阅读说明：本技术 一种激发式秸秆原位行间掩埋还田地力培育方法 (Excitation type straw in-situ intertidal burying returning soil fertility cultivation method ) 是由 张丛志 张佳宝 潘慧 李健鹏 谭钧 邢文军 于 2021-08-06 设计创作，主要内容包括：一种激发式秸秆原位行间掩埋还田地力培育方法,在作物收获后,玉米秸秆利用秸秆粉碎机进行粉碎,小麦秸秆直接还田。向秸秆中均匀混入氮肥,然后按照100kg/亩用量均匀混入微生物激发调节剂。然后进行行间开沟,秸秆掩埋行间距离为60cm,开挖深度为30cm,作物播种行间距为40cm。先将秸秆、氮肥、微生物激发调节剂组合物掩埋进沟间,再然后进行覆土及镇压。在玉米-小麦轮作旱地土壤中,施氮肥,剩余氮肥玉米季分别在拔节期和灌浆期以4:6追肥,小麦季剩余氮肥在返青期追磷肥和钾肥。最后播种并镇压,保证播种均匀,播深一致,覆盖严密,播后要适时浇水,以加速土壤沉实和促进秸秆有机碳和养分向土壤中转化。(An excitation type straw in-situ inter-row burying and returning soil fertility cultivation method is characterized in that after crops are harvested, corn straws are smashed by a straw smashing machine, and wheat straws are directly returned to the field. Evenly mixing nitrogen fertilizer into the straws, and then evenly mixing the microorganism excitation regulator according to the dosage of 100 kg/mu. Then, ditching among rows is carried out, the distance between the straw burying rows is 60cm, the excavating depth is 30cm, and the spacing between the crop sowing rows is 40 cm. Burying the straw, the nitrogen fertilizer and the microorganism excitation regulator composition into the ditch, and then covering soil and pressing. In the dry land soil of corn-wheat rotation, nitrogen fertilizer is applied, the residual nitrogen fertilizer is applied in the ratio of 4:6 in the elongation stage and the filling stage of corn, and the residual nitrogen fertilizer is applied in the wheat season in the green turning stage. And finally, sowing and compacting, ensuring uniform sowing, consistent sowing depth and tight coverage, and watering at proper time after sowing to accelerate soil compaction and promote the conversion of organic carbon and nutrients of the straws into the soil.)

1. An excitation type straw in-situ intertidal burying returning soil fertility cultivation method is characterized by comprising the following steps:

step 1, after crops are harvested, smashing corn straws, and returning the wheat straws to the field directly;

step 2, uniformly mixing nitrogen fertilizer into the straws, and then uniformly mixing a microorganism excitation regulator;

step 3, ditching among rows, wherein the distance among rows and the excavating depth need to be adjusted according to the crop variety, the planting density and the straw returning amount;

step 4, burying the straw, the nitrogen fertilizer and the microorganism excitation regulator composition into the ditch, and then covering soil and pressing;

and step 5, fertilizing, sowing and pressing, ensuring uniform sowing, consistent sowing depth and tight coverage, and watering at proper time after sowing to accelerate soil compaction and promote the conversion of organic carbon and nutrients of the straws into the soil.

2. The method for cultivating the excited straw in situ by burying the straw between lines and returning the straw to the field as claimed in claim 1, wherein the corn straw in step 1 needs to be crushed to a size not exceeding 10 cm.

3. The method as claimed in claim 1, wherein the nitrogen fertilizer in step 2 is chemical nitrogen fertilizer or decomposed organic fertilizer, and the amount is 2 kg/mu, and the microbial excitation regulator comprises amino acids, fulvic acid, rock wool, algal oligosaccharides, and organic carbon as matrix carrier, and the amount is 100 kg/mu.

4. The method for cultivating the excited straw in-situ intertidal buried field returning soil as claimed in claim 3, wherein the nitrogen fertilizer is refined chicken manure.

5. The excitation type straw in-situ inter-row burying field-returning soil productivity cultivation method as claimed in claim 1, wherein in the step 3, the distance between the straw burying rows is 60cm, the excavation depth is 5-30cm, and the crop seeding row spacing is 40 cm.

6. The method for cultivating the excited straw in-situ intertidal burying returning field soil as claimed in claim 1, wherein the conventional fertilization in the step 5 is to apply 200kg/ha of nitrogen fertilizer, 105kg/ha of phosphate fertilizer and 105kg/ha of potassium fertilizer.

Technical Field

The invention belongs to the technical field of soil improvement, and particularly relates to an excitation type straw in-situ intertidal burying returning soil fertility cultivation method.

Background

Crop straws are an important biological resource in agricultural production, and relate to the sustainable development problems of soil fertility, water and soil conservation, environmental safety, effective utilization of regenerated agricultural resources and the like in the whole agricultural ecosystem. China is one of the most abundant countries of straw resources, and according to the measurement and calculation, the yield of main crop straws in Huang-Huai-Hai region reaches about 1.5 hundred million tons in 2015 years, the yield of grain crop straws accounts for more than 70%, and the yield of corn and wheat straws accounts for 43.4% (both wheat and corn are 21.7%). In the past, straws are mostly used as domestic fuel and livestock feed for a long time, or are directly burned in the open air or are randomly piled and abandoned in large quantities, so that the problems of resource waste and environmental pollution are caused seriously. With the development of rural economy and the improvement of the level of grain per unit yield, the residual quantity of straws is more and more. How to treat the straws becomes a great problem for agricultural production and environmental protection in China. On the other hand, long-term chemical agriculture reduces soil fertility, deteriorates soil structure, and poses serious threat to agricultural sustainable development. According to statistics, the fertile high-yield field of the Huang-Huai sea tide land area is only 18.2 percent, the medium-low yield field accounts for 81.8 percent, the nitrogen deficiency of the cultivated land is over 60 percent, and the organic matter of the soil is generally low. The core of cultivating the farmland is to increase the organic matters of the soil, and the straws are important resources for increasing the organic matters of the soil. The scientific straw returning technology not only promotes the smooth implementation of straw returning, but also is an important measure and a key way for improving soil fertility, improving soil structure and ensuring efficient and continuous output of land.

Although many researches show that straw returning has the potential of improving soil fertility and increasing crop nutrient absorption and yield, the straw returning also has a series of problems, such as influence on seeding and seedling emergence, reduction of surface soil water and fertilizer retention capacity, and reduction of crop yield caused by carbon input disorder of a soil microbial system due to a large amount of straw returning, so that the positive and negative effects of the straw returning are not determined all the time. Therefore, how to exert the positive effect of straw returning to the field and avoid the negative effect thereof is very important to establish a suitable straw returning method.

Disclosure of Invention

The technical problem to be solved is as follows: aiming at the technical problems, the invention provides an excitation type straw in-situ intertidal burying and returning soil fertility cultivation method, which has the advantages of alleviating the accumulation and hardening of straw nutrient organic matter on the surface, reducing oxygen partial pressure, increasing the composting effect, reducing the probability of difficult seedling emergence of crops, promoting the accumulation of soil organic matter in a full plough layer, being beneficial to the improvement of the soil structure condition of the full plough layer and the like.

The technical scheme is as follows:

an excitation type straw in-situ intertidal burying returning soil fertility cultivation method is characterized by comprising the following steps:

step 1, after crops are harvested, smashing corn straws, and returning the wheat straws to the field directly;

step 2, uniformly mixing nitrogen fertilizer into the straws, and then uniformly mixing a microorganism excitation regulator;

step 3, ditching among rows, wherein the distance among rows and the excavating depth need to be adjusted according to the crop variety, the planting density and the straw returning amount;

step 4, burying the straw, the nitrogen fertilizer and the microorganism excitation regulator composition into the ditch, and then covering soil and pressing;

and step 5, fertilizing, sowing and pressing, ensuring uniform sowing, consistent sowing depth and tight coverage, and watering at proper time after sowing to accelerate soil compaction and promote organic carbon and nutrients of the straws to transfer to the soil.

Preferably, the corn stalks in the step 1 need to be crushed to be not more than 10 cm.

Preferably, the nitrogen fertilizer in the step 2 is a chemical nitrogen fertilizer or a decomposed organic fertilizer, the dosage is 2 kg/mu, the effective components of the microbial excitation regulator are amino acid, fulvic acid, rock wool and algal oligosaccharide, and the organic carbon is used as a matrix carrier for matching, and the dosage is 100 kg/mu.

Preferably, the nitrogen fertilizer is refined chicken manure.

Preferably, in the step 3, the distance between the straw burying lines is 60cm, the excavation depth is 30cm, and the spacing between the crop sowing lines is 40 cm.

Preferably, the conventional fertilization in the step 5 is to apply 200kg/ha of nitrogenous fertilizer, 105kg/ha of phosphate fertilizer and 105kg/ha of potash fertilizer.

The principle of the technology of the invention is as follows:

the soil organic matter-microorganism-aggregate synergistic improvement mechanism comprises the following steps:

driving soil organic matters and promoting other soil fertility indexes in a synergetic way: long-term positioning test data of the Chinese academy of sciences for up to 28 years in the dune farmland ecological test station show that: the improvement of soil fertility takes the increase of soil organic matters as a core to drive other indexes to be synergistically enhanced (the activity of soil microorganisms is enhanced, the agglomeration degree is high, the water and fertilizer storage capacity is large, and the water and fertilizer supply capacity is strong), but the slow accumulation process of the soil organic matters restricts the rapid formation of a high-quality plough layer. The fertilizer can promote the increase of organic matters in low-yield soil, but the effect is limited; the necessary condition for the organic matter to be greatly increased is sufficient supply of exogenous organic materials, however, the organic matter accumulation process is long, and about 20 years is needed for 1% increase. The breakthrough points of soil organic matter increase are as follows: one requirement (sufficient carbon source supply to increase the carbon balance point), two key processes (microbial community fertilization, soil aggregation).

Secondly, constructing a soil microbe community structure: after organic materials are added into a poor and low-yield soil plough layer to increase soil organic matters, the diversity and species abundance of soil microorganisms can be rapidly restored (less than 1 year), after short-term domestication (less than 2 years), the microbial community structure is adjusted to the direction of enriching the soil with rich type flora, the abundance of microorganisms for efficiently converting nutrient elements such as carbon, nitrogen, phosphorus, potassium and the like is increased rapidly to enrich (such as bacillus, Mortierella and a specific phosphorus-dissolving bacterial population), the conversion rate of the microorganisms on the carbon and the nutrients of the soil is improved, and substrates formed by the organic matters are increased. If no organic substrate is added, the microorganisms (mainly oligotrophic floras) are limited by nitrogen, and decompose soil organic matters to release nitrogen to meet the growth requirement (nitrogen extraction theory) and accelerate the mineralization loss of the soil organic matters; after the organic material and the nitrogen source are added, the carbon-nitrogen ratio meets the growth proper range of the microorganism, the microorganism (mainly eutrophic flora) preferentially utilizes easily-decomposed organic components (such as cellulose) to excite an exogenous organic substrate to be rapidly decomposed (a stoichiometric theory), and the formation and accumulation of soil organic matters are accelerated by the microbial flora through soil erosion.

Thirdly, the soil structure is clustered and stabilized: soil agglomeration provides physical protection of soil organic matter against decomposition, and is a key process for increasing and stabilizing soil organic matter. When the active organic materials which are easy to decompose are added into the soil, the organic materials have the starting and boosting effects on microorganisms, can remarkably promote the formation of large aggregates, and can quickly promote the aggregation of the soil (less than 1 year). The microorganisms rapidly decompose the organic materials to form sufficient humus substances and key functional macromolecular organic matter (such as extracellular polymeric substances), increasing their polymerization in the powdery clay particles and distribution and accumulation in the micro-aggregates. The increase of the powder clay particles and the micro-aggregate organic matters directly promotes the formation of stable macro-aggregates on one hand, and promotes the soil aggregation by reducing hydration/electrostatic repulsion between the soil powder clay particles and enhancing van der Waals force/bonding force to circulate back and forth on the other hand, so that the proportion and the content of the macro-aggregates are continuously increased, and the stability of the soil aggregates is further promoted (less than 2 years).

Based on the soil organic matter-microorganism-aggregate synergistic lifting mechanism, the main principle of the technology is as follows:

adding a proper amount of nitrogen (2 kg/mu) into the straws when returning the straws to the field, so that the carbon-nitrogen ratio of the returned straws can be reduced, and the dosage effect of the carbon-nitrogen ratio required by mass propagation of microorganisms is met; the reduction of soil organic matters caused by the nitrogen digging effect of microorganisms at the earlier stage of returning the conventional straws to the field is reduced; is beneficial to the rapid conversion of the organic carbon and nutrients in the straw to the soil.

Secondly, when returning to the field, the straw is added with a microorganism excitation regulator (100 kg/mu), so that the whole soil microorganism metabolism activity can be improved by utilizing the excitation type detonation effect, the rapid mass propagation of soil indigenous microorganisms can be promoted, and the microorganisms can grow to fertile soil.

And the straw returning depth is 5-30cm, so that the accumulation and hardening of the organic matter surface of the straw nutrients can be relieved, the oxygen partial pressure is reduced, the corrosion piling effect is increased, the probability of difficult seedling emergence of crops is reduced, the accumulation of the organic matter of the soil in a full plough layer is promoted, and the improvement of the structural condition of the soil of the full plough layer is facilitated.

Fourthly, burying among lines to return the straws to the field in a staggered way. The conventional straw composting takes long time, the straws are subjected to in-situ composting in the field, and the compost effect can be utilized for decomposing when crops grow. The composting of a large amount of straws is difficult, and the inter-row space for the growth of crops is utilized for composting. The direct contact between the root system and the straws in the growth process of the crops is avoided, so that the adverse effects of diseases, pests, weeds and the like which have close relation with the biochemical allelopathy effect are reduced.

The soil nutrient is beneficial to the return flow of the soil nutrient from the crops, the basic fertility level of the soil is increased, and the consumption of the fertilizer is reduced.

Has the advantages that: 1. and (5) cultivating soil fertility. The method can relieve the accumulation and hardening of the organic matter surface of the straw nutrients, reduce the oxygen partial pressure, increase the composting effect, reduce the probability of difficult seedling emergence of crops, promote the accumulation of the organic matter of the soil in the full plough layer, and is favorable for improving the soil structure condition of the full plough layer.

2. Has time and space advantages in the conversion of organic carbon and nutrients in the straws. The conventional straw composting takes long time, the straws are subjected to in-situ composting in the field, and the compost effect can be utilized for decomposing when crops grow. The composting of a large amount of straws is difficult, and the inter-row space for the growth of crops is utilized for composting.

3. The direct contact between the root system and the straws in the growth process of the crops is avoided, so that the adverse effects of diseases, pests, weeds and the like which have close relation with the biochemical allelopathy effect are reduced.

4. The fertilizer is beneficial to the backflow of soil nutrients from crops, increases the basic fertility level of soil and reduces the consumption of fertilizers.

5. The nitrogen fertilizer uses refined chicken manure which can bring more exogenous active microorganisms for promoting straw decomposition, provide more energy and degradation substrates for indigenous microorganisms of soil, play an excitation type detonation effect for improving the overall soil microorganism metabolic activity, accelerate the degradation of straws and the accumulation of soil organic matters, and have a positive excitation effect for the nutrient release of background soil stable organic matters.

Drawings

FIG. 1 is a schematic diagram of the technical principle and mode of the method of the present invention;

FIG. 2 is a photograph of a soil plough layer, the left figure being a depth map of the soil plough layer, the right figure being the soil plough layer;

FIG. 3 is a graph of organic carbon content of soils treated differently;

FIG. 4 is a graph of crop yield under different treatments.

Detailed Description

The following soil tests further illustrate the contents of the present invention but should not be construed as limiting the invention. Modifications and substitutions to methods, procedures, or conditions of the invention may be made without departing from the spirit and substance of the invention. Unless otherwise indicated, the technical means used in the following examples are conventional means well known to those skilled in the art, and the specific measurement methods not indicated in the test are all the measurement methods described in Shanghai, Kun et al, soil agricultural chemical analysis, Chinese agricultural science and technology Press 1999.

Example 1

An excitation type straw in-situ intertidal burying returning soil fertility cultivation method is disclosed, and with reference to fig. 1, the method comprises the following steps:

step 1, after crops are harvested, smashing corn straws, wherein the corn straws need to be smashed to be not more than 10cm, and returning the wheat straws to the field directly;

step 2, uniformly mixing nitrogen fertilizer into the straws with the use amount of 2 kg/mu, and then uniformly mixing a microorganism excitation regulator with the use amount of 100 kg/mu;

step 3, ditching among rows is carried out, the distance among the rows and the excavating depth need to be adjusted according to the crop variety, the planting density and the straw returning amount, the distance among the straw burying rows is 60cm, the excavating depth is 5-30cm, and the crop sowing row spacing is 40cm in the embodiment;

step 4, burying the straw, the nitrogen fertilizer and the microorganism excitation regulator composition into the ditch, and then covering soil and pressing;

and 5, fertilizing, sowing and compacting, ensuring uniform sowing, consistent sowing depth and tight coverage, watering at proper time after sowing to accelerate soil compaction and promote the conversion of organic carbon and nutrients of the straws into the soil, wherein the conventional fertilizing in the embodiment is to apply 200kg/ha of nitrogenous fertilizer, 105kg/ha of phosphate fertilizer and 105kg/ha of potash fertilizer.

Application example 1

Materials and methods

1. General description of the test site

The test site is located at the national test station (35 degrees 01 'N, 114 degrees 32' E) of the dune agricultural ecosystem of the national academy of Chinese science in the area of the mound, Henan province. The area belongs to a semiarid and semihumid warm-temperate zone monsoon climate, average annual precipitation is 615mm, 67% of precipitation is concentrated in 6-9 months; the average temperature is 13.9 ℃, the average temperature in the lowest month is 1 month, is-1.0 ℃, and the average temperature in the highest month is 27.2 ℃, and is 7 months. The soil in the area develops into the tidal soil of the yellow river alluvial substance, and the basic fertility indexes of the soil of the experimental primary plough layer are as follows: organic matter 8.00g kg^-10.54g kg of total nitrogen^-10.86 kg of total phosphorus^-1Total potassium 19.17gkg^-140.92mg kg of alkaline hydrolyzable nitrogen^-1Effective phosphorus 16.71mgkg^-1Quick-acting potassium 63.67mgkg^-1，pH 8.57。

2. Design of experiments

The experiment totally designs 3 straw returning modes:

(1) straw removal (NSF0, NSFR): manually moving the straws out of the cell after the crops in the previous season are harvested;

(2) conventional coverage returning (SF0, SFR): returning the wheat straws to the field in the previous season to be smashed fresh corn straws with the diameter less than 10mm, and returning the corn straws to the field directly without smashing after harvesting the wheat.

(3) The excitation type straw dislocation wheel is also used for mixing nitrogen fertilizers (ISOM and ISFR): by the method of example 1, nitrogen fertilizer (chemical nitrogen fertilizer and decomposed organic fertilizer both can be used, the amount is 15 wt.% of the total nitrogen application, about 2 kg/mu), then microbial excitation regulator is mixed evenly according to 100 kg/mu. Before sowing, digging 30 cm-deep grooves among planting rows and burying crushed straws.

Wherein 2 treatments are set for each straw returning mode, fertilization and non-fertilization treatments are set for both straw removal and conventional covering returning, and the nitrogen fertilizer types in the straws in the removal and excitation type straw dislocation wheel returning mode are 2 chemical nitrogen fertilizers and decomposed chicken manure. And 4 treatments are arranged, each treatment is 4 times, each cell is 8m long and 5m wide, and the periphery of each cell is isolated by a 1m deep-water mud baffle which penetrates into the underground for 80cm and is 20cm higher than the ground. The tested wheat variety is Zhengmai 9023, and the corn variety is Zhengdan 958. Recommended nitrogen fertilizer application of 200 kg.N.hm^-2The residual nitrogen fertilizer is applied to the corn in the jointing stage and the filling stage at a ratio of 4:6 respectively, and the residual nitrogen fertilizer is applied to the wheat in the green turning stage; the application amount of the phosphate fertilizer is 105 kg.P₂O₅·hm^-2The application amount of the potassium fertilizer is 105 kg.K₂O·hm^-2. And finally, sowing and compacting, ensuring uniform sowing, consistent sowing depth and tight coverage, and watering at proper time after sowing to accelerate soil compaction and promote the conversion of organic carbon and nutrients of the straws into the soil.

(II) test results

1. Topsoil water-stable agglomerates

As can be seen from the data in tables 1 and 2, the water-stable soil aggregates in the region are mainly distributed in the range of 250-2000 μm, the straw returning (SF0 and SFR) and fertilization (NSFR) measures can promote the particle size of the soil aggregates to be transferred from 53-250 μm to 250-2000 μm, but the straw returning measures have stronger promotion effect on the transfer of the micro aggregates to the fine aggregates, and the excitation type straw intercross burying (ISOM and ISFR) measures not only promote the transfer of the particle size of the soil from 53-250 μm to 250-2000 μm, but also show an increasing trend in the percentage content of the particle fraction of >2000 μm.

TABLE 1.0-10 cm soil Water-stable aggregate composition under different treatments

Note: the data in the table are the average of 4 replicates; different letters after the same column of data indicate significant differences between different treatments (P <0.05) (LSD method test)

Analysis of the composition data of the soil water-stable aggregates of 0-10cm in table 2 shows that the contents of the coarse aggregates and the micro aggregates in each treatment are remarkably reduced, the contents of the fine aggregates and the large aggregates are remarkably increased, and all levels of aggregates have a tendency of gathering together the fine aggregates and the large aggregates, wherein the fine aggregates and the large aggregates (250-2000 μm) > the micro aggregates (53-250 μm) > the powdery micro aggregates (<53 μm) > the coarse aggregates (2000 μm). Under the condition of no fertilization (NSF0 and SF0), the straw returning can obviously increase the content of fine and large aggregates, the amplification reaches 42.17%, and the content of coarse aggregates and micro aggregates is reduced. Under the conventional fertilization conditions (NSFR, SFR and ISFR), the proportion of fine and large aggregates increased by straw mulching and returning is 25.16%, and the proportion of fine and large aggregates increased by straw inter-row burying and returning is 28.11%. Under the condition of straw-free returning to field (NSF0 and NSFR), the conventional fertilization can increase the fine and large aggregates by 15.15 percent. Compared with NSF0, the excited straw can also increase the content of fine and large aggregates by 48.30-58.88%, wherein the treatment effect of the organic nitrogen fertilizer excitation (ISOM) is better than that of the inorganic nitrogen fertilizer excitation (ISF) under the same excitation nitrogen fertilizer proportioning condition.

TABLE 2.10-20 cm soil Water-stable aggregate composition under different treatments

Note: the data in the table are the average of 4 replicates; different letters after the same column of data indicate significant differences between different treatments (P <0.05) (LSD method test)

From table 2, in a soil layer of 10-20cm, the distribution rule of soil water-stable aggregates of each size fraction is similar to that of a soil layer of 0-10cm, but the dominant advantages of the fine and large aggregates are less obvious than that of the upper soil layer, the distribution ratio of the fine and large aggregates to the micro aggregates is relatively even, and the effect of different treatments on the increase of the fine and large aggregates is less obvious than that of the upper soil layer. In the absence of fertilizer (NSF0 and SF0), straw return reduces the content of fine and large aggregates and increases the content of coarse aggregates, unlike other treatments. Under the conventional fertilizing conditions (NSFR, SFR and ISFR), the proportion of the fine and large aggregates increased by straw mulching and returning is 6.11%, and the proportion of the fine and large aggregates increased by straw inter-row burying and returning is 5.46%. Under the condition of straw-free returning to field (NSF0 and NSFR), the conventional fertilization can increase the fine and large aggregates by 5.17%. Compared with NSF0, the excited straw can also increase the content of fine and large aggregates by 12.44% -32.44%, wherein the treatment effect of the organic nitrogen fertilizer excitation (ISOM) is better than that of the inorganic nitrogen fertilizer excitation (ISF) under the same excitation nitrogen fertilizer proportioning condition.

2. Soil organic matter

As shown in fig. 3, comparing the organic carbon content of 0-10cm soil under different treatments, it is known that, compared with NSF0, the organic carbon content of soil can not be significantly increased by single straw mulching and returning (SF0) or conventional fertilization (NSFR) measures, but the organic carbon content of soil can be significantly increased under the combined (SFR) condition, the increase is 27.75%, the difference between ISFR and SFR in the increase of organic carbon in soil is not significant, and the difference between excited straw deep return (ISOM and ISF) in the increase of organic carbon in undisturbed soil is significant, and the increase is 31.66% -43.95%. Compared with the organic carbon content of the soil with the soil thickness of 10-20cm under different treatments, the organic carbon content of the soil can be obviously improved by straw mulching or conventional fertilization measures, the IS treatment has a more obvious effect, the amplification reaches 67.16%, and the increase of the organic carbon content of the soil by the excitation type straw deep returning (ISOM and ISF) reaches 76.72% -112.5%. Comparing organic carbon in soil in the same treatment layer, the excitation type straw burying and returning treatment shows that the organic carbon content in the soil in the lower layer is higher than that in the upper layer, and the rest treatments are opposite.

3. Yield of crops

As shown in FIG. 4, the yield of crops obtained by different treatments is reduced due to straw mulching and returning compared with deep straw because: 1. the soil penetration depth of the straws is less than 20cm, so that the soil gap is large, and the seedling emergence and root system rolling of crops are influenced; 2. the straw surface layer is covered and returned to the field, so that the water holding capacity of the surface soil is reduced, and the straw decomposed by microorganisms absorb water, so that the straw is not easy to decompose and become thoroughly decomposed; 3. when the soil microorganisms decompose the straws, a certain amount of nitrogen is needed, and the straws are returned to the field without fertilization, so that the C/N imbalance of the soil is caused, and the microorganisms and wheat seedlings compete for the nitrogen in the soil, so that the yield is reduced finally.