A method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid

Abstract

This invention provides a method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid, comprising the following steps: S1 site selection and land preparation, S2 variety selection and treatment, S3 application of organic base fertilizer and planting, S4 replanting and weeding, S5 irrigation management, S6 foliar fertilizer application, S7 cassava stem and leaf harvesting, and S8 cassava stem and leaf treatment. This invention effectively reduces the hydrocyanic acid content in cassava stems and leaves, improves photosynthesis, and promotes stem and leaf growth through steps such as site selection, seedling selection, application of organic base fertilizer, irrigation management, foliar fertilizer application, and controlled harvesting time, thereby obtaining high-yield cassava stems and leaves with low hydrocyanic acid content. The coumarin, sodium citrate, and desulfurizing Vibrio in the foliar fertilizer inhibitor of this invention work synergistically through different mechanisms to block the synthesis of hydrocyanic acid in cassava stems and leaves, thus achieving the goal of more effectively reducing the hydrocyanic acid content in cassava stems and leaves. The obtained cassava stems and leaves can be used as feed cassava stems and leaves without further treatment.

Description

Technical Field

[0001] This invention relates to the field of cassava cultivation technology, specifically to a method for cultivating feed cassava that blocks the synthesis of hydrocyanic acid. Background Technology

[0002] Cassava, also known as tapioca or cassava potato, is a plant native to South America, belonging to the genus *Cassava* in the family Euphorbiaceae. Cassava tubers are rich in starch, making them a major raw material for starch production in industry. Furthermore, cassava flour is an important raw material in the food, beverage, and pharmaceutical industries. Cassava leaves are rich in various nutrients and bioactive substances, providing a good source of protein, minerals, and vitamins. Cassava is highly adaptable, drought-tolerant, and grows rapidly in poor soil, making it widely cultivated in tropical and subtropical regions. In my country, it is mainly grown in Guangdong, Guangxi, Hainan, and Yunnan provinces.

[0003] The feed value of cassava cannot be ignored. Its tubers are rich in carbohydrates and, after proper processing, can be used as animal feed. Cassava, as feed, is high in energy and easily digestible, making it particularly suitable for the needs of animal husbandry. In animal husbandry, cassava flour is widely used in the feeding of pigs, chickens, cattle, sheep, and other animals, effectively improving animal growth rates and feed conversion rates. At the same time, cassava leaves are also a high-quality feed source, rich in protein and minerals, and are a renewable green feed resource in animal husbandry. Cassava leaf powder is also a good feed for livestock and poultry, and can also be used to feed fish and silkworms, possessing both edible and feed utilization value. Statistics show that the yield of cassava stems and leaves is comparable to that of tubers, but a small portion is used for feed processing, while the majority is discarded and wasted, indicating a relatively lagging development and utilization of its resources. The high hydrocyanic acid content in cassava leaves is a limiting factor for its feed utilization. Although low-hydrocyanic acid varieties have been bred for the tubers, even these varieties still have high levels of hydrocyanic acid in their stems and leaves, requiring further treatment to reduce the hydrocyanic acid content before they can be used as feed ingredients. Summary of the Invention

[0004] In view of this, the present invention proposes a method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid in order to solve the above problems.

[0005] The technical solution of this invention is achieved as follows: a method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid, comprising the following steps:

[0006] S1 Site Selection and Land Preparation: Select flat or gently sloping land with good drainage and sufficient sunlight; when preparing the land, first remove weeds, then level the land, and then dig planting trenches.

[0007] S2 Variety Selection and Treatment: Select heat-resistant, low-hydrocyanic acid content, no mutation, no pests, and plump buds cassava varieties as seed tubers, cut the seed tubers into 10-20cm pieces, and apply wood ash to both sides of the cut surface of the seed tubers.

[0008] S3 Apply organic base fertilizer and plant: Sprinkle organic base fertilizer in the planting trench, and place the seed stems in the planting trench by laying them flat or inserting them at an angle, with a plant spacing of 40-60cm. The planting time is late February or early March.

[0009] S4 Replanting and Removal: Replant missing plants 10-15 days after planting, and remove excess buds, leaving 1-2 strong buds per plant.

[0010] S5 Irrigation Management: Irrigation is carried out via drip irrigation or micro-sprinkler irrigation.

[0011] S6 Foliar Fertilizer: The foliar fertilizer contains the following ingredients: potassium dihydrogen phosphate, urea, methionine, trace elements, seaweed extract, and blocking agent. Preferably, the blocking agent is a combination of coumarin, sodium citrate, and desulfurized Vibrio.

[0012] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 60-70 days after planting. The second to seventh harvests are carried out every 15-20 days, and the eighth to tenth harvests are carried out every 25-30 days.

[0013] S8 Cassava Stem and Leaf Processing: Dry or freeze-dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0014] Furthermore, the S1 planting furrow is 25-35cm deep, with a row spacing of 60-80cm, and one row of cassava is planted in each furrow.

[0015] Furthermore, the S2 cassava variety is one of the following: South China 8013, South China 124, South China 7, South China 5, or South China 205.

[0016] Furthermore, S3 organic base fertilizer comprises the following raw materials by weight: 40-50 parts well-rotted manure, 30-40 parts crop straw, 10-20 parts soil conditioner, 3-5 parts superphosphate, and 2-5 parts lactic acid bacteria fermentation liquid, with an application rate of 200-400 kg / mu. The well-rotted manure is one or a combination of well-rotted cow manure, well-rotted sheep manure, well-rotted pig manure, well-rotted rabbit manure, well-rotted chicken manure, well-rotted duck manure, and well-rotted goose manure. The crop straw is one or a combination of rice straw, pineapple straw, cassava straw, peanut straw, sesame straw, sugarcane straw, and corn straw.

[0017] Furthermore, the soil conditioner is one or a combination of vermiculite powder, perlite powder, peat powder, weathered coal powder, and sepiolite powder.

[0018] Furthermore, the S5 irrigation management water volume is 1.5-2.0 tons / acre. Irrigation is carried out the day after harvesting, and the irrigation frequency is once every 10-12 days. If it rains during this period, irrigation is not required.

[0019] Furthermore, the composition of each component of S6 foliar fertilizer is as follows: 20-30 parts potassium dihydrogen phosphate, 5-10 parts urea, 5-10 parts inhibitor, 0.6-1.0 parts methionine, 0.4-0.8 parts trace elements, and 0.4-0.8 parts seaweed extract; the application rate is 6-10 kg, which should be diluted with 8-10 times the amount of water and sprayed in the early morning or evening 40-50 days after planting and 10-12 days after harvesting.

[0020] Furthermore, the component ratios of the blocking agent are as follows: 15-25% coumarin, 70-80% sodium citrate, and 2-6% desulfurized Vibrio, with a desulfurized Vibrio vibrio count ≥ 1 × 10⁻⁶. 6 cfu / g.

[0021] Furthermore, trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon.

[0022] Furthermore, S7 harvesting involves harvesting young stems and leaves, and the harvesting time is from 16:00 to 19:00 in the afternoon.

[0023] Compared with the prior art, the beneficial effects of the present invention are: the present invention effectively reduces the hydrocyanic acid content in cassava leaves, improves the photosynthesis of cassava stems and leaves, and promotes the growth of cassava stems and leaves through steps such as selecting planting sites, selecting seedlings, applying organic base fertilizer, irrigation management, applying foliar fertilizer, and controlling harvesting time, thereby obtaining high-yield, low-hydrocyanic acid content, and nutrient-rich cassava leaves.

[0024] This invention reduces the hydrocyanic acid content in cassava stems and leaves by applying a specific ratio of foliar fertilizer to block the synthesis of hydrocyanic acid. The sodium citrate in the foliar fertilizer blocker regulates the environment within the cassava stems and leaves to a weakly alkaline state, weakening the activity of β-glucosidase and thus reducing hydrocyanic acid synthesis. Desulfovibrio consumes sulfate in the cassava stems and leaves by reducing sulfate to produce hydrogen sulfide and other products, affecting the hydrocyanic acid synthesis pathway and thus reducing its content. Simultaneously, sodium citrate provides nutrients to Desulfovibrio, increasing its activity and promoting its colonization and reproduction within the cassava stems and leaves. Coumarin reacts with the remaining β-glucosidase, depriving cyanogenic glycosides of their active sites and blocking hydrocyanic acid synthesis, thereby reducing its content. In this invention, coumarin, sodium citrate, and desulfurized Vibrio work synergistically through different mechanisms in foliar fertilizer to jointly block the synthesis of hydrocyanic acid in cassava stems and leaves, thereby achieving the goal of more effectively reducing the hydrocyanic acid content in cassava stems and leaves. The obtained cassava stems and leaves can be used as feed cassava stems and leaves without further treatment.

[0025] The organic fertilizer provided by this invention fully considers the nutrient absorption pattern during cassava growth, and can meet the needs of cassava for macronutrients such as nitrogen, phosphorus and potassium. When combined with foliar fertilizer, it can meet the needs of cassava for micronutrients such as calcium, magnesium and iron. Therefore, it can improve photosynthesis, promote the growth of cassava stems and leaves, and increase the yield of cassava stems and leaves during cassava planting. Detailed Implementation

[0026] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0027] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0028] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0029] Example 1

[0030] A method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid includes the following steps:

[0031] S1 Site Selection and Land Preparation: Select well-drained, sunny, flat or gently sloping land. First, remove weeds, then level the land, and then dig planting trenches. The trenches should be 25cm deep with a row spacing of 60cm, planting one row of cassava per trench.

[0032] S2 Variety Selection and Treatment: Select the heat-resistant, low-hydrocyanic acid content, non-mutated, pest-free, and plump buds South China 8013 cassava variety as seed stems, cut the seed stems into 10cm pieces, and apply wood ash to both sides of the cut surface of the seed stems.

[0033] S3. Application of Organic Base Fertilizer and Planting: Spread the organic base fertilizer in the planting trench, then place the seedlings flat in the trench, spacing them 40cm apart. Planting time is late February. The organic base fertilizer consists of the following ingredients by weight: 40 parts well-rotted manure, 30 parts crop straw, 10 parts soil conditioner, 3 parts superphosphate, and 2 parts lactic acid bacteria fermentation liquid, applied at a rate of 200 kg / mu. The soil conditioner is vermiculite powder.

[0034] S4 Replanting and Removal: Replant missing plants 10 days after planting and remove excess buds, leaving one strong bud per plant.

[0035] S5 Irrigation Management: Irrigation is carried out by drip irrigation. The irrigation amount is 1.5 tons / acre. Irrigation is carried out the day after harvest and every 10 days. If it rains, irrigation is not required.

[0036] S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials by weight: 20 parts potassium dihydrogen phosphate, 5 parts urea, 0.6 parts methionine, 0.4 parts trace elements, 0.4 parts seaweed extract, and 5 parts inhibitor. The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon. The inhibitor is a combination of coumarin, sodium citrate, and desulfurized Vibrio. The ratio of each component in the inhibitor is as follows: 15% coumarin, 80% sodium citrate, and 5% desulfurized Vibrio, with a desulfurized Vibrio vibrio activity of 1×10⁻⁶. 6 cfu / g. The application rate is 6 kg, which is diluted with 8 times the amount of water and sprayed in the early morning 40 days after planting and 10 days after harvest.

[0037] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 60 days after planting. The second to seventh harvests are carried out every 15 days, and the eighth to tenth harvests are carried out every 25 days. Harvest young stems and leaves and tender stems and leaves, and harvest time is from 16:00 to 19:00 in the afternoon.

[0038] S8 Cassava Stem and Leaf Processing: Dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0039] Example 2

[0040] A method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid includes the following steps:

[0041] S1 Site Selection and Land Preparation: Select well-drained, sunny, flat or gently sloping land. First, remove weeds, then level the land, and then dig planting trenches. The planting trenches should be 35cm deep, with a row spacing of 80cm, and plant one row of cassava per trench.

[0042] S2 Variety Selection and Treatment: Select the heat-resistant, low-hydrocyanic acid content, no mutation, no pests, and plump buds South China 124 cassava variety as seed stems, cut the seed stems into 20cm pieces, and apply wood ash to both sides of the cut surface of the seed stems.

[0043] S3. Application of Organic Base Fertilizer and Planting: Spread the organic base fertilizer in the planting trench, then place the seedlings flat in the trench, spacing them 60cm apart. Planting time is late February. The organic base fertilizer consists of the following ingredients by weight: 40 parts well-rotted manure, 30 parts crop straw, 10 parts soil conditioner, 3 parts superphosphate, and 2 parts lactic acid bacteria fermentation liquid, with an application rate of 400 kg / mu. The soil conditioner is a 1:1 combination of perlite powder and peat powder.

[0044] S4 Replanting and Removal: Replant missing plants 15 days after planting and remove excess buds, leaving one strong bud per plant.

[0045] S5 Irrigation Management: Irrigation is carried out via drip irrigation. The irrigation amount is 2.0 tons / acre. Irrigation is carried out the day after harvest and every 12 days. If it rains, irrigation may not be necessary.

[0046] S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials by weight: 20 parts potassium dihydrogen phosphate, 5 parts urea, 0.6 parts methionine, 0.4 parts trace elements, 0.4 parts seaweed extract, and 5 parts inhibitor. The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon. The inhibitor is a combination of coumarin, sodium citrate, and desulfurized Vibrio. The ratio of each component in the inhibitor is as follows: 25% coumarin, 70% sodium citrate, and 5% desulfurized Vibrio, with a desulfurized Vibrio vibrio activity of 5 × 10⁻⁶. 6 cfu / g. The application rate is 10 kg, which is diluted with 10 times the amount of water and sprayed in the early morning 50 days after planting and 12 days after harvest.

[0047] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 70 days after planting. The second to seventh harvests are carried out every 20 days, and the eighth to tenth harvests are carried out every 30 days. Harvest young stems and leaves and tender stems and leaves, and harvest time is from 16:00 to 19:00 in the afternoon.

[0048] S8 Cassava Stem and Leaf Processing: Dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0049] Example 3

[0050] A method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid includes the following steps:

[0051] S1 Site Selection and Land Preparation: Select well-drained, sunny, flat or gently sloping land. First, remove weeds, then level the land, and then dig planting trenches. The trenches should be 30cm deep with a row spacing of 70cm, planting one row of cassava per trench.

[0052] S2 Variety Selection and Treatment: Select the heat-resistant, low-hydrocyanic acid content, no mutation, no pests, and plump buds South China No. 7 cassava variety as seed stems, cut the seed stems into 15cm pieces, and apply wood ash to both sides of the cut surface of the seed stems.

[0053] S3. Application of Organic Base Fertilizer and Planting: Spread the organic base fertilizer in the planting trench, then place the seedlings flat in the trench, spacing them 50cm apart. Planting time is late February. The organic base fertilizer consists of the following ingredients by weight: 45 parts well-rotted manure, 35 parts crop straw, 15 parts soil conditioner, 4 parts superphosphate, and 3.5 parts lactic acid bacteria fermentation liquid, with an application rate of 300 kg / mu. The soil conditioner is a 1:1:1 combination of vermiculite powder, perlite powder, and peat powder.

[0054] S4 Replanting and Removal: Replant missing plants 13 days after planting and remove excess buds, leaving 2 strong buds per plant.

[0055] S5 Irrigation Management: Irrigation is carried out using micro-sprinklers. The irrigation amount is 1.75 tons / acre. Irrigation is carried out the day after harvest and every 11 days. If it rains, irrigation is not required.

[0056] S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials by weight: 25 parts potassium dihydrogen phosphate, 7.5 parts urea, 0.8 parts methionine, 0.6 parts trace elements, 0.6 parts seaweed extract, and 7.5 parts inhibitor. The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon. The inhibitor is a combination of coumarin, sodium citrate, and desulfurized Vibrio. The ratio of each component in the inhibitor is as follows: 20% coumarin, 75% sodium citrate, and 5% desulfurized Vibrio, with a desulfurized Vibrio vibrio activity of 1×10⁻⁶. 7 cfu / g. The application rate is 8 kg, which is diluted with 9 times the amount of water and sprayed in the early morning or evening 45 days after planting and 11 days after harvest.

[0057] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 65 days after planting. The second to seventh harvests are carried out every 18 days, and the eighth to tenth harvests are carried out every 28 days. Harvest young stems and leaves and tender stems and leaves, and harvest time is from 16:00 to 19:00 in the afternoon.

[0058] S8 Cassava Stem and Leaf Processing: Dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0059] Example 4

[0060] A method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid includes the following steps:

[0061] S1 Site Selection and Land Preparation: Select well-drained, sunny, flat or gently sloping land. First, remove weeds, then level the land, and then dig planting trenches. The trenches should be 25cm deep with a row spacing of 60cm, planting one row of cassava per trench.

[0062] S2 Variety Selection and Treatment: Select the heat-resistant, low-hydrocyanic acid content, no mutation, no pests, and plump buds South China No. 5 cassava variety as seed stems, cut the seed stems into 10cm pieces, and apply wood ash to both sides of the cut surface of the seed stems.

[0063] S3. Application of Organic Base Fertilizer and Planting: Spread the organic base fertilizer in the planting trench, and place the seedlings in the trench at an angle, with a plant spacing of 40cm. Planting time is in early March. The organic base fertilizer consists of the following ingredients by weight: 50 parts well-rotted manure, 40 parts crop straw, 20 parts soil conditioner, 5 parts superphosphate, and 5 parts lactic acid bacteria fermentation liquid, with an application rate of 200 kg / mu. The soil conditioner is a 1:1 combination of weathered coal powder and sepiolite powder.

[0064] S4 Replanting and Removal: Replant missing plants 10 days after planting and remove excess buds, leaving 1-2 strong buds per plant.

[0065] S5 Irrigation Management: Irrigation is carried out using micro-sprinklers. The irrigation amount is 1.5 tons / acre. Irrigation is carried out the day after harvest and every 10 days. If it rains during this period, irrigation is not required.

[0066] S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials by weight: 30 parts potassium dihydrogen phosphate, 10 parts urea, 1.0 part methionine, 0.8 parts trace elements, 0.8 parts seaweed extract, and 10 parts inhibitor. The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon. The inhibitor is a combination of coumarin, sodium citrate, and desulfurized Vibrio. The ratio of each component in the inhibitor is as follows: 18% coumarin, 76% sodium citrate, and 6% desulfurized Vibrio, with a desulfurized Vibrio vibrio activity of 2 × 10⁻⁶. 7 cfu / g. The application rate is 7 kg, which is diluted with 8 times the amount of water and sprayed in the evening 40 days after planting and 10 days after harvest.

[0067] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 60 days after planting. The second to seventh harvests are carried out every 15 days, and the eighth to tenth harvests are carried out every 25 days. Harvest young stems and leaves and tender stems and leaves, and harvest time is from 16:00 to 19:00 in the afternoon.

[0068] S8 Cassava Stem and Leaf Processing: Freeze-dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0069] Example 5

[0070] A method for cultivating cassava for feed that blocks the synthesis of hydrocyanic acid includes the following steps:

[0071] S1 Site Selection and Land Preparation: Select well-drained, sunny, flat or gently sloping land. First, remove weeds, then level the land, and then dig planting trenches. The planting trenches should be 35cm deep, with a row spacing of 80cm, and plant one row of cassava per trench.

[0072] S2 Variety Selection and Treatment: Select the heat-resistant, low-hydrocyanic acid content, no mutation, no pests, and plump buds South China 205 cassava variety as seed stems, cut the seed stems into 20cm pieces, and apply wood ash to both sides of the cut surface of the seed stems.

[0073] S3. Application of Organic Base Fertilizer and Planting: Spread the organic base fertilizer in the planting trench, and place the seedlings in the trench at an angle, with a plant spacing of 60cm. Planting time is in early March. The organic base fertilizer consists of the following ingredients by weight: 50 parts well-rotted manure, 40 parts crop straw, 20 parts soil conditioner, 5 parts superphosphate, and 5 parts lactic acid bacteria fermentation liquid, with an application rate of 400 kg / mu. The soil conditioner is a 1:1 combination of vermiculite powder and sepiolite powder.

[0074] S4 Replanting and Removal: Replant missing plants 15 days after planting and remove excess buds, leaving 2 strong buds per plant.

[0075] S5 Irrigation Management: Irrigation is carried out using micro-sprinklers. The irrigation amount is 2.0 tons / acre. Irrigation is carried out the day after harvest and every 12 days. If it rains, irrigation is not required.

[0076] S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials by weight: 30 parts potassium dihydrogen phosphate, 10 parts urea, 1.0 part methionine, 0.8 parts trace elements, 0.8 parts seaweed extract, and 10 parts inhibitor. The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon. The inhibitor is a combination of coumarin, sodium citrate, and desulfurized Vibrio. The ratio of each component in the inhibitor is as follows: 25% coumarin, 73% sodium citrate, and 2% desulfurized Vibrio, with a desulfurized Vibrio vibrio activity of 5 × 10⁻⁶. 7 cfu / g. The application rate is 10 kg, which is diluted with 10 times the amount of water and sprayed in the evening 50 days after planting and 12 days after harvest.

[0077] S7 Cassava Stem and Leaf Harvesting: The first harvest is carried out 70 days after planting. The second to seventh harvests are carried out every 20 days, and the eighth to tenth harvests are carried out every 30 days. Harvest young stems and leaves and tender stems and leaves, and harvest time is from 16:00 to 19:00 in the afternoon.

[0078] S8 Cassava Stem and Leaf Processing: Freeze-dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

[0079] Comparative Example 1

[0080] The difference between Comparative Example 1 and Implementation 3 is that the foliar fertilizer in step S6 does not contain an inhibitor.

[0081] Comparative Example 2

[0082] The difference between Comparative Example 2 and Example 3 is that the content ratio of each component of the foliar fertilizer inhibitor in step S6 is as follows: 10% coumarin, 83% sodium citrate, and 7% desulfurized Vibrio.

[0083] Comparative Example 3

[0084] The difference between Comparative Example 3 and Example 3 is that the foliar fertilizer inhibitor in step S6 does not contain coumarin.

[0085] Comparative Example 4

[0086] Compared with Example 3, Comparative Example 4 differs in that the content of each component of the foliar fertilizer in step S6 is as follows: 35 parts potassium dihydrogen phosphate, 15 parts urea, 1.5 parts methionine, 1.0 part trace elements, 1.2 parts seaweed extract, and 3 parts inhibitor.

[0087] Comparative Example 5

[0088] The difference between Comparative Example 5 and Example 3 is that the harvesting time in step S7 is in the morning or at noon.

[0089] Comparative Example 6

[0090] The difference between Comparative Example 6 and Implementation 3 is that in step S7, the second to seventh harvests are harvested once every 28 days, and the eighth to tenth harvests are harvested once every 18 days.

[0091] I. Determination of Hydrogen Cyanide Content

[0092] Fresh cassava stems and leaves from the 1st, 5th, and 10th harvests were collected, washed, drained, and pulverized. The following method was used to determine the concentration and average value: 20g of sample was placed in a flask, 500ml of distilled water was added, and the flask was capped. After hydrolysis at room temperature for 6 hours, the sample was quickly connected to a steam distillation apparatus for distillation, collecting 150mL of distillate. 10mL of 0.5% wt lead nitrate solution was added to the distillate, mixed thoroughly, and allowed to stand for 15 minutes. Insoluble matter was filtered out, and the volume was adjusted to 250mL. 100mL of the filtrate was placed in an Erlenmeyer flask, 8mL of 6mol / L ammonia solution and 2mL of potassium iodide were added, mixed thoroughly, and titrated with silver nitrate standard solution until a distinct, persistent, and non-disappearing white precipitate appeared in the solution. The volume of silver nitrate standard solution consumed was recorded. A blank test was performed using distilled water instead of the distillate, titrated with silver nitrate standard solution, and the volume consumed was recorded. The hydrocyanic acid content was calculated using the following formula:

[0093]

[0094] In the formula: X is the content of hydrocyanic acid in the sample, in mg / kg; m is the sample mass, in g; c is the silver nitrate standard solution, in mol / mL; V is the volume of silver nitrate standard solution consumed during the determination, in mL; V0 is the volume of silver nitrate standard solution consumed in the blank test, in mL; and 54 is the mass of hydrocyanic acid consumed when 1 mL of 1 mol / mL silver nitrate solution is consumed, in mg. The measured results are shown in Table 1.

[0095] II. Total Output Statistics

[0096] After each harvest, the harvested cassava stems and leaves were weighed, and the total yield was calculated after 10 harvests. The annual yield of cassava stems and leaves per acre is shown in Table 1.

[0097] Table 1

[0098] Sample Hydrocyanic acid content (mg / kg) Total yield of stems and leaves (kg / mu) Example 1 40.6 2520 Example 2 41.3 2507 Example 3 39.8 2516 Example 4 41.1 2489 Example 5 40.8 2513 Comparative Example 1 109.7 2519 Comparative Example 2 77.4 2498 Comparative Example 3 65.9 2515 Comparative Example 4 85.3 2108 Comparative Example 5 50.6 2450 Comparative Example 6 57.2 2211

[0099] As shown in Table 1, the cultivation methods in Examples 1-5 can effectively reduce the content of hydrocyanic acid in cassava stems and leaves, and the effect of Example 3 is more significant.

[0100] Comparing Example 3 with Comparative Example 1, it can be seen that the addition of an inhibitor to the foliar fertilizer plays a crucial role in reducing hydrocyanic acid in cassava stems and leaves. Sodium citrate in the inhibitor regulates the environment within the cassava stems and leaves to a weakly alkaline state, weakening the activity of β-glucosidase and thus reducing hydrocyanic acid synthesis. Desulfovibrio consumes sulfate in the cassava stems and leaves by reducing sulfate to produce hydrogen sulfide and other products, affecting the hydrocyanic acid synthesis pathway and thus reducing its content. Simultaneously, sodium citrate provides nutrients to Desulfovibrio, increasing its activity and promoting its colonization and reproduction within the cassava stems and leaves. Coumarin reacts with the remaining β-glucosidase, depriving cyanogenic glycosides of their active sites, blocking hydrocyanic acid synthesis, and thus reducing its content. In this invention, coumarin, sodium citrate, and Desulfovibrio synergistically work through different mechanisms in the foliar fertilizer to jointly block the synthesis of hydrocyanic acid in cassava stems and leaves, thereby achieving the goal of more effectively reducing the hydrocyanic acid content in cassava stems and leaves.

[0101] By comparing Example 3 with Comparative Example 2, it can be seen that the synergistic effect between the components of the blocker can only be maximized under a specific ratio, thereby achieving the best effect of reducing the hydrogen cyanide content.

[0102] By comparing Example 3 with Comparative Example 3, it can be seen that coumarin plays a crucial role in the inhibitor and cannot be replaced by the other two components. Through the reaction of coumarin with β-glucosidase, the active site of cyanogenic glycosides is deprived, blocking the synthesis of hydrocyanic acid and further reducing the content of hydrocyanic acid.

[0103] By comparing Example 3 with Comparative Example 4, it can be seen that there are significant differences in the reduction of hydrocyanic acid content by foliar fertilizers with different proportions. Only by applying a specific proportion of foliar fertilizer to the stems and leaves of cassava can a better effect be achieved in reducing hydrocyanic acid content.

[0104] Comparing Example 3 with Comparative Example 5, cassava plants are in a well-lit environment during the morning and midday hours, when photosynthesis is more vigorous. During photosynthesis, plants absorb carbon dioxide and release oxygen, while also producing some organic matter, including some intermediate products that may be converted into hydrocyanic acid. Therefore, the hydrocyanic acid content in cassava plants may be relatively high during the morning and midday hours. Thus, to obtain cassava stems and leaves with lower hydrocyanic acid content, it is more suitable to harvest them in the afternoon when photosynthesis is weaker.

[0105] Comparing Example 3 with Comparative Example 6, the growth cycle and metabolic rate of cassava are influenced by various factors, including temperature, light, water, and nutrients. In the early stages, due to ample organic fertilizer, cassava plants grow and metabolize rapidly. At this time, a shorter 18-day interval helps with timely harvesting and reduces the accumulation of hydrocyanic acid. However, in the later stages, as the organic fertilizer is consumed, the nutrient content in the fertilizer gradually decreases. Furthermore, as the cassava plants grow, their metabolic rate slows down after a certain stage. Using a longer 28-day interval for the later 8-10 harvests helps decompose hydrocyanic acid, and this harvesting timing may result in cassava stems and leaves with lower hydrocyanic acid content.

[0106] Meanwhile, comparing Examples 1-5 with Comparative Example 1, it can be seen that the addition of the inhibitor has no adverse effect on the growth of cassava plants. Comparing Example 3 with Comparative Example 4, the foliar fertilizer ratio in Example 3 is more suitable for cassava plant growth because it is closer to the nutrient requirements of cassava plants at a specific growth stage, avoiding nutrient excess or waste, and promoting the absorption and utilization of other components. It is evident that applying a specific ratio of foliar fertilizer can yield higher cassava stem and leaf yields. Compared to Comparative Example 4, the yield of Example 3 increased by 19.4%. Comparing Example 3 with Comparative Example 6, the harvesting interval in Example 3 is more in line with the growth characteristics of cassava plants, thus obtaining better cassava stem and leaf yields. In the early, vigorous growth period of cassava plants, when nutrients are abundant and cassava plants grow rapidly, an 18-day harvesting interval facilitates timely harvesting. In the later stages, when cassava growth has stabilized and the growth rate of cassava plants decreases somewhat due to the consumption of nutrients in the basal fertilizer, a 28-day harvesting interval is more conducive to the growth and recovery of cassava plants. Therefore, the harvesting method of Example 3 can achieve a higher yield of cassava stems and leaves, which is 13.8% higher than that of Comparative Example 6.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid, characterized in that, Includes the following steps: S1 Site Selection and Land Preparation: Select flat or gently sloping land with good drainage and sufficient sunlight; when preparing the land, first remove weeds, then level the land, and then dig planting trenches; S2 Variety Selection and Treatment: Select heat-resistant, low hydrocyanic acid content, no mutation, no pests, and plump buds cassava varieties as seed tubers, cut the seed tubers into 10-20cm pieces, and apply wood ash to both sides of the cut surface of the seed tubers. S3 Apply organic base fertilizer and plant: Sprinkle organic base fertilizer in the planting trench, and place the seed stems in the planting trench in a flat or oblique manner, with a plant spacing of 40-60cm. The planting time is late February or early March. S4 Replanting and Removal: Replant missing plants 10-15 days after planting and remove excess buds, leaving 1-2 strong buds per plant. S5 Irrigation Management: Irrigation is carried out via drip irrigation or micro-sprinkler irrigation; S6 Foliar Fertilizer: The foliar fertilizer contains the following raw materials: potassium dihydrogen phosphate, urea, methionine, trace elements, seaweed extract, and blocking agent, wherein the blocking agent is a combination of coumarin, sodium citrate, and desulfurized Vibrio. S7 cassava stem and leaf harvesting: The first harvest is carried out 60-70 days after planting, the second to seventh harvests are carried out every 15-20 days, and the eighth to tenth harvests are carried out every 25-30 days. S8 Cassava Stem and Leaf Processing: Dry or freeze-dry the harvested cassava stems and leaves, then crush them, pack them into bags, and seal them for storage.

2. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The S1 planting furrow is 25-35cm deep, with a row spacing of 60-80cm, and one row of cassava is planted in each furrow.

3. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The S2 cassava variety is one of the following: South China 8013, South China 124, South China 7, South China 5, or South China 205.

4. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The S3 organic base fertilizer comprises the following raw materials in parts by weight: 40-50 parts decomposed manure, 30-40 parts crop straw, 10-20 parts soil conditioner, 3-5 parts superphosphate, and 2-5 parts lactic acid bacteria fermentation liquid, with an application rate of 200-400 kg / mu.

5. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 4, characterized in that, The soil conditioner is one or a combination of vermiculite powder, perlite powder, peat powder, weathered coal powder, and sepiolite powder.

6. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The S5 irrigation management system requires 1.5-2.0 tons of water per mu (approximately 0.067 hectares). Irrigation should be carried out the day after harvesting, with a frequency of once every 10-12 days. If it rains during this period, irrigation may not be necessary.

7. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The components of the S6 foliar fertilizer are as follows: 20-30 parts potassium dihydrogen phosphate, 5-10 parts urea, 5-10 parts inhibitor, 0.6-1.0 parts methionine, 0.4-0.8 parts trace elements, and 0.4-0.8 parts seaweed extract. The application rate is 6-10 kg, which is diluted with 8-10 times the amount of water and sprayed in the early morning or evening 40-50 days after planting and 10-12 days after each harvest.

8. The method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 7, characterized in that, The components of the blocking agent are in the following proportions: 15-25% coumarin, 70-80% sodium citrate, and 2-6% desulfurized Vibrio, wherein the viability count of the desulfurized Vibrio is ≥1×10⁻⁶. 6 cfu / g.

9. A method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 7, characterized in that, The trace elements include the following components: iron, copper, calcium, zinc, magnesium, manganese, selenium, and silicon.

10. A method for cultivating cassava for feed by blocking the synthesis of hydrocyanic acid as described in claim 1, characterized in that, The S7 harvesting involves harvesting young stems and leaves, and the harvesting time is from 16:00 to 19:00 in the afternoon.

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