Protective seeding cultivation method of alfalfa in sandy land based on oat mixed seeding

Abstract

The present invention discloses a method for the protective seeding and cultivation of sandy land alfalfa based on oat mixed seeding. This cultivation method consists of pre-sowing preparation, sowing, field management of the first crop, harvesting of the mixed grass, field management of the second crop, harvesting of alfalfa, and field management before winter. Through the spring sowing of alfalfa and the method of protective seeding of oats, it makes full use of the land space, effectively inhibits the growth of weeds, increases the yield and quality of forage grass, and improves the economic benefits in the first year of alfalfa establishment; it also improves the emergence rate and survival rate of alfalfa, promotes the downward penetration of alfalfa roots, effectively solves the technical problem of poor wintering ability of sandy land alfalfa in the first year of spring sowing establishment, has high reference value for the sustainable development of the sandy land alfalfa grass industry, and is suitable for popularization and utilization.

Description

Technical Field

[0001] The embodiments of the present invention belong to the technical field of plant cultivation, and particularly relate to a method for protected seeding cultivation of sandy land alfalfa based on oat mixed seeding. Background Art

[0002] Alfalfa (Medicago sativa.L) is a perennial leguminous forage grass, known as the "king of forage grasses". It has the characteristics of high protein content, good palatability, strong adaptability and stress resistance. At the same time, it also has ecological restoration functions such as soil and water conservation, enhancing soil fertility, and improving soil. As the forage grass with the widest cultivation area, alfalfa plays an important role in maintaining the balanced and coordinated development of animal husbandry and the health and stability of the ecosystem. Planting alfalfa in desertified land can provide forage for animal husbandry, improve the soil microenvironment, and effectively prevent the process of desertification, having certain economic and environmental protection values.

[0003] In recent years, with the rapid development of animal husbandry, the planting area of large-scale high-quality alfalfa grass has increased accordingly. However, in the process of planting alfalfa in sandy land, many enterprises and farmers face a series of problems. The most important problem is the low overwintering rate of alfalfa, which will reduce the sustainable utilization years of alfalfa. The root growth of spring-sown alfalfa is better than that of summer-sown alfalfa. However, due to strong spring sandstorms and obvious late spring cold snaps in Aqi area, alfalfa suffers serious sandstorm disasters during the spring establishment process of alfalfa, resulting in low emergence survival rate and continuous reseeding, greatly increasing the production cost. Therefore, exploring a cultivation technical measure suitable for the establishment of spring-sown alfalfa in sandy land has great significance for production practice. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a protected seeding cultivation method for spring-sown alfalfa and oats with high seedling preservation rate, high yield, significant economic benefits and suitable for the establishment of sandy land alfalfa.

[0005] The embodiments of the present invention provide a method for protected seeding cultivation of sandy land alfalfa based on oat mixed seeding:

[0006] (1) Preparation before sowing: One week before spring sowing, first conduct soil closure to control weeds. The soil closure herbicide is generally 48% butralin emulsifiable concentrate or 48% trifluralin, with an application rate of 100 - 150 milliliters per mu, diluted with 30 - 40 kilograms of water. First, wet the ground surface, evenly spray the herbicide on the ground surface, and then conduct an irrigation with a depth of 5 centimeters. Sowing can be carried out after one week.

[0007] (2) Sowing:

[0008] ① Spring-sown oats: In late March, select early and medium-maturing oat varieties with strong stress resistance, high yield and good quality, and use a no-till precision seeder for sowing. The seeding rate is 5 - 7 kilograms per mu, the seeding depth is 4 - 5 centimeters, and the row spacing is 14.5 centimeters. When sowing, apply 20 kilograms per mu of compound fertilizer in a strip with the seeds and fertilizer together.

[0009] ② Spring sowing of alfalfa: In mid-April, choose alfalfa varieties with fall dormancy level ≤ 4 and sow them in a cross-cross pattern. The sowing rate is 1.5-2.5 kg / mu, the sowing depth does not exceed 2 cm, and the row spacing is 14.5 cm. After each sowing, set the sprinkler to water at 75% speed to prevent the seeds from being lost with soil erosion;

[0010] (3) First crop field management:

[0011] ① Irrigation: Irrigation is mainly carried out during the growth period of oats, following the irrigation principle of "early irrigation for tillering, late irrigation for jointing, and irrigation for ear formation". 230-250 cubic meters / mu of irrigation is carried out during the whole growth period;

[0012] ② Fertilization: During the growth period, nitrogen fertilizer is mainly applied. Through water-fertilizer integration, 25 kg / mu of urea and 5 kg / mu of nitrate phosphate are sprayed each season. Topdressing begins when the oats have three leaves and one heart, and 4-5 times of topdressing are applied during the entire growth period;

[0013] ③ Pest and disease control: Under the premise of sealing the soil before sowing, in principle, weed control is not carried out in mixed sowing fields. Prevention of pests and diseases is the main approach. Use drones for aerial control according to the occurrence of the pests. Commonly used pesticides include thiamethoxam and 5% acetamiprid, which are sprayed in the morning and evening when pests are most active. Stop using pesticides ten days before harvest.

[0014] (4) Harvesting mixed grass: mowing is carried out in late June when oats are filling, leaving a stubble height of 8 cm. After drying, the grass is raked and baled. When baling, the moisture content of the grass strips should be controlled at 9%-10%, and the moisture content of the bales should be controlled below 14%;

[0015] (5) Second crop field management:

[0016] ① Irrigation: Irrigation should be carried out according to the growth period of alfalfa, following the irrigation principle of "large amount of water and long intervals, dry on top and wet on bottom", combined with climate and soil moisture conditions, with an irrigation rate of 90-100 cubic meters per mu;

[0017] ② Fertilization: During the growth period of alfalfa, nitrogen fertilizer is mainly applied, supplemented by phosphorus and potassium fertilizers. Through soil testing and formula technology, combined with water and fertilizer integration, foliar spraying is carried out 3-4 times;

[0018] ③ Disease, insect and weed control: After the first crop of mixed grass is harvested, weed control is carried out according to the growth of weeds in the field. Spray control is carried out when the weeds are 3-5 leaves. For grass weed control, 108 g / L high-efficiency fluazifop-butyl emulsifiable concentrate is used, and for broad-leaved weed control, 5% imazethapyr is used. Targeted control is carried out according to the occurrence of diseases and insect pests during the later growth period of alfalfa;

[0019] (6) Harvesting alfalfa: In late August, cut the alfalfa at the budding stage according to the weather conditions, leaving a stubble height of 3 - 5 cm. After cutting and sun-drying, rake the hay and bale it, strictly following the principles of raking the hay when it is damp and baling. The moisture content of the dry hay bales should be controlled below 16%.

[0020] (7) Field management before winter: After the alfalfa harvest is completed, continue to do a good job in field water and fertilizer management for overwintering with a high stubble. When the alfalfa grows to 10 cm, stop watering appropriately to temper the roots and promote the development of the alfalfa roots. In addition, do a good job in winter irrigation before winter. After the winter irrigation is completed, conduct a freezing water irrigation at the end of November.

[0021] The spring sowing of alfalfa in step (2) also includes: Select alfalfa varieties with a fall dormancy level ≤ 4 for sowing in mid-April. Use cross-sowing, with a seeding rate of 2 kg / mu, a sowing depth not exceeding 2 cm, a row spacing of 14.5 cm. Immediately set up a sprinkler irrigation machine to water at a 75% rotation speed after each sowing to avoid the loss of seeds due to soil wind erosion.

[0022] In the first stubble field management of step (3): The insecticide is a mixture of 80 ml / mu of thiamethoxam and 150 ml / mu of 5% acetamiprid. Use a plant protection drone to spray it during the peak activity period of pests in the morning and evening. Stop using pesticides ten days before harvest.

[0023] In the second stubble field management of step (5): The herbicide is made by mixing 120 ml / mu of imazethapyr with a mass concentration of 5% and 60 ml / mu of haloxyfop-P-methyl 108 g / l emulsifiable concentrate. When using, add 40 liters of water for chemical weeding by spraying on the stems and leaves.

[0024] In the field management before winter of step (7): The irrigation volume from the completion of alfalfa harvest to winter water irrigation is 10 - 20 cubic meters / mu, the winter water is 50 - 60 cubic meters / mu, and the freezing water is 5 - 10 cubic meters / mu.

[0025] The beneficial effects of the present invention include:

[0026] (1) In the present invention, spring-sown oats are used to protect the sowing of alfalfa. In the early growth stage, oats grow faster than alfalfa, providing shade for alfalfa, improving its emergence rate and survival rate, and also making full use of the land space to effectively inhibit the growth of weeds.

[0027] (2) In the present invention, spring-sown oats are used to protect the sowing of alfalfa. On the premise of ensuring overwintering with a high stubble in the year of establishment, one stubble of mixed grass and one stubble of alfalfa grass are also harvested, increasing the forage yield and quality and improving the economic benefits in the year of alfalfa establishment.

[0028] (3) By protecting the seeding technology, it can effectively reduce the damage of strong winds and low temperatures in spring to alfalfa seedlings, extend the growth duration of alfalfa in the current year, promote the downward penetration of alfalfa roots, effectively solve the technical problem of poor overwintering ability of alfalfa in the year of establishment, and is conducive to the sustainable development of the sandy land alfalfa grass industry, with certain value for popularization and adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a diagram of the growth trend of forage grass under different treatments provided by an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of the change in hay yield of each cutting under different treatments provided by an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of the change in underground biomass of alfalfa before overwintering under different treatments provided by an embodiment of the present invention;

[0032] Figure 4 It is a diagram of the root morphology of spring single-sown and mixed-sown alfalfa before overwintering provided by an embodiment of the present invention;

[0033] Figure 5 It is a protective seeding cultivation method for sandy land alfalfa based on oat mixed sowing provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The following will be described in conjunction with the drawings and specific embodiments. The embodiments are only for explanation and do not limit the scope of the rights:

[0035] Embodiment 1

[0036] A protective seeding cultivation method for sandy land alfalfa based on oat mixed sowing provided by the embodiment, the cultivation method includes pre-sowing preparation, sowing, field management and harvesting steps, and is specifically composed of the following steps (see Figure 5 ):

[0037] (1) Pre-sowing preparation: One week before spring sowing, first conduct soil closure to control weeds. The soil closure herbicide is generally 48% butralin emulsifiable concentrate or 48% trifluralin, with an application rate of 100-150 ml / mu, diluted with 30-40 kg of water. First, wet the surface of the land, evenly spray the herbicide on the surface of the land, and then conduct an irrigation with a depth of 5 cm. Sowing can be carried out after one week;

[0038] (2) Sowing:

[0039] ① Spring sowing of oats: In late March, select early and medium-maturing oat varieties with strong stress resistance, high yield and good quality, and use a no-till precision seeder for sowing. The seeding rate is 5-7 kg / mu, the seeding depth is 4-5 cm, the row spacing is 14.5 cm, and 20 kg / mu of compound fertilizer is applied in a strip with the seeds during sowing;

[0040] ② Spring sowing of alfalfa: In mid-April, select alfalfa varieties with a fall dormancy level of ≤4 and sow them in a cross-cross pattern. The sowing rate is 2.0 kg / mu, the sowing depth does not exceed 2 cm, and the row spacing is 14.5 cm. After each sowing, set the sprinkler to irrigate at 75% speed to prevent the seeds from being lost with wind erosion of the soil.

[0041] (3) First crop field management:

[0042] ① Irrigation: Irrigation is mainly carried out during the growth period of oats, following the irrigation principle of "early irrigation for tillering, late irrigation for jointing, and irrigation for ear formation". 230-250 cubic meters / mu of irrigation is carried out during the whole growth period;

[0043] ② Fertilization: During the growth period, nitrogen fertilizer is mainly applied. Through water-fertilizer integration, 25 kg / mu of urea and 5 kg / mu of nitrate phosphate are sprayed each season. Topdressing begins when the oats have three leaves and one heart, and 4-5 times of topdressing are applied during the entire growth period;

[0044] ③ Pest and disease control: Under the premise of sealing the soil before sowing, in principle, weed control is not carried out in mixed sowing fields. Prevention of pests and diseases is the main approach. Use drones for aerial control according to the occurrence of the pests. The commonly used insecticide thiamethoxam 80 ml / mu is mixed with 5% acetamiprid 150 ml / mu. Spray it in the morning and evening when pests are most active. Stop using pesticides ten days before harvest.

[0045] (4) Harvesting mixed grass: mowing is carried out in late June when oats are filling, leaving a stubble height of 8 cm. After drying, the grass is raked and baled. When baling, the moisture content of the grass strips should be controlled at 9%-10%, and the moisture content of the bales should be controlled at 14%;

[0046] (5) Second crop field management:

[0047] ① Irrigation: Irrigation should be carried out according to the growth period of alfalfa, following the irrigation principle of "large amount of water and long intervals, dry on top and wet on bottom", combined with climate and soil moisture conditions, with an irrigation rate of 90-100 cubic meters per mu;

[0048] ② Fertilization: During the growth period of alfalfa, nitrogen fertilizer is mainly applied, supplemented by phosphorus and potassium fertilizers. Through soil testing and formula technology, combined with water and fertilizer integration, foliar spraying is carried out 3-4 times;

[0049] ③ Pest and disease control: After the first crop of mixed grass is harvested, weed control is carried out according to the growth of weeds in the field. Spray control is carried out when the weeds are 3-5 leaves. For grass weed control, 108 g / L high-efficiency flupyramide EC 60 ml / mu is used, and for broad-leaved weed control, 5% imazethapyr 120 ml / mu is used. Targeted control is carried out according to the occurrence of pests and diseases during the later growth period of alfalfa.

[0050] (6) Harvesting alfalfa: In late August, cut the alfalfa at the budding stage according to the weather conditions, leaving a stubble height of 3 - 5 cm. After cutting and drying, rake the hay and bale it, strictly following the principles of raking and baling when the hay is damp. The moisture content of the dry hay bales should be controlled at 16%.

[0051] (7) Field management before winter: After the alfalfa is harvested, continue to do a good job in field water and fertilizer management for overwintering with a high stubble. Irrigate 10 - 20 cubic meters per mu. When the alfalfa grows to 10 cm, stop watering appropriately to temper the roots and promote the development of the alfalfa roots. In addition, before winter, do a good job in winter irrigation, with 50 - 60 cubic meters per mu of winter irrigation water. After the winter irrigation is completed, conduct a freezing water irrigation at the end of November, with 5 - 10 cubic meters per mu of irrigation water.

[0052] To verify the beneficial effects of the present invention, the inventor conducted a field experiment on the method of Example 1, and the experimental conditions include:

[0053] 1.1 General situation of the test plot

[0054] The test area is located at 43°33′57″N, 120°14′21″E. This area belongs to a typical temperate semi - arid continental climate. The average annual temperature is 5.5°C, the frost - free period is 95 - 140 days, the average annual accumulated temperature is 2900 - 3400°C, the average annual rainfall is 300 - 400 mm, and the annual sunshine hours are 2760 - 3030 h. The soil in this area is mostly sandy soil, with low soil organic matter content, strong ventilation and water permeability, and poor water and fertilizer retention capacity. The previous crop was two - season oats.

[0055] 1.2 Test materials

[0056] The tested alfalfa variety is Liangmu; the oat variety is Lingxiu.

[0057] 1.3 Test design

[0058] The test selected a sprinkler irrigation circle, with each span set as a treatment group. There were a total of 3 mixed - sowing treatments, namely 5 kg of oats + 2 kg of alfalfa per mu (abbreviated as YM5), 6 kg of oats + 2 kg of alfalfa per mu (abbreviated as YM6), and 7 kg of oats + 2 kg of alfalfa per mu (abbreviated as YM7), with 2 kg of single - sown alfalfa per mu as the control (abbreviated as CK). In addition, in each span, a flat and relatively uniform area was selected, and a fixed sample plot of 50 m × 50 m was demarcated for sampling and monitoring. Figure 1 It is the growth trend map of forage grass in each treatment group during the growth period.

[0059] Other field management is the same as that in Example 1

[0060] 1.4 Determination items and methods

[0061] 1.4.1 Determination of alfalfa plant height and seedling retention number

[0062] At each harvest, 15 alfalfa and oat plants were randomly selected from each treatment group. The plant height was measured from the ground with a tape measure. After the harvest, the survival number of alfalfa in each treatment group was determined, and the process was repeated 3 times.

[0063] 1.4.2 Forage yield determination

[0064] One day before each harvest, small quadrats (1 m × 1 m) were selected in each fixed plot, and the above-ground part of the forage was cut, leaving a stubble height of 4 - 5 cm. Non-sown plants in the mixed forage were not included in the total yield. The fresh weight of the forage was recorded separately, with 3 replicates. The forage was placed in a cool and ventilated place and air-dried to a constant weight to measure the forage yield.

[0065] 1.4.3 Forage quality determination

[0066] In the fixed plot, random sampling was carried out using the multi-point mixing method. For the mixed sown grassland, the overall grass sample was used to determine the forage quality. The mixed grass sample was taken back to the laboratory, blanched at 105 °C for 30 min, dried at 65 °C to a constant weight, and then ground for later testing. The measured indexes included crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). The calculation of the relative feeding value (RFV) was as shown in formula (1).

[0067] RFV (%) = (88.9 - 0.779 × ADF) × (120 / NDF) / 1.29 (1)

[0068] 1.4.4 Root characteristics determination

[0069] Before the winter of alfalfa, 3 small quadrats (1 m × 1 m) were randomly selected in the fixed plot. The whole alfalfa plants in the quadrats were dug out and taken back to the laboratory. 40 alfalfa plants were randomly selected, and their taproot length, taproot diameter, crown diameter, the position of the first lateral root, and the number of lateral roots at 0 - 10 cm were measured respectively. All the alfalfa roots in the quadrat were divided into three layers (0 - 10 cm, 10 - 20 cm, > 20 cm), blanched at 105 °C for 30 min in an oven, and then dried at 65 °C to a constant weight to calculate the underground biomass.

[0070] 2. Experimental results

[0071] 2.1 Plant height at cutting and survival number of alfalfa in each treatment for different cuttings

[0072] As can be seen from Table 1, the plant height of the first cut of CK alfalfa was significantly higher than that of YM6 and YM7 (P<0.05), and there was no significant difference from YM5 (P>0.05); the plant height of the first cut of oats decreased with the increase of density, and YM7 was significantly lower than the other two treatment groups (P<0.05); after the first cut of alfalfa, the survival plant number of CK was the highest, significantly higher than that of YM6 and YM7 (P<0.05), and there was no significant difference from YM5 (P>0.05). The plant height of the second cut of CK alfalfa was significantly higher than that of the mixed sowing treatment group (P<0.05). Among them, the plant height of alfalfa in the mixed sowing group decreased with the increase of oat density, and there were significant differences among all treatments (P<0.05); after the second cut of alfalfa, the survival plant number of alfalfa was YM7>YM6>YM5>CK, but there was no significant difference (P>0.05). It can be seen that although the survival plant number of the first cut of single sowing is higher than that of the mixed sowing group, the mixed sowing can improve the survival plant number of spring sown alfalfa before winter.

[0073] Table 1 Plant height and survival plant number at the time of mowing under different treatments

[0074]

[0075] Note: Different letters marked for the same column of numbers indicate significant differences (P<0.05).

[0076] 2.2 Changes in hay yield of each cutting under different treatments

[0077] As Figure 2 can be seen, the hay yield of the first cut of YM6 was the highest, which was 8299.83 kg / hm 2 , significantly higher than that of YM5 and CK (P<0.05), and there was no significant difference from YM7 (P>0.05); the hay yield of the second cut of CK was the highest, which was 4362.33 kg / hm 2 , significantly higher than that of YM6 (P<0.05), and there was no significant difference from YM5 and YM7 (P>0.05). It can be seen that the mixed sowing increases the hay yield of the first cut and improves the economic value of spring sown alfalfa in the establishment year.

[0078] 2.4 Changes in forage quality of each cutting under different treatments

[0079] As can be seen from Table 2, in the first crop of forage grass, the crude protein content was the highest in CK, which was significantly higher than that in the mixed sowing treatment group (P<0.05). There were significant differences among the mixed sowing groups (P<0.05), and the order was YM6>YM7>YM5; the neutral detergent fiber was the lowest in CK, which was significantly lower than that in the mixed sowing treatment group (P<0.05). There were significant differences among the mixed sowing groups (P<0.05), and the order was YM7<YM5<YM6; the acid detergent fiber was the lowest in CK, which was significantly lower than YM5 and YM6 (P<0.05), but there was no significant difference from YM7 (P>0.05). The order of the mixed sowing groups was YM7<YM6<YM5; the relative feeding value was the highest in CK, which was significantly higher than that in the mixed sowing treatment group (P<0.05). Among the mixed sowing groups, YM7 was the highest, which was significantly higher than YM6 and YM5 (P<0.05). In the second crop of forage grass, the crude protein content was the highest in YM7, which was significantly higher than that in CK (P<0.05), and there was no significant difference from YM6 and YM5 (P>0.05); the neutral detergent fiber was the lowest in YM7, which was significantly lower than that in CK (P<0.05), and there was no significant difference from YM6 and YM5 (P>0.05); the acid detergent fiber was the lowest in YM5, which was significantly lower than that in CK (P<0.05), and there was no significant difference from other treatments (P>0.05); the relative feeding value was the highest in YM7, which was significantly higher than that in CK (P<0.05), and there was no significant difference from other treatments (P>0.05). It can be seen from this that although the quality of the first crop of single-sown alfalfa was good, compared with single-sown oats, mixed sowing improved its quality, and the quality of the second crop of mixed sowing was significantly better than that of single sowing.

[0080] Table 2 Changes in the quality of forage grass in each crop under different treatments

[0081]

[0082] Note: Different letters indicate significant differences among different treatments in each crop (P<0.05).

[0083] 2.5 Root characteristics of alfalfa before winter under different treatments

[0084] As can be seen from Table 3, among different treatments, the longest main root length of alfalfa before overwintering was YM5, which was significantly higher than that of YM7 and CK (P<0.05), and there was no significant difference from YM6 (P>0.05). The sizes of each mixed sowing group were YM5>YM6>YM7; the thickest main root diameter was CK, and there was no significant difference from other treatments (P>0.05). The sizes of each mixed sowing group were YM5>YM6>YM7; the thickest root collar diameter was CK, which was significantly higher than that of the mixed sowing treatment group (P<0.05). The sizes of each mixed sowing group were YM5>YM6>YM7; the deepest position of the first lateral root was YM7, and there was no significant difference from other treatments (P>0.05). The sizes of each mixed sowing group were YM5>YM6>YM7; the largest number of lateral roots in the 0-10 cm layer was CK, which was significantly higher than that of the mixed sowing treatment group (P<0.05). The sizes of each mixed sowing group were YM5<YM6<YM7. It can be seen from this that mixed sowing reduces the number of surface lateral roots and helps to promote the downward growth of roots.

[0085] Table 3 Morphological characteristics of alfalfa roots before overwintering under different treatments

[0086]

[0087] Note: Different letters marked for the same row of numbers indicate significant differences (P<0.05).

[0088] It can be Figure 3 seen that except that there was no significant difference in underground biomass between the 10-20 cm and >20 cm soil layers under the YM7 treatment (P>0.05), there were significant differences between different soil layers of the same treatment (P<0.05). The largest underground biomass in the 0-10 cm soil layer under different treatments was CK, which was significantly higher than that of the mixed sowing treatment group (P<0.05). The sizes of each mixed sowing group were YM5>YM6>YM7; the largest underground biomass in the 10-20 cm soil layer was YM5, and there was no significant difference from other treatments (P>0.05). The sizes of each mixed sowing group were YM5>YM7>YM6; the largest underground biomass in the >20 cm soil layer was YM5, and the sizes of each treatment group were YM5>YM7>YM6>CK. It can be seen from this that the proportion of deep root biomass in mixed sowing is large, which helps the healthy growth of roots.

[0089] Example 2

[0090] Aqi Pastoral Grass Industry applies a sowing and cultivation method of sandy land alfalfa based on oat mixed planting protection. After popularizing the protective sowing cultivation method of spring-sown alfalfa and oats, the average yield of the first cut of mixed grass silage is 1,054.94 kg / mu, and the average yield of the second cut of alfalfa silage is 334.5 kg / mu. Compared with the two cuts of alfalfa silage harvested by single-sowing alfalfa in spring, the annual yield increase is 452.65 kg / mu. Combining the cost input of the current year and the forage market for economic benefit analysis (Table 4), the economic benefit of protective sowing (spring mixed sowing) is 134.62 yuan / mu higher than that of single-sowing alfalfa in the establishment year. In addition, as can be seen from Table 5, the average number of surviving alfalfa plants per mu of spring mixed sowing before and after winter are 156,000 plants / mu and 96,900 plants / mu respectively, which are 24,800 plants / mu and 11,200 plants / mu higher than those of single-sowing alfalfa in spring respectively. And the root system of spring mixed sowing alfalfa is in an "upright type", and the main root penetrates deeper, ensuring better overwintering of alfalfa( Figure 4 ).

[0091] Table 4 Economic benefit analysis of the current year under different cultivation methods

[0092]

[0093] Table 5 Number of surviving alfalfa plants before and after winter under different cultivation methods

[0094]

[0095] This application determines that the protective sowing technology of spring-sown alfalfa and oats has certain popularization and utilization value in solving the problem of difficult overwintering of sandy land alfalfa. As mentioned above, it is only a preferred embodiment of the present invention and is only used for the explanation of the technical solution. Any changes and substitutions without creative labor based on the idea of the present invention should be covered within the protection scope. Therefore, the protection scope of the present invention should be subject to the protection scope required by the claims.

Claims

1. A method for protective seeding cultivation of alfalfa in sandy land based on oat mixed seeding, characterized in that, The method comprises: step 1: sealing the soil before sowing to prevent weeds; step 2: sowing oats and alfalfa in spring; step 3: managing the first crop of the field and harvesting the mixed grass; Step 4: Carry out the second field management and harvest alfalfa; Step 5: Carry out field management before wintering; Step 2 specifically includes: oat spring sowing includes: selecting early-to-mid-maturing and stress-resistant oat varieties in late March, using a no-till precision seeder for sowing, with a sowing amount of 5-7 kg / mu, a sowing depth of 4-5 cm, and a row spacing of 14.5 cm. When sowing, 20 kg / mu of compound fertilizer is applied in combination with seeds and fertilizers; alfalfa spring sowing includes: selecting alfalfa varieties with a fall dormancy level of ≤4 for sowing in mid-April, using cross sowing, a sowing amount of 1.5-2.5 kg / mu, a sowing depth of no more than 2 cm, and a row spacing of 14.5 cm. After each sowing is completed, a sprinkler is immediately set to water at a speed of 75% to prevent seeds from being lost with soil erosion.

2. The method for the protective seeding cultivation of sandy land alfalfa based on oat mixed seeding according to claim 1, characterized in that, Step 1 specifically includes: one week before spring sowing, soil sealing is carried out to prevent weeds. The soil sealing herbicide is 48% butralin emulsifiable concentrate or 48% fluralin, the per mu dosage is 100-150 ml / mu, and it is diluted with 30-40 kg of water. The surface is first sprayed wet, the herbicide is evenly sprayed on the surface, and then watering is carried out again. The irrigation depth is 5 cm. Sowing can be carried out one week later.

3. The method for protective seeding cultivation of alfalfa in sandy land based on oat mixed seeding according to claim 2, characterized in that, Step 3 specifically includes: Carry out the first field management including: Irrigation: Irrigation according to the growth period of oats, follow the irrigation principle of "early irrigation for tillering, late irrigation for jointing, and irrigation for ear formation", and 230-250 cubic meters / mu of irrigation during the whole growth period; Fertilization: Nitrogen fertilizer is mainly applied during the growth period, and 25 kg of urea / mu and 5 kg of nitrate / mu are sprayed each season through water-fertilizer integration. Topdressing begins when the oats have three leaves and one heart, and topdressing is done 4-5 times during the whole growth period; Disease, insect and weed control: Prepare the soil before sowing Under the premise of soil closure, in principle, weed control is not carried out in mixed sowing fields, and prevention is the main approach for pests and diseases. Drones are used for aerial spraying according to the occurrence situation. The insecticides used are thiamethoxam and 5% acetamiprid, which are sprayed in the morning and evening when pests are active, and pesticides are stopped ten days before harvest. Harvesting mixed grass includes: mowing during the oat filling period in late June, leaving a stubble height of 8 cm, raking and baling after drying, and the moisture content of the grass strips is controlled at 9%-10% when baling, and the moisture content of the bales is controlled at 14%.

4. A method for protective seeding cultivation of alfalfa in sandy land based on oat mixed seeding according to claim 3, characterized in that, Step 4 specifically includes: Irrigation: Irrigate according to the growth period of alfalfa, following the irrigation principle of "large water volume with long intervals, dry upper part and wet lower part", and irrigate according to the climate and soil moisture content, with an irrigation volume of 90 - 100 cubic meters per mu; Fertilization: During the growth period of alfalfa, topdressing with nitrogen fertilizer is mainly carried out, supplemented by phosphorus and potassium fertilizers. Through soil testing and formulated fertilization technology, foliar spraying is carried out 3 - 4 times in combination with integrated water and fertilizer management; Prevention and control of diseases, pests and weeds: After the first cut of the mixed grass, weed control is carried out according to the growth status of weeds in the field. Spray control is carried out at the 3 - 5 leaf stage of weeds. For the control of gramineous weeds, 108 grams per liter of haloxyfop - R - methyl EC is selected, and for the control of broad - leaf weeds, 5% imazethapyr is selected; Prevention and control are carried out targeted according to the occurrence status of diseases and pests during the later growth period of alfalfa; Harvesting alfalfa includes: In late August, mow at the budding stage of alfalfa according to the weather conditions, with a stubble height of 3 - 5 cm. After mowing and drying, rake and bale, following the principles of raking and baling when getting damp. The moisture content of the dry hay bales is controlled at 16%.

5. A method for the protective seeding and cultivation of sandy alfalfa based on oat mixed seeding according to claim 4, characterized in that, Step 5 specifically includes: After the alfalfa harvest is completed, continue to do a good job in field water and fertilizer management for overwintering with high stubble. When the alfalfa grows to 10 cm, stop watering to temper the roots and promote the development of alfalfa roots. Do a good job in winter irrigation before winter. After the winter irrigation is completed, carry out a freezing water irrigation at the end of November.

6. The protective seeding cultivation method of sandy land alfalfa based on oat mixed seeding according to claim 5, characterized in that The spring sowing of alfalfa in Step 2 also includes: In mid - April, select alfalfa varieties with a fall dormancy level ≤ 4 for sowing. Use cross - cross sowing, with a seeding rate of 2 kg per mu, a sowing depth not exceeding 2 cm, a row spacing of 17.5 cm. Immediately after each sowing, set up a sprinkler irrigation machine to water at a 75% rotation speed to avoid the loss of seeds due to soil wind erosion.

7. A method for the protective seeding cultivation of sandy alfalfa based on oat mixed seeding according to claim 6, characterized in that, In the first - cut field management of Step 3: The insecticide is composed of 80 ml per mu of thiamethoxam and 150 ml per mu of 5% acetamiprid, and is sprayed using a plant protection UAV during the peak activity period of pests in the morning and evening. Stop using pesticides ten days before harvesting.

8. A method for protective seeding cultivation of alfalfa in sandy land based on oat mixed seeding according to claim 7, characterized in that, In the second - cut field management of Step 4: The herbicide is prepared by mixing 120 ml per mu of 5% imazethapyr with 60 ml per mu of 108 grams per liter of haloxyfop - R - methyl EC. When using, add 40 liters of water for stem - leaf spray chemical weeding.

9. A method for protective seeding cultivation of sandy land alfalfa based on oat mixed seeding according to claim 8, characterized in that In the pre - winter field management of Step 5: The irrigation volume from the completion of alfalfa harvest to winter water irrigation is 10 - 20 cubic meters per mu, the winter irrigation water is 50 - 60 cubic meters per mu, and the freezing water is 5 - 10 cubic meters per mu.

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