High-yield cultivation method for medicago sativa in rainy and hot regions in south of Yunnan

Abstract

The invention discloses a high-yield cultivation method for medicago sativa in rainy and hot regions in the south of Yunnan, and belongs to the technical field of crop cultivation. Aiming at the climate contradictions of high temperature and rainy summer and drought and less rain in winter and spring in the region, the problem of alfalfa planting is solved through a systematic scheme. The method comprises the following steps: 1, selecting a non-autumn sleep type heat-resistant variety with the autumn sleep level greater than or equal to 8; 2, optimizing the sowing time; 3, deeply ploughing, applying organic fertilizer, ditching, bedding and constructing a drainage system; 4, threshold irrigation in dry seasons and real-time drainage in rainy seasons; 5, implementing precise fertilization of'base fertilizer + seed fertilizer + topdressing '; 6, mowing in a squaring stage in a dry season, and mowing when the plant height is 60-70cm or lodging in a rainy season. According to the method, the death rate of medicago sativa is reduced to 5% or below, the yield of fresh grass reaches 11-15 tons / mu / year, the yield is increased by 200% or above compared with a traditional mode, the technical bottleneck of planting in the tropical-subtropical rainy and hot regions in the same period is broken through, and the technical blank of industrial planting is filled up.

Description

Technical Field

[0001] The present invention belongs to the technical field of crop cultivation, and particularly relates to a high-yield cultivation method of alfalfa suitable for the regions with concurrent rainfall and heat in southern Yunnan. In particular, aiming at the climate characteristics of high temperature and abundant rainfall in summer and drought in winter in this region, the variety selection, water management, fertilization strategy and mowing system are optimized to achieve low mortality and high and stable yield of alfalfa. Background Art

[0002] Alfalfa is known as the "king of forages" and has the advantages of high yield, rich nutrition and good palatability, and is widely used in animal husbandry. However, alfalfa is native to temperate regions and is suitable for growing in dry and cool climate conditions. There are significant contradictions between its biological characteristics and the tropical-subtropical monsoon climate in southern Yunnan: the rainfall in summer (May - October) in this region accounts for more than 80% of the annual rainfall, the monthly average precipitation reaches more than 200 mm, the maximum monthly precipitation can exceed 600 mm, and the monthly average temperature > 25°C; in winter and spring (November to April of the next year), it is continuously dry, and the monthly average precipitation is less than 50 mm. Due to the failure to coordinate the water contradiction between high temperature and high humidity and drought alternation in the traditional cultivation mode, problems such as poor root development of alfalfa (slow root development in the seedling stage and root rot in the rainy season), lodging and rot (lodging rate reaches 70% in the rainy season), and continuous death (survival rate in the seedling stage and rainy season < 50%) occur, resulting in this region being long listed as a "technical no-go zone" for alfalfa planting. Although multiple introduction experiments have been carried out in the past decade, the annual fresh grass yield has always hovered around 3 - 5 tons per mu and has not been able to break through the industrial planting threshold.

[0003] The main problems of the existing technology include:

[0004] 1. Improper variety selection: Failure to select heat-tolerant and non-autumn-dormant varieties, resulting in growth stagnation in the dry season and low yield.

[0005] 2. Unreasonable water management: Poor drainage in the rainy season is prone to waterlogging, affecting the survival rate of alfalfa, and insufficient irrigation in the dry season is prone to drought, resulting in low alfalfa yield.

[0006] 3. Improper sowing period arrangement: Sowing too late (such as after November), the root development of seedlings is poor, and it is difficult to resist the drought in the dry season.

[0007] 4. Extensive fertilization management: Insufficient base fertilizer and untimely top dressing affect the growth rate and regeneration ability of alfalfa.

[0008] 5. Improper mowing method: Mowing still at the budding stage in the rainy season, resulting in lodging and rot, and a large number of plants die.

[0009] Therefore, there is an urgent need for a high-yield cultivation technology of alfalfa that adapts to the climate characteristics of southern Yunnan to improve its survival rate and yield, so as to solve the problem of lack of high-quality forage in Yunnan Province. Summary of the Invention

[0010] In view of the above problems, the present invention provides a high-yield cultivation method for alfalfa in the rain-heat synchronous area in southern Yunnan Province. By optimizing variety selection, land preparation methods, water management, fertilization strategies and mowing systems, high and stable yields of alfalfa in the rain-heat synchronous area in southern Yunnan Province are achieved.

[0011] 1. Plot selection.

[0012] Select a plot with good drainage and convenient irrigation, and the groundwater level should not be higher than 1 meter. Sandy loam or light soil with good air permeability is preferred for the soil, and soils with relatively high viscosity need to be improved (such as by applying more organic fertilizers).

[0013] 2. Variety selection.

[0014] Select alfalfa varieties with strong heat resistance and non-fall dormancy, and the fall dormancy level ≥ 8 (such as WL525HQ, WL903, etc.).

[0015] 3. Sowing period arrangement.

[0016] The best sowing period is from mid-September to the end of October, taking advantage of the soil moisture at the end of the rainy season to promote the rooting of seedlings.

[0017] 4. Preparation before sowing.

[0018] Land preparation: Deep plow to 25 - 30 cm, rotary till to break up the soil, and improve soil air permeability.

[0019] Application of base fertilizer: Apply 200 - 300 kg of organic fertilizer or 1000 - 2000 kg of well-rotted farmyard manure per mu.

[0020] Ditching and ridging: The width of the ridge is 1.8 - 2.5 m, the width of the ditch is 30 cm, and the depth is 15 - 20 cm, which is convenient for drainage during the rainy season.

[0021] 5. Sowing techniques.

[0022] Sowing method: Drill sowing (row spacing 25 - 30 cm, sowing depth 2 cm) or broadcast sowing, and the seeding rate is 1.5 - 2 kg / mu.

[0023] Application of seed fertilizer: Apply 30 - 40 kg of calcium magnesium phosphate fertilizer + 5 - 10 kg of ternary compound fertilizer (N - P 2 O 5 - K 2 O = 15 - 15 - 15) per mu.

[0024] Rolling after sowing: Ensure that the seeds are in close contact with the soil to improve the emergence rate.

[0025] 6. Fertilization management.

[0026] Topdressing during the seedling stage: Depending on the growth vigor, apply 5 - 10 kg / acre of urea during the greening stage and the branching stage to promote growth.

[0027] Topdressing after mowing: Apply 5 - 10 kg / acre of ternary compound fertilizer after each mowing to accelerate regrowth.

[0028] 7. Weed control.

[0029] Weed control during the seedling stage: Spray 5% imazethapyr aqueous solution (130 g / acre) when the weeds are at the 2 - 5 leaf stage.

[0030] Weed control during the rainy season: Select 10% quizalofop - p - ethyl emulsifiable concentrate (60 ml / acre) + 25% fomesafen (40 ml / acre) for stem - leaf spraying.

[0031] 8. Water management.

[0032] Irrigation during the dry season: Water 1 - 2 times a week during the seedling stage to keep the soil moisture content ≥ 70%; irrigate in time when it is lower than 60% after mowing.

[0033] Drainage during the rainy season: Timely clean the drainage ditches to prevent waterlogging in the field.

[0034] 9. Mowing management.

[0035] Dry season (October - May): Mow from the budding stage to the early flowering stage, leaving a stubble height of 5 - 7 cm.

[0036] Rainy season (June - September): Mow when the plant height reaches 60 - 70 cm or mow immediately when lodging is found to avoid rotting and death.

[0037] The technical solution of the present invention aims at the special climatic conditions in the rain - heat synchronous area in southern Yunnan Province. By systematically optimizing each key link of alfalfa cultivation, it realizes low mortality and high and stable yield of alfalfa in this area.

[0038] Compared with the prior art, the present invention has the following advantages and technical effects:

[0039] 1. Breakthrough in variety adaptability.

[0040] Select non - fall - dormancy heat - resistant varieties with a fall dormancy level above 8 (such as varieties like WL525HQ), which solves the problem of the growth stagnation of traditional temperate varieties in the tropical monsoon climate in winter and spring, enables alfalfa to continue growing during the dry season, and increases the annual forage yield by more than 200%.

[0041] 2. Innovation in water management.

[0042] Drainage during the rainy season: Through the land preparation method of digging ditches and making ridges (ditch depth 15 - 20 cm, ridge width 2 m), the waterlogging rate in the field during the rainy season is reduced by more than 90%, and the mortality rate of alfalfa due to waterlogging is reduced from more than 50% in the traditional method to less than 5%.

[0043] Dry-season irrigation: Establish a management standard for soil moisture content thresholds (≥70% at the seedling stage and ≥60% after mowing), and cooperate with timely irrigation to ensure that the biomass accumulation rate in the dry season increases by more than 50%.

[0044] 3. Scientific optimization of the sowing period.

[0045] Limit the sowing period to mid-September to the end of October. Utilize the soil moisture advantage at the end of the rainy season to enable the seedlings to form well-developed roots (root length increases by 50%) before the dry season, with a survival rate of over 95%; and effectively suppress weeds at the seedling stage by sowing in autumn, reducing the cost of weed control.

[0046] 4. Dynamic fertilization system.

[0047] Construct a three-dimensional fertilization plan of "base fertilizer + seed fertilizer + growth topdressing + topdressing after mowing":

[0048] Use organic fertilizer (200 - 300 kg / mu or 1000 - 2000 kg / mu of well-rotted farmyard manure) as the base fertilizer to improve the soil structure;

[0049] Add calcium magnesium phosphate fertilizer (30 - 40 kg / mu) as the seed fertilizer to promote early root development;

[0050] Apply urea (5 - 10 kg / mu) as the growth topdressing to promote plant robustness;

[0051] Apply high-potassium compound fertilizer (5 - 10 kg / mu) after mowing to accelerate regeneration.

[0052] 5. Innovation of the rainy-season mowing system.

[0053] Change the traditional mowing mode at the budding stage. Adopt the mowing strategy when the plant height reaches 60 - 70 cm or when it lodges from June to September, avoiding death caused by stem and leaf rot, increasing the number of rainy-season harvests from 2 to 4 times, doubling the single-season yield, and reducing the rainy-season mortality rate to less than 5%.

[0054] Integrated weed control.

[0055] Implement precise control of different weeds at the seedling stage (imazethapyr) and in the rainy season (quizalofop-p-ethyl + fomesafen), with a weeding efficiency of over 85%, reducing the labor cost by 60% compared to traditional manual weeding.

[0056] 7. Soil improvement effect.

[0057] Combining the application of organic fertilizer with rotary tillage and soil preparation (deep plowing of 25 - 30 cm) improves the air permeability of the sticky red soil, creates a good environment for the roots, and reduces the incidence of root rot in the rainy season.

[0058] Applicable regions.

[0059] The present invention is particularly applicable to the southern part of Yunnan Province (such as Dehong, Honghe, Wenshan, Pu'er, Xishuangbanna, etc.) and similar climate regions with concurrent rainfall and heat, providing reliable technical support for the cultivation of alfalfa in the south. Brief Description of the Drawings

[0060] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic examples and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0061] Figure 1 It is a on-site picture of bed formation in Step 3.2 of Embodiment 1 of the present invention;

[0062] Figure 2 It is a on-site picture of emergence of sowing in rows in Step 4.1 of Embodiment 1 of the present invention;

[0063] Figure 3 It is a on-site picture of the field growth of alfalfa in Embodiment 1 of the present invention. Detailed Embodiments

[0064] The following combines the drawings of the embodiments of the present invention to elaborate on the technical solutions in detail. The described embodiments are only partial embodiments of the present invention and not all limitations. Based on the content of the present invention, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0065] Embodiment 1:

[0066] 1. Plot Selection and Variety Selection

[0067] 1.1 Plot conditions: Select sandy loam plots in the dam area of Dehong Prefecture, with the groundwater level below 1 meter and convenient drainage and irrigation.

[0068] 1.2 Variety selection: Select non-dormant alfalfa varieties (dormancy level ≥ 8), including: WL525HQ (heat-resistant, drought-tolerant, with strong persistence), WH656HQ (moisture-tolerant, lodging-resistant, with strong regeneration), WL712 (strong adaptability, resistant to diseases and pests), and Saidi 10 (high-yield and high-quality, with active growth in winter).

[0069] 2. Sowing Period Arrangement

[0070] 2.1 Optimal sowing period: From the end of September to the middle of October, avoiding the risks of flood in the rainy season and water shortage in the dry season.

[0071] 2.2 Adjustment principle: If there is continuous heavy rainfall, sowing can be appropriately postponed; if there is irrigation condition, the latest sowing can be extended to December.

[0072] 3. Preparation before Sowing

[0073] 3.1 Land preparation: After the previous crop is harvested, shallow tillage is carried out to kill the stubble; use a rotary tiller to deeply plow 25 - 30 cm to ensure that the soil is fine and level; apply 300 kg of decomposed organic fertilizer per mu and mix it evenly by rotary tillage.

[0074] 3.2 Ditching and bed formation: The width of the bed surface is 1.8 m, the width of the ditch is 30 cm, and the depth is 15 - 20 cm. For the actual situation of bed formation, see Figure 1 ; Use a medium-sized rotary tiller to complete the rotary tillage and bed formation operations at one time to improve efficiency.

[0075] 4. Sowing techniques

[0076] 4.1 Sowing method: Use a small-seed drill for strip sowing, with a row spacing of 25 cm, a sowing depth of 2 cm, and a sowing rate of 2 kg / mu. For the actual situation of alfalfa strip sowing emergence, see Figure 2 .

[0077] 4.2 Application of seed fertilizer: Synchronously apply per mu: 30 kg of calcium magnesium phosphate fertilizer (to promote root development); 10 kg of ternary compound fertilizer (to provide nutrients for seedlings).

[0078] 4.3 Rolling: Moderately roll after sowing (avoid when the soil is too wet) to ensure that the seeds are in close contact with the soil.

[0079] 5. Field management

[0080] 5.1 Weeding:

[0081] Seedling stage: Spray 5% imazethapyr (130 g / mu) when the weeds are at the 2 - 5 leaf stage;

[0082] High-incidence period of weeds in the rainy season: Select quizalofop-p-ethyl (60 ml / mu) + fomesafen (40 ml / mu) for foliar spraying.

[0083] 5.2 Water and fertilizer management:

[0084] Irrigation: Water 1 - 2 times a week during the drought in the seedling stage (reduce the irrigation frequency if there is sufficient rain), and keep the soil moisture content ≥ 70%; Immediately irrigate when the soil moisture content < 60% after mowing in the dry season.

[0085] Topdressing: Greening stage / branching stage: Topdress 5 - 10 kg / mu of urea; After each mowing: Apply 5 - 10 kg / mu of ternary compound fertilizer.

[0086] 5.3 Drainage in the rainy season: Timely clean the drainage ditch to prevent waterlogging in the field.

[0087] 6. Mowing strategy

[0088] 6.1 Dry season (October - May): Mow from budding to early flowering stage, leaving a stubble of 5 - 7 cm;

[0089] 6.2 Rainy season (from June to September): Cut when the plant height is 60-70 cm or immediately after the plant lodges, to avoid the decay of stems and leaves.

[0090] Figure 3 These are the field growth condition diagrams of several alfalfa varieties in Example 1 of the present invention. Figure 3 It can be seen that the alfalfa cultivated by the cultivation method provided by the present invention grows well.

[0091] Actual application effect: In the experimental base in Dehong Prefecture, Yunnan Province, after adopting this technology, the mortality rate of alfalfa due to waterlogging during the rainy season is <5%, and the survival rate during the dry season is >95%. It can be cut 9-11 times a year, with a fresh grass yield of 11-15 tons per mu per year and a dry grass yield of 2-2.5 tons per mu per year (see Table 1 for the grass yield details), with a yield increase of more than 200% compared to the traditional method. This technology has successfully broken through the climate restrictions of growing northern grasses in the south, providing reliable technical support for the development of the grass and livestock industry in the south.

[0092] Table 1. Annual grass yield of four alfalfa varieties in Dehong Prefecture for three consecutive years (unit: times / year, kg / mu)

[0093]

[0094] Precautions

[0095] 1. For sticky red soil, it is necessary to increase the application of organic fertilizer to improve the soil structure and increase the air permeability;

[0096] 2. After cutting during the rainy season, it is necessary to promptly clean up the stubble to prevent the breeding of diseases;

[0097] 3. When the number of rhizobia is small or the activity is insufficient, the proportion of nitrogen fertilizer in topdressing needs to be increased.

[0098] The above embodiments are only for illustrative purposes. In actual application, the parameters can be slightly adjusted according to local climate, soil and other environmental conditions. Any equivalent replacement or improvement within the technical framework of the present invention belongs to the protection scope of the present invention.

Claims

1. A high-yield cultivation method for alfalfa in the rainy and hot areas in southern Yunnan, characterized in that: The following steps are involved: (1) Site selection: Select a site with good drainage, convenient irrigation and a groundwater level no higher than 1 meter. The soil should preferably be sandy loam or light soil with good air permeability. (2) Variety selection: Choose non-fall dormancy alfalfa varieties with fall dormancy level ≥ 8; (3) Sowing period: from mid-September to the end of October; (4) Preparation before sowing: including land preparation, application of base fertilizer and furrowing and bed making; (5) Sowing: Use drill sowing or broadcast sowing, with a sowing rate of 1.5-2 kg / mu; (6) Field management: including weeding, water and fertilizer management, and mowing management.

2. The cultivation method according to claim 1, characterized in that In the step (4), the land is prepared by deep plowing of 25-30 cm and then rotary tilling to break up the soil; 200-300 kg / mu of organic fertilizer or 1000-2000 kg / mu of decomposed farmyard manure is applied as base fertilizer; the width of the furrows is 1.8-2.5 m, the furrow width is 30 cm, and the depth is 15-20 cm.

3. The cultivation method according to claim 1, characterized in that In the step (5), the row spacing is 25-30 cm, the sowing depth is 2 cm, and the sowing amount is 1.5-2 kg / mu; seed fertilizer is applied simultaneously during sowing, including 30-40 kg / mu of calcium magnesium phosphate fertilizer and 5-10 kg / mu of triple compound fertilizer; and soil is compacted after sowing.

4. The cultivation method according to claim 1, characterized in that: The weed control management in step (6) includes: spraying 5% imazethapyr aqueous solution 130g / mu when the weeds are in the 2-5 leaf stage; spraying 10% quizalofop-p-ethyl emulsifiable concentrate 60ml / mu + 25% fomesafen 40ml / mu in the rainy season.

5. The cultivation method according to claim 1, characterized in that: The water and fertilizer management in step (6) includes: maintaining soil moisture ≥ 70% in the dry season, irrigating when the soil moisture is < 60% after mowing; applying urea at 5-10 kg / mu during the greening and branching period; applying 5-10 kg / mu of triple compound fertilizer after each mowing; and draining water in time during the rainy season.

6. The cultivation method according to claim 1, characterized in that: The mowing management in step (6) includes: mowing from the budding to early flowering stage in the dry season, leaving 5-7 cm stubble; and mowing immediately when the plant height is 60-70 cm or lodging in the rainy season.

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