Alfalfa Planting Time, Technical Key Points and Field Management Methods

AbstractPlanting time: divided into spring sowing, summer sowing and autumn sowing. Spring sowing is from late March to early April each year, summer sowing is from June to July each year, and autumn sowing is from late August to early September each year. Site selection: it is advisable to choose first- and second-class land with good soil fertility and complete irrigation facilities for planting. Land preparation: before sowing, plow deep, harrow and compact to facilitate emergence after sowing. Fertilization: apply base fertilizer before planting. Irrigation amount: frequent irrigation is not advisable during the growing period, as it will cause root rot. Weeding: alfalfa is easily harmed by weeds, so chemical weeding is needed.

Alfalfa is a forage grass with relatively large current market demand, so the number of people who need alfalfa planting techniques is also constantly increasing. When planting alfalfa, mastering the growth habits of alfalfa is very important, so the most intuitive method is to choose a time suitable for planting alfalfa and act on the experience of predecessors.

Alfalfa Planting Methods

1. Site selection and land preparation

1. Site selection: choose first- and second-class land with 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 to improve the soil and increase fertility, and cannot obtain ideal benefits. Plots that are low-lying and prone to water accumulation after rain cannot be planted, because alfalfa will suffocate and die after being soaked in water for 48 hours. In planting, emphasis should be placed on large contiguous areas to facilitate various mechanical operations.

2. Land preparation

① Alfalfa is a perennial leguminous forage grass, and a rotation period of 5-6 years is generally more reasonable. Therefore, before sowing, plow deep, harrow and compact to meet various requirements and facilitate emergence after sowing.

② Level the land well. The ground surface is required to be level and must not be full of pits and bumps, so as to avoid affecting mechanical harvesting and baling operations and the income of growers (uneven land will lead to problems such as stubble being too high 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 harm. 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, and 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 ridge raising and border building to facilitate future field watering. At present, the width of the mower used is 2.5 m.

Alfalfa Planting Time

Alfalfa seed germination requires two conditions: first, the ground temperature is 5°C-6°C, and the optimum temperature is within 25°C; second, more water is needed. Spring sowing and autumn sowing give the best results. Slightly saline-alkali plots are not suitable for spring sowing, as it easily causes dead seedlings.

① Spring sowing. In spring, sowing should be done before Qingming (late March to early April). At this time, soil moisture is high, and full stands are easy to obtain. If too late, it coincides with spring drought and emergence is difficult.

② Summer sowing. Generally in June-July. During this period, temperatures are high and there is more rain, so seedlings grow quickly, but there are also many weeds and frequent outbreaks of diseases and insect pests.

③ Autumn sowing. Generally in late August to early September. During this period, after the rainy season, soil moisture is good, the temperature is suitable, weed growth slows down, and the sowing success rate is the highest. No matter which sowing method is used, it should be combined with rain or irrigation; after rain is best. After sowing, press the soil to facilitate seed germination.

Field Management of Alfalfa

1. Irrigation amount

Alfalfa has luxuriant stems and leaves and a large transpiration area, so its water requirement is greater than that of general crops. Generally, the annual irrigation amount for alfalfa is about 250 cubic meters per mu, and a single irrigation amount is about 80 cubic meters. When the irrigation amount for alfalfa is 50-60% of the soil saturated water-holding capacity, alfalfa growth is most suitable. As for irrigation frequency and timing, before alfalfa fully turns green, water once for greening. From the bud stage to before flowering, water once. In addition, after each cutting, irrigation must be carried out (this is especially important on saline-alkali land). Frequent irrigation is not advisable during the growing period, because purple alfalfa is afraid of water accumulation; if there is water accumulation, it will cause root rot.

2. Weed control

Perennial alfalfa grows extremely slowly in the early stage and is easily harmed by weeds. Manual weed control is labor-intensive and time-consuming, and the effect is not ideal, so at present chemical weeding is mainly used. Types of weeds: there are many weeds that harm the growth of perennial alfalfa. Some weeds have a certain range of harm to forage grass, while dodder is seriously harmful to purple alfalfa and should be controlled as a priority. Chemical control. Chemical herbicides are divided into two major categories according to their action: one is selective herbicides, and the other is non-selective herbicides. Selective herbicides only kill weeds and do not harm forage grass or crops, such as 2,4-D, simazine, oxyfluorfen, etc.; non-selective herbicides make no distinction between good and bad and kill everything they contact, such as diuron, penta◇◇glyphosate, etc. Only after 20-30 days of spraying herbicides can grazing or cutting be carried out, so as to avoid poisoning accidents.

Harvesting Methods of Alfalfa

The daily average change in alfalfa feed quality is very large, such as crude protein, acid detergent fiber, neutral detergent fiber, etc. In the United States, we commonly use a forage quality ruler. The ruler is marked with measurement indicators such as pH, and through this ruler we can measure from the soil surface the most suitable harvest height for alfalfa. During measurement, we must measure from the soil surface to the plant stem tip, not to the tip of the highest leaf. In each sample plot, estimate 4-5 points; the tallest stem is not necessarily the best maturity.

In addition, it is best to use wide swath cutting. The advantages of wide swath cutting are faster drying speed, reduced respiration loss, and higher harvested forage quality. After cutting, respiration will still continue until the forage is air-dried to 60% moisture content, and during respiration starch and sugar decompose, producing carbon dioxide, with dry matter loss of 2-8%. During the alfalfa drying process, the initial 20% decrease in moisture is carried out through transpiration via the opening of stomata on the leaf surface.

Different bales have different moisture contents. Small bales (3 feet X 3 feet) safe moisture content <20%; medium bales safe moisture content <16%; large bales (4 feet X 4 feet, 1.2 m x 1.2 m) safe moisture content: <14%. For dry storage, we should note that a portion of hay additives can be added, such as desiccants and preservatives, thereby increasing the humidity range for safe storage; mold easily grows at 20%-35% humidity. Hay storage needs to be under a controlled or inhibited process.

During the harvesting process, the mower causes an additional 2-3% field loss to alfalfa. The loss is entirely in the leaves, so forage quality is significantly reduced. We can often see processing in which stems are crushed to facilitate drying.

To grow alfalfa, one must master alfalfa planting time and planting techniques. At the same time, field management of alfalfa and effective harvesting of alfalfa are also important factors in ensuring alfalfa production benefits, and are important links that all alfalfa growers must not ignore.