A method for planting herbivorous animal feed plants using polluted waste land

Abstract

The present invention relates to the technical field of production of forage plants planted on polluted waste land, and in particular to a planting method for planting herbivorous animal feed plants on polluted waste land. In the present invention, land planting areas are divided according to cadmium pollution conditions, and forage plants are planted annually and corresponding planting patterns are adopted, so that the feed raw materials obtained by cutting forage plants planted in different areas of cadmium-contaminated land can achieve large yields, high nutritional value, and cadmium content that meets feed hygiene standards. At the same time, planting forage plants can improve the land and reduce soil erosion, thereby utilizing polluted waste land to increase its added value, turning waste into treasure, alleviating the problem of shortage of forage for herbivorous animals in the south, and also improving the economic benefits of local residents.

Description

Technical Field

[0001] The invention relates to the technical field of production of forage plants planted on polluted waste land, and in particular to a planting method for planting herbivorous animal feed plants on polluted waste land. Background Art

[0002] In order to accelerate the adjustment of the livestock industry structure, the south is currently vigorously developing herbivorous livestock, but there is still a shortage of forage. The large amount of roughage needed is mainly purchased from the north, resulting in extremely high transportation costs and waste of resources. This affects the safety of roughage supply for herbivorous livestock in the south, and makes it impossible to supply effectively under unfavorable factors such as freezing weather, which greatly increases the cost of herbivorous livestock breeding and reduces breeding efficiency.

[0003] Due to industrial reasons such as mining, a large amount of cadmium-contaminated land has been generated in southern Jiangxi. For land with cadmium pollution exceeding the safe range, when the cadmium content is higher than the risk screening value, safe utilization measures must be taken for planting economic crops. When the cadmium pollution is higher than the risk control value, it is strictly prohibited to plant any economic crops because the cadmium content of crops exceeds the standard. Land with cadmium pollution higher than the risk control value is idle and wasted because it cannot be used to plant economic crops. Restoration methods such as plant removal or passivation have problems such as long restoration time (up to more than ten years), extremely high cost, and damage to the nutritional structure of the land. In addition, it is impossible to completely eliminate cadmium pollution in some contaminated areas with unknown sources of pollution. How to plant fodder plants on land with cadmium pollution exceeding the safety range (especially land above the risk control value) is of great significance to improving land utilization.

[0004] The southern part of Jiangxi Province has many mountains and little arable land. In addition, the area of ​​cadmium pollution is the largest among the existing heavy metal pollution in cultivated land. Some of the cultivated land has cadmium content exceeding the safe range (cadmium content is higher than the risk control value), and no economic crops can be grown in it. Therefore, how to use cadmium-contaminated abandoned land to plant herbivorous animal feed plants is an important breakthrough in solving the current shortage of herbivorous animal forage and the difficulty in using cadmium-contaminated land. Summary of the invention

[0005] In order to overcome the above-mentioned shortcomings, the purpose of the present invention is to provide a planting method for planting herbivorous animal feed plants using polluted abandoned land, which divides the land planting areas according to the cadmium pollution situation, plants feed plants according to an annual model and adopts a corresponding planting sequence model, which can ensure that the feed raw materials obtained by cutting the feed plants planted in different areas of cadmium-contaminated land can achieve high yield, high nutritional value, and cadmium content that meets the requirements of feed hygiene standards. At the same time, planting feed plants can improve the land and reduce soil erosion, thereby utilizing polluted abandoned land to increase its added value, turning waste into treasure, alleviating the problem of shortage of herbivorous animal feed in the south, and also improving the economic benefits of local residents.

[0006] The technical solution of the present invention to solve the technical problem is:

[0007] A method for planting herbivorous animal feed plants using polluted waste land, comprising the following steps:

[0008] 1. Divide the planting area of ​​polluted land:

[0009] On the contaminated waste land, the cadmium concentration of 2.5mg / kg to 4mg / kg is set as Zone A, the cadmium concentration of 4mg / kg to 7mg / kg is set as Zone B, and the cadmium concentration of 7mg / kg to 10mg / kg is set as Zone C;

[0010] 2. Regional planting model:

[0011] First year planting pattern:

[0012] Dig trenches in area A to plant fodder mulberry trees, with a mowing height of 1.2m to 1.4m and a stubble height of 35cm to 45cm;

[0013] Dig trenches in area B and plant elephant grass, with a mowing height of 1.5m to 1.7m and a stubble height of 75cm to 85cm;

[0014] Dig trenches in area C and plant Pennisetum, with a mowing height of 0.8m to 1.1m;

[0015] Planting pattern for the second year:

[0016] In area A, the mowing height of fodder mulberry is 1.3m-1.5m, and the stubble height is 15cm-25cm;

[0017] In area B, the main root system of elephant grass is removed and fodder mulberry is planted. The cutting height of fodder mulberry is 1.1m to 1.3m, and the stubble height is 45cm to 55cm.

[0018] In area C, the mowing height of Pennisetum was 0.9m to 1.2m;

[0019] Planting pattern for the third year:

[0020] In area A, the main root system of fodder mulberry is removed and elephant grass is planted. The mowing height is 1.7m to 2.0m and the stubble height is 55cm to 65cm.

[0021] In area B, the mowing height of fodder mulberry is 1.2m-1.4m, and the stubble height is 15cm-25cm;

[0022] In area C, the main root system of Pennisetum was removed and fodder mulberry was planted. The cutting height was 1.0m to 1.2m and the stubble height was 45cm to 55cm.

[0023] Planting pattern for the fourth year:

[0024] In area A, the mowing height of elephant grass is 1.8m to 2.1m, and the stubble height is 20cm to 25cm;

[0025] In area B, the mowing height of fodder mulberry is 1.2m-1.4m, and the stubble height is 15cm-25cm;

[0026] In area C, the mowing height of fodder mulberry is 1.1m to 1.3m, and the stubble height is 15cm to 25cm;

[0027] 3. Fertilization and planting:

[0028] The fodder mulberry, elephant grass and pennisetum to be transplanted are first soaked in fodder mulberry nutrient solution, elephant grass nutrient solution and pennisetum nutrient solution respectively. The fodder mulberry nutrient solution is prepared by diluting the earthworm selenium stock solution 5 times, the elephant grass nutrient solution is prepared by diluting the earthworm selenium stock solution 4 times and then adding zinc, and the pennisetum nutrient solution is prepared by diluting the earthworm stock solution 5 times.

[0029] As an improvement of the present invention, when fertilizing and planting, the roots of the mulberry trees are wrapped with mulberry-based fertilizer, and the roots of the elephant grass are wrapped with elephant grass-based fertilizer, wherein the mulberry-based fertilizer is prepared by diluting the mulberry-based fertilizer by 2 times and adding it to earthworm castings at a ratio of 0.1%, and the elephant grass-based fertilizer is prepared by diluting the elephant grass-based fertilizer by 6 times and adding it to earthworm castings at a ratio of 0.5%.

[0030] As a further improvement of the present invention, when fertilizing and planting, the feed mulberry leaves in area A, area B and area C are respectively applied with feed mulberry leaf top fertilizer in area A, feed mulberry leaf top fertilizer in area B and feed mulberry leaf top fertilizer in area C, wherein the feed mulberry leaf top fertilizer in area A, feed mulberry leaf top fertilizer in area B and feed mulberry leaf top fertilizer in area C are respectively prepared by diluting the earthworm selenium stock solution by 55, 50 and 45 times and then adding 4.0% to 6.0% enzymatic molasses.

[0031] As a further improvement of the present invention, when fertilizing and planting, foliar fertilizer of elephant grass in area A and foliar fertilizer of elephant grass in area B are applied to the elephant grass in area A and area B respectively, wherein the foliar fertilizer of elephant grass in area A and the foliar fertilizer of elephant grass in area B are prepared by diluting the elephant grass nutrient solution by 16 times and 13 times respectively, and then adding 0.1% to 0.2% urea, 0.16% to 0.22% ammonium phosphate, and 3.5% to 5.0% enzymatic molasses.

[0032] As a further improvement of the present invention, in the fourth year of planting, rapeseed is planted in areas A and B during the winter idle time of that year, and annual ryegrass is planted in area C during the winter idle time of that year.

[0033] As a further improvement of the present invention, the planting pattern in the fifth year and thereafter all adopts the planting pattern in the fourth year.

[0034] As a further improvement of the present invention, in area A, fodder mulberry is planted with a plant spacing of 20 cm and a row spacing of 32 cm, and the furrows are strip-shaped furrows with a depth of 25 cm and a width of 20 cm.

[0035] As a further improvement of the present invention, in area B, elephant grass is planted with a plant spacing of 25 cm and a row spacing of 42 cm, and the furrows are strip-shaped furrows with a depth of 32 cm and a width of 27 cm.

[0036] The present invention has the following advantages:

[0037] 1. The cadmium-contaminated land, especially the heavily cadmium-contaminated land, was developed and utilized, solving the problem of insufficient cultivated land in the hilly southern region.

[0038] 2. To alleviate the shortage of forage for the development of herbivorous livestock in the south, forage plants such as mulberry, elephant grass and rapeseed are planted. The cadmium content of these forage plants meets the requirements of feed hygiene standards and can be used as feed for herbivorous livestock such as cattle and sheep.

[0039] 3. By utilizing the interaction of organic selenium, mineral elements, zinc, nitrogen, phosphorus, amino acids, sugars in earthworm selenium, and mineral elements in enzymatic molasses, the problem of yellowing leaves of feed plants planted in cadmium-contaminated areas can be solved, the yield of feed plants can be increased, the formation of plant protein, fat, etc. can be promoted, the problem of low nutritional quality of plants planted in cadmium-contaminated land can be solved, and the nutritional value can be improved. Moreover, according to testing, the cadmium content in the feed plants after cutting also meets the requirements of the national health standards for feed raw materials, thus realizing the safe planting of feed mulberry, elephant grass and rapeseed in cadmium-contaminated abandoned land. It also achieves selenium-enrichment and can be used as selenium feed with higher added value, turning waste into treasure, thereby improving the economic benefits of local residents.

[0040] 4. Use ryegrass and pennisetum to absorb and remove cadmium from the soil to improve the land.

[0041] 5. Planting fodder plants can be used to combat soil erosion, especially on heavily cadmium-contaminated land that is abandoned because planting of any cash crops is strictly prohibited. By planting fodder plants all year round, the soil can be stabilized to prevent soil erosion. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] A method for planting herbivorous animal feed plants using polluted waste land of the present invention specifically comprises the following steps:

[0044] Step S1, dividing the polluted land into planting areas:

[0045] On the polluted waste land, the land with cadmium concentration in the range of 2.5mg / kg to 10mg / kg is divided into three areas: A, B and C. Among them, the land with cadmium concentration of 2.5mg / kg to 4mg / kg is set as area A, the land with cadmium concentration of 4mg / kg to 7mg / kg is set as area B, and the land with cadmium concentration of 7mg / kg to 10mg / kg is set as area C;

[0046] Step S2, preparing planting additives - feed plant nutrient solution, feed plant base fertilizer and feed plant foliar fertilizer:

[0047] The feed plant nutrient solution includes feed mulberry nutrient solution, elephant grass nutrient solution and pennisetum nutrient solution; the feed mulberry nutrient solution is prepared by diluting earthworm selenium stock solution 5 times; the elephant grass nutrient solution is prepared by diluting earthworm selenium stock solution 4 times and then adding zinc; the pennisetum nutrient solution is prepared by diluting earthworm selenium stock solution 5 times; among them, the earthworm selenium stock solution adopts the organic selenium earthworm selenium disclosed in the patent name of a biological organic selenium earthworm selenium and its preparation method (publication number CN114468143A), which can increase the content of organic selenium in the soil, and also can increase the selenium content of the planted plants at the same time, thereby improving their nutritional value; the earthworm stock solution is a clear liquid obtained by enzymolysis of collected earthworms at 50°C to 55°C for 12h to 20h, cooling to room temperature, and filtering with double-layer gauze.

[0048] The feed plant base fertilizer includes feed mulberry base fertilizer and elephant grass base fertilizer, wherein the feed mulberry base fertilizer is prepared by diluting the feed mulberry nutrient solution by 2 times and then adding it to earthworm manure at a ratio of 0.1%; the elephant grass base fertilizer is prepared by diluting the elephant grass nutrient solution by 6 times and then adding it to earthworm manure at a ratio of 0.5%;

[0049] The fodder plant foliar fertilizer includes fodder mulberry foliar fertilizer and elephant grass foliar fertilizer. The fodder mulberry foliar fertilizer in Area A, Area B and Area C is prepared by diluting earthworm selenium stock solution by 55, 50 and 45 times, respectively, and then adding 4.0% to 6.0% enzymatic molasses; the elephant grass foliar fertilizer in Area A and Area B is prepared by diluting elephant grass nutrient solution by 16 and 13 times, respectively, and then adding 0.1% to 0.2% urea, 0.16% to 0.22% ammonium phosphate and 3.5% to 5.0% enzymatic molasses.

[0050] Step S3, a method for fertilizing and planting fodder plants, specifically includes the following:

[0051] Step S31, spraying the elephant grass to be transplanted next year with elephant grass nutrient solution, transplanting all of them indoors after mowing, covering them with film, and using elephant grass base fertilizer to protect the roots of the elephant grass;

[0052] Step S32, digging trenches in the polluted wasteland and adding calcium oxide into the trenches;

[0053] Step S33, filling the groove with fodder plant base fertilizer;

[0054] Step S34, transplanting the soaked fodder plants into the trench, and covering the fodder plant base fertilizer and uncontaminated normal soil to the trench surface;

[0055] Step S35, spraying the forage plants with foliar fertilizer for the forage plants;

[0056] Step S36, cutting the fodder plants and using them as fodder raw materials;

[0057] Step S4, the time and space planting pattern system of fodder plants, specifically includes the following:

[0058] Step S41, planting mode in the first year:

[0059] 1) Apply 50 kg / mu of calcium oxide in areas A, B and C;

[0060] 2) In Area A, dig trenches to plant fodder mulberry, with a mowing height of 1.2m to 1.4m and a stubble height of 35cm to 45cm; in Area B, dig trenches to plant elephant grass, with a mowing height of 1.5m to 1.7m and a stubble height of 75cm to 85cm; in Area C, dig trenches to plant Pennisetum, with a mowing height of 0.8m to 1.1m;

[0061] 3) The remaining height of plants after mowing in areas A and B and the Pennisetum in area C were used to prepare biochar;

[0062] Step S42, planting mode for the second year:

[0063] 1) In Area A, the mowing height of fodder mulberry is 1.3m-1.5m, and the stubble height is 15cm-25cm; in Area B, the main root system of elephant grass is removed and fodder mulberry is planted. The mowing height is 1.1m-1.3m, and the stubble height is 45cm-55cm; in Area C, the mowing height of Pennisetum is 0.9m-1.2m;

[0064] 2) The remaining height of plants after mowing in area B and Pennisetum in area C were used to prepare biochar;

[0065] Step S43, planting mode in the third year:

[0066] 1) Apply 10kg / mu to 30kg / mu of calcium oxide, and then apply the same concentration every other year;

[0067] 2) In Area A, the main root system of fodder mulberry was removed and elephant grass was planted. The mowing height was 1.7m-2.0m and the stubble height was 55cm-65cm. In Area B, the mowing height of fodder mulberry was 1.2m-1.4m and the stubble height was 15cm-25cm. This planting pattern was adopted in Area B every year. In Area C, the main root system of Pennisetum was removed and fodder mulberry was planted. The mowing height was 1.0m-1.2m and the stubble height was 45cm-55cm.

[0068] 3) The remaining height of plants after mowing in areas A and C was used to prepare biochar.

[0069] Step S44, planting mode in the fourth year:

[0070] 1) The mowing height of elephant grass in Area A is 1.8m to 2.1m, and the stubble height is 20cm to 25cm; the mowing height of fodder mulberry in Area C is 1.1m to 1.3m, and the stubble height is 15cm to 25cm;

[0071] 2) Areas A and B planted rapeseed during the winter off-season for use as feed raw material; Area C planted annual ryegrass during the winter off-season for the production of biochar;

[0072] 3) The three districts adopted this planting pattern every year thereafter.

[0073] In the present invention, in step S32, specifically, the fodder mulberry is planted at a spacing of 20 cm and a row spacing of 32 cm. Such planting is most conducive to the growth of the fodder mulberry, improves its yield, is conducive to the subsequent foliar fertilizer application, and does not interfere with the adjacent fodder mulberry; the elephant grass is planted at a spacing of 25 cm and a row spacing of 42 cm. Such planting is most conducive to the growth of the elephant grass, improves its yield, and also provides convenience for the subsequent foliar fertilizer application, and does not interfere with the adjacent elephant grass; and the grooves of the fodder mulberry are strip-shaped trenches with a depth of 25 cm and a width of 20 cm, and the grooves of the elephant grass are strip-shaped trenches with a depth of 32 cm and a width of 27 cm; the grooves adopt strip-shaped trenches with a specific depth and width. In order to facilitate the planting of the corresponding fodder plants, combined with the newly added specific fertilizer and soil, most of the roots of the corresponding fodder plants are wrapped, the absorption of cadmium is reduced, and the yield of fodder mulberry and elephant grass is increased.

[0074] In the present invention, in step S33, specifically, the filling depth of the mulberry-based fertilizer filled in the groove is 10 cm, and the coverage of the mulberry-based fertilizer is 4 cm. Experiments have shown that in the case of a 25 cm deep and 20 cm wide strip-shaped groove, the mulberry-based fertilizer with this filling depth and coverage thickness is the best, that is, there is no waste, and it can maximize its role, reduce the plant's absorption of cadmium, and make the soil rich in selenium; the filling depth of the elephant grass-based fertilizer filled in the groove is 13 cm, and the elephant grass-based fertilizer covers 7 cm, which can maximize the role of the elephant grass-based fertilizer and is more conducive to the competition between selenium, zinc, etc. and cadmium.

[0075] In the present invention, in step S34, specifically, at room temperature, the roots of the mulberry tree are first immersed in the nutrient solution for 15 hours at room temperature, which is beneficial to the growth of the root system of the mulberry tree and the roots take root in the grooves, which can reduce the absorption of cadmium by the roots and alleviate the harm of cadmium to plants, and is also beneficial to its growth in polluted areas and increase its yield; the roots of the elephant grass are immersed in the nutrient solution for 10 hours to 14 hours, which is beneficial to the growth of the roots of the elephant grass in the grooves and the roots take root in the grooves, which reduces the absorption of cadmium and increases the yield of the elephant grass; the roots of the foxtail grass are immersed in the nutrient solution for 12 hours to 16 hours, which is beneficial to the growth of the root system of the foxtail grass and increases the yield of the foxtail grass.

[0076] In the present invention, in step S35, specifically, 21 days after the fodder mulberry is planted, the fodder mulberry is sprayed with fodder mulberry leaf fertilizer at a rate of 0.15 kg / plant. Spraying the fodder mulberry leaf fertilizer at a specific time after transplanting is beneficial to the growth of the fodder mulberry, and can increase the absorption of selenium by the leaves and stems of the fodder mulberry, and reduce the harm of cadmium to the fodder mulberry; 14 days after the elephant grass is planted, the elephant grass is sprayed with foliar fertilizer at a rate of 0.45 kg / plant. By spraying the elephant grass foliar fertilizer at a specific time, the selenium content of the elephant grass can be increased, the cadmium content of the elephant grass can be reduced, and its yield can also be increased.

[0077] In the present invention, in step S36, specifically, 30 days before harvesting, the mulberry cutting liquid is used to spray the mulberry, the mulberry cutting liquid is obtained by diluting the earthworm selenium stock solution 42 times and adding 5.0% to 7.0% enzymatic molasses, and the amount of the mulberry cutting liquid is 0.10 kg / plant. If it is not sprayed before harvesting, the yield of the mulberry will be reduced, the leaves will be yellowish, and the content of nutrients (crude protein, crude fat, etc.) will be low. At the same time, the selenium in the mulberry will be The content will also decrease; 15 days before mowing, use elephant grass mowing liquid to spray the target grass. The elephant grass mowing liquid is made by diluting the earthworm selenium stock solution 20 times and adding 0.04%-0.08% urea, 0.10%-0.14% ammonium phosphate, and 4.5%-6.0% enzymatic molasses. The dosage of elephant grass mowing liquid is 0.30kg / plant, which can increase the selenium content of elephant grass, reduce the cadmium content of elephant grass, increase the yield of elephant grass, and also improve the nutritional quality of elephant grass.

[0078] In the present invention, the enzymatically hydrolyzed molasses is prepared by diluting molasses 5 times, adding 0.05% to 0.10% sucrase, performing enzymatic hydrolysis at 50°C to 55°C for 12h to 18h, and acting at 75°C to 80°C for 10min to 20min. By enzymatically hydrolyzing molasses, the main sugar source (i.e., sucrose) in the molasses is decomposed into monosaccharides (glucose and fructose), which can be directly absorbed and utilized by plants, thereby preventing the problem that the plant leaves absorb sucrose very slowly, and the feed plants planted in cadmium-contaminated areas are affected by cadmium stress, resulting in reduced yield and hindered growth metabolism, which makes it difficult to absorb the applied sucrose and causes plant diseases and insect pests.

[0079] In the present invention, in the fourth year of area C, annual ryegrass is planted in November of that year, and the annual ryegrass is mowed when the height reaches 25cm to 30cm, and can be harvested multiple times until February of the next year, that is, ryegrass is planted during the winter idle period of that year, and after it is harvested, it is used to prepare biochar, and the characteristics of ryegrass super-enrichment of cadmium are utilized to fully utilize the winter idle period to reduce the cadmium content in the soil, improve the contaminated soil, and provide soil requirements for the subsequent planting of elephant grass and fodder mulberry, that is, there is no waste of land, and the soil is improved at the same time; in addition, annual ryegrass can also be planted during the winter idle period of the first three years of area A and area B (November of that year); ryegrass has thin rhizomes, clustered stalks, soft texture, and roots on the base nodes; it can be mowed for the first time 40-50 days after sowing, and biochar is prepared after it is harvested, and the characteristics of ryegrass super-enrichment of cadmium are utilized to fully utilize the winter idle period to reduce the cadmium content in the soil, which is conducive to the subsequent planting of elephant grass.

[0080] In the present invention, in step S44, in the fourth year of area A and area B, rapeseed is planted in November of that year. The rapeseed is planted by seed drill sowing method. The seeds are first soaked in elephant grass nutrient solution at room temperature for 6 h to 10 h before sowing. When harvested in the next year, the stubble height is 25 cm to 30 cm. Rapeseed, which is an annual or biennial herb, is sown early at an appropriate time, which is beneficial to increase the effective growing period in winter and increase the effective nitrogen and organic matter content of the soil. The reason is that after the planting of the plant, its dead branches and leaves, residual roots, root secretions, and metabolic processes are all beneficial to the growth of soil organic matter. The available phosphorus content of saline-alkali soil can be significantly increased in the planting year. Moreover, rapeseed is a plant with a high protein content. When used as cattle and sheep feed, it can reduce the use of soybean meal and alleviate the problem of excessive dependence on imports of soybean meal in my country's animal husbandry.

[0081] Feed mulberry is a new variety with good benefits in my country's mulberry industry. It has strong regional adaptability and direct ecological value and feed value. The biological and ecological characteristics of feed mulberry are drought-resistant and can survive in areas with 50mm precipitation. It can grow, bloom and bear fruit normally with 250mm natural precipitation and complete its life cycle. The survival rate of one-year-old seedlings planted in desert areas without irrigation can reach more than 80%. It can withstand severe cold and grow normally at -30℃. It can withstand barrenness and grow normally in desert areas. It can bloom and bear fruit normally in barren rocky mountainous areas. Protein mulberry functional feed enterprises can be established to implement industrial production of protein mulberry functional feed. The crude protein content is generally not less than 18%. 1kg of protein mulberry powder is equivalent to more than 2kg of crude protein in corn. The per mu dry protein yield in semi-humid areas is 2.5-3.5 kg. 1.5t of powder; 0.8-1.0t in semi-arid areas; 0.8-1.0t in arid areas, appropriate supplementary irrigation can also reach 0.8-1.0t. According to the nutritional structure required by various livestock and poultry, corresponding nutrients are proportioned, and functional pellet feed is made through a pellet feed processing unit to implement factory production; in the present invention, Yue Sang No. 51 can be selected as feed mulberry. Yue Sang No. 51 has strong adaptability and high nutritional value for herbivorous livestock. Yue Sang No. 51 is a mulberry variety with strong stress resistance bred by the Sericulture and Agricultural Products Processing Research Institute of Guangdong Academy of Agricultural Sciences. It has the characteristics of high protein content, high yield, large leaves, good leaf quality, and stems and leaves are not easy to accumulate cadmium.

[0082] Elephant grass has a very large yield, high nutritional value, strong stress resistance, and has a certain enrichment effect on cadmium. Elephant grass has strong ecological adaptability. It can generally withstand high temperatures of 37.9°C and endure cold and dry climate conditions of 1-2°C in winter and relative humidity of 20%-25% without death. Elephant grass can grow in both sandy soil and clay, and has strong resistance to soil acidity. It is planted in red soil with a pH value of 4-5. It is more adaptable than fodder crops such as Sudan grass, Guatemala rub grass, kenya grass, sorghum, corn, and sugarcane. Elephant grass is an excellent fodder for animals. It is named because elephants like to eat it. It is easy to plant, has good palatability, and has high nutritional value. The value is higher than that of general plants, and it is a good feed for wild and domestic animals. Elephant grass can be used as silage or prepared into hay; tender elephant grass has better palatability, and silage and hay generally need to be added with soybeans and the like to improve its palatability and digestibility. Therefore, large-scale planting of elephant grass is one of the effective methods to solve the problem of feed shortage; in the present invention, the elephant grass adopts Guimu No. 1 elephant grass, which has strong ecological adaptability and is an excellent forage for animals. The tender elephant grass has better palatability, and adding soybeans and the like after elephant grass silage can improve its palatability and digestibility.

[0083] Pennisetum has high yield, is not strict on soil, has strong stress resistance, and is tolerant to cadmium-contaminated land. Under 6 mg / kg to 10 mg / kg cadmium stress, the biomass of Pennisetum does not decrease but slightly increases; the cadmium content in the stems, leaves and roots of Pennisetum is relatively high, and Pennisetum has a stronger cadmium enrichment effect than elephant grass; in the present invention, Pennisetum is planted and fertilized according to conventional methods, and the characteristic of Pennisetum enriching cadmium is utilized, and conventional planting methods are adopted to absorb the effective cadmium in the soil, and prepare biochar to reduce the effective cadmium content in the soil, thereby providing a planting environment for the third year of planting forage mulberry in Area C, and alleviating the adverse effects of the high-cadmium soil environment on the growth of forage mulberry.

[0084] In the present invention, the cut elephant grass is mixed with bean dregs and navel orange dregs in a mass percentage of 65:15:20, and fermentation bacteria is added to ferment for 30 to 40 days before storage for use as feed for herbivorous livestock; the cut rapeseed is mixed with stevia dregs for silage and used as feed. Rapeseed is a plant with a high protein content. When used as cattle and sheep feed, the amount of soybean meal used can be reduced, and the problem of excessive dependence on imported soybean meal in my country's animal husbandry can be alleviated; the cut fodder mulberry and corn dregs added with 12 mg / kg sodium selenite are mixed for fermentation and silage in a mass percentage of 88:12, so that the soil of the polluted land can be improved and the fodder mulberry can be recycled and utilized as silage, which has a double effect.

[0085] In the present invention, the earthworm selenium stock solution adopts the organic selenium earthworm selenium disclosed in the patent name of a biological organic selenium earthworm selenium and its preparation method (publication number CN114468143A), which can increase the content of organic selenium in the soil, and can also simultaneously increase the selenium content of cultivated plants, thereby improving their nutritional value; the total selenium content of the earthworm selenium stock solution is 180 mg / kg~220 mg / kg, the organic selenium content is greater than 80%, and it is rich in amino acids.

[0086] In the present invention, the zinc content is 1.2% of the elephant grass nutrient solution. Since selenium, zinc and cadmium compete for absorption in plants, the Guimu No. 1 elephant grass reduces cadmium absorption technology, thereby reducing the impact of cadmium on the Guimu No. 1 elephant grass.

[0087] The present invention utilizes the competitive absorption of earthworm selenium, zinc and cadmium in elephant grass to form the Guimu No. 1 elephant grass cadmium absorption reduction technology; utilizes the interaction of selenium, iron, manganese and other elements in earthworm selenium, zinc, nitrogen, phosphorus, amino acids, sugars, and mineral elements such as potassium and magnesium in enzymatic molasses to promote the formation of chlorophyll, solve the problem of yellowing leaves of elephant grass planted in cadmium-contaminated land, enhance plant photosynthesis, and increase elephant grass yield; utilizes the interaction of earthworm selenium, nitrogen, phosphorus, amino acids, sugars, mineral elements, etc. to promote the formation of plant protein, fat, etc., solves the problem of low nutritional quality of elephant grass planted in cadmium-contaminated land, and improves nutritional value.

[0088] In the present invention, the application amount of calcium oxide at the bottom of the ditch is 50kg / mu in the first year, and then 10kg / mu to 30kg / mu is applied every other year. Calcium oxide can be used to condition the soil to the maximum extent, promote plant growth, provide planting conditions for growing feed plants, and reduce the impact of cadmium. If the ditch is not dug in the year, calcium oxide can be applied by spraying, drilling, grooving, etc.

[0089] In the present invention, after being tested after mowing, the planted elephant grass and rapeseed will neither exceed the cadmium standard nor cause soil selenium pollution, thus solving the technical defects of excessive cadmium content, low yield, poor nutritional quality, soil alkalization and compaction due to excessive use of alkaline substances, and low land utilization rate in plants planted on existing cadmium-contaminated land. At the same time, the forage plant Guimu No. 1 elephant grass is enriched with selenium, the added value is increased, and waste is turned into treasure.

[0090] In the present invention, the stubble height of the biochar-making plants is 8 cm to 12 cm.

[0091] In the present invention, after a large number of experiments, it was found that the cadmium content in the plant parts remaining at the height after mowing is relatively high and is not suitable for use as a feed raw material. However, the cadmium content in the plant tissue above this plant part (i.e. above the corresponding stubble height) is lower and can be used as a feed raw material.

[0092] In the present invention, the cadmium content of the leaves and stems of the fodder mulberry after planting and harvesting is low, which is far below the national feed raw material hygiene standard, and the selenium content is high, mainly organic selenium, while the selenium content in the soil does not change significantly, and will not cause selenium pollution to the soil. The pH value is slightly alkaline, and it is not hardened or overly alkalinized.

[0093] The present invention provides 11 embodiments and 5 comparative examples, which are as follows: Example 1

[0094] Embodiment 1 comprises the following steps:

[0095] A. Planting herbivorous livestock feed plants on land with a cadmium concentration of 3.23 mg / kg (area A);

[0096] B. Configure planting additives:

[0097] Feed plant nutrient solution:

[0098] The mulberry nutrient solution was prepared by diluting the earthworm selenium stock solution 5 times; the elephant grass nutrient solution was prepared by diluting the earthworm selenium stock solution 4 times and then adding zinc, wherein the zinc content was 1.2% of the elephant grass nutrient solution;

[0099] Feed plant base fertilizer:

[0100] The mulberry-based fertilizer was prepared by diluting the mulberry-based nutrient solution by 2 times and then adding it to the earthworm castings at a ratio of 0.1%; the elephant grass-based fertilizer was prepared by diluting the elephant grass-based nutrient solution by 6 times and then adding it to the earthworm castings at a ratio of 0.5%;

[0101] Foliar fertilizer for feed plants:

[0102] The mulberry leaf fertilizer was prepared by diluting the earthworm selenium stock solution 55 times and adding 4.5% enzymatic molasses; the elephant grass foliar fertilizer was prepared by diluting the elephant grass nutrient solution 16 times and adding 0.13% urea, 0.18% ammonium phosphate, and 3.8% enzymatic molasses.

[0103] Feed plant cutting fluid:

[0104] The mulberry cut liquid for feed is obtained by diluting the earthworm selenium stock solution 42 times and then adding 5.6% enzymatic molasses; the elephant grass cut liquid is obtained by diluting the earthworm selenium stock solution 20 times and then adding 0.05% urea, 0.11% ammonium phosphate, and 4.7% enzymatic molasses.

[0105] The enzymatic molasses was prepared by diluting molasses 5 times, adding 0.07% sucrase and performing enzymatic hydrolysis at 53 °C for 15 h, and then at 78 °C for 16 min.

[0106] C. Fertilization and planting methods of fodder plants:

[0107] (1) Spray the elephant grass to be transplanted next year with elephant grass nutrient solution, transplant all of them indoors after mowing, cover them with film, and use elephant grass base fertilizer to protect the roots of the elephant grass;

[0108] (2) Dig trenches in the polluted wasteland and add calcium oxide in the trenches; fodder mulberry is planted with a spacing of 20 cm between plants and 32 cm between rows, and the trenches are 25 cm deep and 20 cm wide. Elephant grass is planted with a spacing of 25 cm between plants and 42 cm between rows, and the trenches are 32 cm deep and 27 cm wide.

[0109] (3) Fill the trench with fodder plant base fertilizer, wherein the filling depth of fodder mulberry base fertilizer is 10 cm, and the filling depth of elephant grass base fertilizer is 13 cm;

[0110] (4) Soak the roots of the transplanted fodder mulberry in the nutrient solution of fodder mulberry for 15 hours at room temperature, and soak the roots of elephant grass in the nutrient solution of elephant grass for 12 hours; transplant the soaked fodder plants into the trench, and cover them with fodder plant base fertilizer and uncontaminated normal soil to the trench surface; the fodder mulberry base fertilizer is covered with 4 cm, and the elephant grass base fertilizer is covered with 7 cm.

[0111] (5) 21 days after the fodder mulberry is planted, spray the fodder mulberry with foliar fertilizer at a rate of 0.15 kg / plant; 14 days after the elephant grass is planted, spray the elephant grass with foliar fertilizer at a rate of 0.45 kg / plant.

[0112] (6) Forage plants are cut and used as feed raw materials. Forage mulberry should be sprayed with forage mulberry cutting liquid at a rate of 0.10 kg / plant 30 days before cutting; elephant grass should be sprayed with elephant grass cutting liquid at a rate of 0.30 kg / plant 15 days before cutting.

[0113] (7) Plant annual ryegrass during the winter idle time of the three years before planting, and mow it when it reaches a height of about 29 cm for biochar production; the stubble height of the biochar plants is about 10 cm;

[0114] D. Time and space planting system of fodder plants:

[0115] (1) Planting pattern in the first year: Apply 50 kg / mu of calcium oxide; plant fodder mulberry, cut at a height of about 1.35 m, and leave a stubble height of about 39 cm; the remaining height of the fodder mulberry after cutting is used to prepare biochar;

[0116] (2) Planting pattern in the second year: the cutting height of fodder mulberry is about 1.4m, and the stubble height is about 21cm;

[0117] (3) Planting pattern in the third year: remove the main root system of fodder mulberry, apply 18 kg / mu of calcium oxide, and then apply this concentration every other year, plant elephant grass, cut at a height of about 1.8 m, and leave a stubble height of about 62 cm. The remaining height of the elephant grass after cutting is used to prepare biochar;

[0118] (4) Planting pattern in the fourth year: The mowing height of elephant grass is about 2.0 m, and the stubble height is about 22 cm. Rapeseed is planted during the winter off-season of that year as a feed raw material. This planting pattern is adopted every year thereafter. Example 2

[0119] The difference between Example 2 and Example 1 is that the following method is adopted in Example 2:

[0120] A. Planting herbivorous livestock feed plants on land with a cadmium concentration of 5.64 mg / kg;

[0121] B. Foliar fertilizer for fodder plants: Foliar fertilizer for fodder mulberry is prepared by diluting earthworm selenium stock solution 50 times and adding 5.2% enzymatic molasses; Foliar fertilizer for elephant grass is prepared by diluting elephant grass nutrient solution 13 times and adding 0.16% urea, 0.20% ammonium phosphate and 4.3% enzymatic molasses;

[0122] D. Constructing a time and space planting system for fodder plants:

[0123] (1) Planting pattern in the first year: Plant elephant grass, with a mowing height of about 1.65 m and a stubble height of about 81 cm. The remaining height of the elephant grass after mowing is used to prepare biochar.

[0124] (2) Planting pattern in the second year: remove the main root system of elephant grass and plant fodder mulberry. The mowing height is about 1.25 m and the stubble height is about 52 cm. The remaining height of the fodder mulberry after mowing is used to prepare biochar.

[0125] (3) Planting pattern in the third year: The cutting height of fodder mulberry is about 1.33m, and the stubble height is about 22cm. This planting pattern is adopted every year thereafter.

[0126] (4) Planting pattern in the fourth year: Rapeseed is planted during the winter off-season of that year and used as feed raw material. This planting pattern is adopted every year thereafter. Example 3

[0127] The difference between Example 3 and Example 1 is that the following method is adopted in Example 3:

[0128] A. Planting herbivorous livestock feed plants on land with a cadmium concentration of 9.08 mg / kg;

[0129] B. Pennisetum nutrient solution was prepared by diluting earthworm stock solution 5 times; mulberry leaf fertilizer was prepared by diluting earthworm selenium stock solution 45 times and adding 5.7% enzymatic molasses;

[0130] C. Fertilization and planting methods of fodder plants:

[0131] (4) Soak the roots of the transplanted Pennisetum in Pennisetum nutrient solution at room temperature for 15 hours; plant and fertilize the Pennisetum according to conventional methods;

[0132] D. Time and space planting system of fodder plants:

[0133] (1) Planting pattern in the first year: Planting Pennisetum, mowing height is about 1.0 m, Pennisetum is used to prepare biochar;

[0134] (2) Planting pattern in the second year: Pennisetum was cut to a height of about 1.15 m and used to prepare biochar;

[0135] (3) Planting pattern in the third year: remove the main root system of Pennisetum and plant fodder mulberry, with the mowing height of about 1.08 m and the stubble height of about 49 cm; the remaining height of the fodder mulberry after mowing is used to prepare biochar;

[0136] (4) Planting pattern in the fourth year: the fodder mulberry is mowed at a height of about 1.25 m, and the stubble height is about 21 cm; annual ryegrass is planted during the winter idle time of that year for the preparation of biochar; this planting pattern is adopted every year thereafter. Example 4

[0137] The difference between Example 4 and Example 1 is that the foliar fertilizer for feed plants does not contain enzymatic molasses, and the cutting liquid for feed plants does not contain enzymatic molasses. Example 5

[0138] The difference between Example 5 and Example 2 is that the foliar fertilizer for feed plants does not contain enzymatic molasses, and the cutting liquid for feed plants does not contain enzymatic molasses. Example 6

[0139] The difference between Example 6 and Example 1 is that only elephant grass is planted in spring, summer and autumn.

[0140] D. Temporal and spatial planting system of fodder plants: There are differences in the planting patterns between the first and second years;

[0141] (1) Planting pattern in the first year: Plant elephant grass, mowing height is about 1.7m, and stubble height is about 65cm. The remaining height of elephant grass after mowing is used to prepare biochar;

[0142] (2) Planting pattern in the second year: The mowing height of elephant grass is about 1.75m, and the stubble height is about 64cm. Example 7

[0143] The difference between Example 7 and Example 3 is that only fodder mulberry is planted in spring, summer and autumn;

[0144] D. Temporal and spatial planting system of fodder plants: There are differences in the planting patterns in the first and second years:

[0145] (1) Planting pattern in the first year: Planting fodder mulberry, mowing height is about 1.1m, and stubble height is about 55cm; the remaining height of fodder mulberry after mowing is used to prepare biochar;

[0146] (2) Planting pattern in the second year: The fodder mulberry trees are mowed at a height of about 1.15 m, and the stubble height is about 53 cm; the remaining height of the fodder mulberry trees after mowing is used to prepare biochar. Example 8

[0147] The difference between Example 8 and Example 1 is that:

[0148] D. Time and space planting system of fodder plants: Fodder mulberry and elephant grass are harvested according to the conventional mowing height and stubble height. Among them, the mowing height of fodder mulberry is about 1.6m and the stubble height is about 13cm, and the mowing height of elephant grass is about 2.2m and the stubble height is about 10cm. Example 9

[0149] The difference between Example 9 and Example 2 is that:

[0150] D. Temporal and spatial planting system of fodder plants: Fodder mulberry and elephant grass are harvested according to the conventional stubble height, among which the mowing height of fodder mulberry is about 1.55m and the stubble height is about 13cm, and the mowing height of elephant grass is about 2.15m and the stubble height is about 10cm. Example 10

[0151] The difference between Example 10 and Example 3 is that:

[0152] D. Construct a time and space planting system for fodder plants: Fodder mulberry is harvested according to the conventional mowing height (about 1.5m) and stubble height (about 13cm). Embodiment 11

[0153] The difference between Example 11 and Example 1 is that no plants are planted in winter, that is, no plants such as ryegrass and rapeseed are interplanted in winter.

[0154] Comparative Example 1

[0155] In Comparative Example 1, fodder mulberry was planted in strips on cadmium-contaminated abandoned land, with a planting spacing of 40 cm and a row spacing of 50 cm. 150 kg / mu of calcium oxide, 400 kg / mu of fermented cow dung, and 15 kg / mu of silicon fertilizer were applied as basal fertilizers, and 180 g / mu of silicon fertilizer was sprayed on the leaves. Calcium oxide was applied once a year, and the application was stopped for one year after the soil pH reached 7.0. Conventional planting, fertilization and harvesting methods were adopted.

[0156] Comparative Example 2

[0157] In Comparative Example 2, elephant grass was planted in strips on cadmium-contaminated waste land with a planting spacing of 50 cm and a row spacing of 80 cm. 150 kg / mu of calcium oxide, 450 kg / mu of fermented cow dung, and 18 kg / mu of silicon fertilizer were applied as basal fertilizers, and 200 g / mu of silicon fertilizer was sprayed on the leaves. Calcium oxide was applied once a year. After the soil pH reached 7.0, the application was stopped for one year, and conventional planting, fertilization and harvesting methods were adopted.

[0158] Comparative Example 3

[0159] In comparative example 3, fodder mulberry was planted in strips on cadmium-contaminated waste land, with a planting spacing of 40 cm and a row spacing of 50 cm. 150 kg / mu calcium oxide, 400 kg / mu fermented cow dung, and 90 g / mu sodium selenite were applied as basal fertilizers, and 2.2 g / mu sodium selenite was sprayed on the leaves. Calcium oxide was applied once a year, and after the soil pH reached 7.0, it was stopped for one year, and conventional planting, fertilization and harvesting methods were adopted.

[0160] Comparative Example 4

[0161] The difference between Comparative Example 4 and Example 1 is that sodium selenite aqueous solution is used instead of earthworm selenium as raw material to prepare selenium nutrient solution, selenium-based fertilizer, selenium foliar fertilizer and selenium cutting liquid, and the total selenium concentration is the same as that of earthworm selenium.

[0162] Comparative Example 5

[0163] The difference between Comparative Example 5 and Example 1 is that nano-selenium is used instead of earthworm selenium as raw material to prepare selenium nutrient solution, selenium-based fertilizer, selenium foliar fertilizer and selenium cutting liquid, and the total selenium concentration is the same as that of earthworm selenium.

[0164] In the present invention, 11 embodiments and 5 comparative examples were tested, and the cadmium test results of the feed raw materials produced in the cadmium-contaminated wasteland are shown in Table 1, the selenium test results of the feed raw materials produced in the cadmium-contaminated wasteland are shown in Table 2, the annual output of feed plants planted in the cadmium-contaminated wasteland is shown in Table 3, and the cadmium and selenium content of the soil in the fourth year of the cadmium-contaminated wasteland and the nutritional index of feed plants are shown in Table 4, as shown below:

[0165] Table 1:

[0166]

[0167] From Table 1 we can see that:

[0168] 1. The cadmium content of Examples 4, 6, 8, and 11 is significantly higher than that of Example 1, indicating that in area A:

[0169] 1.1 Example 4 Adding enzymatic molasses, spraying enzymatic molasses on the leaves can promote the growth of plant stems and leaves, and the increase in plant biomass indirectly plays a role in diluting the cadmium content in the stems and leaves;

[0170] 1.2 Example 6: Instead of planting mulberry trees for feed first, elephant grass was planted from the first year. The cadmium content of the elephant grass harvested in the first year exceeded the feed hygiene standard.

[0171] 1.3 Example 8 Targetedly increasing the cutting height can reduce the cadmium content of the harvested feed raw materials;

[0172] 1.4 Example 11 does not interplant in winter, and fails to plant annual ryegrass to absorb and remove cadmium in the soil, resulting in a significant increase in the cadmium content of the harvested feed raw materials. Rapeseed is not planted, resulting in a significant decrease in land use efficiency, and the land quality cannot be improved by enriching soil organic matter through planting rapeseed.

[0173] 2. The cadmium content of Examples 5 and 9 was significantly higher than that of Example 2, indicating that in Area B, if enzymatic molasses was not applied to the leaves and the cutting height was not adjusted in a targeted manner, the cadmium content of the harvested feed raw materials would be relatively increased.

[0174] 3. The cadmium content in Examples 7 and 10 is significantly higher than that in Example 3, indicating that in area C:

[0175] 3.1 Example 7 does not use the cadmium-enriching plant Pennisetum to absorb and remove part of the cadmium in the soil, but instead plants fodder mulberry from the first year. The cadmium content in the harvested fodder mulberry is higher than the cadmium content in the corresponding fodder mulberry in Example 3. Among them, the fodder mulberry harvested in the first and second years cannot be directly fed to animals according to the feed hygiene standards, and can only be used as a feed raw material and mixed with other low-cadmium feed raw materials for feeding;

[0176] 3.2 Targetedly increasing the cutting height can reduce the cadmium content in harvested fodder mulberry.

[0177] 4. The cadmium content in Example 2 is the highest. In Example 2, elephant grass is planted using conventional methods. Elephant grass has a certain enrichment effect on cadmium, and the conventional planting method cannot isolate the plant from cadmium absorption to a certain extent. The application of conventional soil conditioners (calcium oxide + silicon fertilizer) and conventional fertilization methods cannot effectively reduce the plant's absorption of cadmium.

[0178] 5. Comparative Examples 1 and 3 adopted conventional methods to plant fodder mulberry, and used soil conditioners of calcium oxide + silicon fertilizer and calcium oxide + sodium selenite, respectively. The cadmium content of the fodder raw materials harvested in the first three years exceeded the fodder hygiene standards.

[0179] 6. The cadmium content of Comparative Example 4 is significantly higher than that of Example 1. Sodium selenite is an inorganic selenium with strong toxicity. Its absorption and utilization efficiency by plants is slower than that of organic selenium, and the effect of inorganic selenium on plants is worse than that of organic selenium.

[0180] 7. The cadmium content of Comparative Example 5 is significantly higher than that of Example 1. Nano-selenium belongs to organic selenium, and its organic selenium is a macromolecular organic matter (such as microbial nano-selenium). Plant leaves absorb small molecular organic matter (such as monosaccharides, amino acids, etc.) faster, resulting in low absorption efficiency of nano-selenium by the leaves. Its use effect is worse than that of earthworm selenium (Example 1).

[0181] Table 2:

[0182]

[0183] From Table 2 we can see that:

[0184] 1. The selenium content of Examples 4, 6, 8, and 11 is significantly lower than that of Example 1. Enzymatic hydrolysis of molasses can promote plant growth and chlorophyll synthesis. Interplanting annual ryegrass in winter can reduce the cadmium content in the soil and promote healthy plant growth, all of which are beneficial to increasing the selenium content in plants. The leaves absorb nutrients from foliar fertilizer and cutting fluid, and the selenium content in the leaves is higher. Reducing the cutting height will reduce the selenium content of the harvested feed raw materials.

[0185] 2. The selenium content of Examples 5 and 9 is significantly lower than that of Example 2.

[0186] 3. The selenium content of Examples 7 and 10 is significantly lower than that of Example 3.

[0187] 4. The selenium content of Comparative Examples 1, 2, and 3 is significantly lower than that of Example 1, and the selenium content is also the lowest, indicating that conventional planting and fertilization methods are not ideal for increasing the selenium content of harvested feed raw materials.

[0188] 5. The selenium content of Comparative Examples 4 and 5 is improved, but still significantly lower than that of Example 1, indicating that sodium selenite and nano-selenium cannot achieve the same effect as earthworm selenium, because earthworm selenium is rich in organic selenium and is easily absorbed by plant leaves and roots.

[0189] Table 3:

[0190]

[0191] From Table 3 we can see that:

[0192] 1. The yields of Examples 4 and 11 are significantly lower than those of Example 1, because the sugar in the enzymatically hydrolyzed molasses is a monosaccharide that is easily absorbed by plant leaves and does not cause plant diseases and insect pests; and the sugar and mineral elements such as potassium and magnesium in the enzymatically hydrolyzed molasses interact with selenium, iron, manganese, zinc, nitrogen, phosphorus, amino acids, etc. in earthworm selenium to promote the formation of chlorophyll, solve the problem of yellowing of elephant grass leaves planted in cadmium-contaminated areas, enhance plant photosynthesis, and increase the yield of elephant grass;

[0193] 2. In Example 11, cadmium has a certain toxic effect on plant growth. Failure to interplant annual ryegrass in winter failed to effectively reduce the effective cadmium content in the soil, affecting the yield of feed plants;

[0194] 3. The output of Example 5 is significantly lower than that of Example 2;

[0195] 4. The yield of Example 7 is significantly lower than that of Example 3. Example 7 does not use Pennisetum to absorb and remove effective cadmium in the soil, which affects the yield of subsequent forage plants.

[0196] 5. The yields of fodder plants planted in Comparative Examples 1, 2, and 3 were the lowest, indicating that conventional planting methods on cadmium-contaminated land are not conducive to the production of fodder plants and result in low yields.

[0197] 6. The yields of Comparative Examples 4 and 5 are significantly lower than those of Example 1. The effects of sodium selenite and nano-selenium on increasing the yield of feed plants are not as good as those of earthworm selenium, because earthworm selenium contains rich easily absorbable organic selenium, amino acids, mineral elements, etc., which can interact with zinc, nitrogen, phosphorus, sugar, and mineral elements in enzymatic molasses, solve the problem of yellowing leaves of feed plants planted in cadmium-contaminated areas, promote chlorophyll synthesis and plant growth, and increase the yield of feed plants.

[0198] Table 4:

[0199]

[0200] From Table 4 we can see that:

[0201] 1. The cadmium content in the soil of Example 7 is significantly higher than that of Example 3, because the planting of Pennisetum absorbs and removes a large amount of cadmium in the soil, making the cadmium content in the soil of Example 3 lower;

[0202] 2. The cadmium content in the soil of Example 11 is significantly higher than that of Example 1, because the interplanting of annual ryegrass in winter absorbs and removes a large amount of cadmium in the soil, making the cadmium content in the soil of Example 1 lower;

[0203] 3. The cadmium content in the soil of Example 6 is significantly lower than that of Example 1, because elephant grass can absorb cadmium in the soil better than fodder mulberry, thus reducing the cadmium content in the soil;

[0204] 4. Comparative Example 2 has the lowest soil cadmium content because its feed plants have high cadmium content, which absorbs and removes a large amount of cadmium in the soil. However, the cadmium content of the produced feed raw materials exceeds the feed hygiene standards.

[0205] 5. Comparative Examples 1 and 2 applied a large amount of calcium oxide to increase soil pH and reduce cadmium toxicity, but it was very easy to cause soil compaction, reduce soil fertility and plant yield, and long-term large-scale application of silicon fertilizers caused serious silicon (Si) residues, resulting in serious secondary pollution of the soil;

[0206] 6. The selenium content in the soil of Comparative Examples 3, 4, and 5 is the highest. Because a large amount of inorganic selenium is applied to the soil in Comparative Example 3, a large amount of inorganic selenium remains in the soil. The inorganic selenium is highly toxic and has poor safety, resulting in extremely serious secondary pollution of the land. The absorption of selenium fertilizer by the leaves in Comparative Examples 4 and 5 is relatively poor, so that the unabsorbed selenium fertilizer enters the soil, resulting in a large amount of inorganic selenium and nano-selenium in the soil. The total selenium content in the soil is significantly higher than that in Example 1;

[0207] 7. The crude protein content of Examples 4 and 11 is significantly lower than that of Example 1, and the crude fiber content is significantly higher than that of Example 1, because the monosaccharides and mineral elements in the enzymatic hydrolysis molasses can interact with the organic selenium, mineral elements, zinc, nitrogen, phosphorus, amino acids, etc. in the earthworm selenium, thereby promoting the formation of plant protein, fat, etc., solving the problem of low nutritional quality of plants planted on cadmium-contaminated land and improving the nutritional value;

[0208] 8. Example 11: Winter intercropping was not used to reduce the effective cadmium content in the soil. Cadmium has a certain toxic effect on plants and reduces the nutritional quality of feed plants;

[0209] 9. The crude protein content of Example 5 is significantly lower than that of Example 2, and the crude fiber content is significantly higher than that of Example 2;

[0210] 10. The crude protein content of Example 7 is significantly lower than that of Example 3, and the crude fiber content is significantly higher than that of Example 3, because Pennisetum was not used to reduce the effective cadmium content in the soil;

[0211] 11. The crude protein of the forage plants planted in Comparative Examples 1, 2, and 3 was the lowest, and the crude fiber was the highest, indicating that conventional planting methods on cadmium-contaminated land would reduce the nutritional quality of plants;

[0212] 12. The crude protein content of the forage plants grown in Comparative Examples 4 and 5 is significantly lower than that in Example 1, and the crude fiber content is significantly higher than that in Example 1. The effects of sodium selenite and nano-selenium on improving the nutritional quality of forage plants are not as good as earthworm selenium.

[0213] In the present invention, the land is divided into planting areas according to the cadmium pollution situation, and feed plants (two or more of feed mulberry, elephant grass, pennisetum, ryegrass, and rapeseed) are planted annually and the corresponding planting pattern method is adopted, which can ensure that the feed raw materials obtained by cutting the feed plants planted in different areas of cadmium-contaminated land can achieve high yield, high nutritional value, and cadmium content that meets the feed hygiene standards. At the same time, planting feed plants can improve the land and reduce soil erosion, thereby utilizing polluted abandoned land to increase its added value, turning waste into treasure, alleviating the problem of shortage of fodder for herbivorous livestock in the south, and also improving the economic benefits of local residents.

[0214] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for planting herbivorous animal feed plants using polluted waste land, characterized in that: The steps include:

1. Divide the planting area of ​​polluted land: On the contaminated waste land, the area with cadmium concentration of 2.5mg / kg to 4mg / kg is set as zone A, the area with cadmium concentration of 4mg / kg to 7mg / kg is set as zone B, and the area with cadmium concentration of 7mg / kg to 10mg / kg is set as zone C; 2. Regional planting model: First year planting pattern: Dig trenches in area A to plant fodder mulberry trees, with a mowing height of 1.2m to 1.4m and a stubble height of 35cm to 45cm; Dig trenches in area B and plant elephant grass, with a mowing height of 1.5m to 1.7m and a stubble height of 75cm to 85cm; Dig trenches in area C and plant Pennisetum, with a mowing height of 0.8m to 1.1m; Planting pattern for the second year: In area A, the mowing height of fodder mulberry is 1.3m-1.5m, and the stubble height is 15cm-25cm; In area B, the main root system of elephant grass is removed and fodder mulberry is planted. The cutting height of fodder mulberry is 1.1m to 1.3m, and the stubble height is 45cm to 55cm. In area C, the mowing height of Pennisetum was 0.9m to 1.2m; Planting pattern for the third year: In area A, the main root system of fodder mulberry is removed and elephant grass is planted. The mowing height is 1.7m to 2.0m and the stubble height is 55cm to 65cm. In area B, the mowing height of fodder mulberry is 1.2m-1.4m, and the stubble height is 15cm-25cm; In area C, remove the main root system of Pennisetum and plant mulberry trees for forage. The cutting height is 1.0m to 1.2m and the stubble height is 45cm to 55cm. Planting pattern for the fourth year: In area A, the mowing height of elephant grass is 1.8m to 2.1m, and the stubble height is 20cm to 25cm; In area B, the mowing height of fodder mulberry is 1.2m-1.4m, and the stubble height is 15cm-25cm; In area C, the mowing height of fodder mulberry is 1.1m to 1.3m, and the stubble height is 15cm to 25cm; 3. Fertilization and planting: The fodder mulberry, elephant grass and pennisetum to be transplanted are first soaked in fodder mulberry nutrient solution, elephant grass nutrient solution and pennisetum nutrient solution respectively. The fodder mulberry nutrient solution is prepared by diluting the earthworm selenium stock solution 5 times, the elephant grass nutrient solution is prepared by diluting the earthworm selenium stock solution 4 times and then adding zinc, and the pennisetum nutrient solution is prepared by diluting the earthworm stock solution 5 times.

2. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 1, characterized in that: When fertilizing and planting, the roots of mulberry are wrapped with mulberry-based fertilizer, and the roots of elephant grass are wrapped with elephant grass-based fertilizer. The mulberry-based fertilizer is prepared by diluting mulberry nutrient solution by 2 times and adding it to earthworm manure at a ratio of 0.1%, and the elephant grass-based fertilizer is prepared by diluting elephant grass nutrient solution by 6 times and adding it to earthworm manure at a ratio of 0.5%.

3. A method for planting herbivorous animal feed plants using polluted waste land according to claim 1 or 2, characterized in that: When fertilizing and planting, the fodder mulberry leaves in area A, area B and area C were applied with fodder mulberry leaf top fertilizer in area A, area B and area C respectively. Among them, the fodder mulberry leaf top fertilizer in area A, area B and area C were made by diluting the earthworm selenium stock solution by 55, 50 and 45 times respectively and then adding 4.0% to 6.0% enzymatic molasses.

4. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 2, characterized in that: When fertilizing and planting, the elephant grass in area A and area B were applied with foliar fertilizer for elephant grass in area A and area B respectively. The foliar fertilizer for elephant grass in area A and area B was made by diluting the elephant grass nutrient solution 16 times and 13 times respectively, then adding 0.1%-0.2% urea, 0.16%-0.22% ammonium phosphate, and 3.5%-5.0% enzymatic molasses.

5. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 1, characterized in that: In the fourth year of planting, rapeseed was planted in areas A and B during the winter fallow period of that year, and annual ryegrass was planted in area C during the winter fallow period of that year.

6. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 5, characterized in that: The planting pattern for the fifth year and thereafter will follow the planting pattern for the fourth year.

7. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 1, characterized in that: In area A, fodder mulberry is planted with a spacing of 20 cm between plants and 32 cm between rows, and the furrows are 25 cm deep and 20 cm wide.

8. The method for planting herbivorous animal feed plants using polluted wasteland according to claim 1, characterized in that: In area B, elephant grass was planted with a spacing of 25 cm between plants and 42 cm between rows, and the furrows were 32 cm deep and 27 cm wide in strips.

Images