Cultivation measures of pollution-free asparagus in Northern Zhejiang Province

Cultivation measures of pollution-free asparagus in Northern Zhejiang Province

Northern Zhejiang is close to Shanghai, Suzhou, Hangzhou and other areas of the Yangtze River Delta, cultivated asparagus has a broad sales market. In addition, asparagus can promote human digestion, enhance appetite, has a high health care value. The yield of asparagus in northern Zhejiang is 1 000 ~ 1 400 kg/667 m ~ 2 and the income is 6 000 ~ 8 000 yuan / 667m ~ 2, which provides a new idea and direction for farmers to plant, and improves the agricultural industry chain.

1 Variety selection

Seed selection is the basic link for high yield of asparagus. Selecting asparagus varieties with high quality, high yield and resistance to diseases and insect pests can not only increase the yield of asparagus planting, but also reduce diseases and insect pests and improve product quality. Summing up the experience of experiment and demonstration in recent years, it is found that Grant, 308 and other varieties can be selected. it is characterized by early sprouting, fast growth, uniform rhizome thickness, compact head scales, full and thick green color, good commodity performance and high output value. In addition, its growing plants belong to the dwarf type, resistant to diseases and insect pests and lodging, and belong to both green and white bamboo shoots, which is an ideal variety for production at the present stage.

2 optimize the cultivation model

2.1 cultivation for shelter from rain in greenhouse

Stem blight is a common disease of asparagus, which can lead to asparagus death in serious cases. The original pathogen produced by the disease is fungal demi-phylum, which mainly acts on the stems and branches of asparagus. The pathogen spent the winter with conidia in the field where the plant grew, and produced conidia in the spring of the following year, in which 20-30 ℃ was the most suitable temperature for germination. The plum rain season with high temperature and humidity is the best stage of disease and spread. The use of greenhouse through rain shelter cultivation, can isolate the transport channel of water molecules.

2.2 Ridge cultivation

This cultivation method is to avoid the effect of stagnant water in the field on asparagus. Normally, 4 ridges with a length of 6 m and a width of 145 cm are suitable, and the deep operation ditch and drainage ditch with a depth of 25 cm are dug between the ridges. When transplanting, the seedlings are planted in the middle of the ridge, and the distance between each plant is 30 ~ 35 cm.

2.3 Micro-drip irrigation system

Due to the limitation of asparagus cultivation conditions, asparagus field should set up a good drainage and irrigation system, so that irrigation operation can be carried out under different conditions as far as possible to meet the planting conditions. Among them, the micro-drip irrigation system can gradually infiltrate water into the soil and reduce water evaporation and permeability, which helps to solve the problem of high humidity environment caused by traditional irrigation, and is not easy to preserve and absorb water. avoid high incidence of diseases and loss of fertilizer and water.

3 pre-broadcast preparation

3.1 sowing

24-48 hours before sowing, install the nutrient soil in the nutrition bowl in advance, cover it with thin film after watering thoroughly, and cover it tightly, so that the nutrient soil can be completely infiltrated into the breeding [2]. The film was lifted on the sowing day, and a hole 1 cm deep was pouted out with the help of a medium stick. The seeds were cultivated in a hole during sowing, and covered with nutrient soil 1 cm thick after sowing, and covered with film again the next day after sowing. If it is summer, cover the film with straw or straw, build the arch shed after a series of processes are completed, and cover the top with sunshade facilities to prevent rain

Washed away by water.

3.2 Seedling stage management

First of all, temperature. From the completion of sowing to the stage of seedling growth, the temperature in the pot soil should not be higher than 30 ℃, and the best temperature was 20-28 ℃ after emergence. Secondly, humidity. Irrigation in the early stage was relatively humid, dry and wet according to the need of water, and mainly dry when the growth height reached 10 cm. Finally, the cultivated land was treated. Asparagus is suitable for growing in sandy soil with deep and loose soil layer, rich in organic matter, low groundwater level, good drainage and irrigation performance and acid-alkali adaptation. However, the soil viscosity is serious in northern Zhejiang. Therefore, in order to meet the cultivation conditions of asparagus, the organic matter with heavier fiber, that is, mushroom residue, is selected as the soil improver to improve the local stickiness [Jishan Huayao].

4 field management

4.1 colonization

It is generally required that it can be planted between about 5 bamboo shoots. The seedlings with strong growth were planted in the furrow according to the classification, and the distance of each plant was 30 ~ 35 cm. The transplanted plants were evenly extended on the soil surface, compacted tightly with a cover, and then evenly mixed with 1 000.0 kg of water, added 40% of manure and 0.2 kg of asparagus green, shaken evenly and applied to the planting ditch, and covered with loose soil of 5-6 cm, similar to the shape of tortoise back [3]. It should be noted that the seedlings are planted with one end of the scale buds on the underground stem, and the buds are concentrated in the central position, scattered and symmetrical, so as to improve the yield and quality of asparagus.

4.2 fertilization management

Asparagus is a perennial crop, the planting years and management level are different, and the yield gap is large. Therefore, according to the actual soil fertility and yield level, fully consider the demand for fertilizer of asparagus, determine the scientific amount of fertilizer application, and achieve the purpose of improving yield and quality. The yield of normal 667m2 adult bamboo shoots was higher than 1 000.0 kg, and the application rates of nitrogen, phosphorus and potassium were 27.2 kg, 17.5 kg and 23.75 kg, respectively. According to the different characteristics of different stages of asparagus growth and development, three key fertilizers were applied every year.

4.3 watering management

Irrigation is the most important link, which controls the growth demand of stems and leaves, and ensures the good growth of young stems through timely drainage. After autumn, water was irrigated every 10 days to ensure the healthy growth of stems and leaves, prolong the time of nutrient accumulation, and the soil was irrigated with overwintering water before freezing. Pruning of stems and branches should also be reasonable, avoid being affected by diseases and insect pests, and reduce water evaporation.

4.4 stay the mother bamboo shoots and set up sparse plants.

4.4.1 the stem of spring mother is retained. Keeping the mother stem of spring is related to the high yield and success of summer bamboo shoots. The retention time of spring mother stem is generally determined according to the actual yield and age quality of spring bamboo shoots in the same year. Normally, it is from early April to late April. Rain Water's early sunny season was the best time for spring bamboo shoots to stay on the mother stem. About 3 biennial asparagus, 4 3-year-old asparagus and 5 4-year-old asparagus, no more than 8 asparagus at most. The strong buds were selected for keeping, and after leaving the mother stem, the weak branches, residual branches, diseased branches and weeds were removed in time, and topped when the pile was 1.5 m high.

4.4.2 the autumn mother stem is retained. Raise the mother stem of autumn hair and store enough nutrients to lay a high-quality foundation for the cultivation of spring bamboo shoots next year. The time of keeping the mother stem of autumn usually starts from the first ten days of August, and it is normal and uniform to keep 6 and 8 plants per plant (plate), scattered and distributed. Due to the large number of autumn mother stems and exuberant, it is necessary to clean up the pruning in time to remove thin, weak, diseased branches and weeds, so as to facilitate ventilation and light and reduce the incidence of diseases and insect pests. In order to avoid the occurrence of typhoon anti-lodging, timely improve the top driving, piling work, pull double-line construction.

(5) Disease and pest control

5.1 Stem blight

Generally, the disease occurs in the area of the main stem 30 cm from the ground, there will be infiltrating brown spots at intervals, and then gradually evolve into bluish gray or grayish brown, and synchronously expand into a diamond, and there are most disease spots connected into strips. The periphery of the lesion is reddish brown on the edge, and the depression in the middle is grayish brown, densely dotted with pointed dots. For the prevention and control of this kind of disease, the first thing is to choose the area with high terrain, dry and conducive to drainage for planting. Secondly, it is necessary to thoroughly clean the countryside, remove the diseased stems and burn or bury them; when fertilizing, control the amount of nitrogen fertilizer to prevent excessive growth. Pay attention to close observation in the process of daily management and prevention. Once this kind of disease is found, a certain proportion of methyl topiramate solution, Bordeaux solution and Dysenamine solution are used at the initial stage of the disease, spraying once every 7 days, two or three times continuously.

5.2 Rust, root rot and sclerotiorum

The occurrence of rust will affect the cultivation effect, so it is necessary to burn the diseased stem thoroughly, top the comb branch timely, improve the ventilation and light transmission condition in the field, reduce the field humidity, and use chlorothalonil solution and germicidal Dan to control in the early stage of the disease. Root rot will begin to rot in the local cortex of the stem, and the root will also be affected by this, causing the main stem to rot [4] until aging. In the seedling planting stage, carbendazim was used to infiltrate the roots for 15 min. Sclerotinia sclerotiorum often occurs in the young stem near the ground growth stage, first fade and gradually turn brown, and finally give birth to black mouse shit-like sclerotia, the control method is similar to stem blight.

5.3 insect pests

Including grubs, mole crickets, seed flies, golden needles and other types, 25% trichlorfon powder and 5 times fine soil can be used in the field, or 80% dichlorvos emulsion solution can be sprayed while fertilizing.

6 harvesting

The harvest time should be effectively adjusted according to the needs of the market, and the asparagus should be broken and pulled up together with the underground rhizome by hand during harvest, or the stubble should be harvested at 2 cm underground with a sharp knife. The harvest time is mainly concentrated in spring and summer, which can be divided into two times in the morning and afternoon. Harvest usually begins in early April and ends when the average quality of bamboo shoots decreases significantly. The spring mother stem began to be retained in late March before harvest, and the autumn mother stem began to be retained in early August.

Three or four years after planting, the harvest period is usually two or three months. Green asparagus young stems can be harvested when they reach 25 cm, while white asparagus young stems can be harvested at about 18 cm. In addition, according to the quality pricing requirements of the products in the market, they can only be picked when they grow 20-24 cm above the ground, and be harvested at 2 cm under the soil and sold centrally and graded.