A method for treating cassava stems to improve the survival rate of cassava seedlings

Abstract

The invention discloses a kind of seed stem processing method improving cassava seedling survival rate, specifically operates as follows: collect the high stalk of lignification degree of cassava bottom 1m above the ground as cassava seed stem next year;Then put into soaking agent A to soak, dry, preserve overwintering;Plant in the spring of next year, before planting, the seed stem is cut into 15-20cm planting stem, ensure that each section has at least one healthy bud point, put into soaking agent B to soak;Dig planting hole, cassava planting stem is laid flat in planting hole, covered with soil and planted.The present invention adopts soaking agent A to process cassava seed stem before winter preservation, and soaking liquid is made up of water-retaining material, biogenic pesticide and growth regulator, can effectively reduce cassava seed stem water loss during storage, increase cold resistance, reduce pest and disease damage cassava seed stem and prevent cassava seed stem from prematurely sprouting during storage and consuming nutrition, enhance seed stem activity. Before planting cassava, soaking agent B was used again to treat the cassava seed stems to reduce the rapid loss of water during planting, prevent the invasion of pests and diseases, promote the emergence of cassava seedlings and root growth, and improve the resistance of seedlings.

Description

Technical Field

[0001] The invention belongs to the technical field of cassava agricultural production, and particularly relates to a seed stem processing method for improving the survival rate of cassava seedlings. Background Art

[0002] Cassava (Manihot esculenta Crantz), also known as sweet potato or manioc, is a member of the Euphorbiaceae family, Cassava genus. Native to tropical America, it is a key crop in tropical and subtropical regions. Cassava cultivation in my country is primarily distributed in southern provinces such as Guangxi, Guangdong, Hainan, Yunnan, and Fujian, making it a highly valued cash crop. In today's global context of food shortages and energy crises, cassava, as a dual-purpose crop for food, energy, and feed, has attracted global attention and holds enormous development potential.

[0003] Cassava is typically cultivated asexually using seed stems. Agricultural production typically involves harvesting the stalks of the current year's planting to serve as seed stems for the following year. Because cassava seed stems have a thin epidermis and poor water retention, they are often exposed to low temperatures during storage. Improper storage can lead to water loss and inactivation, causing the stems to dry out, rot, and drop buds, significantly reducing their survival rate. Poor overwintering of cassava seed stems can also result in low budding rates the following year, leading to an increase in the number of weak and missing seedlings, directly reducing cassava yields and reducing above-ground growth and tuber production. The critical temperature for cold and frost damage to cassava seed stems is 4-5°C. Guangxi, Guangdong, northern Yunnan, Hunan, Jiangxi, and Zhejiang provinces experience relatively low winter temperatures, with frost and low temperatures occurring annually. Improper overwintering storage of cassava seed stems can severely impact their quality and even lead to necrosis. Currently, existing patents for cassava stem preservation methods include open-air stacking, pit burial, wax sealing, and stem storage devices. These methods require significant manpower and material resources or specialized storage devices, resulting in demanding, complex, and difficult storage conditions. Consequently, in my country's cassava-producing regions, cassava stems are still preserved using traditional methods, primarily open-air stacking, trench storage, and underground storage. These methods, however, are less than ideal, significantly hindering the healthy development of the cassava industry.

[0004] Regardless of the method used to store cassava stems over the winter, they experience varying degrees of moisture loss, impacting germination and seedling growth. Furthermore, unstable weather conditions often prevent timely planting, leading to premature sprouting of new shoots. This further depletes the stems' moisture and other nutrients, significantly impacting their quality and reducing their seedling emergence rate. In recent years, some cassava-growing areas have experienced extreme weather conditions during the planting season, with periods of continuous rain or prolonged drought, severely impacting the timing of cassava stem planting and seedling emergence.

[0005] The existing patent application is "A Cassava Cultivation Method", application number CN202111405480.6, which mainly collects the connection between the base seed stem and the cassava stem head as the planting material for cassava cultivation in the current year, and then uses cultivation technology to achieve the effect of increasing production. However, due to the large workload of the collection and preservation process, only one cassava plant can be bred in the next year, and this technology cannot be used to expand and promote cassava planting materials; "A Cassava Seed Stem Preservation Device and Preservation Method", application (patent) number: CN201910307760.X, provides a better protective environment for cassava seed stems, greatly reduces the incidence of insect bites in the soil, and at the same time can well insulate the cassava seed stems, improve their survival rate and survival quality, thereby increasing yield. However, its structure is complex, and there is no product promotion on the market, which cannot effectively solve the problem of planter seed stem preservation; "Cassava seed stem water retainer and use method", application number is CN202211727928.0, which mainly acts together by the water-retaining functional substance, insect repellent and film-forming agent in the cassava seed stem water retainer, reduces the water loss of cassava seed stem during storage, reduces the occurrence of diseases and insect pests, enhances the activity of seed stem, thereby improving the survival rate of seedlings planted by cassava. However, it does not require the cassava seed stem material, does not consider the resistance of the seed stem itself, and the resistance of different parts of the seed stem is significantly different. Secondly, the water retainer is described in the article. Although it can reduce the water loss of cassava seed stem during storage, reduce the occurrence of diseases and insect pests, it is impossible to prevent the seed stem from consuming too much nutrition prematurely during storage, and the treatment before planting does not include the effect of accelerating germination and rooting, it is impossible to effectively shorten the cassava seed stem emergence time, promote rooting, so that the cassava seedlings themselves have the ability to absorb nutrients and water from the environment, and improve the resistance to adverse environments.

[0006] Therefore, how to effectively ensure the safe wintering of cassava seed stems, reduce the loss of nutrients caused by premature sprouting of cassava seed stems, shorten the time for cassava seedlings to take root, and increase the emergence rate of cassava seed stems should be a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0007] In response to the above problems, the present invention provides a method for treating cassava seed stems to improve the survival rate of cassava seedlings. The method selects the lower stems with high maturity and high lignification as the cassava seed stems for planting next year. At the same time, the cassava seed stems are pre-treated with a soaking agent A before winter storage. The soaking agent is composed of a water-retaining functional substance, a biogenic pesticide, and a growth regulator. The soaking agent can effectively reduce the water loss of the cassava seed stems during storage, improve cold resistance, reduce the damage of pests and diseases to the cassava seed stems, and prevent the cassava seed stems from premature sprouting and consuming the nutrition of the seed stems during storage, thereby enhancing the activity of the seed stems and improving the cassava seed stem emergence rate. Before cassava planting, another soaking agent B is configured. The soaking agent is composed of a water-retaining functional substance, a biogenic pesticide, and a growth regulator. The soaking agent reduces the excessive water loss of the cassava seed stems during cassava planting, reduces the damage of pests and diseases to the cassava seed stems, shortens the emergence time of the cassava seed stems, promotes rooting, and enables the cassava seedlings to absorb nutrients and water from the environment and improve their resistance to adverse environments.

[0008] The present invention is achieved through the following technical solutions:

[0009] A seed stem processing method for improving the survival rate of cassava seedlings comprises the following steps:

[0010] (1) After harvesting cassava tubers, collect the cassava stems at a height of 1 m above the ground that are not damaged, have no insect eyes, and have intact buds as cassava seed stems;

[0011] (2) placing the harvested cassava stems in soaking agent A for 1 to 10 minutes and then placing them in an open space to dry; the soaking agent A comprises 5-10 g / L maleic hydrazide, 1-5 g / L ABA, 10-12 g / L sodium carboxymethyl cellulose, and 250-300 mg / L crude extract of Jatropha curcas alkaloids;

[0012] (3) Place the dried cassava stems in a greenhouse or indoors for winter storage, and pay attention to temperature control regularly;

[0013] (4) In March and April of the following year, before planting, the cassava planting field should be prepared, furrowed and ridged, basal fertilizer applied, and soil covered;

[0014] (5) Cut the preserved seed stems into 15-20 cm long planting stems, ensuring that each node has at least one healthy bud, and then place them in soaking agent B for 1-5 minutes, remove them and place them in an open space to dry; the soaking agent B contains 10-12 g / L sodium carboxymethyl cellulose, 250-300 mg / L crude extract of Jatropha curcas alkaloids, 30-50 mg / L gibberellins, and 30-50 mg / L cytokinins;

[0015] (6) digging planting holes on the cassava planting ridges, placing the cassava planting stems processed in step (5) flat in the planting holes, and then covering them with soil. Subsequently, field management and pest control are carried out according to routine procedures.

[0016] As a preferred technical solution, 15-20 cassava seed stems collected in step (1) are packed into a bundle and marked with the variety.

[0017] As a preferred technical solution, the soaking agent A comprises 5 g / L maleic hydrazide, 5 g / L ABA, 12 g / L sodium carboxymethyl cellulose, and 300 mg / L crude extract of Jatropha curcas alkaloids.

[0018] As a preferred technical solution, in step (3), the cassava seed stems are regularly monitored during winter storage. When the indoor temperature is below 0°C, the cassava seed stems are covered with sugarcane leaves or straw to protect them from the cold; when the temperature is above 10°C, the covering is removed in time.

[0019] As a preferred technical solution, the soaking agent B comprises 12 g / L sodium carboxymethyl cellulose, 300 mg / L crude extract of Jatropha curcas alkaloids, 50 mg / L gibberellin, and 50 mg / L cytokinin.

[0020] As a preferred technical solution, the extraction operation of the crude extract of Jatropha curcas alkaloids is as follows: Jatropha curcas leaf sample powder and 80% ethanol by mass are added at a solid-liquid ratio of 1:30, ultrasonic extraction is performed at 40° C., filtration is performed, rotary evaporation is performed, extraction and separation is performed using dichloroethane, and then 10% sodium carbonate solution is added to the obtained aqueous phase for alkalization. After extraction and separation with dichloroethane, the obtained organic phase is placed in an oven for drying to obtain a crude extract of alkaloids.

[0021] Beneficial effects of the present invention:

[0022] 1. The method of the present invention is simple to operate, easy to use, low in cost, easy to manage, has broad market prospects, has significant economic benefits and promotion and application value, and has broad market prospects.

[0023] 2. The present invention adopts the lower stem of cassava which is rich in nutrition and has a high degree of lignification as the cassava seed stem. The lower stem of cassava has strong cold and frost resistance and the nutrients it contains can provide sufficient nutrients for the germination and growth of side buds.

[0024] 3. The present invention performs soaking treatment with soaking agent A before the seed stem is preserved, thereby reducing frost damage and water loss of the cassava seed stem during storage, reducing the occurrence of insect pests and preventing the cassava seed stem from sprouting too early after wintering and consuming nutrients, enhancing the activity of the seed stem, and laying the foundation for the emergence rate of the seed stem. The maleic hydrazide in the soaking agent A is a bud inhibitor and a delay agent, which can be used to inhibit the germination of cassava axillary buds and increase the cold resistance of the plant. ABA (abscisic acid) is a plant hormone that inhibits growth, causes the buds to enter a dormant state, and also has an inhibitory effect on the extension of cells. It also reduces the plant MDA content and relative conductivity, promotes soluble sugar, soluble protein, proline content and protective enzyme activity, and increases the cold resistance of the plant. It is used in conjunction with maleic hydrazide to inhibit the germination of cassava axillary buds and improve the cold resistance of the cassava seed stem. Sodium carboxymethyl cellulose is non-toxic, biodegradable, biocompatible, inherently antioxidant, and film-forming. It exhibits excellent mechanical properties and selective gas permeability, improving the mechanical and biological properties of the membrane, reducing and mitigating the effects of the external environment on the membrane's contents, and isolating them from external moisture and temperature influences. Its purpose is to increase the water retention and air permeability of cassava stems. Jatropha curcas alkaloid crude extract exhibits broad-spectrum anthelmintic, insecticidal, and antibacterial effects.

[0025] 4. The present invention soaks cassava in a soaking agent B before planting. The soaking agent is composed of a water-retaining functional substance, an antibacterial agent, and a growth regulator. This reduces the rapid water loss of cassava stems during cassava planting, reduces the damage to cassava stems caused by pests and diseases, promotes cassava seedling emergence and root growth, and improves seedling resistance. Soaking agent B is formulated with sodium carboxymethylcellulose, a crude extract of Jatropha curcas alkaloids, gibberellins, and cytokinins. Sodium carboxymethylcellulose improves the water retention and air permeability of cassava stems, preventing rapid water loss during planting. The crude extract of Jatropha curcas alkaloids has insect repellent, insecticide, and antibacterial effects, reducing the infection rate of pathogens in the soil and preventing them from rotting in the soil before budding. Gibberellins are used to promote the synthesis of growth hormones and increase cytokinins, thereby increasing the activity of enzymes in the plant and promoting metabolism, which can promote the germination of dormant cassava lateral buds. The physiological function of cytokinins is mainly to cause cell division, break the dormancy of axillary buds, promote the growth of lateral buds, and simultaneously promote the growth of cassava adventitious roots. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram of seedling emergence 20 days after the seed stems of the Huanan 205 variety of cassava were planted using the method of the present invention.

[0027] Figure 2 This is a control picture of the emergence of seedlings of the control group 20 days after planting the seed stems of the Huanan 205 variety of cassava. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through examples. These examples are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0029] The Jatropha curcas alkaloid crude extract of the present invention is pre-extracted and treated as follows: 0.5 g of Jatropha curcas leaf sample powder and 80% ethanol by mass are added at a material-liquid ratio of 1:30 (g / mL), ultrasonically extracted at 40° C., filtered, concentrated by rotary evaporation, extracted and separated by dichloroethane, and then alkalized by adding 10% sodium carbonate solution (pH 10) to the obtained aqueous phase. After extraction and separation by dichloroethane, the obtained organic phase is placed in an oven for drying to obtain a crude alkaloid extract.

[0030] Example 1

[0031] A seed stem processing method for improving the survival rate of cassava seedlings comprises the following steps:

[0032] (1) Cassava tubers were harvested in November and December 2022, and then the stems without damage, insect holes, and intact buds at the bottom of the cassava tubers 1 m above the ground were collected as cassava seed tubers; 15-20 tubers were packed into a bundle and marked with varieties such as Huanan 205 and NK-10.

[0033] (2) Soak the harvested cassava stems in soaking agent A for 1 to 2 minutes, and then place them in an open space to dry; the soaking agent A contains 5 g / L maleic hydrazide, 5 g / L ABA, 12 g / L sodium carboxymethyl cellulose, and 300 mg / L crude extract of Jatropha curcas alkaloids, which are prepared in advance.

[0034] (3) Place the dried cassava stems in a greenhouse for winter storage and monitor them regularly. When the indoor temperature is below 0°C, cover the cassava stems with sugarcane leaves or straw to keep them warm. When the temperature is above 10°C, remove the covering in time to prevent the internal temperature of the cassava stems from being too high.

[0035] (4) In March and April 2023, before planting, the cassava planting area will be prepared, furrows and ridges will be dug, base fertilizer will be applied, and soil will be covered;

[0036] (5) Cut the seed stems that have been stored over the winter into 15-20 cm long planting stems, ensuring that each node has at least one healthy bud, and place them in soaking agent B for 1-2 minutes. Then remove them and place them in an open space to dry. The ingredients of soaking agent B are 12 g / L sodium carboxymethyl cellulose, 300 mg / L crude extract of jatropha curcas alkaloids, 50 mg / L gibberellin, and 50 mg / L cytokinin, which are prepared in advance.

[0037] (6) Dig planting holes on the cassava planting ridges, place the cassava planting stems processed in step (5) flat in the planting holes and cover with soil, then carry out field management and pest control according to routine procedures, and record the experimental data of the planting process in Table 1.

[0038] Record the emergence rate and seedling status of cassava on the 10th and 20th day after planting. Figure 1 As shown in the figure, the cassava seeds have emerged and are growing well.

[0039] Comparative Example 1

[0040] The traditional cassava stem preservation and processing method is as follows:

[0041] (1) From November to December 2022, the tubers of Huanan 205 and NK-10 cassava were harvested. Immature and thin stems were removed, and the remaining healthy and mature stems were collected as cassava seed stems. 15-20 tubers were packed into bundles and labeled with the variety. They were then placed in a greenhouse to dry and preserve over the winter.

[0042] (2) In March and April 2023, before planting, the cassava planting field should be prepared, furrows and ridges should be dug, base fertilizer should be applied, and soil should be covered;

[0043] (3) Dig planting holes on the cassava planting ridges, cut the planting stems into 15-20 cm long planting stems, ensure that each node has at least one healthy bud point, lay the planting stems flat in the planting holes, and then cover them with soil. Subsequently, carry out field management and pest control according to routine procedures, and record the experimental data of the planting process in Table 1. Record the cassava seedling emergence rate and seedling status on the 10th and 20th days after planting. Figure 2 As shown, the cassava seedlings are lacking, and the emergence of seedlings is uneven and the growth is uneven.

[0044] Table 1 Record of cassava seedling emergence of different varieties

[0045]

[0046]

[0047] Note: In this experiment, the statistical standard for the seed stem storage trial survey was: 100 stems were randomly selected from each treatment for statistical description of the health of the seed stems; the selection standard for planting seed stems was the traditional production standard: the seed stems that were obviously dehydrated and dried and the seed stems that had already sprouted were cut off, and the remaining parts were planted as seed stems. The number of cassava seedlings was counted on the 10th and 20th days respectively, and the growth of the seedlings was recorded.

[0048] As shown in Table 1, the cassava stems treated with the present invention performed exceptionally well after winter storage: all stems were healthy, not dehydrated or withered, and had not sprouted. In contrast, the cassava stems treated with conventional methods, whether Huanan 205 or NK-10, showed some dehydration and withering, while others had already sprouted. This demonstrates that the present method can effectively reduce water loss during storage, prevent premature sprouting and nutrient consumption, and enhance stem activity.

[0049] A comparison of cassava stem emergence revealed that, for the same cassava variety, the present invention achieved over 93% seedling emergence within 10 days, with all seedlings emerging after 20 days and maintaining good growth. The comparative example achieved only a 10-day emergence rate of 58.67%-63.33%, and a 20-day emergence rate of 74.67%-82.67%. The cassava seedlings were lacking, with uneven emergence and uneven growth. This demonstrates that the present method can effectively promote the survival rate of seed stems. Firstly, this is related to the good winter preservation of the seed stems, and secondly, it is related to pre-soaking in a rooting-promoting medicinal solution before planting. The medicinal solution reduces excessive water loss in the cassava stems during planting, prevents disease infection, shortens the time it takes for the cassava stems to emerge, promotes rooting, and enables the cassava seedlings to absorb nutrients and water from the environment, improving their resistance to adverse environments.

[0050] Example 2

[0051] A seed stem processing method for improving the survival rate of cassava seedlings comprises the following steps:

[0052] (1) In November 2022, the tubers of Huanan 205 cassava were harvested, and then the stems of the cassava with no damage, no insect holes, and intact buds at a height of 1m above the ground were collected as cassava seed stems; 15-20 stems were packed into a bundle and marked.

[0053] (2) Soak the harvested cassava stems in soaking agent A for 5 to 10 minutes and then place them in an open space to dry; the soaking agent A contains 10 g / L maleic hydrazide, 1 g / L ABA, 10 g / L sodium carboxymethyl cellulose, and 350 mg / L crude extract of Jatropha curcas alkaloids, which are prepared in advance.

[0054] (3) Place the dried cassava stems in a greenhouse for winter storage and monitor them regularly. When the indoor temperature is below 0°C, cover the cassava stems with sugarcane leaves or straw to keep them warm. When the temperature is above 10°C, remove the covering in time to prevent the internal temperature of the cassava stems from being too high.

[0055] (4) In March and April 2023, before planting, the cassava planting area will be prepared, furrows and ridges will be dug, base fertilizer will be applied, and soil will be covered;

[0056] (5) Cut the seed stems that have been stored over the winter into 15-20 cm long planting stems, ensuring that each node has at least one healthy bud, and place them in soaking agent B for 3-5 minutes. Then remove them and place them in an open space to dry. The ingredients of soaking agent B are 10 g / L sodium carboxymethyl cellulose, 350 mg / L crude extract of jatropha curcas alkaloids, 30 mg / L gibberellin, and 30 mg / L cytokinin, which are prepared in advance.

[0057] (6) Digging planting holes on the cassava planting ridges, placing the cassava planting stems processed in step (5) flat in the planting holes and covering them with soil, and subsequently performing field management and pest control according to routine procedures, and recording experimental data of the planting process.

[0058] The cassava seedling emergence rate and seedling status were recorded on the 10th and 20th days after planting. On the 20th day after planting, the cassava seedling survival rate reached 100%, and the growth was relatively good.

[0059] Example 3

[0060] A seed stem processing method for improving the survival rate of cassava seedlings comprises the following steps:

[0061] (1) In December 2022, the NK-10 cassava tubers were harvested, and then the cassava stems with no damage, no insect holes, and intact buds at the bottom 1m above the ground were collected as cassava seed stems; 15-20 stems were packed into a bundle and marked.

[0062] (2) Soak the harvested cassava stems in soaking agent A for 3 to 5 minutes, and then place them in an open space to dry; the soaking agent A contains 5 g / L maleic hydrazide, 5 g / L ABA, 12 g / L sodium carboxymethyl cellulose, and 300 mg / L crude extract of Jatropha curcas alkaloids, which are prepared in advance.

[0063] (3) Place the dried cassava stems in a greenhouse for winter storage and monitor them regularly. When the indoor temperature is below 0°C, cover the cassava stems with sugarcane leaves or straw to keep them warm. When the temperature is above 10°C, remove the covering in time to prevent the internal temperature of the cassava stems from being too high.

[0064] (4) In April 2023, before planting, the cassava planting land will be prepared, furrows and ridges will be dug, base fertilizer will be applied, and soil will be covered;

[0065] (5) Cut the seed stems that have been stored over the winter into 15-20 cm long planting stems, ensuring that each node has at least one healthy bud, and place them in soaking agent B for 1-2 minutes. Then remove them and place them in an open space to dry. The ingredients of soaking agent B are 12 g / L sodium carboxymethyl cellulose, 300 mg / L crude extract of jatropha curcas alkaloids, 50 mg / L gibberellin, and 50 mg / L cytokinin, which are prepared in advance.

[0066] (6) Digging planting holes on the cassava planting ridges, placing the cassava planting stems processed in step (5) flat in the planting holes and covering them with soil, and subsequently performing field management and pest control according to routine procedures, and recording experimental data of the planting process.

[0067] Record the emergence rate and seedling status of cassava on the 10th and 20th days after planting. The survival rate of cassava seedlings reached 100% after 20 days of planting, and the growth was relatively good.

Claims

1. A method for treating cassava stems to improve the survival rate of cassava seedlings, characterized in that: The following steps are involved: (1) After harvesting cassava tubers, collect the cassava stems at a height of 1 m above the ground that are not damaged, have no insect eyes, and have intact buds as cassava seed stems; (2) placing the harvested cassava stems in soaking agent A for 1 to 10 minutes and then placing them in an open space to dry; the soaking agent A comprises 5-10 g / L maleic hydrazide, 1-5 g / L ABA, 10-12 g / L sodium carboxymethyl cellulose, and 250-300 mg / L crude extract of Jatropha curcas alkaloids; (3) Place the dried cassava stems in a greenhouse or indoors for winter storage, and pay attention to temperature control regularly; (4) In March and April of the following year, before planting, the cassava planting field should be prepared, furrows and ridges should be dug, base fertilizer should be applied, and soil should be covered; (5) Cut the preserved seed stems into 15-20 cm long planting stems, ensuring that each node has at least one healthy bud, and then place them in soaking agent B for 1-5 minutes, remove them and place them in an open space to dry; the soaking agent B contains 10-12 g / L sodium carboxymethyl cellulose, 250-300 mg / L crude extract of Jatropha curcas alkaloids, 30-50 mg / L gibberellins, and 30-50 mg / L cytokinins; (6) digging planting holes on the cassava planting ridges, placing the cassava planting stems processed in step (5) flat in the planting holes and covering them with soil, and subsequently performing field management and pest control according to conventional procedures.

2. The method for treating cassava seedlings according to claim 1, wherein the method comprises: 15-20 cassava seed stems collected in step (1) are packed into a bundle and marked with the variety.

3. The method for treating cassava seedlings according to claim 1, wherein: The soaking agent A comprises 5 g / L of maleic hydrazide, 5 g / L of ABA, 12 g / L of sodium carboxymethyl cellulose, and 300 mg / L of crude extract of Jatropha curcas alkaloids.

4. The method for treating cassava seedlings according to claim 1, wherein the method comprises: In step (3), the cassava seed stems are regularly monitored during winter storage. When the indoor temperature is below 0°C, the cassava seed stems are covered with sugarcane leaves or straw to protect them from the cold. When the temperature is above 10°C, the covering is removed in time.

5. The method for treating cassava seedlings according to claim 1, wherein: The soaking agent B comprises 12 g / L of sodium carboxymethyl cellulose, 300 mg / L of crude extract of Jatropha curcas alkaloids, 50 mg / L of gibberellin, and 50 mg / L of cytokinin.

6. The method for treating cassava stems to improve the survival rate of cassava seedlings according to claim 1, wherein: The extraction operation of the crude extract of Jatropha curcas alkaloids is as follows: Jatropha curcas leaf sample powder and 80% ethanol by mass are added at a solid-liquid ratio of 1:30, ultrasonic extraction is performed at 40°C, filtration is performed, rotary evaporation is performed, and separation is performed by dichloroethane extraction. Then, 10% sodium carbonate solution is added to the obtained aqueous phase for alkalization. After separation by dichloroethane extraction, the obtained organic phase is placed in an oven for drying to obtain a crude extract of alkaloids.

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