Sweet potato-tobacco crop rotation mutual promotion planting method

Abstract

The invention discloses a sweet potato-tobacco crop rotation mutual promotion planting method. The method comprises the following steps: (1) selecting a purple dry slope with subtropical monsoon climate in Guangdong region; (2) ridging and banding; (3) film covering; (4) sweet potato transplanting: transplanting sweet potatoes in late August; (5) sweet potato harvesting: harvesting sweet potatoes in mid-to-late November; (6) covering and turning the sweet potato waste, namely covering and turning sweet potato vines before tobacco transplanting; (7) flue-cured tobacco transplanting: performing flue-cured tobacco transplanting from late January to early February of the next year, and transplanting tobacco seedlings by adopting a well cellar type transplanting technology; (8) harvesting tobacco leaves; (9) masking, turning and pressing the tobacco waste; and (10) planting in the next year, and carrying out a new round of crop rotation planting according to the steps (2) to (9) in the last ten days of August in the next year. The waste of tobacco and sweet potatoes is fully utilized, soil can be effectively improved, plant diseases and insect pests of two crops are reduced, the yield and quality of tobacco and sweet potatoes are improved, and economic benefits are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of crop planting, and particularly to a planting method for promoting the rotation and mutual promotion of sweet potato and tobacco. Background Art

[0002] Tobacco is a solanaceous crop and avoids continuous cropping. Due to the difficulty of rotation in flue-cured tobacco planting, most tobacco-growing areas are mainly monoculture, and the phenomenon of leaving the land fallow after planting flue-cured tobacco is relatively prominent. Long-term continuous cropping of flue-cured tobacco causes problems such as biological singularity, partial depletion of soil nutrients, deterioration of the plough layer structure, serious soil compaction, serious nutrient loss, frequent occurrence of flue-cured tobacco diseases, and increasing occurrence of pests and diseases year by year, which in turn leads to a decline in the yield and quality of tobacco leaves. The aroma of flue-cured tobacco on sloping land is strong and the combustibility is good, which is easily favored by Chinese tobacco enterprises. The soil for planting flue-cured tobacco on purple soil dry sloping land is barren, fertilizers are easily lost, and the soil water retention performance is poor. Therefore, it is necessary to plant green manure through rotation to achieve the purpose of increasing organic matter, improving soil structure, and enhancing the soil water retention, fertilizer retention and fertilizer supply capabilities. Explore a planting mode that is more conducive to flue-cured tobacco production.

[0003] Sweet potato is a perennial twining vine plant of the Dioscoreaceae family and the Dioscorea genus. Sweet potato has the characteristics of high yield, strong stress resistance, wide adaptability, high nutritional abundance and wide uses. In particular, commercial sweet potatoes have high nutritional value and excellent taste. However, commercial sweet potatoes avoid continuous cropping. Long-term continuous cropping will lead to a decline in soil physical and chemical properties, an increase in soil-borne diseases, a reduction in the number of tuberous roots, and seriously affect the yield and quality of commercial sweet potatoes. Sweet potato is the seventh most important food crop in the world and one of the main tuberous root crops. At the same time, as a health food, for the production of fuel ethanol and modified starch, etc., it has been widely valued by domestic and foreign scholars. The planting area of sweet potato in China ranks first in the world. With people's attention and emphasis on food diversity and healthy diet. In recent years, sweet potato has shown large-scale and intensive production, and the damage of pests and diseases has become increasingly serious, which has risen to the main restricting factor for the development of the sweet potato industry. For the occurrence and prevalence of pests and diseases, growers usually choose fast and broad-spectrum chemical agents for prevention and control; the abuse of chemical pesticides brings problems such as enhanced drug resistance, pesticide residue pollution, and pest resurgence.

[0004] Crop rotation has a long history in China. Reasonably adopting the planting method of crop rotation can effectively control pests and diseases, improve the yield and quality of subsequent crops, reduce continuous cropping obstacles, and reduce the application of pesticides and chemical fertilizers. The mechanism of its beneficial effect on crops lies in changing the nutrient distribution in the field, changing the physical and chemical properties of the soil, reducing nutrient depletion, and reducing soil-borne diseases. For many years, tobacco farmers have mainly adopted "tobacco-rice rotation" or "tobacco-vegetable (green manure) rotation". This rotation method not only avoids the problems of pests, diseases and the decline of tobacco quality caused by continuous cropping, but also solves the land use problem. However, this model has the following problems: First, the season is tight, and the phenomenon of rough tillage and rough sowing is serious. In the arrangement of rice varieties, only early indica rice with a short growth period can be used, resulting in low yield and poor rice quality. Second, the traditional tobacco-vegetable rotation mainly focuses on planting green manure crops such as rye, and the promotion effect on the growth of subsequent tobacco is limited. Third, due to limited effects, some smokers choose to fallow, and the utilization efficiency of the fields is not high.

[0005] Studies have shown that through its unique chemical composition, tobacco waste can effectively reduce the incidence of diseases of subsequent crops after being returned to the field, and has a certain degree of resistance and prevention effect on diseases. Through the brand-new sweet potato-tobacco-sweet potato rotation planting model described in this patent, the tobacco waste can be turned into green manure, which can effectively utilize the stems and underground parts of the harvested tobacco, which were originally waste. And by returning it to the field, the content of soil organic matter can be increased, and the yield of subsequent sweet potatoes can be improved. At the same time, sweet potatoes are special food crops harvested by underground tubers. The above-ground biomass is large, and the waste rate of the above-ground part is high in the traditional planting model, and the development and utilization degree of the above-ground vines of sweet potatoes is not high. Through the brand-new rotation planting model of this patent, the waste of the above-ground vines can be fully developed, achieving the effect of reducing costs and increasing benefits. At the same time, by rotating high-value and high-yield crops such as sweet potatoes, the phenomenon of low income of subsequent crops in the original planting model (tobacco-rice rotation or tobacco-vegetable rotation) can be broken, which can effectively improve the planting enthusiasm and intention of farmers, thereby effectively reducing the fallow rate of the soil and breaking the problem of quality reduction caused by continuous tobacco cropping. This has extremely important and irreplaceable significance for ensuring China's food security and ensuring the raw material security of the tobacco industry. And the tobacco-sweet potato rotation is currently rarely used in tobacco planting, there are few research reports on the interaction between the above two crops in production, and neither has been widely promoted and applied on a large scale. Summary of the Invention

[0006] Object of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a sweet potato-tobacco rotation planting method that can make full use of the waste of tobacco and sweet potatoes, and can improve the soil structure, enhance the water retention, fertilizer retention and fertilizer supply capabilities of the soil, and reduce the occurrence of diseases of sweet potatoes and tobacco in the rotation mode.

[0007] The present invention provides a planting method for promoting the mutual growth of sweet potato and tobacco in rotation, comprising the following steps:

[0008] (1) Select purple dry sloping land with a subtropical monsoon climate in the Guangdong region;

[0009] (2) Ridging and forming strips: Adopt the ridge and furrow planting method, and form strips on the plot according to the specifications of a ridge width of 60 - 80 cm and a ridge height of 20 - 30 cm, and then level and smooth;

[0010] (3) Film mulching: Tighten and flatten the plastic film, press it firmly so that the plastic film closely adheres to the ridge surface, and press at intervals on the plastic film on the ridge surface to form a relatively airtight state;

[0011] (4) Transplanting sweet potatoes: Transplant sweet potatoes in late August;

[0012] (5) Harvesting sweet potatoes: Harvest sweet potatoes in late November; 30 to 45 days before transplanting tobacco, conduct green manure turning of sweet potato vines, and the turning should be thorough, and the waste should be broken to a certain extent;

[0013] (6) After transplanting sweet potatoes and tobacco, manage them according to the conventional cultivation method, check and supplement seedlings in the field, conduct intertillage and weed control regularly, fertilize, water, and prevent and control diseases and pests. After the crops mature, harvest them in time;

[0014] (7) Green manure turning of sweet potato waste: Conduct green manure turning of sweet potato vines before transplanting tobacco;

[0015] (8) Transplanting flue-cured tobacco: Transplant tobacco seedlings in late January to early February of the next year, and adopt the "well cell transplanting technology" to transplant tobacco seedlings;

[0016] (9) Harvesting tobacco leaves: Start grading and batchwise baking of tobacco leaves in early July of the next year, and finish harvesting in early August;

[0017] (10) Green manure turning of tobacco waste: Turn over tobacco waste after harvesting tobacco and before transplanting sweet potatoes;

[0018] (11) Planting in the next year: Conduct a new round of sweet potato transplanting in late August of the next year and carry out rotational planting according to steps (2) to (10).

[0019] The sweet potato variety is Guangshu 87.

[0020] The tobacco variety is Yueyan 97.

[0021] In the well cell transplanting technology, the diameter of the well cell is 8 - 12 cm, the depth of the well cell is 15 - 21 cm, and the plant spacing of tobacco seedlings is 100 - 120 cm; when transplanting, the tobacco seedlings are with soil, the tobacco seedlings are placed into the well cell, and fermented nutrient soil is added and the roots are covered.

[0022] The ridge planting method is carried out horizontally.

[0023] The sweet potato waste is buried green and turned over, including burying and turning over the sweet potato vines 30 to 45 days before tobacco transplanting, and burying and turning over the sweet potato waste after it is broken.

[0024] The tobacco seedlings are in the seedbed stage for 50 - 55 days, with a stem height of 3 - 5 cm and 4 - 5 functional leaves. The selected tobacco seedlings should be of uniform size, strong growth, free from diseases and pests, mechanical damage, and have well-developed roots.

[0025] The tobacco seedlings are transplanted in the late January to early February of the following year. The transplanting time should be selected from any one of early or late, cloudy or light rain days for transplanting.

[0026] The present invention forms a brand-new sweet potato - tobacco rotation planting mode, makes full use of the waste of tobacco and sweet potato. By burying and turning over the sweet potato waste to increase soil organic matter, improve soil structure, and enhance the water retention, fertilizer retention and fertilizer supply capacity of the soil, reduce the diseases and pests of the two crops, thereby improving the yield and quality of sweet potato and tobacco; and makes full use of the growth and maturity time between tobacco and sweet potato and the relationship between fertilizer and plants, improving economic benefits.

[0027] Specifically, by burying and turning over the tobacco waste to increase soil nutrients, thereby increasing the yield of sweet potato, and enhancing the ability of the subsequent sweet potato to resist diseases through the tobacco waste.

[0028] The present invention can further improve and amend the soil and increase fertility through the ridge planting technology: Through ridging and making ridges, the ridge planting can loosen the soil, increase soil aeration, and is beneficial to the respiration and growth of crop roots. During the ridging process, the deep soil underground can be turned to the surface to realize the rotation use of deep and shallow soil layers and enhance the soil fertilizer supply capacity. The ridge structure is conducive to the full contact between the soil and the air, promotes the reproduction and activity of soil microorganisms, accelerates the decomposition and transformation of fertilizers, and improves soil fertility. Drainage and waterlogging prevention, reducing diseases and pests: The ditches formed between the ridges are conducive to drainage, avoiding waterlogging damage to crops due to water accumulation. A well-drained soil environment is not conducive to the breeding and reproduction of diseases and pests, and can effectively reduce the incidence of diseases and pests. Raising the ground temperature and increasing sunlight:

[0029] The ridge-furrow structure can increase the light-receiving area of the soil, raise the soil temperature, and is beneficial to the growth of crop roots and nutrient absorption. The crops on the ridge-furrows can receive light from all directions, improving the photosynthesis efficiency and being conducive to the growth and development of the crops. Ridge-furrow planting can make full use of land resources and improve land utilization rate by ridging and making furrows. The ditches between the ridge-furrows can serve as channels for irrigation and drainage, optimizing water resource utilization. It is convenient for field management: Ridge-furrow planting makes field management more convenient. Operations such as fertilization, irrigation, weeding, and pest control can be more productive.

[0030] By transplanting tobacco seedlings through the well-cellar method, the well-cellar transplanting technology can advance the transplanting period, enabling the tobacco seedlings to grow in a more suitable growth environment, thus shortening the seedling-recovery period and increasing the survival rate. Compared with the traditional transplanting method, the well-cellar transplanting technology can save a large amount of labor and water resources and reduce production costs. The well-cellar transplanting technology can create a soil and humidity environment suitable for the growth of tobacco seedlings, promote the early growth and rapid development of tobacco seedlings, and improve the yield and quality of tobacco leaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the solutions in the present application, the following will give a brief introduction to the drawings required for the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a schematic diagram of the crop rotation pattern of the present invention;

[0033] Figure 2 It is an effect diagram of the inhibition of tobacco waste on soil bacteria of the present invention;

[0034] Figure 3 It is a schematic diagram of pest control in the soil by turning under tobacco waste while green;

[0035] Figure 4 It is a schematic diagram of the improvement of the nutritional components of sweet potato tubers by turning under tobacco waste while green; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further details the present invention in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0037] It should be noted that the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. Additionally, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or inability to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] A planting method for promoting the rotation and mutual promotion of sweet potato and tobacco, comprising the following steps: (1) Select purple dry sloping land with a subtropical monsoon climate in the Guangdong region; (2) Ridging and forming strips: Adopt the ridge and furrow planting method, and form strips on the plot according to the specifications of a ridge width of 60 - 80 cm and a ridge height of 20 - 30 cm, and level and tidy up; (3) Film mulching: Tighten and flatten the plastic film, press it firmly so that the plastic film closely adheres to the ridge surface, and press at intervals on the plastic film on the ridge surface to form a relatively airtight state; (4) Sweet potato transplanting: Conduct sweet potato transplanting in late August; Do a good job in checking and supplementing seedlings in the field, regularly conduct intertillage and weed control, fertilize and water, and prevent and control pests and diseases. After the crops mature, harvest them in a timely manner; (5) Sweet potato harvest: Harvest sweet potatoes in late November; Conduct green manure incorporation and turning of sweet potato vines 30 to 45 days before tobacco transplanting. The turning should be thorough, and the waste should be broken to a certain extent; (6) Manage according to the conventional cultivation method after sweet potato and tobacco are transplanted; (7) Green manure incorporation and turning of sweet potato waste: Conduct green manure incorporation and turning of sweet potato vines before tobacco transplanting; The green manure incorporation and turning of sweet potato waste includes conducting green manure incorporation and turning of sweet potato vines 30 to 45 days before tobacco transplanting, and turning the sweet potato waste after it is broken; (8) Flue-cured tobacco transplanting: Transplant tobacco seedlings in mid-to-late March of the following year, and transplant the tobacco seedlings using the "well cell transplanting technology"; When the tobacco seedlings are in the seedbed stage for 50 - 55 days, with a stem height of 3 - 5 cm and 4 - 5 functional leaves, the selected tobacco seedlings should be of uniform size, strong growth, free from pests and diseases, free from mechanical damage, and have well-developed roots. In the well cell transplanting technology, the diameter of the well cell is 8 - 12 cm, the depth of the well cell is 15 - 21 cm, and the plant spacing of the tobacco seedlings is 100 - 120 cm; When transplanting, the tobacco seedlings are taken with soil, the tobacco seedlings are placed into the well cell, and fermented nutrient soil is added and the roots are covered; (9) Tobacco leaf harvest: Start grading and batchwise baking of tobacco leaves in early July of the following year, and finish harvesting in early August; (10) Green manure incorporation and turning of tobacco waste: Conduct turning of tobacco waste after tobacco is harvested and before sweet potato transplanting; (11) Next year's planting, conduct a new round of sweet potato transplanting in late August of the following year and carry out rotation according to steps (4) to (10).

[0039] The sweet potato variety is Guangshu 87. The tobacco variety is Yueyan 97.

[0040] The tobacco seedlings are transplanted in late January to early February of the following year. The transplanting time is preferably in the early morning or evening, or on cloudy days or light rain days.

[0041] This patent is implemented in Qingyuan City, Guangdong Province, and is a rotation model of sweet potato - tobacco suitable for the unique subtropical monsoon climate in Guangdong. Purple soil dry sloping land is a relatively special type of soil. The purple soil dry sloping land is infertile, fertilizers are easily lost, the soil water retention performance is poor, and rotation is needed to improve the soil structure and increase soil nutrients. However, the purple soil dry sloping land is not suitable for the common tobacco - rice rotation in Guangdong. The tobacco yield is low when planted on purple soil dry sloping land, but the quality is relatively high, with a special aroma. The tobacco aroma is strong and the combustibility is good, which is favored by tobacco enterprises.

[0042] 2. Promoting effect of incorporating sweet potato waste into the soil on tobacco cultivation in the sweet potato - tobacco rotation model

[0043] a. Incorporating sweet potato waste into the soil in the sweet potato - tobacco rotation model can increase soil nutrients

[0044] By statistically analyzing the sweet potato - tobacco rotation model, returning sweet potato vines to the field can effectively increase the effective components in the soil. As shown in Table 1, in terms of soil organic matter, available phosphorus, available potassium, and urease content, the sweet potato - tobacco rotation planting model has improved compared with monoculture tobacco (fallow). These nutrients are also the nutrient elements required for plant growth, and improving the content of these substances has a very significant promoting effect on the growth of the subsequent tobacco leaves.

[0045] Table 1 Statistical table of soil nutrients under different treatments

[0046]

[0047]

[0048] b. Incorporating sweet potato waste into the soil in the sweet potato - tobacco rotation model can promote tobacco growth

[0049] To further explore the effect of incorporating sweet potato waste into the soil on tobacco growth in the sweet potato - tobacco rotation model, we statistically analyzed the agronomic traits of tobacco at the budding stage under different treatments. As shown in Table 2, in the sweet potato - tobacco rotation planting model, the plant height, stem girth, internode distance, and number of effective leaves of tobacco (at the budding stage) have increased by 42.8%, 16.4%, 20.6%, and 16.6% respectively compared with monoculture tobacco (fallow). The plant height, stem girth, and internode distance are significantly different from those of monoculture tobacco (fallow) (p > 0.05), and the growth promotion effect is significant. At the budding stage, the plant height and internode distance of tobacco - sweet potato rotation are higher than those of tobacco - ryegrass rotation. This shows that in promoting tobacco growth, the new sweet potato - tobacco rotation model has a significantly better effect than the traditional green manure crop rotation.

[0050] Table 2 Statistics of agronomic traits at bud stage under different treatments

[0051]

[0052] c. In the sweet potato-tobacco rotation model, the sweet potato waste covering and pressing has a significant effect on increasing tobacco yield and quality

[0053] In order to further quantify the increased economic benefits in the sweet potato-tobacco rotation system, we conducted a statistical analysis of the economic traits of tobacco under different treatments (Table 3). We found that the tobacco-sweet potato rotation planting model increased the yield, output value, upper and middle tobacco ratio and average price by 8.1%, 11.9%, 0.03% and 0.03% respectively compared with the monoculture tobacco (fallow). All economic traits except yield were significantly different from the monoculture tobacco (fallow) (p>0.05), and the effect of increasing production and income was significant. In addition, the output value, upper and middle tobacco ratio and average price were also significantly different from those of the tobacco-ryegrass rotation (p>0.05), indicating that the new sweet potato-tobacco rotation model is far superior to the traditional green manure (ryegrass) rotation in increasing income and production.

[0054] Table 3 Statistics of economic properties of different treatments

[0055] Processing <![CDATA[Yield / (kg / hm 2 )]]> <![CDATA[Output value / (yuan / hm 2 )]]> Proportion of medium and upper grade tobacco / % Average price / (yuan / kg) Sweet potato + flue-cured tobacco <![CDATA[2544.45 a > <![CDATA[58624.128 a > <![CDATA[97.13 a > <![CDATA[23.04 a > Ryegrass + flue-cured tobacco <![CDATA[2390.55 a > <![CDATA[49054.086 b > <![CDATA[93.16 b > <![CDATA[20.52 b <!-- 5 -->]]> Fallow + flue-cured tobacco <![CDATA[2352.75 a > <![CDATA[52395.7425 b > <![CDATA[94.46 b > <![CDATA[22.27 b >

[0056] At the same time, in order to further explore the impact of returning sweet potato waste to the field on the quality of flue-cured tobacco, we counted the chemical substances in the two grades of tobacco leaves under different rotation modes and evaluated their coordination. After our measurement (Table 4), we found that after our unique sweet potato-tobacco rotation mode, the coordination score of the middle orange three (C3F) grade leaves was significantly improved, the chemical components of tobacco leaves became more coordinated, and the quality was significantly improved. At the same time, the upper orange two (B2F) grade leaves were significantly improved, and the coordination score was increased by 16 points and 7 points respectively compared with the monoculture and Masali (another sweet potato variety) tobacco rotation, which not only shows the significant promotion effect of sweet potato-tobacco rotation on tobacco quality, but also shows the uniqueness and excellence of our new sweet potato (Guangshu 87)-tobacco rotation mode in variety selection.

[0057] Table 4 Effects of different crop rotations on the coordination of tobacco leaf chemical components

[0058]

[0059] In summary, our new sweet potato - tobacco rotation model effectively promotes the growth of the subsequent tobacco leaves after the rotation model by making full use of sweet potato waste, improves the quality of the subsequent tobacco leaves, increases the economic benefits of the overall rotation model, and can also reduce the amount of chemical fertilizer input in the early stage by returning sweet potato waste to the field, thus playing a role in reducing costs.

[0060] 3. Promotion effect of tobacco waste green manure incorporation and plowing in the sweet potato - tobacco rotation model on sweet potato cultivation

[0061] a. Tobacco waste has a resistance effect on fungi and bacteria

[0062] Through indoor experiments on tobacco waste, by extracting tobacco waste and adding the extract into petri dishes in different amounts (0 ml, 0.5 ml, 1 ml, 2 ml, 4 ml), it can be visually seen that ( Figure 2 ), as the amount of the added extract increases, its inhibitory effect on the growth of fungi gradually improves. When the addition amount reaches 4 ml, the inhibitory effect reaches the highest, and the inhibition ratio reaches 80%. Through this experiment, we can visually observe the inhibitory effect of tobacco waste on fungi. See Figure 2 Tobacco waste has an inhibitory effect on fungi.

[0063] And by dropping the tobacco waste extract into the bacterial petri dish in different amounts (0 μl, 20 μl, 40 μl) ( Figure 2 ), it can be observed that as the dropping amount of the tobacco waste extract increases, the inhibitory effect on bacteria gradually strengthens, and the formed inhibition zone increases with the increase of the dropping amount. When the dropping amount is 40 μl, the diameter of the formed inhibition zone reaches 30 mm. Through this experiment, we can visually observe the inhibitory effect of tobacco waste on bacteria.

[0064] b. Tobacco waste in the sweet potato - tobacco rotation model has a prevention and control effect on pests and diseases during the growth process of sweet potatoes

[0065] After determining that sweet potato waste has resistance to both bacteria and fungi, we counted the incidence of sweet potato virus disease and brown spot disease in the sweet potato-tobacco rotation pattern. Among them, disease level: 50 plants were continuously selected for each treatment and counted: 0 (no occurrence), corresponding index 0; 1 (slight occurrence), corresponding index 0 < M ≤ 5; 2 (moderate to slight occurrence), corresponding index 5 < M ≤ 20; 3 (moderate occurrence), corresponding index 20 < M ≤ 35; 4 (moderate to severe occurrence), corresponding index 35 < M ≤ 50. It can be found from Table 5 that after adopting the sweet potato-tobacco rotation pattern and incorporating tobacco waste into the soil by plowing it under, the incidence of both brown spot disease and virus disease has decreased compared to fallow, and this reduction in incidence does not weaken with the growth of sweet potatoes. This indicates that for sweet potato cultivation in the sweet potato-tobacco rotation pattern, its control effect is obvious and persistent.

[0066] Table 5 Incorporating tobacco waste into the soil by plowing it under has a control effect on sweet potato diseases

[0067]

[0068] And by counting the post-harvest sweet potato tubers, we found that incorporating tobacco waste into the soil by plowing it under also has an obvious inhibitory effect on pests ( Figure 3 ). We counted the proportion of tuber roots damaged by pests under control conditions (CK) and in the sweet potato-tobacco rotation patterns (A, B), and found that in the sweet potato-tobacco rotation pattern, the proportion of tuber roots damaged by pests has been significantly reduced, with a reduction of approximately 10%. This indicates that by plowing tobacco waste into the field, there is an obvious inhibitory and preventive effect on harmful insects in the soil.

[0069] c. Tobacco waste in the sweet potato-tobacco rotation pattern significantly improves the quality of sweet potato tubers

[0070] By counting the nutritional components in the sweet potato-tobacco rotation pattern, we found that the sweet potato-tobacco rotation can significantly increase the sugar content in sweet potato tubers ( Figure 4 ), and it also has an enhancing effect on most of the amino acids required by the human body. This indicates that by incorporating tobacco waste into the soil by plowing it under, the quality of sweet potatoes has been improved and enhanced.

[0071] In summary, by explaining the phenomenon of the promotion of sweet potato waste on tobacco quality and yield and the promotion of tobacco waste on sweet potato quality and yield, it is proved that the new sweet potato-tobacco rotation system formed by this patent has a significant improvement effect on the production of both sweet potato and tobacco. And by comparing with fallow, traditional rotation patterns and different sweet potato varieties in rotation, the uniqueness and effectiveness of this patent are confirmed. Through the sweet potato-tobacco rotation system formed by this patent, the traditional planting mode can be reformed to achieve the purpose of reducing costs, increasing yields and improving quality, with the effect of multiple benefits from one cause. At the same time, a new feasible solution is proposed for solving China's food security problem and ensuring the raw material security of the tobacco industry.

[0072] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A planting method for mutual promotion of sweet potato and tobacco crop rotation, characterized in that: The following steps are involved: (1) Select purple dry slopes with subtropical monsoon climate in Guangdong; (2) Ridge and strip planting: adopt the ridge and bed planting method, and make ridges and strips on the plot according to the specifications of ridge width 60-80cm and ridge height 20-30cm, and make them flat; (3) Film covering: tighten and flatten the ground film, press and compact it so that it is tightly attached to the ridge surface, and press the ground film on the ridge surface at intervals to form a relatively closed state; (4) Sweet potato transplanting: Sweet potato transplanting is carried out in late August; (5) Sweet potato harvest: Sweet potatoes are harvested in late November. The sweet potato vines should be covered and pressed 30 to 45 days before tobacco transplanting. The pressing should be thorough and the waste should be crushed to a certain extent. (6) After transplanting sweet potatoes and tobacco, they should be managed according to conventional cultivation methods, including checking and replanting seedlings in the field, regularly cultivating and weeding, fertilizing and watering, and preventing and controlling pests and diseases. When the crops are mature, they should be harvested in time; (7) Covering and pressing sweet potato waste: Before transplanting tobacco, cover and press the sweet potato vines; (8) Transplanting of flue-cured tobacco: Transplanting of tobacco seedlings is carried out from late January to early February of the following year, using the "well-cellar transplanting technique"; (9) Tobacco leaf harvesting: Tobacco leaves are graded and harvested in batches starting in early July of the following year, and are harvested in early August. (10) Covering and pressing tobacco waste: After tobacco harvesting and before sweet potato transplanting, tobacco waste is pressed; (11) Planting in the next year, a new round of sweet potato transplanting is carried out in late August of the next year and crop rotation is carried out according to steps (2) to (10).

2. The method for promoting mutual growth of sweet potato and tobacco by crop rotation according to claim 1, characterized in that: The sweet potato variety is Guangshu 87.

3. The method for promoting mutual growth of sweet potato and tobacco by crop rotation according to claim 1, characterized in that: The tobacco variety is Yueyan 97.

4. The method for promoting mutual growth of sweet potato and tobacco by crop rotation according to claim 1, characterized in that: In the well-pit transplanting technology, the diameter of the well is 8-12 cm, the depth is 15-21 cm, and the tobacco seedling spacing is 100-120 cm; when transplanting, the tobacco seedlings are placed in the well with soil, and fermented nutrient soil is added to cover the roots.

5. The method for promoting mutual growth of sweet potato and tobacco by crop rotation according to claim 1, characterized in that: The ridge planting method is carried out in a horizontal direction.

6. The method for promoting mutual growth of sweet potato and tobacco by crop rotation according to claim 1, characterized in that: The method of covering and turning the sweet potato waste includes covering and turning the sweet potato vines 30 to 45 days before tobacco transplanting, and covering and turning the sweet potato waste after crushing.

7. The method for mutually promoting sweet potato-tobacco crop rotation according to claim 1, characterized in that: The tobacco seedlings are in the seedbed for 50-55 days, with a stem height of 3-5 cm and 4-5 functional leaves. The selected tobacco seedlings should be uniform in size, grow healthily, be free of pests and diseases, mechanical damage, and have a well-developed root system.

8. The method for mutually promoting sweet potato-tobacco crop rotation according to claim 1, characterized in that: The tobacco seedlings are transplanted in late January to early February of the following year. The transplanting time is preferably selected in the morning or evening, on a cloudy day or on a light rainy day.

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