Planting method for soil recarburization and fertility improvement of slight saline-alkali soil

Abstract

The invention relates to the technical field of soil improvement, in particular to a planting method for soil recarburization and fertilization of slight saline-alkali soil, and solves the problems that the existing saline-alkali soil is low in organic matter content and low in productivity, the recarburization and fertilization effect on the saline-alkali soil is poor, the cost is high, and straw is not fully utilized easily in an industrial compound fertilizer applying mode. The method is used for recarburizing and fertilizing soil of the slight saline-alkali land for planting wheat and corn, and comprises four returning modes of CK, T1, T2 and T3. The CK is a conventional organic-free material returning mode, specifically a wheat and corn rotation planting mode; t1 is a corn straw smashing and returning mode, and particularly is a wheat and corn rotation planting mode. According to the method, wheat, corn and soybean diversified planting and straw returning in different modes are carried out on the saline-alkali soil, the usage amount of industrial compound fertilizer can be effectively reduced, the planting cost is reduced, and recarburization and fertilization can be conveniently carried out on the saline-alkali soil.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a planting method for increasing carbon and fertilizing soil in slightly saline-alkali land. Background Art

[0002] my country has a large amount of agricultural waste and rich resources. The irrational use of agricultural waste will not only cause resource waste, but also pollute the environment. Crop straw is a huge byproduct of agricultural production. Fully utilizing the potential of straw resources is of great significance to promoting the sustainable development of agriculture. Returning organic materials such as straw to the field is a common and widely used agricultural management measure, which is often used to increase soil organic carbon fixation;

[0003] Returning organic materials to saline-alkali land can increase soil carbon sequestration and improve soil quality, which plays an important role in improving the productivity of saline-alkali arable land. Saline-alkali land is an important reserve strategic arable land resource in my country, and has played an extremely important role in ensuring national food security and expanding arable land resources.

[0004] The existing saline-alkali land has low organic matter content and low production capacity. The effect of carbon-enhancing and fertilizing the saline-alkali land by applying industrial compound fertilizer is poor, the cost is high, and it is not conducive to the full utilization of straw. Therefore, it does not meet the existing needs. In this regard, we propose a planting method for carbon-enhancing and fertilizing mild saline-alkali land. Summary of the invention

[0005] The object of the present invention is to provide a planting method for carbon-enhancing and fertilizing mildly saline-alkali soil, so as to solve the problems raised in the above background technology that the existing saline-alkali soil has low organic matter content and low production capacity, and the carbon-enhancing and fertilizing effect of the saline-alkali land by applying industrial compound fertilizers is poor, the cost is high, and it is not conducive to the full utilization of straw.

[0006] To achieve the above object, the present invention provides the following technical solutions: a planting method for carbon-enhancing and fertilizing mild saline-alkali soil, which is used for carbon-enhancing and fertilizing mild saline-alkali soil for planting wheat, corn and soybeans, and the planting method for carbon-enhancing and fertilizing mild saline-alkali soil includes four field return treatment methods of CK, T1, T2 and T3;

[0007] The CK is a conventional non-organic material return to the field mode, specifically a wheat-corn rotation planting mode;

[0008] T1 is a corn straw crushing and returning mode, specifically a wheat-corn rotation planting mode;

[0009] The T2 is a corn straw biochar returning mode, specifically a wheat-corn rotation planting mode;

[0010] The T3 is a corn and soybean straw biochar return model, specifically an intercropping model of wheat, corn and soybeans;

[0011] The planting method for carbon enhancement and fertilization of slightly saline-alkali soil comprises the following steps:

[0012] S1: Four field positioning test areas were determined according to the return of organic materials to the field and the planting mode, and the effects of different farmland management modes on crop yield, soil organic carbon fixation, soil nutrients and enzyme activity of wheat, corn and soybean were studied respectively. The four field positioning test areas were specifically divided into four field return treatments: CK, T1, T2 and T3. When the field positioning test area in CK was tested, the straw was removed from the field, and rotary tillage, wheat sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land wheat in the wheat season were applied, and the field was compacted with a roller after sowing. Wintering water was applied before the wheat overwintered, and urea was applied during the jointing period. After the wheat was harvested, the wheat straw was crushed and returned to the field, corn was sown with a no-till planter, seeds and fertilizers were sown at the same time, and nitro-compound fertilizers specially used for saline-alkali land corn in the corn season were applied. No topdressing or irrigation was done during the entire growth period of corn.

[0013] S2: When conducting the field positioning test area in T1, after corn is harvested with a combine harvester, corn stalks are crushed and returned to the field, land is tilled and prepared, wheat is sown with seeds and fertilizers, nitro compound fertilizers specially used for wheat in saline-alkali land in the wheat season are applied, and the field is compacted with a roller after sowing. Wintering water is applied before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro compound fertilizers specially used for corn in saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of corn.

[0014] S3: When conducting the field positioning test area in T2, after the corn is harvested with a combine harvester, the corn stalks are removed from the plots, biochar burned from the previous season's corn stalks is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land in the wheat season are applied, and the wheat is compacted with a roller after sowing. Wintering water is irrigated before the wheat overwintering and urea is applied during the jointing period. After the wheat is harvested, the wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro-compound fertilizers specially used for saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of the corn.

[0015] S4: When conducting the field positioning test area in T3, after corn and soybeans are harvested with a combine harvester, the corn and soybean straws are removed from the plots, biochar burned from the corn and soybean straws of the previous season is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, and nitro compound fertilizers for wheat in saline-alkali land in the wheat season are applied, and the fields are compacted with a roller after sowing. Wintering water is irrigated before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, the wheat straw is crushed and returned to the field and the intercropping pattern of corn and soybeans is converted. Corn and soybeans are sown with a no-till seeder, and then nitro compound fertilizers for corn in saline-alkali land in the corn season and nitro compound fertilizers for soybeans in saline-alkali land in the soybean season are applied. In the intercropping pattern, corn and soybeans are rotated every year, and no topdressing or irrigation is done during the entire growth period of corn and soybeans;

[0016] S5: The four field return treatments of CK, T1, T2 and T3 were repeated three times. After the repeated treatments in the four field test areas were completed, the soil was sampled, and the soil nutrient content and enzyme activity of the saline-alkali land were measured and analyzed.

[0017] Preferably, the rotary tillage depth in the CK, T1, T2 and T3 is 15 cm, the wheat sowing amount is 15 kg / mu, the wheat variety is Jimai 44, and the application amount of the special nitro compound fertilizer for wheat in saline-alkali land in the wheat season is 50 kg.

[0018] Preferably, the components and mass percentages of the nitro compound fertilizer for wheat in saline-alkali land during the wheat season are: N16%; P20520%; K205%, and the winter water irrigation amount in CK, T1, T2 and T3 is 40-60m 3 / mu, the topdressing amount of urea is 16kg / mu.

[0019] Preferably, the corn variety in CK, T1, T2 and T3 is Denghai 605, the corn planting density is 67,500 plants / hm, the application amount of the special nitro compound fertilizer for corn in saline-alkali land applied in the corn season is 50 kg, and the components and mass percentages of the special nitro compound fertilizer for corn in saline-alkali land applied in the corn season are: N28%; P2O510%; K2O13%.

[0020] Preferably, the biochar in T2 is made by burning corn stalks in saline-alkali land, and the application amount of the biochar is converted with the carbon amount of corn stalks harvested in the previous season. The components and mass percentages of the biochar are: C 39.7%; N 1.44%; P 0.20%; K 3.65%.

[0021] Preferably, the biochar in T3 is made by burning corn and soybean straw in saline-alkali land, and the application amount of the biochar is converted into an equal amount of carbon content in the corn and soybean straw harvested in the previous season. The components and mass percentages of the biochar are: C40.5%; N1.57%; P0.19%; K3.48%.

[0022] Preferably, the soybean variety in T3 is Qihuang 34, the planting density of the soybeans is 225,000 plants / hm, the application amount of the nitro-compound fertilizer specifically for soybeans in saline-alkali land in the soybean season is 50 kg, and the nitro-compound fertilizer specifically for soybeans in saline-alkali land in the soybean season contains 12% N, 18% P2O5, and 15% K2O.

[0023] Preferably, the width of the corn and soybean strips in the intercropping pattern is 480 cm, each strip includes four rows of corn strips with a width of 240 cm and four rows of soybean strips with a width of 240 cm, and the row spacing between the corn and soybeans is 60 cm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention determines four field positioning test areas according to the return of organic materials to the field and the planting mode, and studies the effects of wheat, corn and soybean planting under the four farmland management modes on crop yield, soil organic carbon fixation, soil nutrients and enzyme activity, etc., and distinguishes the diversified planting of wheat, corn and soybean and the different ways of returning straw to the field under the premise of controlling the same factors of the four farmland management modes, so as to ensure effective comparability between the soils of the four test areas, realize the selection of methods for carbon enhancement and fertilization of mild saline-alkali soil, reduce the difficulty and cost of planting in saline-alkali land, and improve planting yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the comparison of wheat yield in the experiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the comparison of the yield of corn in the experiment of the present invention;

[0028] Figure 3 It is a schematic parameter diagram of the effect of the test of the present invention on soil quality;

[0029] Figure 4 It is a columnar comparison schematic diagram of the effect of the test of the present invention on peroxidase in soil;

[0030] Figure 5 It is a columnar comparison schematic diagram of the effect of the test of the present invention on polyphenol oxidase in soil;

[0031] Figure 6It is a bar chart comparison diagram of the effect of the test of the present invention on N-acetylglucosamine enzyme in soil;

[0032] Figure 7 It is a columnar comparison schematic diagram of the effect of the test of the present invention on β-glucosidase in soil;

[0033] Figure 8 The present invention is an overall flow chart. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] See also Figure 8 , an embodiment provided by the present invention: a planting method for carbon-enhancing and fertilizing mild saline-alkali soil, used for carbon-enhancing and fertilizing mild saline-alkali soil for planting wheat, corn and soybeans, and the planting method for carbon-enhancing and fertilizing mild saline-alkali soil includes four field return treatment methods of CK, T1, T2 and T3;

[0036] CK is the conventional mode without returning organic materials to the field, specifically the wheat-corn rotation planting mode;

[0037] T1 is the mode of crushing corn straw and returning it to the field, specifically the wheat-corn rotation planting mode;

[0038] T2 is the corn straw biochar return mode, specifically the wheat-corn rotation planting mode;

[0039] T3 is the corn and soybean straw biochar return model, specifically the intercropping model of wheat, corn and soybean;

[0040] The planting method for carbon enrichment and fertilization of slightly saline-alkali soil includes the following steps:

[0041] S1: Four field positioning test areas were determined according to the return of organic materials to the field and the planting mode, and the effects of different farmland management modes on crop yield, soil organic carbon fixation, soil nutrients and enzyme activity of wheat, corn and soybean were studied respectively. The four field positioning test areas were specifically divided into four field return treatments: CK, T1, T2 and T3. When the field positioning test area in CK was tested, the straw was removed from the field, and rotary tillage, wheat sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land wheat in the wheat season were applied, and the field was compacted with a roller after sowing. Wintering water was applied before the wheat overwintered, and urea was applied during the jointing period. After the wheat was harvested, the wheat straw was crushed and returned to the field, corn was sown with a no-till planter, seeds and fertilizers were sown at the same time, and nitro-compound fertilizers specially used for saline-alkali land corn in the corn season were applied. No topdressing or irrigation was done during the entire growth period of corn.

[0042] S2: When conducting the field positioning test area in T1, after corn is harvested with a combine harvester, corn stalks are crushed and returned to the field, land is tilled and prepared, wheat is sown with seeds and fertilizers, nitro compound fertilizers specially used for wheat in saline-alkali land in the wheat season are applied, and the field is compacted with a roller after sowing. Wintering water is applied before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro compound fertilizers specially used for corn in saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of corn.

[0043] S3: When conducting the field positioning test area in T2, after the corn is harvested with a combine harvester, the corn stalks are removed from the plots, biochar burned from the previous season's corn stalks is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land in the wheat season are applied, and the wheat is compacted with a roller after sowing. Wintering water is irrigated before the wheat overwintering and urea is applied during the jointing period. After the wheat is harvested, the wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro-compound fertilizers specially used for saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of the corn.

[0044] S4: When conducting the field positioning test area in T3, after corn and soybeans are harvested with a combine harvester, the corn and soybean straws are removed from the plots, biochar burned from the corn and soybean straws of the previous season is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, and nitro compound fertilizers for wheat in saline-alkali land in the wheat season are applied, and the fields are compacted with a roller after sowing. Wintering water is irrigated before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, the wheat straw is crushed and returned to the field and the intercropping pattern of corn and soybeans is converted. Corn and soybeans are sown with a no-till seeder, and then nitro compound fertilizers for corn in saline-alkali land in the corn season and nitro compound fertilizers for soybeans in saline-alkali land in the soybean season are applied. In the intercropping pattern, corn and soybeans are rotated every year, and no topdressing or irrigation is done during the entire growth period of corn and soybeans;

[0045] S5: The four field return treatments of CK, T1, T2 and T3 were repeated three times. After the repeated treatments in the four field test areas were completed, the soil was sampled, and the soil nutrient content and enzyme activity of the saline-alkali land were measured and analyzed.

[0046] The rotary tillage depth in CK, T1, T2 and T3 was set to 15 cm, the wheat sowing rate was 15 kg / mu, the wheat variety was Jimai 44, the application rate of nitro compound fertilizer for wheat in saline-alkali land during the wheat season was 50 kg, and the components and mass percentages of nitro compound fertilizer for wheat in saline-alkali land during the wheat season were: N16%; P20520%; K205%, and the winter water irrigation rate in CK, T1, T2 and T3 was 40-60 m 3 / mu, the topdressing rate of urea was 16kg / mu. By controlling the wheat planting parameters in the four modes in the same way, the experimental variables can be reduced.

[0047] The corn variety in CK, T1, T2 and T3 is Denghai 605, and the corn planting density is 67,500 plants / hm2. -2 The application amount of nitro-compound fertilizer for corn in saline-alkali land during the corn season is 50kg. The components and mass percentages of nitro-compound fertilizer for corn in saline-alkali land during the corn season are: N28%; P2O510%; K2O13%. The biochar in T2 is made by burning corn straw in saline-alkali land. The application amount of biochar is converted with the carbon amount of corn straw harvested in the previous season. The components and mass percentages of biochar are: C39.7%; N1.44%; P0.20%; K3.65%. The composition content of biochar is adjusted accordingly according to the changes in planting types, so as to facilitate the stability of experiments in different modes.

[0048] The biochar in T3 was made from corn and soybean straw in saline-alkali land. The amount of biochar applied was equivalent to the carbon content in the corn and soybean straw harvested in the previous season. The components and mass percentages of biochar were: C40.5%; N1.57%; P0.19%; K3.48%. The soybean variety in T3 was Qihuang 34, and the planting density of soybean was 225,000 plants / hm2. -2 , the application amount of nitro-compound fertilizer specially used for soybeans in saline-alkali land during soybean season is 50kg, the N12%; P2O518%; K2O15% of nitro-compound fertilizer specially used for soybeans in saline-alkali land during soybean season, the width of corn and soybean strips in intercropping pattern is 480cm, each strip includes four rows of corn strips with a width of 240cm and four rows of soybean strips with a width of 240cm, the row spacing between corn and soybeans is 60cm, by controlling the planting of corn and soybeans, the yield can be avoided from being affected by density.

[0049] See also Figure 1 , is a statistical comparison diagram of wheat yields obtained by the experiment completed by the above steps. In the previous year, the wheat yields in T2 and T3 were 16.3% and 19.2% higher than those in CK, respectively, while the wheat yield in T1 was no different from that in CK;

[0050] In the following year, the wheat yield in T3 was 35.2% higher than that in CK, while the wheat yield in T2 and T1 was not different from that in CK.

[0051] See also Figure 2 In the first year, the corn yield in T2 and T3 was 22.1% and 18.6% higher than that in CK, respectively, while the corn yield in T1 was no different from that in CK. In the second year, the corn yield in T3 was 12.0% higher than that in CK.

[0052] See also Figure 3 , the test completed by the above steps was statistically analyzed for the impact on soil quality, and the parameters finally obtained were tabulated. T3 can reduce the bulk density of the 0-20cm soil layer, and the soil pH of the 0-20cm soil layer in T1 and T2 is 0.41 and 0.37 units lower than that in CK;

[0053] The soil pH of T2 was 0.25 units lower than that of CK in the 20-40 cm soil layer depth, and the soil electrical conductivity of T1 and T3 was 32.0% and 25.3% lower than that of CK in the 20-40 cm soil layer depth, respectively.

[0054] See also Figure 4 , is a statistical comparison diagram of the effect of peroxidase in soil on the test completed by the above steps. In the 20-40cm soil layer depth, the soil peroxidase activity in T3 is 36.0% higher than that in T1.

[0055] See also Figure 5 , is a statistical test of the effects of polyphenol oxidase in soil using the above steps. The final columnar comparison diagram shows that soil polyphenol oxidase activity was increased by T3. In the 0-20 cm soil layer depth, soil polyphenol oxidase activity in T3 was 7.5% higher than that in CK, while soil polyphenol oxidase activity in T1 and T2 was no different from that in CK.

[0056] See also Figure 6 The activity of soil N-acetylglucosaminidase was increased by T3. In the 0-20 cm soil layer, the activity of soil N-acetylglucosaminidase in T3 was 14.8% higher than that in CK. In the 20-40 cm soil layer, the activity of soil N-acetylglucosaminidase in T1, T2 and T3 was 70.1%, 63.8% and 92.3% higher than that in CK, respectively.

[0057] See also Figure 7 , is a statistical comparison diagram of the effects of β-glucosidase in soil in the experiment completed by the above steps. In the 0-20 cm soil layer depth, the soil β-glucosidase activities in T1, T2 and T3 were 12.1%, 19.1% and 19.7% higher than that in CK, respectively. In the 20-40 cm soil layer depth, the soil β-glucosidase activities in T2 and T3 were 68.3% and 54.1% higher than that in CK, respectively.

[0058] Compared with CK, T3 increased wheat yield by 19.2% and 35.2% and corn yield by 18.6% and 12.0% in two years. T3 can improve soil salinity, increase soil organic carbon and soil nutrient conditions, and improve soil enzyme activity. The content of soil organic carbon in the 0-20cm soil layer of T3 was 14.3% higher than that of CK, and the content of water-soluble salt in the soil was 11.8% lower than that of CK. The activities of polyphenol oxidase, N-acetylglucosaminidase and β-glucosidase in the 0-20cm soil of T3 were 7.5%, 14.8% and 92.3% higher than those of CK, respectively.

[0059] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A planting method for carbon enhancement and fertilization of slightly saline-alkali soil, characterized in that: The steps include: S1: Four field test areas were determined according to the return of organic materials to the field and the planting mode, and the effects of different farmland management modes on crop yield, soil organic carbon fixation, soil nutrients and enzyme activity of wheat, corn and soybean were studied respectively. The four field test areas were specifically divided into four return treatment methods: CK, T1, T2 and T3. When the field test area in CK was tested, the straw was removed from the field, and rotary tillage, wheat sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land wheat in the wheat season were applied, and the field was compacted with a roller after sowing. Wintering water was applied before the wheat overwintered, and urea was applied during the jointing period. After the wheat was harvested, the wheat straw was crushed and returned to the field, corn was sown with a no-till planter, seeds and fertilizers were sown at the same time, and nitro-compound fertilizers specially used for saline-alkali land corn in the corn season were applied. No topdressing or irrigation was done during the entire growth period of corn. S2: When conducting the field positioning test area in T1, after corn is harvested with a combine harvester, corn stalks are crushed and returned to the field, land is tilled and prepared, wheat is sown with seeds and fertilizers, nitro compound fertilizers specially used for wheat in saline-alkali land in the wheat season are applied, and the field is compacted with a roller after sowing. Wintering water is applied before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro compound fertilizers specially used for corn in saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of corn. S3: When conducting the field positioning test area in T2, after the corn is harvested with a combine harvester, the corn stalks are removed from the plots, biochar burned from the previous season's corn stalks is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, nitro-compound fertilizers specially used for saline-alkali land in the wheat season are applied, and the wheat is compacted with a roller after sowing. Wintering water is irrigated before the wheat overwintering and urea is applied during the jointing period. After the wheat is harvested, the wheat stalks are crushed and returned to the field, corn is sown with a no-tillage seeder, seeds and fertilizers are sown together, and nitro-compound fertilizers specially used for saline-alkali land in the corn season are applied. No topdressing or irrigation is done during the entire growth period of the corn. S4: When conducting the field positioning test area in T3, after corn and soybeans are harvested with a combine harvester, the corn and soybean straws are removed from the plots, biochar burned from the corn and soybean straws of the previous season is evenly spread, rotary tillage and land preparation are carried out, wheat is sown with seeds and fertilizers, and nitro compound fertilizers for wheat in saline-alkali land in the wheat season are applied, and the fields are compacted with a roller after sowing. Wintering water is irrigated before wheat overwintering and urea is applied during the jointing period. After wheat is harvested, the wheat straw is crushed and returned to the field and the intercropping pattern of corn and soybeans is converted. Corn and soybeans are sown with a no-till seeder, and then nitro compound fertilizers for corn in saline-alkali land in the corn season and nitro compound fertilizers for soybeans in saline-alkali land in the soybean season are applied. In the intercropping pattern, corn and soybeans are rotated every year, and no topdressing or irrigation is done during the entire growth period of corn and soybeans; S5: The four field return treatments of CK, T1, T2 and T3 were repeated three times. After the repeated treatments in the four field test areas were completed, the soil was sampled, and the soil nutrient content and enzyme activity of the saline-alkali land were measured and analyzed.

2. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 1, characterized in that: The CK returning to the field treatment method in step S1 is a conventional non-organic material returning to the field mode, specifically a wheat-corn rotation planting mode; In step S1, the T1 returning to the field treatment mode is a corn stalk crushing and returning to the field mode, specifically a wheat-corn rotation planting mode; In step S1, the T2 field returning treatment method is a corn straw biochar field returning mode, specifically a wheat-corn rotation planting mode; The T3 field returning treatment method in step S1 is a corn and soybean straw biochar field returning mode, specifically a wheat, corn and soybean intercropping mode.

3. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 2, characterized in that: The rotary tillage depth in CK, T1, T2 and T3 is 15 cm, the wheat sowing amount is 15 kg / mu, the wheat variety is Jimai 44, and the application amount of the special nitro compound fertilizer for wheat in saline-alkali land in the wheat season is 50 kg.

4. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 3, characterized in that: The components and mass percentages of the special nitro compound fertilizer for wheat in saline-alkali land during the wheat season are: N 16%; P2O5 20%; K2O5%, the winter water irrigation amount in CK, T1, T2 and T3 is 40-60m 3 / mu, the topdressing amount of urea is 16kg / mu.

5. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 4, characterized in that: The corn planting density in CK, T1, T2 and T3 is 67500 plants / hm2. -2 The application amount of the special nitro compound fertilizer for corn in saline-alkali land applied in the corn season is 50kg, and the components and mass percentages of the special nitro compound fertilizer for corn in saline-alkali land applied in the corn season are: N28%; P2O510%; K2O13%.

6. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 5, characterized in that: The biochar in T2 is made from corn stalks burned in saline-alkali land. The application amount of the biochar is converted with the carbon content of corn stalks harvested in the previous season. The components and mass percentages of the biochar are: C39.7%; N1.44%; P0.20%; K3.65％。 7. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 1, characterized in that: The biochar in T3 is made from corn and soybean straw in saline-alkali land. The amount of biochar applied is equivalent to the carbon content in the corn and soybean straw harvested in the previous season. The components and mass percentages of the biochar are: C40.5%; N1.57%; P0.19％； K3.48％。 8. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 7, characterized in that: The soybean variety in T3 is Qihuang 34, and the planting density of the soybean is 225,000 plants / hm2. -2 The application amount of the special nitro-compound fertilizer for soybeans in saline-alkali land during the soybean season is 50kg, and the special nitro-compound fertilizer for soybeans in saline-alkali land during the soybean season contains 12% N, 18% P2O5, and 15% K2O.

9. A planting method for carbon enhancement and fertilization of light saline-alkali soil according to claim 8, characterized in that: The width of the corn and soybean strips in the intercropping pattern is 480 cm, each strip includes four rows of corn strips with a width of 240 cm and four rows of soybean strips with a width of 240 cm, and the row spacing between the corn and soybeans is 60 cm.

10. An application of the planting method for carbon enhancement and fertilization of light saline-alkali soil as claimed in any one of claims 1 to 9, characterized in that: Used to increase carbon content and fertilize slightly saline-alkali soils for growing wheat, corn and soybeans.

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