CN111165112A

CN111165112A - Rice field oxygen-increasing and emission-reducing dry farming method

Info

Publication number: CN111165112A
Application number: CN202010099769.9A
Authority: CN
Inventors: 张卫建; 张俊; 黄山; 董文军; 陆长婴; 邓艾兴; 宋振伟; 郑成岩
Original assignee: Institute of Crop Sciences of Chinese Academy of Agricultural Sciences
Current assignee: Institute of Crop Sciences of Chinese Academy of Agricultural Sciences
Priority date: 2020-02-18
Filing date: 2020-02-18
Publication date: 2020-05-19
Anticipated expiration: 2040-02-18
Also published as: CN111165112B

Abstract

The invention relates to the technical field of crop planting, and particularly discloses an oxygen-increasing and emission-reducing dry ploughing method for a rice field. The method comprises the following steps: (1) after the previous crops are harvested, crushing the whole straws, uniformly throwing and returning the straws to the field; (2) optimizing dry ploughing operation; the first-maturing rice area adopts a one-turning one-rotating wheel ploughing mode; or, the rice and wheat rotation area adopts a rice season ploughing and dry rotary upturned soil crushing mode and a wheat season rotary tillage mode; or, the double-cropping rice area adopts the modes of soil improvement by lime in winter, ploughing, rotary tillage of early rice in spring and rotary tillage of late rice; (3) unpowered stirring and rice stubble burying. Compared with the traditional water ploughing and water preparation, the method improves the soil oxidation-reduction condition in the early stage of rice growth and reduces the toxic action of reducing substances; improving the granular structure of the soil and promoting the growth of root systems; reduce the greenhouse gas emission of the rice field and improve the environment of the rice field.

Description

Rice field oxygen-increasing and emission-reducing dry farming method

Technical Field

The invention relates to the technical field of crop planting, in particular to an oxygen-increasing and emission-reducing dry ploughing method for a rice field.

Background

At present, returning the whole amount of straws to the field is a main way for solving the problem of rice straws. The problems of large straw returning quantity, difficult returning, high methane emission in a rice field and the like of the existing main rice cropping system (a northern first-maturing rice area, a rice and wheat crop rotation area and a double-cropping rice area) are obvious. The full straw returning has great influence on the soil condition of the rice field in the early stage of rice growth, the soil is soaked in water for land preparation before transplanting (or sowing) and is continued to the field sunning in the tillering vigorous stage, the soil is always in a reduction state in the period, and a large amount of straw is added, so that the reduction state of the rice field is aggravated, the seedling delay period is prolonged, the seedling is stiff in the early stage of tillering, hydrogen sulfide poison, rotten roots, CH (CH) are poisoned₄The problems of high discharge and the like limit the early and fast emergence of the seedlings.

Aiming at the problems, the production is mainly solved by changing a farming mode and an early-stage water management mode, such as dry land preparation, dry direct seeding and the like. In the dry land preparation, the traditional field preparation by soaking is changed into the field preparation by soaking in deep water, stirring and harrowing, but the porosity of the soil is reduced after high-strength pulping, the oxygen content and the available nutrient content in the soil are reduced, and the early group construction of the rice growth is not facilitated; the dry direct seeding operation still has some problems in production at present, such as low seeding quality caused by large straw returning quantity, serious weeds, large lodging risk and the like.

Therefore, there is a need to provide an oxygen-increasing and emission-reducing dry-ploughing method for rice fields to alleviate the above problems.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a rice dry ploughing method for improving soil oxidation-reduction property and reducing greenhouse gas emission.

In order to achieve the purpose of the invention, the technical scheme of the invention is as follows:

an oxygen-increasing and emission-reducing dry ploughing method for rice fields comprises the following steps:

(1) after the previous crops are harvested, crushing the whole straws, uniformly throwing and returning the straws to the field;

(2) dry ploughing:

the first-maturing rice area adopts a one-turning one-rotating wheel ploughing mode;

or, the rice and wheat rotation area adopts a rice season ploughing and dry rotary upturned soil crushing mode and a wheat season rotary tillage mode;

or, the double-cropping rice area adopts the modes of soil improvement by lime in winter, ploughing, rotary tillage of early rice in spring and rotary tillage of late rice;

the one-turning one-rotating wheel tillage mode specifically comprises the following steps:

ploughing in autumn in the 1 st year, wherein the depth of ploughing is 18-20 cm, the ploughing depth is consistent, no trench is left, furrow cutting is tight, and no heavy and no leakage occurs; reverse rotation deep burying rotary tillage is carried out in autumn of 2 years, the depth of the reverse rotation deep burying rotary tillage is 15cm-22cm, no missing tillage, no dark ridge and no dragging and piling are achieved, the ground surface is smooth after soil preparation, and the straw and the root stubble do not leak;

the ploughing depth of the rice in the rice and wheat rotation area in the rice season is 25cm-30 cm;

the rotary tillage depth of the wheat season in the rice and wheat rotation area is 10cm-12 cm;

the method is characterized in that the soil is changed by lime in winter and ploughing is carried out once every 3-4 years, and the specific mode is as follows: ploughing up and sunning the furrow after harvesting the previous-stubble late rice, wherein the ploughing depth is 20-25 cm, and simultaneously, matching with lime application operation;

the depth of the early rice rotary tillage and the late rice rotary tillage in spring is 14cm-16 cm;

(3) unpowered slurry stirring and rice stubble burying:

harrowing the first-maturing rice area after the freeze thawing of the soil is finished in spring, firstly irrigating running horse water to ensure that no water is accumulated on the field surface, irrigating a 1-2cm water layer after wetting for 4-6 days, and performing unpowered slurry stirring and rice stubble burying;

for the rice and wheat rotation area, after the furrow is ground in a dry and rotary mode, the rice and wheat rotation area is soaked in water for 2 days, the water depth is 1-2cm, unpowered slurry stirring is carried out, and rice stubble is buried;

for the double-cropping rice area, soaking the field in shallow water after rotary tillage, wherein the water depth is 1-2cm, the field soaking time is 6-10 hours based on the condition that the high part of the field surface is provided with a pier, the low part is provided with water and the field is not waved during operation, and unpowered slurry stirring and rice stubble burying are carried out after the field soaking is finished;

and (4) after the unpowered slurry stirring and rice stubble burying in the step (3) are carried out, the straws are mixed and stirred in the slurry, no straw and stubble float, and the periphery of the field is smooth and consistent.

The invention realizes the dry tillage technology of oxygen increasing and emission reduction through the organic combination of specific dry land preparation, optimized rotation tillage and unpowered slurry stirring and land leveling technology, effectively improves the soil oxidation-reduction condition in the early stage of rice growth, reduces the toxic action of reducing substances, accelerates the decomposition rate of straws, and reduces the emission of greenhouse gases. In addition, the defects of conventional high-strength slurry stirring are effectively avoided, the proportion of soil large aggregates is increased, the soil aggregate structure is improved, the nitrogen supply capacity of a plough layer is increased, and the growth of crop roots is promoted.

In order to improve straw returning effect, improve soil oxidation reduction state and soil aggregate structure, comprehensively consider planting mode and slurry stirring strength and other factors, change the traditional farming mode into dry land preparation in autumn, combine plowing and reverse rotation deep burying, and bury grass on flat ground by shallow water unpowered slurry stirring, so that the rotation plowing and slurry stirring stages are reasonably matched, and the comprehensive effect of reducing greenhouse gas emission of the rice field and improving the rice field environment is realized.

The traditional rotation tillage mode in the rice and wheat rotation area is rice season rotary tillage, power beating and wheat season rotary tillage, and the mode has the problems of poor straw returning effect, rice seedling runt seedling, poor wheat season culturability and the like; the rotary tillage mode in wheat season is used to improve the quality of rice group and reduce the emission of greenhouse gas in rice field.

The invention aims to deepen the plough layer structure and increase the rice field oxidation-reduction property, and changes the paddy field oxidation-reduction property into a mode of timely ploughing in winter, lime application, early rice rotary tillage, late rice rotary tillage and shallow water unpowered slurry stirring to construct a better plough layer soil aggregate structure and reduce the greenhouse gas emission of the rice field.

In the invention, the first-maturing rice region refers to a northern first-maturing rice region, in particular to sandy loam of a first-maturing region for planting first-cropping rice in northern China, such as Heilongjiang, Liaoning, Jilin and the like.

The rice and wheat rotation region refers to the annual rice and wheat rotation region, in particular to the rice and wheat two-cropping region in the middle and lower reaches of Yangtze river in China, such as Jiangsu, Anhui, Hubei and the like.

The double cropping rice region refers to the region where early rice and late rice are planted in the south all the year round, in particular to the region where the early rice and the late rice are ripened in the middle and lower reaches of the Yangtze river in China, such as the soil acidification regions in the Jiangxi, Hunan and southern Anhui.

The invention has the advantages that the rotation tillage optimization is different in the tillage modes of different types of rice fields, the northern once-ripe rice field is used for soil preparation in autumn, the tillage is carried out for 1 year, and the rotary tillage is carried out for 1 year; rice and wheat rotation areas, rice season ploughing, dry rotary upturned soil smashing and wheat season rotary tillage; and (3) ploughing and sunning upturned soil every 3-4 years in the double-cropping rice area, carrying out rotary tillage on early rice in spring and late rice in summer.

The invention adopts unpowered gentle slurry stirring, maintains the soil granular structure, and can adopt the unpowered slurry stirring land leveler to bury stubbles on the ground. The water is shallow, no water surface exists, the water is dragged by a medium tractor (more than or equal to 60 horsepower), the self-weight of the tractor is utilized to compact the straws and break the soil, and the pressure plate at the back screeds the ground. The invention can adopt the unpowered pulper and the improved device which are described in Chinese patents CN205284048U and CN 206977935U.

In the invention, when the straws are ground and returned to the field, a rice harvester with a straw crushing function and a throwing device can be adopted to harvest the previous rice stubble together, and the ground surface is uniformly covered with the crushed straws.

When soil preparation is carried out in a first-maturing rice area, ploughshare plows can be used for ploughing in autumn of 1 year, and a reverse-rotation deep-buried rotary cultivator can be used for rotary tillage in autumn of 2 year.

In the rice and wheat rotation area, ploughing and dry rotary furrow breaking can be respectively carried out by a furrow plough and a rotary cultivator. The wheat season adopts all-in-one rotary tillage operation.

In the double-cropping rice area, the large rotary cultivator can be used for soil preparation in the early rice season and the late rice season to ensure the soil preparation effect after straw returning to the field.

In the invention, the length of the crushed straws is less than or equal to 10cm, and the stubble remaining height of the straws is less than or equal to 10cm, so that the straws are uniformly scattered and covered for returning to the field, the phenomenon of stack dragging in the slurry stirring process is prevented, and the straw returning rate and the stubble burying effect are improved.

In the invention, the water content of the soil during tillage in autumn of 1 year is less than or equal to 30%, and the water content of the soil during reverse-rotation deep-burying rotary tillage in autumn of 2 year is less than or equal to 25%, so that during rush farming, an agricultural machine can be timely put into the field for soil preparation, the soil tiltability is improved, and the working efficiency and the soil preparation effect are improved.

The dry ploughing before rice transplanting: after the previous crops are harvested, no water is added to the field, and when the water holding capacity of the soil is less than or equal to 30%, dry ploughing operation can be carried out by adopting a furrow plough or a rotary cultivator, and the field is dried.

In the invention, quick lime or hydrated lime is selected as the lime, and the dosage of the lime is 90-110kg per mu, so that the pH value of soil is improved, and the decomposition rate of straws is increased.

After the late rice in the double-cropping rice area is harvested, the furrow-drying soil is ploughed as early as possible before winter, and the uniform spreading is carried out by matching with lime application operation.

The method of the invention also comprises the following steps:

(4) dense planting and fertilizer application adjustment:

density increasing planting (the planting density of each rice planting area varies with the land): when the rice transplanting mode is adopted, the planting distance is reduced, the row spacing is kept unchanged, and the transplanting density is increased by 15-25%; when the seedling throwing or direct seeding mode is adopted, the seedling throwing number or the seeding amount is improved by 15 to 25 percent on the basis of the current seedling throwing number or the seeding amount;

adjusting nitrogen fertilizer:

for the first-maturing rice area, reducing the nitrogen fertilizer in the base fertilizer of the current area, wherein the nitrogen fertilizer reduction amount is 20% of the total nitrogen fertilizer application amount of the current area, and adjusting the nitrogen fertilizer, which accounts for 18-22% of the total nitrogen fertilizer application amount of the current area, in spike fertilizer into tiller fertilizer;

and for the rice and wheat rotation area and the double-cropping rice area, reducing the nitrogen fertilizer in the base fertilizer or the spike fertilizer, wherein the nitrogen fertilizer reduction amount is 18-22% of the total nitrogen fertilizer application amount in the current area.

The total amount of nitrogen fertilizer application in the current area of the invention refers to the nitrogen fertilizer usage under the local high-yield level.

The research of the invention finds that in a first-maturing rice area, the improved rotary tillage and slurry stirring mode is matched, the planting density is further increased, the nitrogen fertilizer consumption is properly reduced, the high yield level of rice can be maintained, and the utilization efficiency of nitrogen fertilizer is obviously improved. According to the method, the nitrogen fertilizer amount in the panicle fertilizer in the current planting area is reduced by adjusting the nitrogen consumption of the base fertilizer and simultaneously adjusting the application proportion in each period, and the corresponding reduced amount (the total nitrogen amount is 18-22%) is added into the tiller fertilizer.

In the first-maturing rice area in the north, the existing nitrogen fertilizer is characterized in that the base fertilizer: and (3) fertilizing the tillers: the common application proportion in the spike fertilizer is 40%: 30%: 30 percent, after adjustment, the total amount of the nitrogen fertilizer is reduced by 20 percent (after the nitrogen of the base fertilizer is reduced), and simultaneously the nitrogen fertilizer accounting for 18 to 22 percent of the total amount of the nitrogen fertilizer applied in the current area in the spike fertilizer is adjusted into the tiller fertilizer to obtain the corresponding base fertilizer of the invention: and (3) fertilizing the tillers: the application proportion of the spike fertilizer is 25%: (60% -65%): (10% -15%).

Wherein, in the base fertilizer, N, K₂O、P₂O₅The mass ratio of (7-8): (5-6): (10-15); in the ear fertilizer, N, K₂The mass ratio of O is (3-4): (5-6).

The tillering fertilizer comprises a striking root fertilizer and a tillering fertilizer, wherein the mass ratio of the striking root fertilizer to the tillering fertilizer is (4-5): (5-6).

The research of the invention also discovers that the improved rotation and slurry stirring modes of the invention are matched in the rice and wheat rotation area and the double cropping rice area, so that the planting density is further increased, the use amount of nitrogen fertilizer is properly reduced, and the utilization efficiency of the nitrogen fertilizer can be obviously improved while the high yield level of the rice is maintained.

In rice and wheat crop rotation areas, the existing nitrogen fertilizer is characterized in that the base fertilizer: and (3) tillering fertilizer: the common application proportion in the spike fertilizer is 30%: 40%: 30 percent, the total amount of the nitrogen fertilizer is reduced by 18 to 22 percent after adjustment, and the nitrogen dosage of the spike fertilizer is reduced as an example, so that the corresponding base fertilizer of the invention is obtained: and (3) fertilizing the tillers: the nitrogen application proportion of the spike fertilizer is (36-39%): (48-52%): (10-15%). Wherein, in the base fertilizer, N, K₂The mass ratio of O is (6-7): (2-2.5) applying no phosphate fertilizer; in the ear fertilizer, N, K₂The mass ratio of O is (2-2.5): (2-2.5).

In early season rice in double cropping rice regions, the existing nitrogen fertilizer is characterized in that the base fertilizer: and (3) tillering fertilizer: the common application proportion of the panicle fertilizer is 50 percent to 20 percent to 30 percent, and after adjustment, the nitrogen consumption of the panicle fertilizer is reduced by 18-22 percent of the total amount of the nitrogen fertilizer, so that the corresponding base fertilizer of the invention is obtained: and (3) fertilizing the tillers: the application proportion of nitrogen of the spike fertilizer is (60-65%): (24-26%): (10-15%). Wherein, in the base fertilizer, N, K₂O、P₂O₅The mass ratio of (5-6): (2-3): (4.5-5.5); in the ear fertilizer, N, K₂The mass ratio of O is (0.8-1.4): (2-3).

In late rice seasons of double cropping rice regions, the existing nitrogen fertilizer is characterized in that the base fertilizer: and (3) tillering fertilizer: the common application proportion of the panicle fertilizer is 50 percent to 20 percent to 30 percent, and after adjustment, the nitrogen consumption of the panicle fertilizer is reduced by 18-22 percent of the total amount of the nitrogen fertilizer, so that the corresponding base fertilizer of the invention is obtained: and (3) fertilizing the tillers: the application proportion of nitrogen of the spike fertilizer is (60-65%): (24-26%): (10-15%). Wherein, in the base fertilizer, N, K₂O、P₂O₅The mass ratio of (6-7): (2-3): (4.5-5.5); in the ear fertilizer, N, K₂The mass ratio of O is (1-1.6): (2-3).

The nitrogen regulation technology of each rice area is different from one area to another, and the nitrogen regulation technology is matched with specific rotation tillage optimization and slurry stirring, so that the nitrogen regulation technology can be more reasonably aimed at the characteristics of each area, and the effects of increasing the yield and reducing the environmental burden are realized.

Preferably, when a seedling transplanting mode is adopted, the transplanting density is increased by 20 percent; when the seedling throwing or direct seeding mode is adopted, the seedling throwing number or the seeding amount is improved by 20 percent on the basis of the current seedling throwing number or the seeding amount;

for the first-maturing rice area, adjusting a nitrogen fertilizer accounting for 20% of the total nitrogen fertilizer application amount of the current area in spike fertilizer into the tiller fertilizer;

for the rice and wheat rotation area and the double-cropping rice area, the amount of nitrogen fertilizer reduction is 20% of the total amount of nitrogen fertilizer application in the current area;

the method of the invention also comprises the following steps: protecting seedlings in shallow water after planting, and keeping shallow water after the seedlings are delayed and dried in the field for 2-3 days; drying the field in time before and after the critical leaf age period of tillering; and (4) flower retention in shallow water during booting and flowering stages, and dry-wet alternation after ear emergence.

The method maintains shallow water to promote the seedlings to grow quickly and early through scientific irrigation, and looks at the critical leaf age for effective tillering to dry the seedlings in the field; and (4) flower retention in shallow water during booting and flowering stages, and dry-wet alternation after ear emergence. And can be matched with proper time of overall control operation of diseases, insects and weeds to ensure the growth of rice.

As an implementation mode of the rice dry ploughing method, the specific implementation steps are as follows:

1. variety selection: the rice variety with high yield, high quality and low carbon emission is preferred.

2. Timely harvesting of the previous crops: after the front crops are mature, harvesting by adopting a full-feeding type combine harvester with a throwing device, keeping the height of the stubbles not higher than 10cm, and uniformly scattering the stubbles on the field surface, wherein the smashing length of the straws is not more than 10 cm.

3. Mechanical dry ploughing: the dry ploughing operation is carried out by adopting a furrow plough (or a rotary cultivator) at proper time, so that the straw is uniformly returned to the field without leakage; and (6) airing the field.

4. Unpowered slurry stirring, stubble burying on the ground: the paddy field is soaked in shallow water (determined according to the stubble period of the rice crop region) before transplanting, then, a power-free slurry stirring land leveler which is dragged by a tractor (more than or equal to 60 horsepower) is used for flatly burying stubbles on the ground, straws are mixed in slurry after the paddy field is raked, no straws and stubbles float, and the periphery of the paddy field is leveled and consistent; then keeping the water layer in the field for 2cm to settle.

5. Closed weeding: and 5-10 days before transplanting, adopting 50% pretilachlor to carry out closed operation and carrying out chemical weeding.

6. Transplanting by a seedling raising machine, plant shrinkage and densification: the seedling planting depth is 2-3cm to prevent floating. Compared with the traditional mode in the current area, the planting density is increased by 15-25% (row spacing is unchanged, the plant spacing is reduced), and the machine transplanting specification can adopt the row spacing of 25-30cm multiplied by 10-13cm, and each hole is about 5-6 seedlings.

7. Scientific management of water: shallow water seedling protection, wherein after green turning, shallow water service irrigation is adopted, and the water layer is 2-3cm, so that tillering is promoted, early tillering is realized, and hair growing is accelerated; looking at seedlings and drying in the field at the critical leaf age stage of effective tillering; and (4) flower retention in shallow water during booting and flowering stages, and dry-wet alternation after ear emergence.

8. And (3) reasonably regulating nitrogen:

the amount of nitrogen varies depending on the rice field. According to the nitrogen fertilizer dosage under the local high-yield level, the nitrogen of the basal fertilizer (the total nitrogen content is 20%) is adjusted and reduced in the first-maturing rice area in the north, and the nitrogen of the spike fertilizer (the total nitrogen content is 18-22%) is adjusted to the tillering fertilizer; the dosage of base fertilizer nitrogen or spike fertilizer nitrogen (the total nitrogen amount is 18-22%) is reduced in southern rice and wheat rotation areas, early rice and late rice.

9. And (3) pest control:

preventing and treating sheath blight and chilo suppressalis in the middle and later stages of rice tillering, and preventing and treating rice blast, rice leaf roller, rice planthopper and other diseases and insect pests in the later growth stage.

10. Timely harvesting rice:

draining and airing the field 7-15 days in advance according to the field situation, harvesting by adopting a full-feeding type combine harvester with a throwing device at proper time, keeping the stubble height not higher than 10cm, and uniformly scattering the crushed straw on the field surface, wherein the crushed straw is not more than 10cm in length.

The invention has the beneficial effects that:

compared with the traditional water ploughing and water preparation, the method improves the soil oxidation-reduction condition in the early stage of rice growth and reduces the toxic action of reducing substances; improving the granular structure of the soil and promoting the growth of root systems; reduce the greenhouse gas emission of the rice field and improve the environment of the rice field.

Drawings

FIG. 1 is a graph comparing the distribution of soil agglomerates for example 1 of the present invention and comparative example 1;

FIG. 2 is a graph comparing oxidation-reduction potentials of example 1 of the present invention and comparative example 1;

FIG. 3 is a graph comparing the distribution of soil agglomerates for example 2 of the present invention and comparative example 2;

FIG. 4 is a graph comparing the oxidation-reduction potentials of early season rice of example 2 of the present invention and comparative example 2;

FIG. 5 is a graph comparing oxidation-reduction potentials of late rice of example 2 of the present invention and comparative example 2;

FIG. 6 is a graph comparing the distribution of soil agglomerates for example 3 of the present invention and comparative example 3;

in the figures of the present invention, "+" indicates that the inter-treatment differences reached a significant level of 0.05.

Detailed Description

Preferred embodiments of the present invention will be described in detail with reference to the following examples. It is to be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the present invention. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the spirit and scope of this invention.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1

In this example, production tests were carried out in the democratic test base of the institute of cultivation and cultivation of agriculture academy of sciences of Heilongjiang province in 2018 to 2019. The test field belongs to a first-maturing rice area in the north, and a second temperature accumulation zone in Heilongjiang province, has higher mechanization degree, and is suitable for implementation of the method. The specific implementation mode is as follows:

1. harvesting in autumn timely. The rice is harvested by adopting a rice harvester with a straw smashing function and a throwing device, the smashing length of the straws is less than or equal to 10cm, the smashed straws uniformly cover the ground surface, and the stubble height is less than 10 cm.

In 2.2018, turning over in autumn, and in 2019, reversely rotating to soil preparation. Wherein, ploughing by a furrow plough in 2018 (the soil moisture content is 27.7%); in 2019, a reverse rotation straw returning machine is adopted to carry out reverse rotation stubble burying operation (the water content of soil is 24.1%), and the matching power is more than 90 horsepower; the working width is 210 cm; the working depth is set to be 20cm (ploughing), 22cm (reverse rotation), the straw returning rate is more than or equal to 90%, the soil crushing rate is more than or equal to 95%, and the ground surface flatness is better after the operation.

3. And selecting a high-quality and high-yield rice variety with proper growth period, low carbon emission and strong lodging resistance by combining local accumulated temperature. In this example, the variety of Longdao No. 5 rice was selected.

4. Harrowing the soil in spring. Irrigating running horse water (no accumulated water on the field surface), wetting for 5 days, applying base fertilizer, irrigating (1-2cm water layer to prevent straw from floating), leveling the ground by using a unpowered beating grader, burying rice stubbles, raking the field, mixing the straws in the slurry, preventing the straws and stubbles from floating, and leveling and keeping the periphery of the field uniform.

5. And (5) mechanically transplanting rice seedlings. Transplanting rice seedlings by a rice transplanter with the planting density of 30cm multiplied by 11.5cm and 6 plants per hole (the traditional planting density of the local area is 30cm multiplied by 14 cm).

6. And (5) field management. The application ratio of the nitrogen fertilizer (base fertilizer: tillering fertilizer: spike fertilizer) is 25%: 62.5%: 12.5%. Wherein, the base fertilizer is 2.4kg N/mu and 2kg K₂O/mu, 4.67kg P₂O₅Per mu; 3kg of striking root fertilizer per mu, and 3kgN of tillering fertilizer per mu is applied 10d-12d after striking root; applying spike fertilizer (2 leaf period) 1.2kg N/mu, 2kg K₂O/mu. The application proportion of the traditional nitrogen fertilizer in the local area is as follows: and (3) fertilizing the tillers: the total nitrogen amount of the base fertilizer is reduced by 20% of the total nitrogen amount (the total amount of the traditional nitrogen fertilizer applied in the local area), and the nitrogen fertilizer accounting for 20% of the total amount of the traditional nitrogen fertilizer applied in the local area in the spike fertilizer is adjusted from the spike fertilizer to the tiller fertilizer.

7. And (5) managing water. Shallow water (1-3cm) is kept in the early stage, the field is baked by draining water in the middle stage, and the dry-wet alternation in the later stage (the dry naturally falls after each water filling) is realized.

8. The prevention and control of diseases, insects and weeds are carried out at the right time.

Example 2

In the embodiment, a test is carried out in 2018 in a test base of a red soil research institute in Jiangxi province, Xixian county, Jiangxi province, China, and the test base belongs to a southern double cropping rice district, so that the method is suitable for implementation.

The specific implementation mode is as follows:

1. winter management

1.1 lime soil improvement. Harvesting late rice, crushing the straws to return the field in full, and applying lime as early as possible. The lime material is hydrated lime with the dosage of 100kg per mu, and is uniformly spread. Lime is forbidden to be applied every year, and only needs to be applied once in 3-4 years.

1.2 ploughing before winter. After lime is applied, the sunned upturned soil is ploughed as early as possible to enhance the lime effect, and the ploughing depth is 25 cm. Ploughing and lime application are carried out in a matching way, and ploughing is carried out once in 3-4 years.

2. Early season of rice

2.1 rotary tillage and soil preparation. The land is prepared by adopting a large-scale rotary cultivator, the rotary tillage depth is 15cm, the field is soaked in shallow water after rotary tillage, the water depth is 1-2cm, the field soaking time is 6 hours, and the land is buried by adopting a powerless slurry stirring grader, wherein the water is present at the high position and the water is present at the low position of the field surface, and the operation is not waved. After the field is harrowed, the straws are mixed and stirred in the slurry, no straws and roots float, and the periphery of the field is smooth and consistent.

2.2 densifying and fertilizer adjusting. Jiazao 17 in early rice was selected in this example. The planting density is 25cm multiplied by 11cm, 4 plants are planted in each hole (the traditional planting density in the local area is 25cm multiplied by 13cm), and the spike fertilizer nitrogen is reduced by 20 percent (relative to the total amount of the traditional nitrogen fertilizer application in the local area). Calculated by the target yield per mu of 500kg, 5.5kg of nitrogenous fertilizer (pure nitrogen) and phosphate fertilizer (P) are applied to each mu of base fertilizer₂O₅)5kg of potash fertilizer (K)₂2.5kg of O), 2.2kg of nitrogenous fertilizer per mu of tillering fertilizer, 1.1kg of nitrogenous fertilizer per mu of spike fertilizer and potassium fertilizer (K)₂O)2.5 kg/mu. The amount of nitrogenous fertilizer and potash fertilizer in the traditional spike fertilizer in the local area is 3.3 kg/mu₂O) dosage is 2.5 kg/mu, the dosage of the nitrogen fertilizer in the panicle fertilizer is reduced by 20 percent of the total amount of the traditional nitrogen fertilizer.

2.3 moisture management. Shallow water seedling protection after planting, shallow water service irrigation after the seedlings survive and are exposed in the field for 2-3 days to promote early germination, and the seedlings are lightly placed in turn when the total number of the seedlings reaches 80% of the preset spike number, so that the seedlings do not sink in the field, the leaf color fades, and the leaves are raised. After the field is rested and rehydrated, the dry-wet alternation is kept, a shallow water layer is kept in the booting stage and the heading and flowering stage, and the dry-wet alternation is carried out after the ear is removed.

2.4 the whole amount of the crushed straws is returned to the field. And harvesting the rice mechanically after the rice is mature. The harvester is required to be additionally provided with a straw smashing device, and the length of the straws is ensured to be less than 10cm after being smashed.

3. Late rice season

3.1 rotary tillage and soil preparation. The land is prepared by adopting a large-scale rotary cultivator, the rotary tillage depth is 15cm, the field is soaked in shallow water after rotary tillage, the water depth is 1-2cm, the field soaking time is 6 hours, and the land is buried by adopting a powerless slurry stirring grader, wherein the water is present at the high position and the water is present at the low position of the field surface, and the operation is not waved. After the field is harrowed, the straws are mixed and stirred in the slurry, no straws and roots float, and the periphery of the field is smooth and consistent.

3.2 densifying and fertilizer adjusting. In this example, late rice Wuyou 308 rice was used. The planting density is 25cm multiplied by 13cm, 2 plants are planted in each hole (the traditional planting density in the local area is 25cm multiplied by 16cm), and the amount of the spike fertilizer is reduced. Measured by the target yield per mu of 550kg, 6.5kg of nitrogenous fertilizer (pure nitrogen) and phosphate fertilizer (P) are applied to each mu of base fertilizer₂O₅)5kg of potash fertilizer (K)₂2.5kg of O), 2.6kg of nitrogenous fertilizer per mu of tillering fertilizer, 1.3kg of nitrogenous fertilizer per mu of spike fertilizer and potassium fertilizer (K)₂O)2.5 kg/mu. The amount of nitrogenous fertilizer and potash fertilizer in the traditional spike fertilizer in the local area is 3.9 kg/mu₂O) dosage is 2.5 kg/mu, the dosage of the nitrogen fertilizer in the panicle fertilizer is reduced by 20 percent of the total amount of the traditional nitrogen fertilizer.

3.3. And (5) managing water. Shallow water seedling protection after planting, shallow water service irrigation after the seedlings survive and are exposed in the field for 2-3 days to promote early germination, and the seedlings are lightly placed in turn when the total number of the seedlings reaches 80% of the preset spike number, so that the seedlings do not sink in the field, the leaf color fades, and the leaves are raised. After the field is rested and rehydrated, the dry-wet alternation is kept, a shallow water layer is kept in the booting stage and the heading and flowering stage, and the dry-wet alternation is carried out after the ear is removed.

3.4 the late rice straw is crushed and returned to the field. Harvesting the late rice by a machine after the late rice is mature. The harvester is required to be additionally provided with a straw smashing device, and the length of the straws is ensured to be less than 10cm after being smashed.

Example 3

In this example, a test was conducted in taicang city, Jiangsu province, China in 2018, and the test field belongs to a rice and wheat crop rotation area in south China, and is suitable for implementation of the method of the present invention. The specific implementation mode is as follows:

1. harvesting in good time, and uniformly scattering and returning the straws to the field. The rice is harvested by a rice harvester with a straw smashing function and a throwing device, the smashing length of the straws is less than or equal to 10cm, the smashed straws uniformly cover the ground surface, and the stubble height of the straws is less than or equal to 10 cm. If the stubble is too high and the straw crushing and throwing can not meet the requirement, a straw crushing and returning machine is adopted to carry out one-time straw crushing and returning operation.

2. Ploughing in rice season, dry-rotary crushing upturned soil and rotary tillage in wheat season. Ploughing by a furrow plough and crushing upturned soil by a rotary cultivator in the rice season; land preparation requirement: the cultivation depth is preferably 25 cm; the wheat season adopts all-in-one rotary tillage operation, and the tillage depth is 12 cm.

3. Unpowered slurry stirring is carried out to bury grass on the ground, and the soil aggregate structure is kept. Soaking the field in shallow water with the water depth of 1-2cm before transplanting, and stirring and burying grass by using a power-free stirring grader, wherein the field soaking time is 2 days based on the condition that the high part of the field surface is provided with piers and the low part is provided with water and the operation is not waved. After leveling the land, the straws are mixed and stirred in the slurry, no straws and stubbles float, and the periphery of the field is smooth and consistent.

4. And selecting a high-quality and high-yield rice variety with proper growth period, low carbon emission and strong lodging resistance by combining local accumulated temperature. In this example, Nanjing 5055 is selected as a rice variety.

5. And (5) mechanically transplanting rice seedlings. Transplanting rice seedlings with a transplanter at a planting density of 30cm × 11.5cm and 5 plants per hole (the traditional planting density in the local area is 30cm × 14 cm).

6. And (5) field management. The application ratio of the nitrogen fertilizer (base fertilizer: tillering fertilizer: spike fertilizer) is 37.5 percent to 50 percent to 12.5 percent. Wherein, the base fertilizer is 6.6kg N/mu and 2.25kg K₂O/mu; applying 8.8kg of tillering fertilizer per mu; topdressing of 2.2kg of spike fertilizer and 2.25kg of K per mu₂O/mu. The application proportion of the traditional nitrogen fertilizer in the local area is as follows: and (3) fertilizing the tillers: the total nitrogen content of the ear fertilizer is reduced by 20 percent of the total nitrogen content (the total amount of the traditional nitrogen fertilizer applied in the local area).

Comparative example 1

In this comparative example, a production test was carried out at the same test site as in example 1, and the rice variety Longdao No. 5 was selected. Step 1 is the same as example 1, with the following differences: directly irrigating water in spring and soaking field for 3 days, conventionally stirring pulp with power and leveling land, wherein the shaft speed of the pulp stirrer is 280 r/min.

Comparative example 2

The comparative example is a production test in the same test base as the example 2, the rice variety and the straw crushing and returning mode are the same as the example 2, and the planting mode is different in that: the conventional rotary tillage in rice seasons and no tillage in winter (double-season rotary tillage). Before planting the rice in each season, carrying out rotary tillage for 2 times (the depth is about 15 cm), and stirring the rice pulp by power conventionally to level the ground, wherein the shaft speed of a pulp stirrer is 280 revolutions per minute.

Comparative example 3

In the comparative example, production tests are carried out on the same test base as that of the example 3, the rice variety and the straw crushing and returning mode are the same as that of the example 3, and the planting mode is different from that of the following steps: in the rice season, only a rotary tillage mode (the depth is about 12 cm) is adopted, the power is adopted to stir the pulp conventionally, and the shaft speed of a pulp stirring machine is 280 revolutions per minute.

Experimental example 1

This experimental example compares the rice yield, rice field methane, N in example 1 (optimization mode) and comparative example 1 (conventional mode)₂O emission, greenhouse gas emission intensity (GHGI), nitrogen fertilizer partial productivity, soil aggregate distribution, oxidation-reduction potential, straw floating amount, soil surface descending height and newly grown white root number are counted and tested, and specific test results are shown in a figure 1-figure 2 and a table 1-a table 2.

1. The way of testing the methane emission of the paddy field is as follows,

(1) gas sampling and measurement

Gas sample collection and measurement was performed using static dark box-gas chromatography. Sampling box and base are made by PVC light tight plastic slab, and sampling box length x width x height is 50 x 50cm (use 2 sampling boxes after the growth medium period rice plant height increases), and the box surface is glued well with 2 ~ 3cm thick sponge and aluminium foil glass fiber cloth in proper order to keep the temperature in the box stable during the sampling, reduce the temperature change in the box that arouses because of sunshine irradiation. The top of the box body is perforated, and a thermometer and a silicone tube for gas production are placed. Inside silicone tube one end inserted the sampling case, the other end was arranged the case in and is linked to each other with the three-way valve, and the syringe is connected to another head of three-way valve for gather gas sample. The fan is arranged in the sampling box, so that the air flow in the box is uniformly distributed. The base specification is 50X 10cm, and the base lower extreme is buried in soil, only remains U type recess on the earth's surface.

Before transplanting rice, the sampling base is inserted into a soil layer, and one base is buried in each cell. After the base is buried and stabilized for one week, sampling is performed in clear weather (9: 00 to 11:00 am), and gas samples are collected about every 7 days until the maturation period is finished. During sampling, water is injected into the groove of the base to seal the connection between the soil and the sampling box, then the sampling box is buckled, a 50ml injector is used for collecting gas samples every 0, 5, 10 and 15min after sealing, and meanwhile, the temperature in the box body is recorded.

Simultaneous determination of CH in gas samples using Agilent gas chromatograph (Agilent 7890A, Agilent Technologies, USA)₄And N₂Content of O, wherein CH₄Measurement with FID Detector, N₂O was measured using an ECD detector.

(2)CH₄And the discharge amount of greenhouse gas in unit yield

CH₄The emission flux calculation formula is:

F＝ρ·273/(273+T)·H·dC/dt

wherein F is the discharge flux; rho is CH at standard atmospheric pressure₄Density of 0.714kg m^-3(ii) a T is the average temperature in the sampling box in the sampling process, and the unit is; h is the net height of the box body of the sampling box, and the unit is m; dC/dt is the rate of change of the chamber gas concentration within the sample chamber. For CH of 4 time periods₄Linear fitting of concentration, regression coefficient R²The slope at 0.9 or higher is dC/dt. If R is²Less than 0.9, combining any three concentration data according to time, the slope of the maximum correlation coefficient represents dC/dt of the data, and R is still required²Greater than or equal to 0.9, otherwise, the group of data is eliminated. N is a radical of₂O emission flux calculation method and CH₄Are the same as above. Growing season CH₄And N₂And calculating the O accumulated emission by adopting an average summation method of two adjacent results.

The greenhouse gas emission intensity is tested in the following modes: according to IPCC (2013), rice field CH₄And N₂Conversion of O emissions to CO₂Equivalent weights with coefficients of 26 and 295, respectively (100 year time scale). Will CH₄And N₂The sum of O emissions is the unit areaThe amount of greenhouse Gas (GWP) discharged from the rice field. The unit yield emission is obtained by dividing the GWP by the unit area yield.

2. The soil aggregate distribution is measured by a wet screening method in the following specific test mode,

collecting plough layer soil within 1-2 hours after pulping, collecting representative undisturbed soil samples at multiple points in the field by using PVC pipes with the diameter of 10cm, performing wet sieve analysis on the aggregate analyzer, and simultaneously analyzing 4 soil samples at one time. Before analysis, water is added into 4 buckets, so that the upper edge of the sieve can be just level with the water level when the movement of the sleeve sieve reaches the highest point. Putting the sleeve sieve into a water bucket, starting a motor to move the sleeve sieve up and down, lifting by 4cm, taking out the water surface after 10 minutes, and separating the sieve group. The aggregates remaining on the screen at each stage were flushed into an evaporating dish with a fine stream of water, heated to dryness and weighed.

3. The oxidation-reduction potential was measured using an Eh meter (WTW SenTix ORP Tester).

4. The floating amount of the straws is sampled by adopting a multipoint sampling method, a square frame with the size of 1m multiplied by 1m is used after pulping, 10 points are selected for investigation immediately, the straws are collected, dried and weighed, and then the floating amount is converted into the floating amount in unit area.

5. The soil surface descends to a height. And (3) taking soil with a plough layer of 25cm by using a PVC pipe after pulping, removing the solution above the soil surface, recording the height of the soil surface at the moment, standing to a position where the soil surface height is stable, recording the height of the soil surface at the moment, and taking the difference of the two soil surface heights as the soil surface descending height.

6. The number of newly grown white roots. Immediately selecting 10 plants 7 days after the slow seedling of the rice, and investigating the number of newly added white roots.

TABLE 1 examples 1 and comparative examples 1 Paddy field CH₄And N₂O emission, global warming potential, greenhouse gas emission intensity, yield and nitrogen fertilizer partial productivity are compared

The difference in the letters after the numbers in the same column in the table indicates that the difference reaches a significance level of 0.05.

TABLE 2 soil preparation effect of example 1 and comparative example 1 and comparison of seedling quality

As can be seen from tables 1 to 2 and fig. 1 to 2, example 1 significantly reduced the methane emission, the integrated greenhouse effect and the intensity of greenhouse gas emission in the paddy field by 18%, 18.1% and 18.6%, respectively, as compared to comparative example 1 (table 1); example 1 the specific gravity and soil redox potential of large aggregates in rice field soil prior to rice planting were increased. The proportion of soil macro-aggregates (>2mm and 2-0.25mm) and soil micro-aggregates (0.25-0.05mm) is obviously improved, the soil oxidation-reduction potential is obviously increased in the early stage of tillering (5 months 12 and 5 months 15 days), and the soil aggregate structure and the oxidation-reduction property are improved (figure 1 and figure 2). Compared with the comparative example 1, the floating amount of the straws of the example 1 is reduced by 20.6%, the sinking amplitude of the field surface after flattening is 30.0%, the number of newly grown white roots of the seedlings is increased by 17.2%, and the yield is increased by 6.1% (Table 2).

Experimental example 2

This example compares the rice yields of early and late rice seasons, the rice field methane, and N in example 2 and comparative example 2₂The O emission, the greenhouse gas emission intensity, the nitrogen fertilizer partial productivity, the soil aggregate distribution, the oxidation-reduction potential, the straw floating amount, the soil surface descending height, the seedling burying depth and the new white root number are counted and tested, and the specific test results are shown in a figure 3-figure 5 and a table 3-a table 4. The test was conducted in the same manner as in Experimental example 1.

TABLE 3 comparison of rice yields, nitrogen fertilizer utilization efficiency and gas emissions between early and late rice seasons in example 2 and comparative example 2

TABLE 4 soil preparation effect and comparison of seedling quality between example 2 and comparative example 2

As can be seen from tables 3 to 4 and fig. 3 to 5, the early rice and late rice yields of example 2 were increased by 3.4% and 2.4%, respectively, as compared to comparative example 2; example 2 significant reduction in greenhouse gas emission, CH, in late rice season₄Emission, N₂The reduction amplitudes of O emission, the global warming potential of the rice field and the emission intensity of greenhouse gases are respectively 21.8 percent, 92.1 percent, 31.7 percent and 32.4 percent, the emission of the greenhouse gases in early rice seasons is in a reduction trend, and N is₂O emissions were significantly reduced (table 3). 0-20cm of soil macro-aggregates of example 2 (C) compared to comparative example 2>2mm and 2-0.25mm) are significantly increased (fig. 3); the oxidation-reduction potential of the soil in the early tillering stage (4-30 days in early rice season, 7-30 days in late rice season, 8-1 days in month) is obviously increased (figures 4-5), and the soil aggregate structure and the oxidation-reduction property are improved. Meanwhile, compared with the comparative example 2, the straw floating amount of the example 2 is reduced by 17.1%, the land subsidence amplitude after flattening is 26.1%, the seedling penetration depth is reduced by 19.6%, and the number of new white roots is increased by 45.9%.

Experimental example 3

In the experimental example, statistics and tests were carried out on the rice yield, the nitrogen fertilizer bias productivity, the rice field methane emission, the nitrous oxide emission, the greenhouse gas emission intensity, the soil aggregate distribution, the straw floating amount, the soil surface sinking height, the transplanting depth and the number of new roots in example 3 and comparative example 3, and the specific test results are shown in fig. 6, tables 5 to 6. The test was conducted in the same manner as in Experimental example 1.

TABLE 5 comparison of greenhouse gas emissions and Rice yields and Nitrogen use efficiency between example 3 and comparative example 3

TABLE 6 soil preparation effect and comparison of seedling quality between example 3 and comparative example 3

As is clear from tables 5 to 6 and FIG. 6, example 3 shows the rice season CH in comparison with comparative example 3₄Emission, N₂The O emission, the global warming potential of the rice field and the emission intensity of greenhouse gases are reduced, the reduction amplitudes are respectively 3.7%, 952.7%, 5.0% and 0.9%, and the yield is not changed greatly (Table 5). The proportion of aggregates of 2-0.25mm in the 0-20cm plough layer soil of example 3 was significantly increased compared to comparative example 3, but>The proportion of 2mm agglomerates is low, and overall, the large agglomerates of example 3 (C>2mm and 2-0.25mm) by 5.3% (fig. 6). Comparing the investigation of soil preparation effect and the finding of rice seedling quality (Table 6), the floating amount of the straw was reduced by 9.6%, the sinking amplitude of the field surface after the flat land was 18.2%, and the number of new white roots was increased by 46.4% in example 3, compared with comparative example 3.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. An oxygen-increasing and emission-reducing dry ploughing method for rice fields is characterized by comprising the following steps:

(2) dry ploughing:

(3) unpowered slurry stirring and rice stubble burying:

for the double-cropping rice area, soaking the field in shallow water after rotary tillage, wherein the water depth is 1-2cm, the field soaking time is 6-10h based on the condition that the high part of the field surface is provided with a pier, the low part is provided with water and the field is not waved during operation, and unpowered slurry stirring and rice stubble burying are carried out after the field soaking is finished;

2. The method as claimed in claim 1, wherein in the step (1), the length of the crushed straw is less than or equal to 10cm, and the stubble height of the straw is less than or equal to 10 cm.

3. The method according to claim 1 or 2, wherein the water content of the soil is less than or equal to 30% when the cultivation is carried out in autumn of 1 year, and the water content of the soil is less than or equal to 25% when the reverse-rotation deep-burying rotary cultivation is carried out in autumn of 2 year.

4. The method as claimed in any one of claims 1 to 3, wherein quick lime or hydrated lime is used in an amount of 90 to 110kg per acre.

5. The method according to any one of claims 1-4, further comprising:

(4) dense planting and fertilizer application adjustment:

and (3) dense planting: when the rice transplanting mode is adopted, the planting distance is reduced, the row spacing is kept unchanged, and the transplanting density is increased by 15-25%; when the seedling throwing or direct seeding mode is adopted, the seedling throwing number or the seeding amount is improved by 15 to 25 percent on the basis of the current seedling throwing number or the seeding amount;

adjusting nitrogen fertilizer:

6. The method according to claim 5, wherein when the transplanting mode is adopted, the transplanting density is increased by 20%; when the seedling throwing or direct seeding mode is adopted, the seedling throwing number or the seeding amount is improved by 20 percent on the basis of the current seedling throwing number or the seeding amount;

for the first-maturing rice area, reducing the nitrogen amount of the base fertilizer in the current area by 20% of the total nitrogen amount, and adjusting the nitrogen fertilizer in the panicle fertilizer, which accounts for 20% of the total nitrogen fertilizer application amount in the current area, into the tiller fertilizer;

the amount of nitrogen fertilizer reduction for the rice and wheat rotation area and the double cropping rice area is 20% of the total amount of nitrogen fertilizer application in the current area.

7. The method according to any one of claims 1-6, further comprising: protecting seedlings in shallow water after planting, and keeping shallow water after the seedlings are delayed and dried in the field for 2-3 days; drying the field in time before and after the critical leaf age period of tillering; and (4) flower retention in shallow water during booting and flowering stages, and dry-wet alternation after ear emergence.