Regulation and control method for recarburization and nitrogen fixation of newly-reclaimed desertification saline-alkali soil

Abstract

The invention discloses a regulation and control method for recarburization and nitrogen fixation of newly-reclaimed desertification saline-alkali soil, which is characterized in that the soil microenvironment is improved by combined application of bio-organic fertilizer / charcoal and attapulgite fertilizer, and nitrogen fixation of soil in a growth period and improvement of a soil structure are realized by mixed sowing of gramineous green manure crops and leguminous green manure crops. And after the growth period ends, returning the green manure to the field to realize soil recarburization. According to the recarburization and nitrogen fixation regulation and control method for the newly-reclaimed desertification saline-alkali wasteland, the soil nutrient and carbon reserve can be remarkably improved, and compared with other green manure crops or combinations, the total nitrogen and organic carbon of the soil are remarkably improved after the method is implemented. Therefore, the method has important significance on recarburization, nitrogen fixation and fertilization regulation and control of newly-reclaimed desertification saline-alkali soil, and can provide a development idea for efficient development and utilization of saline-alkali sand and guarantee of agricultural production safety.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and in particular to a method for regulating and controlling carbon and nitrogen fixation in newly reclaimed desertified saline-alkali land. Background Art

[0002] The poor soil, desertification and salinization of newly reclaimed oases will inhibit the growth of crop roots, hinder the supply of water and nutrients to crops, lead to slower crop photosynthesis, low water and fertilizer utilization efficiency and productivity, and seriously restrict regional food production and sustainable agricultural development.

[0003] Uncultivated saline-alkali land can be used as reserve arable land and is an important strategic reserve resource to ensure national food security. Carrying out carbon and nitrogen fixation and fertilization regulation on newly reclaimed desertified saline-alkali wasteland, and carrying out saline-alkali land improvement and comprehensive utilization are of great strategic significance to ensure national food security. However, there is no research on the improvement of newly reclaimed desertified saline-alkali land.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for regulating carbon increase and nitrogen fixation in newly reclaimed desertified saline-alkali land, which can improve the problems of high soil salinity, low fertility, low crop emergence rate, and difficulty in growth and development in newly reclaimed desertified saline-alkali wasteland, realize carbon increase and nitrogen fixation fertilization in newly reclaimed desertified saline-alkali land, improve the utilization rate of saline-alkali wasteland, and ensure sustainable agricultural development.

[0006] Newly reclaimed desertified saline-alkali land is saline-alkali land that has not yet been developed and utilized. Compared with saline-alkali land, newly reclaimed desertified saline-alkali land has more prominent problems in soil structure, biological activity, carbon and nitrogen reserves, nutrient content, and degree of barrenness. These problems combined have greatly increased the difficulty of planting, and a lot of time, energy and resources need to be invested in improvement before normal planting can be achieved.

[0007] In terms of soil structure, the soil particles of newly reclaimed sandy saline-alkali land are coarse, sandy, loose, with many large pores and few capillary pores, and the ability to retain water and fertilizer is extremely poor. At the same time, salinization causes soil colloids to disperse and compact. This poor soil physical structure makes it difficult for plants to take root firmly, and the roots cannot effectively absorb water and nutrients. In addition, the soil has poor ventilation and water permeability, which affects the respiration of plant roots and brings great difficulties to planting. Compared with saline-alkali land, its soil structure is more serious in hindering crop planting.

[0008] In terms of biological activity, due to the harsh soil conditions (high salinity, desertification, barrenness, etc.), only a very small number of salt-alkali and drought-tolerant microorganisms can survive, and the soil biological activity is extremely low, which leads to the lack of sufficient microorganisms in the soil of newly reclaimed desertified saline-alkali land to participate in key processes such as organic matter decomposition and nutrient conversion, making it difficult to effectively release nutrients in the soil for plant absorption. The supply of nutrients required for plant growth is seriously insufficient, increasing the difficulty of planting. Compared with saline-alkali land, it has a greater inhibitory effect on biological activity.

[0009] In terms of soil carbon and nitrogen reserves, newly reclaimed desertified saline-alkali wasteland has a scarce vegetation, a lack of organic carbon sources in the soil, extremely low soil organic matter content, and a small soil carbon pool capacity. Low nitrogen input and low microbial activity make it difficult to effectively mineralize organic nitrogen, resulting in extremely low effective nitrogen content in the soil. Plant growth cannot be separated from an adequate supply of carbon and nitrogen, and the severely insufficient carbon and nitrogen reserves in wasteland cannot meet the needs of normal plant growth, making planting a huge challenge. Compared with saline-alkali land, its carbon and nitrogen supply has more prominent restrictions on planting.

[0010] In terms of nutrient content, in addition to the lack of carbon and nitrogen, the newly reclaimed desertified saline-alkali wasteland also has very low content of other macroelements (such as nitrogen, phosphorus, potassium, etc.) and trace elements (such as iron, manganese, zinc, etc.). The nutrient circulation and replenishment mechanism in the soil is imperfect and cannot meet the needs of plant growth. Plants growing in such extremely nutrient-deficient soil are prone to malnutrition, slow growth, or even death, which greatly increases the difficulty of planting.

[0011] In terms of barrenness, due to extreme barrenness, poor soil structure, low biological activity, and low carbon, nitrogen and nutrient reserves, these factors are not conducive to plant growth. Long-term and comprehensive improvement measures are needed to improve soil fertility and gradually get rid of the barren state to adapt to crop planting. Before effective improvement, it is almost impossible to successfully plant crops directly on newly reclaimed desertified saline-alkali wasteland, which is the core difficulty of its planting.

[0012] In view of the above reasons, the present invention proposes for the first time to combine exogenous organic matter with diversified planting in order to improve newly reclaimed desertified saline-alkali wasteland and make it usable for crop planting. Through the niche complementarity effect and interspecific promotion effect of biological nitrogen fixation of leguminous crops and soil nitrogen utilization of gramineous crops, the above method not only has the effect of enhancing farmland biodiversity, promoting fertilizer utilization efficiency and land utilization efficiency and other farmland ecological functions, but also can improve soil aggregate structure and organic carbon fixation effect. Returning green manure crops to the field during the non-reproductive period combined with organic fertilizer as an exogenous organic material input for newly reclaimed desertified saline-alkali soil can effectively promote the accumulation of soil organic carbon pools in farmland ecosystems. Soil organic carbon is the core element to ensure crop yield and its stability. It can affect crop nutrient utilization by regulating the soil carbon and nitrogen cycle, and also plays a positive role in enhancing soil microbial activity and improving soil physical and chemical properties.

[0013] Specifically, the present invention proposes a method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali land, which comprises the following steps:

[0014] S1. Level the saline-alkali wasteland and clear away large stones, plastics, etc.

[0015] S2. Use mixed fertilizers and apply them together before tilling the land.

[0016] The mixed fertilizer is selected from at least two of bio-organic fertilizer, biochar and attapulgite fertilizer. Specifically, the bio-organic fertilizer can be sheep manure, or other animal manure, such as cow manure, pig manure and horse manure; or it can be a composite bio-fertilizer containing two or more single bio-organic fertilizers.

[0017] In some embodiments, the application amount of attapulgite fertilizer in the mixed fertilizer is 100 kg / mu, and the application amount of biological organic fertilizer is 2.5-3 m 3 / mu, the biochar application rate is 800-1000kg / mu.

[0018] The present invention applies the bio-organic fertilizer / biochar and attapulgite fertilizer in combination in order to improve the soil microenvironment, thereby increasing the biological activity and providing a more suitable growth environment for crop planting.

[0019] In some embodiments, the tillage depth after applying the mixed fertilizer is 15-25 cm.

[0020] S3. Apply base fertilizer after the spring thawing period and till the farmland after the first spring irrigation.

[0021] Among them, the basal fertilizer includes nitrogen fertilizer and phosphate fertilizer. Specifically, the nitrogen fertilizer can be amide nitrogen fertilizer, such as urea; it can also be other types of nitrogen fertilizers, such as ammonium nitrogen fertilizer, ammonia nitrogen fertilizer, nitrate nitrogen fertilizer, ammonium nitrate nitrogen fertilizer and ammonium bicarbonate. The phosphate fertilizer can be superphosphate or other types of phosphate fertilizers, such as double superphosphate, monoammonium phosphate, diammonium phosphate and compound fertilizer.

[0022] In some embodiments, the application amount of nitrogen fertilizer is 5-10 kg / mu, and the application amount of phosphorus fertilizer is 3-5 kg / mu.

[0023] In some embodiments, the first spring irrigation is flooded with 100-150 m 3 / mu.

[0024] S4. Test the test forage grass seeds before sowing.

[0025] In some embodiments, the forage seeds are mainly tested for purity and germination rate. Preferably, seeds with purity and germination rate both above 95% are selected for use.

[0026] S5. Mix green manure crops.

[0027] In the present invention, the green manure crops include gramineous green manure crops and leguminous green manure crops. Specifically, the gramineous green manure crops include oats, and the leguminous green manure crops include hairy vetch and arrow pea.

[0028] Green manure crops are crops that provide fertilizer sources for crops and fertilize the soil. There are many types of green manure crops, mainly leguminous crops, such as astragalus, alfalfa, sweet clover, tamarind, sesbania, broad bean, hairy vetch, and Amorpha fruticosa; non-leguminous crops include radish, buckwheat, and various aquatic green manures. After a certain period of growth, the green stems and leaves of green manure crops are cut off and directly turned into the soil, which can save manpower and reduce transportation costs, and can also be fermented to make soil fertilizer for application. Green manure contains a variety of nutrients and a large amount of organic matter, which can improve soil structure, promote soil maturation, and enhance soil fertility.

[0029] Although there are many types of green manure crops, it was found in the study that it is difficult for glossy purple vetch to take root and grow in sandy soil, and its tolerance to salt and alkali is limited; alfalfa is a perennial crop that requires a large amount of water during its growth process and is extremely sensitive to drought, and its competitiveness is too strong under mixed sowing conditions; white clover has a shallow root system, poor drought tolerance, and difficulty in germination in harsh environments, and its effect on improving the soil in newly reclaimed desertified saline-alkali land is relatively limited. The present invention selects hairy vetch and arrow pea from leguminous green manure crops, and selects oats from gramineous green manure crops, and mixes these three crops of leguminous green manure crops and gramineous green manure crops, and finds that it has the best carbon and nitrogen fixation effect on newly reclaimed desertified saline-alkali land compared to other crops or combinations.

[0030] In some embodiments, the sowing rates of the three crops mixed are: 3-4 kg / mu of oats, 1-1.5 kg / mu of hairy vetch, and 2-3 kg / mu of broad beans.

[0031] Through the mixed sowing of the above green manure crops, soil nitrogen fixation and improvement of soil structure can be achieved during the growing period, and soil carbon can be increased by returning green manure to the fields after the growing period.

[0032] S6. Irrigation and fertilization management during the growing period.

[0033] Among them, micro-sprinkler irrigation is used, and irrigation is carried out three times at the seedling stage, bud stage, and flowering stage, with each irrigation volume of 30m 3 / mu; Fertilization management includes: topdressing at the early stage of flowering, the fertilizer is urea, and the application amount is 10-15kg / mu; irrigation is carried out on the same day to the next day after topdressing.

[0034] S7. After mowing, the straw will be decomposed and returned to the field.

[0035] The above green manure crops are mowed after the flowering period to prevent the seeds from falling after pod formation. The mowed straw is chopped into pieces with a length of ≤10cm and in a torn shape.

[0036] S8. Winter irrigation after ploughing.

[0037] After the straw is decomposed and returned to the field, ploughing is carried out with a ploughing depth of 10 to 20 cm; then the winter irrigation is carried out with a watering amount of 50 to 100 m 3 / mu.

[0038] The present invention has the following beneficial effects:

[0039] The present invention improves the soil microenvironment by the combined application of bio-organic fertilizer / biochar and attapulgite fertilizer, achieves soil nitrogen fixation and improves soil structure during the growth period by mixing gramineous green manure crops and leguminous green manure crops, and achieves soil carbon increase by returning green manure to the field after the growth period. The newly reclaimed desertified saline-alkali wasteland carbon increase and nitrogen fixation control method proposed in the present invention can significantly improve soil nutrients and carbon reserves. Compared with other green manure crops or combinations, the total nitrogen and organic carbon of the soil are significantly increased after the implementation of the method adopted by the present invention. Therefore, the present invention is of great significance for the regulation of carbon increase, nitrogen fixation and fertilization in newly reclaimed desertified saline-alkali land, and can provide a development idea for the efficient development and utilization of saline-alkali sandy land and the guarantee of agricultural production safety. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0041] The present invention is further described below by means of specific examples. However, it should be understood that these examples are only used for more detailed description and should not be construed as limiting the present invention in any form.

[0042] Example 1

[0043] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland, comprising the following steps:

[0044] (1) Use a land grader to level the saline-alkali wasteland (desert oasis area in Zhangye City, Gansu Province) to be reclaimed, and clear away large stones and plastics that affect farming;

[0045] (2) Apply 100 kg of attapulgite fertilizer and 800 kg of biochar per mu, spread evenly and use a tiller to plow the soil to a depth of 20 cm;

[0046] (3) After the spring thawing period, apply 10kg of urea and 5kg of superphosphate per mu as base fertilizer and flood 150m 3 , rotary tillage the farmland after the ground is dry;

[0047] (4) Before sowing, the purity and germination rate of the tested forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0048] (5) Mixed sowing of oat seeds 3 kg / mu, hairy vetch seeds 1 kg / mu, and arrow pea seeds 2 kg / mu;

[0049] (6) Micro-sprinkler irrigation is used during the growth period, and irrigation is carried out at the seedling stage, bud stage, and bud stage respectively; topdressing is carried out at the early flowering stage, and urea is used at an application rate of 15 kg / mu; irrigation is carried out on the same day to the next day after topdressing, and the water consumption for each irrigation is 30 m3. 3 / mu.

[0050] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0051] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 100m 3 / mu.

[0052] Example 2

[0053] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland, comprising the following steps:

[0054] (1) Use a land grader to level the saline-alkali wasteland to be reclaimed and remove large stones and plastics that affect farming;

[0055] (2) Apply 100 kg of attapulgite fertilizer and 2.5 m3 of 3 Sheep manure, evenly spread and plowed with a tiller to a soil depth of 20 cm;

[0056] (3) After the spring thawing period, apply 10kg of urea and 3kg of superphosphate per mu as base fertilizer and flood 150m 3 , rotary tillage the farmland after the ground is dry;

[0057] (4) Before sowing, the purity and germination rate of the test forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0058] (5) Mixed sowing of oat seeds 3 kg / mu, hairy vetch seeds 1 kg / mu, and arrow pea seeds 2 kg / mu;

[0059] (6) Micro-sprinkler irrigation is used during the growth period, and irrigation is carried out at the seedling stage, bud stage, and bud stage. Topdressing is carried out at the early flowering stage, and urea is used at an application rate of 15 kg / mu. Irrigation is carried out on the same day to the next day after topdressing, and the water consumption for each irrigation is 30 m3. 3 / mu.

[0060] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0061] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 100m 3 / mu.

[0062] Example 3

[0063] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland comprises the following steps:

[0064] (1) Use a land grader to level the saline-alkali wasteland to be reclaimed and remove large stones and plastics that affect farming;

[0065] (2) Apply 100 kg of attapulgite fertilizer and 800 kg of biochar per mu, spread evenly, and use a tiller to plow the soil to a depth of 20 cm;

[0066] (3) After the spring thawing period, apply 10kg of urea and 5kg of superphosphate per mu as base fertilizer and flood 150m 3 , rotary tillage the farmland after the ground is dry;

[0067] (4) Before sowing, the purity and germination rate of the test forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0068] (5) Mixed sowing of oat seeds at 4 kg / mu, hairy vetch seeds at 1.5 kg / mu, and arrowroot pea seeds at 3 kg / mu;

[0069] (6) Micro-sprinkler irrigation is used during the growth period, and irrigation is carried out at the seedling stage, bud stage, and bud stage. Topdressing is carried out at the early flowering stage, and urea is used at an application rate of 15 kg / mu. Irrigation is carried out on the same day to the next day after topdressing, and the water consumption for each irrigation is 30 m3. 3 / mu.

[0070] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0071] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 100m 3 / mu.

[0072] Comparative Example 1

[0073] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland comprises the following steps:

[0074] (1) Use a land grader to level the saline-alkali wasteland to be reclaimed and remove large stones and plastics that affect farming;

[0075] (2) Apply 100 kg of attapulgite fertilizer and 2.5 m3 of 3 Sheep manure, evenly spread and plowed with a tiller to a soil depth of 20 cm;

[0076] (3) After the spring thawing period, apply 5kg of urea and 3kg of superphosphate per mu as base fertilizer and flood 100m 3 / mu, and rotary till the farmland after the ground is dry;

[0077] (4) Before sowing, the purity and germination rate of the test forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0078] (5) Mixed sowing of oat seeds 3.5 kg / mu and pea seeds 3 kg / mu;

[0079] (6) Micro-sprinkler irrigation is used during the growth period, with irrigation at the seedling stage, bud stage, and germination stage respectively; topdressing is carried out at the early flowering stage, with urea selected at an application rate of 10 kg / mu; irrigation is carried out on the same day or the next day after topdressing, with a water consumption of 30 m3 / mu each time for three irrigations.

[0080] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0081] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 50m 3 / mu.

[0082] Comparative Example 2

[0083] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland, comprising the following steps:

[0084] (1) Use a land grader to level the saline-alkali wasteland to be reclaimed and remove large stones and plastics that affect farming;

[0085] (2) Apply 100kg of attapulgite fertilizer and 3m per mu 3 Sheep manure, evenly spread and plowed with a tiller to a soil depth of 20 cm;

[0086] (3) After the spring thawing period, apply 10kg of urea and 5kg of superphosphate per mu as base fertilizer and flood 150m 3 / mu, and rotary till the farmland after the ground is dry;

[0087] (4) Before sowing, the purity and germination rate of the tested forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0088] (5) Mixed sowing of hairy vetch seeds at 1.5 kg / mu and arrow pea seeds at 3 kg / mu;

[0089] (6) Micro-sprinkler irrigation is used during the growth period, and irrigation is carried out at the seedling stage, bud stage, and bud stage respectively; topdressing is carried out at the early flowering stage, and urea is used at an application rate of 15 kg / mu; irrigation is carried out on the same day to the next day after topdressing, and the water consumption for each irrigation is 30 m3. 3 / mu.

[0090] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0091] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 100m 3 / mu.

[0092] Comparative Example 3

[0093] A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali wasteland, comprising the following steps:

[0094] (1) Use a land grader to level the saline-alkali wasteland to be reclaimed and remove large stones and plastics that affect farming;

[0095] (2) Apply 100 kg of attapulgite fertilizer and 1000 kg of biochar per mu, spread evenly, and use a tiller to plow the soil to a depth of 20 cm;

[0096] (3) After the spring thawing period, apply 10 kg of urea and 5 kg of superphosphate per mu as basal fertilizer, flood 100 m3 / mu, and rotary till the farmland after the ground is dry;

[0097] (4) Before sowing, the purity and germination rate of the test forage grass seeds shall be tested in accordance with GB / T 2930.2 and GB / T 2930.4 to ensure that they are both above 95%;

[0098] (5) Mixed sowing of hairy vetch seeds at 3 kg / mu and arrow pea seeds at 1.5 kg / mu;

[0099] (6) Micro-sprinkler irrigation is used during the growth period, and irrigation is carried out at the seedling stage, bud stage, and bud stage. Topdressing is carried out at the early flowering stage, and urea is used at an application rate of 15 kg / mu. Irrigation is carried out on the same day to the next day after topdressing, and the water consumption for each irrigation is 30 m3. 3 / mu.

[0100] (7) Mowing should be carried out after the flowering period, and the mowed straw should be chopped into torn pieces ≤ 10 cm. After decomposition, the soil should be plowed to a soil depth of 20 cm around December 20.

[0101] (8) Winter irrigation should be carried out within 3 days of tillage, with a water volume of 50m 3 / mu.

[0102] Comparative Example 4

[0103] The difference from Comparative Example 2 is that the planting method of the green manure crop in this comparative example is single sowing of oats.

[0104] Comparative Example 5

[0105] The difference from Comparative Example 2 is that the planting method of the green manure crop in this comparative example is single sowing of pea.

[0106] Comparative Example 6

[0107] The difference from Comparative Example 3 is that the planting method of the green manure crop in this comparative example is single sowing of hairy vetch.

[0108] Comparative Example 7

[0109] Blank newly reclaimed desertified saline-alkali land without sowing.

[0110] Comparative Example 8

[0111] The difference from Comparative Example 1 is that the green manure crop of this comparative example is planted in a manner that white clover replaces sagittaceous pea.

[0112] Comparative Example 9

[0113] The difference from Comparative Example 2 is that the green manure crop in this comparative example is planted in the form of white clover instead of hairy vetch.

[0114] Comparative Example 10

[0115] The difference from Comparative Example 1 is that the green manure crop in this comparative example is planted in the form of ryegrass instead of oats.

[0116] Experimental example

[0117] After the newly reclaimed desertified saline-alkali land was regulated according to the methods of the embodiments and comparative examples, the total nitrogen and organic carbon of the 0-20 cm soil were detected. The detection methods were all conventional methods in the art. The improvement effects on soil carbon increase and nitrogen fixation are shown in Table 1:

[0118] Table 1 Total nitrogen and organic carbon content of soil in the examples and comparative examples

[0119]

[0120]

[0121] From the results in Table 1, it can be seen that the combination of different green manure crops has a significant difference in the improvement effect on the newly reclaimed desertified saline-alkali land. At the same time, it can be shown that compared with the comparative example, the mixed sowing of leguminous green manure crops and gramineous green manure crops used in the present invention, especially the mixed sowing of oats, hairy vetch and arrow pea, can more effectively increase soil total nitrogen and soil organic carbon. The effect of increasing carbon and fixing nitrogen is significant, and the soil fertility of desertified saline-alkali land is significantly improved.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for regulating carbon and nitrogen fixation in newly reclaimed desertified saline-alkali land, characterized in that: include: Apply exogenous organic matter and soil improving fertilizers on newly reclaimed desertified saline-alkali land, and mix green manure crops of gramineous and leguminous families.

2. The control method according to claim 1, characterized in that: The gramineous green manure crops include oats; the leguminous green manure crops include hairy vetch and arrow pea.

3. The control method according to claim 2, characterized in that: The sowing amount of the mixed sowing is: 3-4 kg / mu of oats, 1-1.5 kg / mu of hairy vetch, and 2-3 kg / mu of arrowroot peas.

4. The control method according to claim 1, characterized in that: The exogenous organic matter includes bio-organic fertilizer and biochar; the soil improving fertilizer is attapulgite fertilizer; The combined application amount of the exogenous organic matter and soil improvement fertilizer is: 2.5-3m3 of biological organic fertilizer 3 / mu, biochar 800-1000kg / mu, attapulgite fertilizer 100kg / mu.

5. The control method according to claim 1, characterized in that: Before the grass green manure crop and leguminous green manure crop are mixed, the exogenous organic matter and soil improvement fertilizer are applied to the newly reclaimed desertified saline-alkali land and then the land is ploughed; after the spring ablation period, base fertilizer is applied, and after the first spring irrigation, the newly reclaimed desertified saline-alkali land is rotary tilled; The basal fertilizer includes nitrogen fertilizer and phosphorus fertilizer.

6. The control method according to claim 5, characterized in that: The nitrogen fertilizer includes urea, and the phosphorus fertilizer includes superphosphate; the application amount of the nitrogen fertilizer is 5-10 kg / mu, and the application amount of the phosphorus fertilizer is 3-5 kg / mu.

7. The control method according to claim 5, characterized in that: The first spring irrigation adopts flood irrigation, with an irrigation volume of 100-150m 3 / mu.

8. The control method according to claim 5, characterized in that: The control method also includes irrigation and fertilization management of green manure crops in the growth period; The irrigation adopts micro-sprinkler irrigation, which is carried out three times at the seedling stage, bud stage and flowering stage, with each irrigation volume of 30m 3 / mu; The fertilization management includes: applying top dressing in the early flowering stage, the fertilizer is urea, and the application amount is 10-15 kg / mu; and irrigating on the same day or the next day after the top dressing.

9. The control method according to claim 8, characterized in that: The control method also includes mowing the green manure crop after its peak flowering period, and chopping the straw into pieces and returning it to the field after composting; The chopped straw has a length of ≤10 cm and is in a torn shape.

10. The control method according to claim 9, characterized in that: The control method also includes ploughing and winter irrigation after returning the soil to the field; The tillage depth is 10-20 cm; the winter irrigation water volume is 50-100 m 3 / mu.

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