Detailed Explanation of the Key Technical Points of Scientific Cultivation and Management of Alfalfa

Alfalfa is the general term for plants of the genus Medicago, commonly known as “clover” (clover may also refer to other plants of the tribe Trifolieae). It is a perennial flowering plant. The most famous among them is alfalfa (Medicago sativa), which is used as forage. It is livestock feed.

Morphological Characteristics of Alfalfa

Annual or perennial herbs, rarely shrubs, without aromatic herbaceous odor. Pinnately compound leaves, alternate; stipules partly fused with the petiole, entire or dentate; leaflets 3, margins usually serrate, lateral veins extending straight to the tooth tips. Racemes axillary, sometimes capitate or solitary, flowers small, generally pedicellate; bracts small or absent; calyx campanulate or tubular, calyx teeth 5, equal in length; corolla yellow, alfalfa and other hybrids often purple, violet-blue, brown, etc., standard obovate to oblong, narrow at the base, often reflexed, wings oblong, with a tooth-like protrusion on one side that hooks onto the auricle of the keel, separating after pollination, keel blunt at the tip; stamens diadelphous, filaments not enlarged at the tip, anthers uniform; style short, conical or linear, slightly flattened on both sides, hairless, stigma terminal, ovary linear, sessile or short-stalked, ovules 1 to many. Pod spirally coiled, reniform, falcate, or nearly straight, longer than the calyx, dorsal suture often with ridges or spines; seeds 1 to many. Seeds small, usually smooth, more or less reniform, without a strophiole; cotyledon base of emerged seedlings not enlarged, and without a joint.

Scientific Cultivation and Management Techniques for Alfalfa

I. Land Preparation

1. Site Selection: Choose first- and second-class land with relatively good soil fertility and complete irrigation facilities for planting. Planting on barren soil or plots without irrigation facilities can only serve as an agricultural measure for improving and fertilizing the land, and cannot achieve satisfactory benefits. Plots that are low-lying and prone to water accumulation after rain cannot be planted, as alfalfa will suffocate and die after being soaked in water for 48 hours. In terms of planting, emphasis should be placed on large contiguous areas, so as to facilitate various mechanical operations.

2. Land Preparation

1) Alfalfa is a perennial leguminous forage, and generally a rotation period of 5-6 years is relatively reasonable. Therefore, before sowing, deep plowing, harrowing, and compaction should be carried out to meet various requirements, so as to facilitate seedling emergence after sowing.

2) The land should be leveled well, requiring a level surface, without pits and unevenness, so as not to affect mechanical harvesting and baling operations and the income of growers (uneven land will result in excessively high stubble and incomplete pickup during harvesting and baling).

3) For plots with severe weed growth, spray the ground with trifluralin (100 mL/mu) 7-10 days before sowing to reduce weed damage. For perennial root-sprouting weeds that are difficult to kill, spray with paraquat, glyphosate, and 2,4-D before sowing.

4) Fertilization: Alfalfa has a well-developed root system and roots deeply, so before planting, in combination with land preparation, deeply apply 1-2 cubic meters of farmyard manure per mu, 50-100 kg of superphosphate as base fertilizer, or 30 kg of diammonium phosphate and 20 kg of urea.

5) For irrigated land without sprinkler irrigation facilities, according to the mowing width of the mower, combine land preparation with ridging and diking to facilitate future field irrigation. Currently, the mower width used is 2.5 meters.

II. Sowing

1. Sowing Time

Alfalfa can be sown in spring, summer, and autumn, but autumn sowing is the best. In autumn sowing, there are fewer weeds and sufficient soil moisture, which is conducive to seedling emergence and root growth. The optimal period is August 10-15, and the suitable sowing period is before September 15.

2. Sowing Method: Use mechanical drilling, with a suitable row spacing of 30 cm, to facilitate intertillage and weeding, and topdressing fertilizer.

3. Seeding Rate: Generally 0.6-0.7 kg/mu (the germination rate of the seeds must be above 95%). Too large a seeding rate will affect the population growth of the field, resulting in thin and weak seedlings. In order to make it easier to control the seeding rate, sieved diammonium phosphate or monoammonium phosphate can be mixed with the seeds for sowing.

4. Sowing Depth: Generally 0.5-2 cm. For soil with greater clay content, it should be shallower, with the aim of achieving full and good seedling emergence.

III. Field Management

1. Intertillage and Weeding

In order to ensure the quality and purity of alfalfa forage, meet the required standards of commercial hay in domestic and international markets, as well as the direct economic benefits of growers, field management of intertillage and weeding is particularly important. Therefore, at all stages of alfalfa growth, intertillage and weeding must be carried out in a timely manner, ensuring no weeds in the field, and ensuring the quality and requirements of procurement and export (weed content below 5%).

2. Topdressing

Each year after green-up and after each harvest, according to soil fertility and the amount of base fertilizer, apply 2.5-5 kg of urea, 2-4 kg of potassium chloride, and 10 kg of phosphate fertilizer per mu. This ensures the growth needs and yield requirements of the next crop.

3. Irrigation

In order to improve alfalfa yield and achieve the goal of high quality, high yield, and high efficiency, according to precipitation and field conditions, in combination with topdressing, timely apply overwintering water and green-up water. After each harvest, irrigation should also be carried out in a timely manner to promote regrowth.

4. Seedling Inspection and Resowing

After emergence, promptly inspect the seedling situation. Where missing seedlings or gaps are found, resow in a timely manner. The resowing method mostly adopts resowing after rain.

5. Pest and Disease Control

The common pests of alfalfa mainly include: aphids, thrips, cutworms, cotton bollworms, etc., but in general years they do not cause damage. Under special natural conditions, if pests occur, targeted control will be carried out according to the actual situation. For rodent damage, control can be carried out by combining irrigation with baiting and plugging holes.