Corn straw deep returning method for constructing thick plough layer and application

Abstract

The invention discloses a corn straw deep returning method for constructing a thick plough layer and application, and relates to the technical field of soil tillage. The method comprises the following steps: ploughing and ditching: after autumn corn is harvested, ditching is carried out, the depth of a ditch is 40-60 cm, and the width of the ditch is 20-40 cm; straw is applied to the ditches, urea is added to the straw, and the carbon nitrogen ratio of the straw is adjusted to be (20-30): 1; the application amount of the straw is 6000 kg.hm <-2 > to 18000 kg.hm <-2 >; soil backfilling: soil dug during ditching is returned to the original position, and precipitation and compaction are performed; corn planting: corn is sown in spring of the next year; and circulation: after harvesting in autumn, avoiding the ditching position in the previous year, and repeating the steps S1 to S4 to finish deep returning of the rice straws to the field and construction of a thick and fertile plough layer. The method increases the organic matter content and thickness of plough layer soil, can be used for comprehensively constructing a deep and fertile dry land soil plough layer, and promotes the increase of crop yield.

Description

Technical Field

[0001] The invention relates to the technical field of soil cultivation, and in particular to a method for deep returning corn stalks to a field for constructing a thick and fertile tillage layer and an application thereof. Background Art

[0002] For dryland corn, harvesting a large amount of grain yields means harvesting more corn stalks. As agricultural solid waste, a large amount of stalks is not only difficult to reduce, but also difficult to handle and has high transportation costs. Therefore, if the excess stalks can be put into the construction of fertile arable land according to the principle of "taking from the soil and giving back to the soil", it will not only solve the problem of soil fertility loss, but also promote the resource utilization of agricultural solid waste, which is of great significance to the sustainable development of agriculture.

[0003] In terms of straw utilization, there are many measures to use straw as energy, but in most places it cannot be realized due to technical limitations. Returning straw to the field is a common method of utilization, which can not only improve the physical, chemical and biological properties of the soil, but also reduce air pollution caused by burning, which is of great significance to soil improvement.

[0004] However, the existing straw return technology can only return the straw to the soil surface or the 0cm to 20cm tillage layer, which has the problem of shallow tillage layer, making the surface soil of the cultivated land loose and breathable, which is not conducive to water and fertilizer conservation in arid and semi-arid areas, affecting the mechanized operation of spring sowing machines, and also prolonging the emergence time and affecting the emergence rate. It has certain limitations in practice and promotion. Other deep soil fertilization methods cannot directly add organic matter to the deep soil, and need to loosen the soil by breaking the plow bottom layer, but cannot fertilize the deep soil to make it fertile. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for deep returning corn straw to fields for constructing a thick and fertile tillage layer and its application, so as to construct a thick and fertile tillage layer soil.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for deep returning corn stalks to fields for constructing a thick fertile tillage layer, the method comprising the following steps:

[0008] S1. Digging trenches in cultivated land: After corn harvest in autumn, dig trenches with a depth of 40cm to 60cm and a width of 20cm to 40cm.

[0009] S2. Returning straw to the field: Add straw to the ditch, add urea to the straw, and adjust the straw carbon-nitrogen ratio to 20-30:1; the amount of straw applied is 6000kg·hm -2 ~18000kg·hm-2 .

[0010] S3. Soil backfill: Return the soil excavated during trenching to its original position and compact it.

[0011] S4. Corn planting: Sow corn in the spring of the second year.

[0012] S5. Cycle: After the autumn harvest, avoid the furrowing location of the previous year and repeat steps S1 to S4 to complete the deep return of rice straw to the field and build a thick fertile arable layer.

[0013] The construction of a thick and fertile tillage layer refers to increasing the total organic carbon content of the soil, the total nitrogen content of the soil and the thickness of the tillage layer.

[0014] Preferably, the construction of a thick and fertile arable layer refers to a soil total organic carbon content of 8.37 g·kg-1 to 16.38 g·kg-1, a soil total nitrogen content of 1.3 g·kg-1 to 2 g·kg-1 and a arable layer soil thickness of 30 cm to 40 cm.

[0015] Preferably, the amount of straw applied in step S2 is 12000 kg·hm -2 .

[0016] Preferably, in step S2, the carbon-nitrogen ratio of the straw is adjusted to 25:1.

[0017] Preferably, the straw applied in step S2 is whole straw.

[0018] Preferably, the method of sowing corn is to first form ridges, and then plant two rows of corn on each ridge.

[0019] An application of a thick fertile tillage layer, the thick fertile tillage layer refers to the thick fertile tillage layer, and the application includes application in promoting the growth of corn roots.

[0020] Preferably, the promoting the growth of corn root system refers to increasing the total root length, total root surface area, total root volume and root diameter of the corn root system.

[0021] Preferably, the application also includes application in improving corn yield and corn kernel quality.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a method for deep returning corn stalks to fields, which comprises the following steps: deep furrowing of cultivated land, applying stalks to the deep furrows, adding urea to the stalks, backfilling the soil in situ, closing ridges, returning the soil dug out during furrowing to its original position, planting corn according to local agricultural experience, and after harvesting in autumn, avoiding the deep returning position of the previous year according to the previous returning method, continuing deep furrowing and deep returning the stalks to fields, and the like. Under the premise of not requiring additional professional operations, the organic matter content and thickness of the tillage layer soil are increased, a deep and fertile dryland soil tillage layer is comprehensively constructed, and daily field management such as fertilization during corn cultivation is coordinated to increase the fertilizer utilization rate of the crop and the absorption of organic nutrients, thereby promoting an increase in crop yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a diagram of the straw deep returning method of the present invention;

[0026] Figure 1 In the figure, a is a method diagram for uniformly returning the straws of two adjacent ridges to the middle of the two ridges in the first year; b is a method diagram for uniformly returning the straws of two adjacent ridges to the middle of the two ridges in the second year by staggering the positions where the straws were buried in the previous year;

[0027] Figure 2 It is the soil C / N, TOC content and MBC content diagram of the present invention;

[0028] Figure 3 is a graph of soil total organic carbon content of the present invention;

[0029] Figure 4 is a soil total nitrogen content diagram of the present invention;

[0030] Figure 5 This is a diagram showing the scanning and analysis results of the corn root systems treated differently by the present invention using the Win RHIZO root scanner;

[0031] Figure 5 In the figure, a is the total root length result diagram; b is the total root surface area result diagram; c is the total root volume result diagram; d is the average root diameter result diagram. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0034] The inventive concept of the present invention is as follows:

[0035] At present, the main methods of returning straw to the field are direct return and indirect return. Among them, direct return includes surface covering and straw crushing and pressing; indirect return includes returning to the field through the belly and returning to the field by composting, but indirect return is difficult to promote in terms of technology, so direct return is the main method. Traditional direct return to the field is mostly surface covering and shallow return to the tillage layer. Surface covering improves the soil's ability to store water and retain moisture, and shallow return to the tillage layer can improve the soil aggregation structure and increase the organic matter content of the tillage layer. However, the straw return technology in the existing technology can only return the straw to the soil surface or the tillage layer position of 0cm to 20cm. There is a problem of shallow tillage layer, which will cause the surface soil of the cultivated land to be loose and breathable, which is not conducive to water and fertilizer conservation in arid and semi-arid areas, affecting the mechanized operation of spring sowing machines, and prolonging the emergence time and affecting the emergence rate. It has certain limitations in practice and promotion. Other deep soil fertilization methods cannot directly add organic matter to the deep soil. It is necessary to loosen the soil by breaking the plow bottom layer, but it is impossible to fertilize the deep soil to make it fertile.

[0036] Based on this, the present invention provides a method for deep returning corn straw to the field to construct a thick fertile tillage layer, the method comprising the following steps:

[0037] S1. Digging trenches in cultivated land: After corn harvest in autumn, dig trenches with a depth of 40cm to 60cm and a width of 20cm to 40cm.

[0038] S2. Returning straw to the field: Add straw to the ditch, add urea to the straw, and adjust the straw carbon-nitrogen ratio to 20-30:1; the amount of straw applied is 6000kg·hm -2 ~18000kg·hm -2 .

[0039] S3. Soil backfill: Return the soil excavated during trenching to its original position and compact it.

[0040] S4. Corn planting: Sow corn in the spring of the second year.

[0041] S5. Cycle: After the autumn harvest, avoid the furrowing location of the previous year and repeat steps S1 to S4 to complete the deep return of rice straw to the field and build a thick fertile arable layer.

[0042] After corn is harvested in autumn, the present invention digs trenches with a depth of 40 cm to 60 cm, and applies straw into the trenches so that the straw is directly buried deep in the field to a soil layer of 40 cm to 60 cm to prevent corn seedlings, roots and the like from directly contacting the straw. By increasing the burial depth, the organic matter content of the tillage layer soil is increased without the need for additional professional operations, thereby solving the problem of being unable to fertilize the deep soil to make it fertile, and increasing the thickness of the tillage layer soil, thereby comprehensively constructing a deep and fertile dryland soil tillage layer, which can not only improve the water storage capacity of the soil and promote the growth of crop roots, but also increase crop yields, improve the sustainable utilization of cultivated land, and realize the construction and long-term utilization of a thick and fertile tillage layer.

[0043] Basic situation of the test site.

[0044] The test site is located in Shenyang City (40°48′N, 123°33′E), which has a temperate humid semi-humid monsoon climate, with an annual rainfall of 574mm~684mm, an annual average evaporation of 1435.6mm, an average temperature of 7.0℃~8.1℃, accumulated temperature above 10℃ of 3300℃~3400℃, and a frost-free period of 148 days to 180 days.

[0045] The soil in the test area is brown soil with a clay texture. Its basic physical and chemical properties are organic matter 13.83 g·kg -1 , total nitrogen 0.80g·kg -1 , total phosphorus 0.38g·kg -1 , total potassium 20.1g·kg -1 , alkaline nitrogen 105.5mg·kg -1 , available phosphorus 6.5 mg kg -1 , fast-acting potassium 97.9 mg kg -1 , pH = 6.5. Plant corn, the variety is Zhengdan 958.

[0046] Material preparation: agricultural straw.

[0047] In order to better illustrate the present invention, the technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0048] Example 1: A method for returning corn stalks to the field

[0049] S1. Ditching of cultivated land

[0050] After the corn is harvested in autumn, dig trenches with a depth of 40cm and a width of 20cm.

[0051] S2. Returning straw to the field

[0052] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 20:1. The amount of straw applied is 6000 kg·hm -2 .

[0053] S3. Soil backfill

[0054] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0055] S4. Corn Planting

[0056] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0057] S5. Cycle

[0058] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0059] Embodiment 2: A method for returning corn stalks to the field

[0060] S1. Ditching of cultivated land

[0061] After the corn is harvested in autumn, dig trenches with a depth of 50cm and a width of 30cm.

[0062] S2. Returning straw to the field

[0063] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 25:1. The amount of straw applied is 6000 kg·hm -2 .

[0064] S3. Soil backfill

[0065] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0066] S4. Corn Planting

[0067] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0068] S5. Cycle

[0069] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0070] Example 3: A method for returning corn stalks to the field

[0071] S1. Ditching of cultivated land

[0072] After the corn is harvested in autumn, dig trenches with a depth of 60cm and a width of 40cm.

[0073] S2. Returning straw to the field

[0074] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 30:1. The amount of straw applied is 6000 kg·hm -2 .

[0075] S3. Soil backfill

[0076] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0077] S4. Corn Planting

[0078] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0079] S5. Cycle

[0080] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0081] Example 4: A method for returning corn stalks to the field

[0082] S1. Ditching of cultivated land

[0083] After the corn is harvested in autumn, dig trenches with a depth of 40cm and a width of 20cm.

[0084] S2. Returning straw to the field

[0085] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 20:1. The amount of straw applied is 12000 kg·hm -2 .

[0086] S3. Soil backfill

[0087] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0088] S4. Corn Planting

[0089] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0090] S5. Cycle

[0091] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0092] Example 5: A method for returning corn stalks to the field

[0093] S1. Ditching of cultivated land

[0094] After the corn is harvested in autumn, dig trenches with a depth of 50cm and a width of 30cm.

[0095] S2. Returning straw to the field

[0096] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 25:1. The amount of straw applied is 12000 kg·hm -2 .

[0097] S3. Soil backfill

[0098] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0099] S4. Corn Planting

[0100] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0101] S5. Cycle

[0102] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0103] Example 6: A method for returning corn stalks to the field

[0104] S1. Ditching of cultivated land

[0105] After the corn is harvested in autumn, dig trenches with a depth of 60cm and a width of 40cm.

[0106] S2. Returning straw to the field

[0107] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 30:1. The amount of straw applied is 12000 kg·hm -2 .

[0108] S3. Soil backfill

[0109] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0110] S4. Corn Planting

[0111] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2, diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0112] S5. Cycle

[0113] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0114] Example 7: A method for returning corn stalks to the field

[0115] S1. Ditching of cultivated land

[0116] After the corn is harvested in autumn, dig trenches with a depth of 40cm and a width of 20cm.

[0117] S2. Returning straw to the field

[0118] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 20:1. The amount of straw applied is 18000 kg·hm -2 .

[0119] S3. Soil backfill

[0120] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0121] S4. Corn Planting

[0122] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0123] S5. Cycle

[0124] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0125] Example 8: A method for returning corn stalks to the field

[0126] S1. Ditching of cultivated land

[0127] After the corn is harvested in autumn, dig trenches with a depth of 50cm and a width of 30cm.

[0128] S2. Returning straw to the field

[0129] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 25:1. The amount of straw applied is 18000 kg·hm -2 .

[0130] S3. Soil backfill

[0131] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0132] S4. Corn Planting

[0133] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0134] S5. Cycle

[0135] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0136] Example 9: A method for returning corn stalks to the field

[0137] S1. Ditching of cultivated land

[0138] After the corn is harvested in autumn, dig trenches with a depth of 60cm and a width of 40cm.

[0139] S2. Returning straw to the field

[0140] Add straw to the furrow and return the straw from two adjacent ridges to the middle of the two ridges. Figure 1 As shown in a, urea is added to the straw to adjust the carbon-nitrogen mass ratio of the straw to 30:1. The amount of straw applied is 18000 kg·hm -2 .

[0141] S3. Soil backfill

[0142] The soil dug out during trenching is returned to its original position and allowed to settle and compact over the winter in preparation for farming in the spring of the following year.

[0143] S4. Corn Planting

[0144] In the spring of the second year, ridges were first formed, and then two rows of corn were sown on each ridge. Each plot was equipped with 235 kg·hm2 of urea fertilizer. -2 , diammonium phosphate 300kg·hm -2 , potassium sulfate 225kg·hm -2 There is no irrigation during the growth of corn, and daily field management such as pesticide spraying is carried out based on local agricultural experience to prevent other pests and diseases.

[0145] S5. Cycle

[0146] After the autumn harvest, considering that the straw returned to the field last year cannot be completely degraded, the location of the furrows dug in the second year is staggered, such as Figure 1 As shown in b in FIG. 1 , steps S1 to S4 are repeated to complete the deep return of rice straw to the field.

[0147] Example 10: Effect of returning corn stalks to fields in depth on improving the thickness of the tillage layer and soil fertility.

[0148] Corn with a full growth period of 130 to 150 days was selected, and three different straw returning methods were set up to construct the soil tillage layer, namely, no straw control (Control, C), straw mulching (M), and straw deep burying (Deep-burying, D).

[0149] At the time of harvest in autumn, the thickness of the tillage layer of the test field was measured with a steel ruler. The tillage layer thickness of the no-straw control was 15 cm, and the tillage layer thickness of the straw-covered control was 16 cm. The thickness of the deep straw-returned tillage layer reached 35 cm, which was significantly higher than that of the straw-covered and no-straw controls.

[0150] In terms of soil C / N (carbon-nitrogen ratio) and soil carbon content, straw mulching significantly increased soil C / N, while there was no significant difference in soil C / N between deep straw return and the control group without straw return. Straw return first significantly increased the content of soil total organic carbon TOC and microbial biomass carbon MBC, and significantly increased the proportion of soil MBC in TOC. The results are as follows: Figure 2As shown. Compared with the control treatment without straw return, straw mulching and deep straw return increased soil TOC by about 2.92%. The soil TOC of straw mulching and deep straw return was not much different, and there was no statistically significant difference. The MBC content of the control treatment without straw return was low, and the straw mulching treatment increased it by 175.66% compared with the control without straw return. The MBC of deep straw return increased by 325.40% compared with the control without straw return, and increased by 54.32% compared with the straw mulching treatment, indicating that deep straw return significantly increased soil TOC by increasing MBC, and promoted the growth and activity of soil organisms. There is no difference in C / N between deep straw return and no straw return, indicating that deep straw return increases the content of soil carbon and nitrogen at the same time, and the increase in soil carbon content by straw mulch is significantly higher than the increase in nitrogen; combined with the above soil nitrogen results, it can be further explained that deep straw return promotes the increase of nitrogen in the soil in the form of organic nitrogen, helps improve the utilization rate of nitrogen fertilizer, and can be used to construct a thick and fertile arable layer.

[0151] Example 11: Effect of deep corn stalk return method on building thick fertile tillage layer

[0152] The method of deep returning corn straw to the field was applied to a dryland farmland in Anshan City, Liaoning Province. A deep trenching method of deep returning corn straw to the field was carried out according to the above method. The role of the method of deep returning corn straw to the field in constructing a thick and fertile tillage layer was judged based on the soil organic matter content and crop yield in the test area.

[0153] The experimental design was a control (CK) without straw application after deep furrowing, and three different straw return rates, namely, 6000 kg·hm2 of whole straw application, -2 (S1), whole straw application rate 12000kg·hm -2 (S2), whole straw application rate: 18000kg·hm -2 (S3) Compare and analyze the changes in soil tillage layer thickness, soil organic nutrients, and deep soil organic matter content after deep straw return to the field.

[0154] The results are as follows Figure 3 As shown in Figure 2, overall, the total organic carbon content of soil in different soil layers in the CK treatment did not change much, which was 8.02 g kg -1 ~8.53g·kg -1 The total organic carbon content of soil varied greatly between different soil layers in other treatments, with the content of total organic carbon in treatment S1 being 8.37 g·kg -1 ~13.64g·kg -1 ; S2 treatment: 9.62g·kg -1 ~16.38g·kg -1 ; S3 treatment: 10.00 g·kg -1 ~14.42g·kg -1In the 0cm-20cm soil layer and the 20cm-40cm soil layer, the S3 treatment had the highest soil total organic carbon content, and the soil total organic carbon content of each treatment was S3>S2>S1>CK. In the M soil layer, the S2 treatment had the highest soil total organic carbon content, and the soil total organic carbon content of each treatment was S2>S3>S1>CK.

[0155] After the autumn harvest, soil samples from different soil layers with different treatments were collected and their total nitrogen content was determined after treatment. The results are as follows: Figure 4 In the U soil layer (upper layer of straw), the differences between S3 treatment and CK treatment, and between S3 treatment and S1 treatment reached a significant difference level of 5%, while the differences between other treatments were not significant. The soil total nitrogen content of each straw deep return treatment increased by 3.65%, 4.38%, and 10.22% compared with that of CK treatment, respectively; in the M soil layer (straw layer), the differences between each straw deep return treatment and CK treatment reached a significant difference level of 5%, but the differences between each straw deep return treatment were not significant. The soil total nitrogen content of each straw deep return treatment increased by 27.07%, 44.36%, and 28.57% compared with that of CK treatment, respectively; in the D soil layer (lower layer of straw), the differences between S3 treatment and CK treatment reached a significant difference level of 5%, while the differences between other treatments were not significant. The soil total nitrogen content of each straw deep return treatment increased by 1.53%, 5.34%, and 9.16% compared with that of CK treatment, respectively.

[0156] Through comparative analysis, the treatment of returning straw to the field with chemical fertilizers yielded higher corn yield and biomass than the treatment without returning straw to the field. The yield of deep returning straw to the field and straw mulching increased by 4.03% and 9.34% respectively compared with the control without returning straw to the field. Among them, the yield of deep returning straw to the field increased by 4.99% compared with the control without returning straw to the field. In addition, the 100-grain weight of corn in the treatment of returning straw to the field was significantly higher than that of the control without returning straw to the field, and the deep returning straw to the field treatment was significantly higher than that of the straw mulching treatment, indicating that deep returning straw to the field can not only increase crop yield, but also significantly improve grain quality. Further, through the seed rate (the percentage of the mass of the grains produced by a single corn ear to the whole corn ear) and the straw-grain mass ratio, it can be found that returning straw to the field significantly increased the seed rate of corn ears, deep returning straw to the field significantly reduced the straw-grain mass ratio, and the straw-grain mass of the straw mulching treatment was not significantly reduced compared with the control without returning straw to the field. This shows that straw mulching can increase corn ear weight and single-plant grain yield; deep straw return to the field not only increases the yield of single corn plant but also improves the fullness of individual grains, thereby comprehensively improving the yield and quality of corn grains.

[0157] In the present invention, corn yields were significantly increased compared with the control treatment, increasing by 8.42%, 18.97% and 15.41%, respectively. The order of corn yields in each treatment was S2>S3>S1>CK. The difference between each deep straw return treatment and the CK treatment reached a significant level of 5%, but there was no significant difference between the S2 treatment and the S3 treatment.

[0158] After corn harvest, the roots of corns with different treatments were collected and scanned and analyzed using Win RHIZO root scanner. The results are as follows: Figure 5 As shown in the data, the total root length of each treatment of deep straw return to the field was significantly higher than that of the CK treatment, and increased by 40.39%, 65.47% and 52.13% respectively compared with the CK treatment; the total root surface area of ​​each treatment was greater than that of the CK treatment, among which the S2 and S3 treatments increased by 107.37% and 70.04% respectively compared with the CK treatment, both reaching the 5% significant difference level, while the S1 treatment increased by 37.36% compared with the CK treatment, and the difference was not significant; from the perspective of total root volume, the S1 and S3 treatments increased by 34.03% and 89.49% respectively compared with the CK treatment, but the difference was not significant, while the S2 treatment increased by 132.13% compared with the CK treatment, reaching the 5% significant difference level; from the perspective of the average root diameter of each treatment, the S2 treatment increased by 46.05% compared with the CK treatment, reaching the 5% significant difference level, the S1 and S3 treatments increased by 25% and 22.37% respectively compared with the CK treatment, but the difference was not significant.

[0159] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for deep returning corn straw to fields to construct a thick fertile tillage layer, characterized in that: The method comprises the following steps: S1. Ditching in cultivated land: After corn harvest in autumn, dig trenches with a depth of 40cm to 60cm and a width of 20cm to 40cm; S2. Returning straw to the field: Add straw to the ditch, add urea to the straw, and adjust the carbon-nitrogen mass ratio of the straw to 20-30:1; the amount of straw applied is 6000kg·hm -2 ~18000kg·hm -2 ; S3, soil backfill: return the soil dug out during trenching to its original position, settle and compact it; S4. Corn planting: Plant corn in the spring of the second year; S5, cycle: after the autumn harvest, avoid the furrowing position of the previous year and repeat steps S1 to S4, that is, complete the deep return of rice straw to the field and build a thick fertile tillage layer; The construction of a thick and fertile tillage layer refers to increasing the total organic carbon content of the soil, the total nitrogen content of the soil and the thickness of the tillage layer.

2. The method for deep returning corn stalks to fields for constructing a thick fertile tillage layer as claimed in claim 1, characterized in that: The construction of thick fertile arable layer refers to the total organic carbon content of the soil being 8.37 g·kg -1 ~16.38g·kg -1 , the total nitrogen content of the soil is 1.3g·kg -1 ~2g·kg -1 The thickness of the tillage layer reaches 30cm to 40cm.

3. The method for deep returning corn stalks to fields for constructing a thick fertile tillage layer as claimed in claim 1, characterized in that: The amount of straw applied in step S2 is 12000 kg·hm -2 .

4. The method for deep returning corn stalks to fields for constructing a thick fertile tillage layer as claimed in claim 1, characterized in that: In the step S2, the carbon-nitrogen ratio of the straw is adjusted to 25:

1.

5. The method for deep returning corn stalks to fields for constructing a thick fertile tillage layer as claimed in claim 1, characterized in that: The straw applied in step S2 is whole straw.

6. The method for deep returning corn stalks to fields for constructing a thick fertile tillage layer as claimed in claim 1, characterized in that: The method of sowing corn is to first form ridges, and then sow two rows of corn on each ridge.

7. An application of a thick fertile arable layer, characterized in that: The thick fertile tillage layer refers to the thick fertile tillage layer described in claim 1, and the application includes application in promoting the growth of corn roots.

8. The use of the thick fertile tillage layer as claimed in claim 7, characterized in that: The promoting the growth of corn root system refers to increasing the total root length, total root surface area, total root volume and root diameter of the corn root system.

9. The use of the thick fertile tillage layer as claimed in claim 7, characterized in that: The application also includes application in improving corn yield and corn kernel quality.

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