost;

[0039] 10 parts of polyether polyol;

[0040] 3 parts of sodium lauryl sulfate;

[0041] 2) Planting of salt-tolerant plants: Based on the types of salt-tolerant plants, soil conditioners are turned into the soil, and seeds of salt-tolerant plants are sown into the soil in strips at a sowing depth of 0.3 cm. The sowing time is early May, and tillage and weeding are performed during the growth period. The salt-tolerant plant is selected from one of white-stemmed halophyte, alkali grass, alfalfa, hairy vetch, or arrow pea.

[0042] Example 2

[0043] A method for promoting plant growth in saline soil in Hexi region, comprising the following steps:

[0044] 1) Preparation of soil conditioner: garden waste compost, flue gas desulfurization gypsum, ammonium bicarbonate, sludge compost, polyether polyol, sodium lauryl sulfate, wherein the weight parts of each substance are respectively:

[0045] 95 parts of garden waste compost;

[0046] 23 parts of flue gas desulfurization gypsum;

[0047] 9 parts of ammonium bicarbonate;

[0048] 33 parts of sewage sludge compost;

[0049] 11 parts of polyether polyol;

[0050] 4 parts of sodium lauryl sulfate;

[0051] 2) Planting of salt-tolerant plants: Based on the types of salt-tolerant plants, soil conditioners are turned into the soil, and the seeds of salt-tolerant plants are sown into the soil in strips at a sowing depth of 2 cm. The sowing time is early May, and tillage and weeding are performed during the growth period. The salt-tolerant plant is selected from one of white-stemmed halophyte, alkali grass, alfalfa, hairy vetch, or arrow pea.

[0052] Example 3

[0053] A method for promoting plant growth in saline soil in Hexi region, comprising the following steps:

[0054] 1) Preparation of soil conditioner: garden waste compost, flue gas desulfurization gypsum, ammonium bicarbonate, sludge compost, polyether polyol, sodium lauryl sulfate, wherein the weight parts of each substance are respectively:

[0055] 100 copies of garden waste compost;

[0056] 26 parts of flue gas desulfurization gypsum;

[0057] 10 parts of ammonium bicarbonate;

[0058] 35 parts of sewage sludge compost;

[0059] 12 parts of polyether polyol;

[0060] 6 parts of sodium lauryl sulfate;

[0061] 2) Planting of salt-tolerant plants: Based on the types of salt-tolerant plants, soil conditioners are turned into the soil, and seeds of salt-tolerant plants are sown into the soil in strips at a sowing depth of 5 cm. The sowing time is early May, and tillage and weeding are performed during the growth period. The salt-tolerant plant is selected from one of white-stemmed halophyte, alkali grass, alfalfa, hairy vetch, or arrow pea.

[0062] Experimental example

[0063] The species of salt-tolerant plants were used as experimental factors, and 12 levels were set, including T0 (bare land), T1 (white-stemmed halophyte), T2 (salt-land sedge), T3 (alkali grass), T4 (alfalfa), T5 (hairy vetch), T6 (arrow pea), T7 (sweet sorghum), T8 (barley), T9 (oats), T10 (barley-hairy vetch, DM), and T11 (oats×arrow pea, Y×J), with a total of 12 treatments, and the experiment was repeated 3 times. The experimental plot was 6m long, 5m wide, and 30m in area. 2The plot spacing was 40 cm, the block group spacing was 50 cm, and protective rows with a width of 1 m were set around the experimental site.

[0064] All plants were sown in rows. The sowing depth of white-stemmed halophyte and Suaeda salsa was 1-2 cm, the row spacing was 50 cm, and the planting density was 1 million plants / hm2. -2 and 1.2 million plants·hm -2 The sowing depth of alkali grass is 0.3-1 cm, the row spacing is 20 cm, and the planting density is 4.5 million plants / hm -2 The sowing depth of alfalfa is 1-2 cm, the row spacing is 20 cm, and the planting density is 8 million plants / hm2. -2 The sowing depth of hairy vetch, arrow pea, barley and oat was 3-5 cm, the row spacing was 20 cm, and the planting density was 8 million plants / hm2 respectively. -2 , 3 million plants·hm -2 , 8 million plants·hm -2 , 10 million plants·hm -2 The planting density of barley-hairy vetch multicropping is the same as that of monocropping. The planting density of oats in mixed cropping of oats and peas is 8 million plants / hm2. -2 , the density of pea is 2.5 million plants / hm -2 (Mixed row sowing in the row); the sowing depth of sweet sorghum is 3-5cm, the row spacing is 50cm, and the planting density is 400,000 plants / hm2 -2 .

[0065] The sowing time for each treatment was May 8, 2022, and the crops were harvested in stages when mature. Each treatment was fertilized with 112.5 kg N·hm -2 、100kg P2O5·hm -2 、75kg K2O·hm -2 The types of nitrogen, phosphorus and potassium fertilizers were urea (containing 46% N), superphosphate (containing 16% P2O5) and potassium sulfate (containing 45% K2O). All fertilizers were used as base fertilizers and spread on each experimental plot before sowing. Sowing was carried out after plowing. Manual weeding was carried out during the growth period.

[0066] Determination indicators and methods

[0067] Investigate the germination rate and survival rate; collect representative samples before harvesting and harvest in different areas; measure the soil bulk density and porosity of the 0-30cm soil layer before sowing, 50 days after sowing and after harvesting; collect soil samples in two layers of 0-30cm and 30-60cm before sowing and after harvesting, and measure the soil chemical properties; refer to the third edition of "Soil Agrochemical Analysis" edited by Bao Shidan for the determination methods of various indicators.

[0068] Salt accumulation and biological salt removal of different plants

[0069] 1. Plant germination rate and survival rate

[0070] As can be seen from the figure ( Figure 1 -a), the germination rates of T1, T2, T3, T6 and T11J were 1.1 to 1.6 times that of other treatments, reaching a significant level; the germination rates of T5 and T8 were significantly lower than those of other treatments by 9.6% to 37.8%. As shown in the figure ( Figure 1 -b), the survival rates of T1, T3, T4, T7, T8, T10D and T10M were significantly higher than those of other treatments by 2.4% to 67.9%; the survival rates of T2, T6 and T11J plants were significantly lower than those of other treatments, and the survival rates of plants in other treatments were 1.5 to 3.1 times that of T2, T6 and T11J.

[0071] The emergence rate and survival rate of plants showed great differences due to the influence of saline-alkali stress and climatic conditions. The emergence rate, survival rate of T1, T3 and the emergence rate of T2 were all at a high level, which is consistent with the high salt tolerance of halophytes; but due to the impact of the epidemic, the sowing time was delayed by about 25 days compared with the usual years. T2 was not resistant to high temperatures during the seedling stage, and its survival rate was significantly lower than that of other treatments due to the influence of high temperature stress. T6 and T11J are different planting patterns of the same plant. Although their emergence rates are high, as the growth process progresses, their survival rates are significantly lower than those of other treatments except T2 by 33.8% to 41.7%. This shows that their salt-alkali tolerance is significantly weaker than other treatments, and they show strong salt-alkali tolerance after emergence.

[0072] The emergence rate of T5, T8, T10D and T10M under saline-alkali stress was only 46.8% to 55.3%, but the survival rate reached 88.5% to 91.7%, which indicated that the germination was more seriously affected by saline-alkali stress, and its salt-alkali tolerance increased with the growth process. The emergence rate and survival rate of T10M were significantly higher than those of T5 by 18.1% and 2.4%, respectively, which indicated that the planting of the previous crop of barley reduced the degree of soil salinity, thereby increasing the emergence rate and survival rate of the double-cropped hairy vetch.

[0073] Through the analysis of germination rate and survival rate, it can be seen that the salt-alkali tolerance of plants has a certain degree of change with the process of their growth and development. Specifically, halophytes always show stronger salt-alkali tolerance than other plants; while the salt-alkali tolerance of legumes varies greatly among species, and alfalfa shows strong salt-alkali tolerance throughout the growth and development process; the salt-alkali tolerance of hairy vetch is weak during the germination and germination period, and the germination rate is low. After germination, its ability to resist salt and alkali gradually increases; the arrow pea shows a high salt-alkali tolerance during the germination period, and the germination rate is high, but with the advancement of the growth process, its salt-alkali tolerance decreases significantly, and the survival rate is lower than that of the other two legumes; the gramineous plants sweet sorghum and oats have stronger salt-alkali tolerance than barley during the germination period, but with the advancement of the growth process, the salt-alkali tolerance of oats decreases, and sweet sorghum still maintains a strong salt-alkali tolerance. The salt-alkali tolerance of barley is significantly improved compared with the germination period, and its survival rate is at a high level.

[0074] 2. Salt content of plants

[0075] Depend on Figure 2 -a shows that the salt content of the aboveground part of T2 is the highest, followed by T1, whose aboveground salt content is 1.4 to 2.6 times that of other treatments; the aboveground salt content of T4 and T7 is significantly lower than that of other treatments, whose aboveground salt content is only 38.0% to 87.5% of that of other treatments. This shows that the salt accumulation capacity of the aboveground part of plants varies greatly.

[0076] Depend on Figure 2-b shows that the salt content in the underground part of T2, T3, T7 and T9 is significantly higher than that of other treatments, which is 1.1 to 2.6 times that of other treatments. Among them, the salt content in the underground part of T2 is the highest, followed by T3. The differences between them and between the two and other treatments have reached a significant level. This is related to the fact that both are halophytes, which have stronger salt-alkali tolerance and ability to absorb soil salt than other plants. Among them, the salt content in the underground part of T3 is 1.5 times that of the aboveground part, which is related to its salt-rejecting and salt-tolerant mechanism. It can prevent salt ions in the environment from entering cells by suberization of the root cortex or store the salt ions that enter the body in safe places such as the root-stem junction to avoid the toxic effects of salt ions. The salt content of the underground part of T4 was significantly lower than that of other treatments, which was 38.3% to 86.1% of the salt content of the underground part of plants in other treatments; followed by T1 and T11J, whose underground salt content was 44.5% to 93.5% of that of other treatments; this was also related to the salt tolerance mechanism of the three. The salt content of the aboveground and underground parts of T4 was significantly lower than that of other plants, indicating that its ability to adapt to salt-alkali stress by controlling ion absorption and reversing water consumption in the root system may be better than that of similar plants, showing a strong salt rejection ability; T1 reduced the harm caused by salt-alkali stress to itself by transporting salt to the fleshy leaves of the aboveground part, and the salt of T11J underground was transported to the aboveground part through the rhizomes. Due to its weak salt-alkali tolerance, a large number of plants died and the survival rate was significantly reduced (see Figure 1 -b). It can be seen that the salt content of the root system may be quite different from that of the aboveground part, which is closely related to its salt tolerance mechanism.

[0077] Depend on Figure 2-c shows that the salt content of plants in T1, T2 and T3 is significantly higher than that in other treatments, which is 1.2 to 4.1 times that of other treatments. The salt content of plants in T2>T1>T3 is at a significant level. The salt content of plants in T4, T5 and T10M is significantly lower than that in other treatments, which is 24.6% to 55.1% of that in other treatments. This is related to the salt tolerance mechanism and salt tolerance of plants in saline-alkali environments. T1, T2 and T3 are all halophytes, which have a strong ability to absorb salt; T4, T5 and T10M are all legumes, showing a high salt rejection ability; T6 and T11J are legumes, but they absorb more salt; T3, T7, T8, T9, T10D and T11Y are all grass plants, T3 is a halophyte, and its plant salt content is higher than other plants except T1 and T2. The salt content of T7, T8, T9, T10D and T11Y plants is at a medium level, among which T7 is significantly lower than T3, T8, T9, T10D and T11Y treatments by 12.9% to 30.5%. It can be seen that the tested grass plants show a stronger ability to absorb salt than legumes, and there are also certain differences within the grass plants, among which the T7 treatment shows a stronger ability to tolerate salt and alkali. At the same time, there was no significant difference between T5, T10M and T8, T10D, and there was no significant difference between T6, T11J and T9, T11Y, which showed that the planting method did not affect the salt absorption of barley, oats, arrow pea and hairy vetch.

[0078] In summary, the ability of plants T1, T2 and T3 to absorb soil salt is stronger than that of other plants, and the ability to absorb soil salt is T2>T1>T3; the ability of T4, T5, T7 and T10M to absorb soil salt is significantly weaker than that of other plants, showing weak salt-alkali tolerance; the absorption capacity of other treatments for soil salt is at a medium level.

[0079] 3. Salt accumulation of plants and biological salt removal

[0080] As shown in Table 1, the aboveground salt accumulation of T2 was significantly higher than that of other treatments, 1.7 to 286.9 times that of other treatments; the aboveground salt accumulation of T1 and T7 was 37.6 to 171.9 times that of other treatments except T2, reaching a significant difference level; although T5 was not significantly different from treatments other than T1, T2 and T7, its aboveground salt accumulation was 1.3 to 4.5 times that of other treatments. The underground salt accumulation of T7 was significantly higher than that of other treatments, 1.4 to 214.2 times; T2 was significantly higher than that of other treatments except T7, 5.6 to 153.3 times; there was no significant difference between T1, T3 and T4, but the three were significantly higher than other treatments except T2 and T7, with the content being 2.9 to 27.6 times. The salt accumulation of plants in T1, T2 and T7 was significantly higher than that in other treatments. This trend was the same as the accumulation of the aboveground parts. The difference was that the difference in salt accumulation per plant among the three reached a significant level. The salt accumulation per plant of T2 was 1.5 to 232.5 times that of other treatments, 1.2 to 151.5 times that of other treatments except T2, and 25.8 to 131.6 times that of other treatments except T2 and T7. The salt accumulation per plant of T1, T2 and T7 was more than 100 times that of Vitis vinifera. There were no significant differences between T5 and T10M, T6 and T11J, T8 and T10D, and T9 and T11Y, which indicated that monocropping or mixed cropping in one growing year did not affect the salt accumulation of Vetch and Oats plants; there was no significant effect on the salt accumulation of hairy vetch plant between monocropping and multiple cropping with barley; as the salt accumulation of T5 was 3.7 times that of T10M, statistical analysis was performed on T5 and T10M separately, indicating that there was a significant difference between the two, and that T10M was lower than T5, which might be related to the shorter growing season of multiple cropping with hairy vetch.

[0081] The amount of salt accumulated by the plant depends on the combined effect of salt content and dry matter accumulation. Figure 2 -a shows that the salt content of the aboveground parts of T1 and T2 is 1.4 to 2.6 times that of other treatments, reaching a significant difference level; Figure 2-b shows that the underground salt content of T2 is significantly higher than that of other treatments, which is more than 1.1 times. As shown in Table 3, the aboveground dry matter accumulation of T1, T2 and T7 is significantly different, showing a trend of T7>T2>T1. The aboveground dry matter mass of each plant is 25.7-205.1 times that of other treatments; the underground dry matter accumulation of each plant of T2 and T7 is 3.7-139.2 times that of other treatments, reaching a significant difference level. The salt accumulation of plants in T1, T2 and T7 is significantly higher than that of other treatments. It can be seen that the salt accumulation of plants depends on their salt content and dry matter accumulation. The higher the salt content and dry matter accumulation of plants, the higher their salt accumulation. Although the salt content of T7 is at the middle level of all treatments, its single plant dry matter accumulation ranks first among all treatments, so its single plant salt accumulation is second only to T2 and ranks at a high level, which shows the great contribution of plant biomass to its salt accumulation ability.

[0082]

[0083]

[0084] Plants growing on saline soil absorb and accumulate soil salt in their bodies. By harvesting the above-ground parts, the salt accumulated in the above-ground parts of the plants can be carried out of the farmland. This part of the salt carried out is called biological salt excretion. Figure 3 It can be seen that the biological salt excretion of plants is T1>T2>T7>other treatments, T1 is 1.8 to 47.6 times that of other treatments; followed by T2 and T7, both of which have biological salt excretion of 1.9 to 26.0 times that of other treatments; T6 soil salt excretion is significantly lower than other treatments, and biological salt excretion is 2.1% to 20.3% of other treatments; T4 and T5 biological salt excretion is also significantly lower than other treatments except T6, which is 10.4% to 71.5%, showing lower salt excretion capacity than other treatments. This is positively correlated with the dry matter accumulation of plants and the salt content of the aboveground parts of plants (see Table 3). The higher the aboveground biological yield and salt content, the stronger the soil salt excretion (see Tables 1, 2 and Figure 2 -a), T1 and T2 had better dry matter accumulation and aboveground salt content than other treatments. Although T7 had lower aboveground salt content, its dry matter accumulation was significantly higher than other treatments (Table 2), which resulted in higher soil salt removal in T1, T2 and T7 than in other treatments. T6 had lower soil salt removal than other treatments, which was related to its significantly lower dry matter accumulation and weaker salt-alkali tolerance than other plants. With the advancement of growth, its survival rate decreased significantly (see Figure 1-b), which resulted in an extremely low soil salt removal; the other treatments had lower soil salt removal, which was related to their lower dry matter accumulation. At the same time, their aboveground salt content was also significantly lower than that of T1 and T2 (see Figure 2 -a); The soil salt carryout of T10 was higher than that of T5 and T8, which was 1.1 times and 2.0 times of that of T5 and T8, indicating that barley and hairy vetch had a significant effect on increasing the soil salt carryout compared with their single cropping; the soil salt carryout of T11 was 27.6% lower than that of T9 and 8.6 times of that of T6, indicating that oat-earth mixed cropping with pea was more conducive to increasing the soil salt carryout than pea-earth mixed cropping in T6, and affected by the sowing ratio of mixed cropping, the hay yield of mixed cropping was lower than that of oat-earth mixed cropping in T9, which led to the soil salt carryout of T11 being lower than that of T9.

[0085] Table 2 Plant dry matter accumulation

[0086]

[0087] Correlation between plant dry matter accumulation, salt content, salt accumulation and biological salt removal

[0088] As shown in Table 3, biological salt removal is significantly positively correlated with the aboveground dry matter accumulation and aboveground salt content of plants, and has no significant correlation with the underground salt content, dry matter accumulation and salt content of plants; the underground salt accumulation of plants is significantly positively correlated with the underground dry matter accumulation and salt content; the aboveground dry matter accumulation of plants is significantly positively correlated with the aboveground salt content. This shows that the dry matter accumulation of plants will affect the absorption of soil salt by plants to a certain extent. The greater the dry matter accumulation of plants, the stronger the ability to absorb soil salt and the greater the salt accumulation; at the same time, it shows that biological salt removal is mainly affected by the aboveground dry matter accumulation and salt content of plants. In order to enhance the biological salt removal, plants with large aboveground dry matter accumulation and high salt content should be selected as plants for saline soil improvement.

[0089] Table 3 Correlation between plant dry matter accumulation, salt content, salt accumulation and biological salt removal

[0090]

[0091] Economic Benefits of Planting Salt-Tolerant Plants on Saline Soil

[0092] As shown in Table 4, the benefits of planting salt-tolerant plants are

[0093] T1>T7>T2>T9>T8>T10>T3>T11>T4>T5>T6. The returns of T1, T2, T3, T4, T7, T8, T9, T10 and T11 are all positive, while the returns of T5 and T6 are negative; T1 has the highest return, which is 1.1 to 17.1 times that of the other treatments with positive returns; followed by T7, whose return is 2.7 to 15.3 times that of the treatments with positive returns other than T2; T2's return is 1.5 to 5.8 times that of the treatments with positive returns other than T1 and T7. Due to the impact of the epidemic, the sowing time was delayed, and it was not resistant to high temperatures during the seedling stage, resulting in a low survival rate, which affected the forage yield. Its actual return should be higher than the current one. The benefits of T3 and T4 were low, mainly because they were perennial plants. In the first year of planting, the grass yield was low due to the influence of plant growth and development characteristics and salinity stress. At the same time, the price of seeds also affected their benefits to a certain extent. The benefits of T5 were negative, mainly because the salinity stress inhibited its dry matter accumulation. At the same time, due to the influence of biological characteristics, its own low dry matter accumulation affected the grass yield. The large sowing amount and relatively high seed price also affected its benefits. Due to the influence of salinity stress, the survival rate of T6 was low (see Figure 1-2 ), the surviving plants were inhibited from growing and developing poorly due to salt-alkali stress, which seriously affected the grass yield and reduced the benefits. At the same time, the higher investment increased the cost, leading to serious losses. Under the influence of salt-alkali stress, the forage yield of T8, T9, T10 and T11 was inhibited, and the investment was relatively high, resulting in relatively low benefits.

[0094] Table 4 Economic benefit analysis of planting salt-tolerant plants in saline soil

[0095]

[0096] Soil alkaline nitrogen

[0097] Depend on Figure 4It can be seen that compared with before sowing, only T3, T5 and T10 increased the soil alkaline nitrogen content by 76.4%, 8.1%, and 15.6%, while the other treatments reduced the soil alkaline nitrogen content by 1.6% to 30.0%, with T0 having the largest decrease. Compared with T0, the soil alkaline nitrogen content of all treatments except T2 increased significantly. Plant planting stabilized or increased the soil alkaline nitrogen content. The alkaline nitrogen content of each treatment was 1.2 to 2.5 times that of T0. The soil alkaline nitrogen content of T3, T5, T7 and T10 was significantly different from that of other treatments. T3 was significantly higher than other treatments, and T5 and T10 were higher than other treatments except T3. This was related to the strong nitrogen fixation of legumes. The soil alkaline nitrogen content of T3, T10, T5 and T7 was 2. The alkaline nitrogen content of soil was 5, 1.7, 1.5 and 1.4 times that of T6; T2 had no obvious effect on the alkaline nitrogen content of soil; while the alkaline nitrogen content of soil in T10 was 1.1 times and 1.4 times that of T5 and T8, respectively, indicating that the effect of barley-hairy vetch multicropping on improving soil alkaline nitrogen was significantly better than that of the two alone; the alkaline nitrogen content of T9 and T11 was not significantly different, but T9 was 1.1 times that of T6, reaching a significant level of difference, which shows that the effect of improving alkaline nitrogen in mixed cropping of oats and peas is not much different from that of oats alone, but is better than that of peas alone.

[0098] Soil Available Phosphorus

[0099] Depend on Figure 5 It can be seen that except for T9, which had no significant change in soil available phosphorus content compared with before sowing, the other treatments increased soil available phosphorus content by 5.7% to 169.2%, which may be related to the application of phosphorus fertilizer at sowing. Compared with T0, except for T5 and T6, the soil available phosphorus content of the other treatments was significantly reduced by 12.9% to 62.8%. Planting reduced the soil available phosphorus content compared with bare land, among which T1 and T9 had the largest decrease, followed by T2, T8, T10 and T11. The differences between the soil available phosphorus content of T1 and T9 and the other treatments reached a significant level. The soil available phosphorus content of T1, T2, T8, T10 and T11 was 25.7% to 59.9% lower than that of T0. The soil available phosphorus content of T10 was significantly lower than that of T5 and T8, which were 2.1 times and 1.6 times that of T10 respectively; the soil available phosphorus content of T11 was significantly higher than that of T9, which was 1.5 times that of T9, but only 56.2% of that of T6. The reduction of soil available phosphorus by mixed cropping of oats and pea was less than that by oats alone, but greater than that by pea alone.

[0100] Soil Available Potassium

[0101] Figure 6The results showed that compared with the pre-sowing period, the available potassium content in the soil of each treatment showed a downward trend. The available potassium content in the soil of T0-T11 decreased by 7.9%-79.4%, with the lowest decrease in T0, indicating that the planting of plants consumed the available potassium nutrients in the soil. Compared with T0, the planting of plants significantly reduced the available potassium content in the soil, with a decrease of 28.8%-77.6%; the available potassium content in the soil of T4 was significantly lower than that of other treatments, which should be related to the high demand for potassium of alfalfa; the next lowest were T3, T5 and T8, and the differences among the three were significant; T3, T4, T5 and T8 reduced the available potassium content in the soil by 72.8%, 77.6%, 71.0% and 67.0% respectively compared with T0; the available potassium content in the soil of T1, T2, T7, T9 and T11 was the highest among the other treatments except T0. The soil available potassium content of T10 was significantly higher than that of T5 and T8, which were 1.4 and 1.3 times higher than those of T5 and T8, respectively, indicating that the reduction of soil available potassium content by barley-hair vetch multicropping was less than that by barley and hairy vetch alone; the soil available potassium content of T11 was significantly higher than that of T6 and T9 treatments by 40.4% and 4%, respectively, and the reduction of soil available potassium content by mixed cropping of oats and vetch was less than that by oats and vetch alone, indicating that the nutritional heterogeneity effect among mixed cropping plants is conducive to the balanced utilization of soil salt.

[0102] In summary, when salt-tolerant plants are planted on relatively poor saline-alkali soils, the soil alkaline nitrogen content remains unchanged or even increases compared with bare land, the soil available phosphorus content remains unchanged or decreases, and the soil available potassium content shows a downward trend.

[0103] Soil sodium adsorption ratio

[0104] Depend on Figure 7 It can be seen that compared with before planting plants, the sodium adsorption ratio of the 0-30cm soil layer in the T0 treatment increased by 16.6%, and the sodium adsorption ratio of the soil decreased by 78.4% to 89.4% in T1 to T11. Planting can significantly reduce the sodium adsorption ratio of the plough layer. Compared with T0, each treatment significantly reduced the sodium adsorption ratio of the 0-30cm soil layer by 81.5% to 90.9%, which once again shows that the planting of salt-tolerant plants has a significant effect on reducing the sodium adsorption ratio of the soil. Among them, T2 and T5 have the most significant reduction effect, followed by T10. T2, T5 and T10 reduce the soil sodium adsorption ratio by 90.9%, 89.9% and 87.4%, respectively. Combined with the effects of planting salt-tolerant plants on various base ions in the soil, it shows that the planting of salt-tolerant plants has a significant effect on alleviating salt stress and reducing sodium damage.

[0105] Soil desalination rate in 0-60cm soil layer

[0106] Figure 7The results showed that the soil desalination rate of the 0-30cm soil layer under T1 to T11 treatments reached 13.3% to 20.3%, while the soil salinity of T0 increased by 20.0% compared with that before sowing, indicating that the planting of plants has a significant desalination effect on the plough layer. Among them, the desalination rate of T5 was significantly higher than that of other treatments, more than 16.8% higher than that of other treatments; followed by T10, whose desalination rate was more than 7.4% higher than that of the remaining treatments except T2 and T4; the desalination rates of T6, T7 and T9 were significantly lower than those of other treatments except T0, and were 3.6% to 34.4% lower than those of other treatments. The desalination rate of T10 was lower than that of T5 but significantly increased by 13.3% compared with T8, indicating that the desalination effect of barley and hairy vetch was enhanced compared with wheat alone; the desalination rate of T11 was 1.1 times and 1.2 times that of T6 and T9, respectively, indicating that the desalination effect of mixed cropping of oats and vetch was more significant than that of single cropping; the salt content of T0 was significantly higher than that before sowing, further proving the obvious effect of plant planting on reducing surface salt accumulation and accelerating soil desalination.

[0107] Depend on Figure 8 It can be seen that the desalination rate of soil in the 30-60cm soil layer was -17.1% in T0, and the desalination rates of other treatments were all above 2.8%, reaching a significant level, which shows that the planting of plants has a significant effect on reducing the salt content of soil in the 30-60cm soil layer. The desalination rates of T2 and T1 were significantly higher than those of other treatments, 1.2 to 9.5 times that of the treatments other than T0. In addition to the fact that their well-developed root systems affect the migration of water and salt, this is mainly due to their strong absorption and enrichment capabilities for salt (Table 2, Figure 3 ) are closely related.

[0108] In summary, the planting of salt-tolerant plants reduces soil salt content and soil sodium adsorption ratio, and has a certain desalination effect. However, there are significant inter-species differences in the reduction of soil salt content and desalination effects. Among the tested plants, white-stemmed halophyte, salsa salsa and sweet sorghum are at the forefront in terms of salt absorption, accumulation and desalination effects.

[0109] The planting of salt-tolerant plants affects the nutrient content of the soil; one year of planting has different results such as increase, decrease and no obvious change, which varies greatly depending on the plant type; multi-year planting can significantly increase the nutrient content of nitrogen, phosphorus and potassium.

[0110] After planting oats, Hunan millet, sesbania, sorghum and sweet clover for 2 years, the total nitrogen and alkaline nitrogen content of the soil increased significantly compared with the control; after planting salt-tolerant plants such as saltwort, long-spiked wheatgrass, tall fescue and new wheatgrass for 3 years, the total nitrogen content of the 0-20cm soil layer increased; after planting castor oil for 3 years, the alkaline nitrogen content of the soil increased significantly; after planting leguminous green manure sesbania and sweet clover for one season, the effective nitrogen content increased; when alfalfa and corn were rotated, the total nitrogen and available nitrogen content of the tillage layer soil increased significantly. At the same time, it was also discovered that after planting reed fescue, tamarisk and oil sunflower, the alkaline nitrogen content of the soil was lower than that of sowing; the alkaline nitrogen content of the soil decreased in the first year of planting Hunan millet, and increased in the second year. The present invention shows that after planting each test plant for one year, the alkaline nitrogen content of the soil in the 0-30 cm soil layer has no significant change except for Suaeda salsa, while the alkaline nitrogen content of the soil is significantly increased under the treatment of white stem halophyte, alkali grass, alfalfa and hairy vetch, among which alkali grass has the most obvious effect on increasing the alkaline nitrogen content of the soil. It can be seen that the change of the alkaline nitrogen content of the soil during plant improvement is closely related to the planting years and species.

[0111] After planting salt-tolerant plants such as Suaeda salsa, Elymus longispinus, oats, castor, Hunan millet, Sesbania serrata, Sorghum sutchuenensis, Sweet clover, tall fescue and Pseudocaliphae for 2 years or more, the content of available phosphorus and available potassium in the soil increased; the content of available phosphorus in the topsoil of alfalfa and corn rotation increased significantly. However, it was also found that the content of available phosphorus and available potassium in the soil decreased after planting leguminous green manure Sesbania serrata and Sweet clover for one season, and the same trend was found after planting Fescue australis, sunflower and Tamarix. The change in the content of available phosphorus in the soil was not obvious in the first year of planting Hunan millet, but the content of available phosphorus increased significantly in the second year, while the content of available potassium decreased. The present invention found that after planting salt-tolerant plants, except for hairy vetch and arrow pea, which had no significant effect on the available phosphorus content of the 0-30cm soil layer, other treatments significantly reduced the available phosphorus content of the soil, among which the available phosphorus content of the soil treated with white-stemmed halophyte and oats was the most significantly reduced; after planting all the tested plants, the content of available potassium in the tillage layer was reduced. This is because the available phosphorus content of the saline soil tested in the present invention is extremely low, and it belongs to a severely phosphorus-deficient soil. Under the conditions of one year of planting, normal application of chemical fertilizers and natural return, the reduction of the available phosphorus content is also inevitable.

[0112] The impact of plant planting on soil nutrient characteristics, in addition to being affected by the basic soil fertility, is largely related to the number of years the plants are planted. After many years of planting, the soil nutrient content tends to increase, while short-term planting is unlikely to produce significant fertilization effects.

[0113] The cultivation of salt-tolerant plants reduces the salt content and sodium adsorption ratio of the soil. The reduction in salt content is mainly reflected in the absorption of Cl - Mg 2+ 、Na + and SO4 2-The reduction of plasma content; high salt accumulation plants enhance the biological salt removal of plants and have a better desalination effect on the soil

[0114] Soil salinity is the main factor limiting the growth of crops. It is an inherent characteristic of saline soil and a key factor affecting the nutrient level and soil structure of saline soil. The primary purpose of improving saline soil is to reduce the total salt content of the soil. The increase of soil salt ions will inhibit the absorption and utilization of other soil nutrients by plants, and the aggregation of salt ions in the soil will cause physiological water shortage in plants, inhibiting the growth and development of plants and causing reduced yields or death. Sweet soil plants are particularly affected by this. Salt-tolerant plants can absorb a large amount of inorganic salt ions from the outside world to perform osmotic regulation to prevent physiological drought caused by cell water loss. They can grow in saline environments and improve saline soils.

[0115] Planting ecologically adaptable plants can reduce the salt content of saline soil. In coastal areas, after planting salt-tolerant plants such as Suaeda salsa and Pseudocaliphate, the salt content of the 0-30cm soil layer was reduced by more than 50%; planting Sesbania sesbania, Sweet Clover and Castor can also effectively reduce the total salt content of the soil. The present invention shows that after planting white-stemmed halophyte, Suaeda salsa and a plant similar to Pseudocaliphate, the total salt content of the cultivated layer soil decreased significantly, and the decrease of the three plants was more than 15%. Soil conductivity and salt content have a certain correlation, and the measured value of conductivity is also often used to indicate the level of salt content. After planting plants such as alfalfa, okra and cassia, the soil conductivity decreased significantly. This article also verified this result. After planting alfalfa, hairy vetch, arrow pea and other green manure and forage plants similar to sesbania and sweet clover, the soil conductivity decreased significantly. Not only that, all the plants tested significantly reduced the soil conductivity compared to bare land.

[0116] Plants have the characteristic of selective absorption of salt ions. After planting forage grasses such as Zoysia, Poa annua, Sesbania, Corona, and Alfalfa, the water-soluble Cl in the soil - 、SO4 2- The content was significantly reduced, reducing soil Cl - The effect of Zoysia japonica is the best, reducing water-soluble SO4 2- The effect of sesbania content was better, and several forage grasses could reduce the soil HCO3 in the heavy salt treated soil - After planting Chinese medicinal materials such as honeysuckle, astragalus and hay, the Na content in the soil + , Ca 2+ Mg 2+ 、SO4 2- , Cl - and the total amount of soluble salts decreased significantly, while K + The soil K content increased after planting okra and cassia + The content of soil K decreased significantly compared with the control treatment.+ The content decreased by 58.1% to 93.9%; okra increased the soil Na + content, Tamarind increased soil Ca 2+ content, okra, cassia and tamarind increase soil SO4 2- The content increased significantly by 87.5% to 220.6%; HCO3 - The content of okra and cassia seed decreased significantly. With the increase of tenuifolia planting years, soil CO3 2- 、HCO3 - and Na + The content gradually decreased, and the soil Cl - The content of soil SO4 2- and K + The content gradually decreased, and the soil Ca 2+ and Mg 2+ The present invention shows that the mixed planting of Suaeda salsa, Puccinellia salsa and oats can improve the soil HCO3 - The content of soil HCO3 - The content of alfalfa decreased significantly. 2+ Except for the content of soil Ca 2+ The planting of salt-tolerant plants reduced soil Cl - Mg 2+ , K + 、Na + and SO4 2- It can be seen that the contribution of plants to the reduction of soil salt content may vary greatly from one ion to another. According to the type of saline soil, selecting plants that have selective absorption characteristics for high-content base ions is one of the keys to plant improvement of saline soil.

[0117] Planting salt-tolerant plants has a soil desalination effect. After planting Sesbania, the soil desalination rate is 20-40cm soil layer>0-20cm soil layer>40-60cm soil layer. After planting rice grass corn, the soil desalination rate reaches 15.7% to 34.5%. Under irrigation conditions, compared with before planting plants, the total salt content of the 0-30cm soil layer after planting plants such as Salicornia salsa was reduced by 20.8% to 55.6%, and the total salt content of the 30-60cm soil layer was reduced by more than 21.8%, while the total salt content of the control increased by 18.3%. The present invention found that all the tested plants had a desalination effect; however, the salt content of the 0-60cm soil layer of the bare land control was significantly increased compared with before planting plants, and the desalination rate of the 0-30cm soil layer under the influence of each salt-tolerant plant reached 13.3% to 20.3%. The localization test shows that after two years of planting alkali grass, the desalination rate of the tillage layer soil reaches 28.5%, and after one year of planting alkali grass in the present invention, the desalination rate of the tillage layer soil reaches 15.6%. It can be seen that the desalination and improvement of saline soil by plants is a gradual and continuous process.

[0118] The effect of plants on saline soil improvement varies greatly depending on the type of saline soil and the growth characteristics of the plants. Appropriate improvement plants should be selected according to local conditions.

[0119] The effect of plants on saline soil improvement varies depending on the type of saline soil. The improvement effect in the Hetao Irrigation Area is: Sesbania truncatula > Sorghum sutchuenensis > Millet tamarisk > Oats; the improvement effect in the Ningxia Yinbei area is: Tamarix chinensis > Festuca australis > Sunflower. The more developed the root system of the plant, the wider the distribution range in the soil layer, the longer the planting time, and the later the harvest time, the more obvious the improvement effect on saline soil

[54] . The present invention also shows that plants such as Salicornia herba, Salicornia salsa, Sorghum kaoliang and Alfalfa, which have a long growth period and a more developed root system than other plants, have a significantly stronger improvement effect on saline soil than plants such as barley, oats and Vetch. The present invention also shows that the length of the plant's growth period has a certain influence on the improvement effect of saline soil. Plants such as Salicornia herba, Salicornia salsa and Sorghum kaoliang, which have a longer growth period, have a more obvious improvement effect on saline soil, which is similar to the experimental invention results conducted in the Ningxia Yinbei area mentioned above. Planting time is only one factor that affects the improvement effect. The improvement effect on the soil is mainly affected by factors such as the salt tolerance of the plant itself. For example, plants such as alkali grass and hairy vetch are harvested late in the present invention, but their improvement effect on saline soil is not very prominent. Related inventions on the improvement of saline soil in Taizhou tidal flats found that the improvement effect on saline soil is alfalfa> sweet clover> sorghum> sesbania> salsa salsa, which is quite different from the invention results of this article. The improvement effect of the present invention is salsa salsa> white stem halophyte> sweet sorghum> alfalfa> barley> alkali grass> oats> hairy vetch> arrowroot pea. It can be seen that due to the influence of factors such as saline soil types and climatic environment differences in different regions, plants may show different improvement effects on different types of saline soils in different regions.

[0120] The above description is only a specific implementation mode of the present disclosure, but the protection scope of the embodiments of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes, replacements or combinations within the technical scope disclosed in the embodiments of the present disclosure or under the ideas disclosed in the embodiments of the present disclosure, which should be included in the protection scope of the embodiments of the present disclosure.

Claims

1. A method for improving plant growth in saline soil in Hexi region, characterized in that The steps include: 1) Preparation of soil conditioner: garden waste compost, flue gas desulfurization gypsum, ammonium bicarbonate, sludge compost, polyether polyol, sodium lauryl sulfate, wherein the weight parts of each substance are respectively: 90-100 copies of garden waste compost; 20-26 parts of flue gas desulfurization gypsum; 8-10 parts of ammonium bicarbonate; 30-35 parts of sludge compost; 10-12 parts of polyether polyol; 3-6 parts of sodium lauryl sulfate; 2) Planting of salt-tolerant plants: Based on the types of salt-tolerant plants, soil conditioners are turned into the soil, and the seeds of salt-tolerant plants are sown into the soil at a depth of 0.3 to 5 cm. The sowing time is early May, and tillage and weeding are carried out during the growth period.

2. The method for promoting plant growth in saline soil in Hexi region according to claim 1, characterized in that The soil conditioner in step 1) is composed of the following raw materials in parts by weight: 92-98 parts of garden waste compost; 22-24 parts of flue gas desulfurization gypsum; 9-10 parts of ammonium bicarbonate; 31-33 parts of sludge compost; 11-12 parts of polyether polyol; and 4-6 parts of sodium dodecyl sulfate.

3. The method for promoting plant growth in saline soil in Hexi region according to claim 1, characterized in that In the step 1), the soil conditioner is composed of the following raw materials in parts by weight: 95 parts of garden waste compost; 23 parts of flue gas desulfurization gypsum; 9 parts of ammonium bicarbonate; 33 parts of sludge compost; 11 parts of polyether polyol; and 4 parts of sodium lauryl sulfate.

4. The method for promoting plant growth in saline soil in Hexi region according to claim 1, characterized in that The salt-tolerant plant is selected from one of white-stemmed halophyte, alkali grass, alfalfa, hairy vetch or arrow pea.

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