Saline-alkali soil ecological improvement method and application thereof

Abstract

The invention discloses a saline-alkali soil ecological improvement method and application thereof. The method specifically comprises the step of planting gramineous plants, leguminous plants and cruciferous plants in a land parcel to be improved in a mixed mode. The method is applied to a crop planting field and serves as a preceding crop of crops. According to the method, by planting the specific plant combination, the purposes of improving the soil structure, increasing soil organic matter, reducing salinity and alkalinity, increasing soil microbial activity and the like are achieved, and therefore a more suitable growth environment is provided for the follow-up crop corn, and the purposes of sustainable utilization, yield increase and efficiency improvement of the saline-alkali soil are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and more particularly to a saline-alkali land ecological improvement method and application thereof. Background Art

[0002] The widespread existence of saline-alkali land poses severe challenges to agricultural production, especially in arid, semi-arid and coastal areas. Saline-alkali land is characterized by high soil salt content, alkaline pH value and insufficient water, which makes it impossible for most crops to grow normally. Existing improvement measures mostly rely on chemical amendments, heavy machinery operations and large-scale irrigation. These methods are not only costly, but also may cause environmental pollution and waste of resources. Therefore, the development of an economical, efficient and ecological saline-alkali land improvement technology, especially one that can stably improve soil fertility in the long term and reduce the trend of salinization, has become an agricultural problem that needs to be solved urgently. Summary of the invention

[0003] In view of this, the present invention proposes a sustainable improvement plan for saline-alkali land through an innovative plant combination and its application, which can not only effectively improve the health of the soil, but also increase the yield and quality of subsequent crops.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] A method for improving saline-alkali land ecology comprises the following steps:

[0006] Plant a mixture of grasses, legumes and crucifers in the land to be improved.

[0007] Preferably, the sowing mass ratio of the Gramineae plants, Leguminosae plants and Cruciferae plants is 1:2:1.

[0008] Furthermore, the grass plant is oat, the legume plant is alfalfa, and the cruciferous plant is rapeseed.

[0009] Among them, oats: a grass plant with a well-developed root system, can loosen the soil, increase soil aeration, and absorb salt and alkali in the soil. Its endophytic bacteria (such as Bacillus subtilis) have a significant disease prevention effect and can promote plant growth by dissolving phosphorus and potassium and producing plant growth hormones. Turning over and pressing into the soil layer can significantly increase soil organic matter and promote soil biological activity.

[0010] Alfalfa: Leguminosae plants, with a variety of rhizosphere growth-promoting bacteria (such as rhizobia) in the rhizosphere soil that have the functions of nitrogen fixation, phosphorus solubilization and auxin secretion, which improves the soil condition of saline-alkali land, increases soil fertility, and increases soil available phosphorus, which is essential for plant growth and development. Turning over and pressing into the soil layer can significantly increase soil organic matter and promote soil biological activity.

[0011] Rapeseed: Cruciferous plant, root endophytes (such as Bacillus amyloliquefaciens) have the ability to degrade lignocellulose, produce siderophores and IAA, have stable nitrogen fixation ability, and show a wide range of growth-promoting and antibacterial activities. By turning over green manure and returning it to the field, the organic matter in the saline-alkali soil can be rapidly increased, and a stable granular structure layer can be formed in the upper layer of the soil, effectively reducing the rise of salt and alkali in the lower layer and reducing the salt and alkali concentration in the cultivated layer.

[0012] The present invention also provides an application of the method described in the above technical solution in a crop planting field.

[0013] Preferably, the method is implemented before crop planting.

[0014] Preferably, the crop is corn.

[0015] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for improving the ecological environment of saline-alkali land and its application, which has the following beneficial effects:

[0016] The method of the present invention achieves the purposes of improving soil structure, increasing soil organic matter, reducing salinity and alkalinity, and increasing soil microbial activity by planting a specific plant combination, thereby providing a more suitable growth environment for subsequent corn crops and achieving the sustainable utilization and yield increase goals of saline-alkali land.

[0017] The plant combination and application method have the following characteristics:

[0018] Multifunctional plant combination: Comprehensively utilize the complementary effects of salt-alkali tolerant plants, organic matter increasing plants and disease prevention and growth promoting bacteria plants to achieve multiple improvements in soil structure, physical and chemical properties and biological activity.

[0019] Ecological restoration improvement: Through the action of plant roots, it can not only reduce the salinity and alkali content of the soil, but also increase the microbial activity of the soil, thereby promoting the ecological restoration of the soil.

[0020] Sustainable yield increase model: Under improved soil conditions, the growth of subsequent crops of corn shows higher salt tolerance, higher yield and higher quality, and has broad application potential. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] 1. Plant combination screening:

[0023] The test site is located at the Environmental Protection Institute base in Zhouzhuang Village, Meichang Town, Wuqing District, Tianjin (39°21′N, 117°12′E). The soil type is tidal soil with an organic matter content of 15.72 g / kg. The average annual precipitation is 550 mm. The moderate saline-alkali land of the base was selected as the test plot. The soil pH value is 8.55, the cation is mainly Na+, and the anion is mainly Cl - Mainly, the conductivity of soil extract is 860μs / cm.

[0024] Experimental treatment (the following ratios are seeding quality ratios):

[0025] CK0: no planting; CK1: planting alkaligrana; CK2: planting sesbania; CK3: planting alkaligrana; Treatment 1: planting oats; Treatment 2: planting alfalfa; Treatment 3: planting rapeseed; Treatment 4: planting a combination of oats and alfalfa (1:1); Treatment 5: planting a combination of oats and rapeseed (1:1); Treatment 6: planting alfalfa and rapeseed (1:1); Treatment 7: planting a combination of oats, alfalfa and rapeseed (1:1:1).

[0026] Plant cultivation:

[0027] The saline-alkali land was loosened in October 2020. Plants and combinations of each group were sown in rows with a 2 cm deep furrow and a row spacing of 20 cm. Water was sprinkled in small amounts and multiple times within 2 weeks after sowing to ensure seedling emergence.

[0028] Determination of soil salinity and alkali related indicators:

[0029] In May 2021, CK and the plants treated were crushed and pressed into a 20 cm soil layer. In June, soil samples were collected and brought back to the laboratory. The soil pH was measured according to the "Potential Method for Determination of Soil pH" (HJ 962-2018), the soil conductivity was measured according to the "Electrode Method for Determination of Soil Conductivity" (HJ 802-2016), and the soil organic matter content was measured according to "Soil Testing Part 6: Determination of Soil Organic Matter" (NY / T1121.6-2006). The microbial biocarbon in the soil was determined with reference to the fumigation extraction method for determining soil microbial biomass (GB / T 39228-2020), the number of Bacillus subtilis in the soil was determined by using a Bacillus subtilis PCR detection and identification specific primer pair (CN 103409549A), the number of rhizobia in the soil was determined by using a phospholipid fatty acid biomarker and biomass measurement method of alfalfa root nodule (CN109752510A), and the number of Bacillus amyloliquefaciens in the soil was determined by using a primer pair detection method and application for specifically detecting Bacillus amyloliquefaciens TF28 (CN110079624B).

[0030] Synergistic coefficient of different previous crop combinations in improving soil salinity-related indicators:

[0031] Referring to the method of synergistic coefficient of pesticides by Sun Yunpei, the synergistic coefficient (CIC value) of plant combinations is calculated according to the following formula:

[0032] The plant combination (CM) includes oats A1, rapeseed A2 and alfalfa A3. Each plant has its own improvement effect on soil salinity-related indicators (the increased or decreased value compared with CK without planting). It is stipulated that the improvement index of A1 is the standard value of 100;

[0033] Improvement index of A2 = Improvement effect of A2 / Improvement effect of A1 × 100;

[0034] Improvement index of A3 = Improvement effect of A3 / Improvement effect of A1 × 100;

[0035] Actual improvement index of CM = Improvement effect of CM / Improvement effect of A1 × 100;

[0036] Theoretical improvement index of CM = Improvement index of A1 × Mass percentage of A1 in CM + Improvement index of A2 × Mass percentage of A2 in CM + Improvement index of A3 × Mass percentage of A3 in CM;

[0037] Synergistic coefficient CIC value = Actual improvement index of CM / Theoretical improvement index of CM × 100;

[0038] CIC ≥ 120 shows a synergistic effect; CIC ≤ 80 shows an antagonistic effect; 80 < CIC < 120 shows an additive effect.

[0039] Result analysis:

[0040] The results are shown in Table 1-2.

[0041] Table 1 Soil salinity-related indicators under different previous crop combinations

[0042]

[0043]

[0044] The results in Table 1 show that the pH values ​​of saline-alkali soils decreased after the previous crop was planted, and the effect order was treatment 7> treatment 4> treatment 2> CK2> treatment 6> CK3> treatment 1= treatment 5> CK1= treatment 3; the soil electrical conductivity decreased, and the effect order was treatment 7> treatment 4> treatment 6> treatment 2> CK2> CK3> CK1> treatment 5> treatment 1> treatment 3; the soil organic matter content increased, and the effect order was treatment 7> treatment 4> treatment 6> treatment 2> CK2> treatment 1> treatment 5> CK1> treatment 3> CK3; the soil microbial biocarbon content increased, and the effect order was treatment 7> treatment 6 >Treatment 2>Treatment 4>CK2>Treatment 1>Treatment 5>CK1>Treatment 3>CK3; the number of soil Bacillus subtilis increased, and the effect order was Treatment 7>Treatment 4>Treatment 1>Treatment 5>CK1>CK2>Treatment 2>Treatment 3>Treatment 6>CK3; the number of soil Rhizobia occasionally increased, and the effect order was Treatment 7>Treatment 2>Treatment 6>Treatment 4>CK2>CK1=CK3=Treatment 1=Treatment 3=Treatment 5; the number of soil Bacillus amyloliquefaciens increased, and the effect order was Treatment 7>Treatment 3>Treatment 6>Treatment 5>Treatment 2>Treatment 4>CK2>CK3>Treatment 1>CK1.

[0045] Table 2 Synergistic coefficients of different combinations of previous crops on improving soil salinity-related indicators

[0046]

[0047] The results in Table 2 show that, except for the rhizobium index, the synergistic coefficients of treatment 7 on the other five soil salinity-related indexes were all greater than 120. The combination of oats, alfalfa and rapeseed had a significant synergistic effect on the improvement of soil salinity-related indexes.

[0048] 2. Plant ratio test

[0049] In order to further improve the improvement effect of the best combination of oats, alfalfa and rapeseed on saline-alkali land related indicators, a ratio test of this plant combination was carried out.

[0050] Test site overview:

[0051] The test site is located at the Environmental Protection Institute base in Zhouzhuang Village, Meichang Town, Wuqing District, Tianjin (39°21′N, 117°12′E). The soil type is tidal soil with an organic matter content of 15.72 g / kg. The average annual precipitation is 550 mm. The moderate saline-alkali land of the base was selected as the test plot. The soil pH value is 8.55, the cation is mainly Na+, and the anion is mainly Cl - Mainly, the conductivity of soil extract is 860μs / cm.

[0052] A moderately saline-alkali land in the base that had not been tested was selected as the test plot. The soil pH was 8.50, and the cations were mainly Na + Mainly, the anion is Cl - Mainly, the conductivity of soil extract is 840μs / cm.

[0053] Experimental treatment (the following ratios are seeding quality ratios):

[0054] CK: not planted; Treatment 1: planted with oats; Treatment 2: planted with alfalfa; Treatment 3: planted with rapeseed; Treatment 4: combination of oats, alfalfa and rapeseed (1:1:1); Treatment 5: combination of oats, alfalfa and rapeseed (1:2:1); Treatment 6: combination of oats, alfalfa and rapeseed (1:3:1); Treatment 7: combination of oats, alfalfa and rapeseed (2:1:1); Treatment 8: combination of oats, alfalfa and rapeseed (1:1:2).

[0055] Plant cultivation:

[0056] Planting in October 2021, other operations are the same as above.

[0057] Determination of soil salinity and alkali related indicators:

[0058] In May 2022, CK and plants from each treatment were crushed and pressed into a 20-cm soil layer. In June, soil samples were collected and brought back to the laboratory. Other determination methods were the same as above.

[0059] The synergistic coefficient of planting different proportions of previous plants in improving soil salinity-related indicators is the same as above.

[0060] Result analysis:

[0061] The results are shown in Table 3-4.

[0062] Table 3 Soil salinity-related indicators under different plant ratios

[0063]

[0064] The results in Table 3 show that the pH value of saline-alkali soil decreased under the planting of different plant ratios in the previous crop, and the effect order was treatment 5 = treatment 6 > treatment 4 > treatment 8 > treatment 7 > treatment 2 > treatment 3 > treatment 1; the soil electrical conductivity decreased, and the effect order was treatment 5 > treatment 6 > treatment 8 > treatment 4 = treatment 7 > treatment 2 > treatment 3 > treatment 1; the soil organic matter content increased, and the effect order was treatment 5 > treatment 6 > treatment 4 > treatment 7 > treatment 8 > treatment 2 > treatment 1 > treatment 3; the soil microbial biocarbon content increased, and the effect order was treatment 5 > treatment 6 > treatment 4 > treatment 7 > treatment 8 > treatment 2 > treatment 1 > treatment 3; Treatment 5 > Treatment 6 > Treatment 4 > Treatment 7 > Treatment 8 > Treatment 2 > Treatment 1 > Treatment 3; the number of soil Bacillus subtilis increased, and the effect order was Treatment 5 > Treatment 7 > Treatment 6 > Treatment 4 > Treatment 8 > Treatment 2 > Treatment 1 > Treatment 3; the number of soil Rhizobia increased occasionally, and the effect order was Treatment 5 > Treatment 6 > Treatment 4 > Treatment 7 > Treatment 8 > Treatment 2 > Treatment 3 > Treatment 1; the number of soil Bacillus amyloliquefaciens increased, and the effect order was Treatment 5 > Treatment 2 > Treatment 6 > Treatment 2 > Treatment 7 = Treatment 8 > Treatment 1 = Treatment 3.

[0065] Table 4 Synergistic coefficients of different plant ratios for improving soil salinity-related indicators

[0066]

[0067] The results in Table 4 show that, except for the rhizobium index, the synergistic coefficients of treatment 5 for the improvement of the other five soil salinity-related indices were the largest and greater than 120. The combination of oats, alfalfa and rapeseed in a ratio of 1:2:1 had the strongest synergistic effect on the improvement of soil salinity-related indices.

[0068] III. Cost-effectiveness of planting patterns

[0069] The application value of the technical model of planting a combination of oats, alfalfa and rapeseed (ratio 1:2:1) as the previous crop and corn as the subsequent crop in saline-alkali land was further verified.

[0070] The test site is located at the Environmental Protection Institute base in Zhouzhuang Village, Meichang Town, Wuqing District, Tianjin (39°21′N, 117°12′E). The soil type is tidal soil with an organic matter content of 15.72 g / kg. The average annual precipitation is 550 mm. The moderate saline-alkali land of the base was selected as the test plot. The soil pH value is 8.55, the cation is mainly Na+, and the anion is mainly Cl - Mainly, the conductivity of soil extract is 860μs / cm.

[0071] A moderately saline-alkali land in the base that had not been tested was selected as the test plot. The soil pH value was 8.51, and the cations were mainly Na + Mainly, the anion is Cl -Mainly, the conductivity of soil extract is 845μs / cm.

[0072] Experimental treatment (the following ratios are seeding quality ratios):

[0073] CK: no previous crop; Treatment 1: Puccinellia sinensis planted in the previous crop; Treatment 2: Sesbania sesbania planted in the previous crop; Treatment 3: Suaeda salsa planted in the previous crop; Treatment 4: Oats, alfalfa and rapeseed combination (1:2:1) planted in the previous crop. The sowing rate of the previous crop was 4kg / mu.

[0074] Planting will take place in October 2022, and other operations are the same as above.

[0075] Planting of corn in mid-June 2023. Apply 30kg of Stanley compound fertilizer per mu as base fertilizer. The density is 5000-6000 plants / mu, with a row spacing of 40cm+70cm and a narrow row configuration, and a plant spacing of 25cm. Irrigation should be carried out in time according to the weather and soil moisture conditions. Pre-seedling weeding is combined with post-seedling weeding, spraying with 50% acetochlor, and post-seedling weeding is carried out when the corn is 3-5 leaves. Harvest corn at full maturity and naturally air-dry and thresh to obtain kernels, then take the 100-kernel weight for yield measurement, and use the Botong DA7250 near-infrared analyzer to determine the protein content in the kernels.

[0076] Result analysis:

[0077] The results are shown in Table 5.

[0078] Table 5 Cost-effectiveness analysis of different planting patterns

[0079]

[0080] The results in Table 5 show that the technical model of the present invention significantly increases the yield and quality of subsequent corn crops. Without considering the value improvement brought by quality, the economic benefit is 420 yuan / mu, which is 2.13 times higher than the control without previous crops, and 2.75, 1.1 and 3.67 times higher than the benefits of planting alkaligrana, sesbania and alkaligrana with the prior art.

[0081] In summary, the technical solution of the present invention has the following effects:

[0082] Soil improvement effect: The previous crop plant combination can effectively improve the soil structure and chemical properties of saline-alkali land, reduce the salt content in the soil, reduce the alkalinity of the soil, and make the soil suitable for crop growth.

[0083] Improved microbial activity: The root system of the previous crop plants increases the beneficial microorganisms in the soil, and the endophytes from the straw pressed into the soil improve the soil's ecological environment, helping to enhance the soil's disease resistance and stress resistance.

[0084] Increased corn yield and improved quality: Due to soil improvement, subsequent corn crops can grow in a more suitable soil environment, showing stronger stress resistance. The crop grows well, with both yield and quality improved.

[0085] In general, this technology not only effectively improved saline-alkali soil and protected farmland biodiversity, but also brought economic benefits of 420 yuan per mu, which were 2.75, 1.1 and 3.67 times higher than existing technologies respectively.

[0086] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the ecological environment of saline-alkali land, characterized in that: The following steps are involved: Plant a mixture of grasses, legumes and crucifers in the land to be improved.

2. The method for improving saline-alkali land ecology according to claim 1, characterized in that: The sowing mass ratio of the grass plants, leguminous plants and cruciferous plants is 1:2:

1.

3. A saline-alkali land ecological improvement method according to claim 1 or 2, characterized in that: The grass plant is oat, the leguminous plant is alfalfa, and the cruciferous plant is rapeseed.

4. Use of the method according to any one of claims 1 to 3 in a crop planting field.

5. The use according to claim 4, characterized in that: The method is implemented before the crop is planted.

6. The use according to claim 4 or 5, characterized in that: The crop is corn.

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