Henan Science and Technology Report Flood Prevention and Disaster Relief Series Science Popularization No. 17 - How to ensure that carrots emerge early and seedlings in autumn after heavy rains

Carrot seeds have the characteristics of slow germination and late emergence, and the autumn carrot sowing time is the high temperature and rainy season in most parts of our province, and recently, most areas of Henan have suffered heavy rains, resulting in water accumulation in farmland and damage to vegetables. At present, it has entered the suitable sowing period of carrots, and some growers have completed sowing, and the rain washes away or the growers do not take effective measures when sowing, which can easily lead to no seedlings, late emergence of seedlings, lack of seedlings and ridges, uneven emergence of seedlings, etc., resulting in low yields and even planting failures. Therefore, how to ensure that autumn carrots and carrots emerge early after heavy rains is the key to high yield and high efficiency in autumn carrot production. The following should be done:

Timely drainage after heavy rain: After the rainstorm, in the case of maintaining safety, ditch and drain in time, try to let the rain flow down the ridge ditch, avoid staying in the field for a long time and cause water staining, and spray 5mg/L copper sulfate or 1%0 potassium permanganate on the ground to prevent algae growth.

Replanting after rain: the field block that has been sown by carrots has been completed at present, after the rain, according to the impact of heavy rain on the sown ridge surface of carrots, if the seedlings have emerged and there is no broken ridge phenomenon, replanting in time according to the emergence of seedlings, and the seedlings have not yet emerged and the ridge panel knots or ridge surfaces are broken by rainwater, re-plough the land, break the surface plate knots, ridges, and replant, the specific measures are as follows:

Fresh seeds are selected

Due to the formation and structure of carrot seeds (its seed is leathery and poorly permeable; the embryo is small and the ability to unearth is poor; due to the climatic influence of flowering sequence and flowering, some seeds are often embryoless or embryonic stunted), the germination rate is low, generally only about 70%. If it is a mature seed, the germination rate will be lower, often causing a large number of seedlings to be missing and affecting the yield, and the fleshy roots of the plant grown by the old seeds are easy to produce branches. Choosing fresh seeds can avoid this. New seeds can be distinguished by smelling and observing the color of the seeds: the new seeds have a spicy fragrance and the seeds are white; the seeds are not spicy, and the seeds are yellow or dark yellow. Carrot seeds generally have a lifespan of 5 to 6 years, while the application period is 2 to 3 years.

seed treatment

When purchasing seeds, try to use treated light seeds, if it is a hair seed, first rub off the thorns on the seed when sowing, so that the seeds can be in close contact with the soil, absorb more water, and facilitate germination. At the same time, select sunny days for 1 to 2 days before sowing, which can improve the germination potential and germination rate of seeds.

Dip the seeds to germinate

In most cases, carrots are directly seeded, and the whole seedling is guaranteed by a large amount of sowing. Soaking and germination can improve the seed germination rate and accelerate the emergence of seedlings. The method is to soak the seeds in warm water of 40oC for 2h, wrap them in gauze after the water comes out, put them in 20oC~25oC conditions to germinate, and the seeds can be sown after 2~3 days.

Fine land preparation

The plot for planting carrots should be sandy loam or loam, deep ploughing fine rake, ploughing depth is not shallower than 25 to 30 cm, thin rake 2 to 3 times, the ground is leveled, and then made into a furrow of 1.2 to 1.5 meters wide or a ridge width of 40 to 50 cm. With the preparation of the land per mu, 4000~5000kg of fully decomposed organic fertilizer, 50kg of ternary compound fertilizer or 20~25kg of calcium superphosphate + 25~30kg of potassium sulfate are applied. If you have the conditions, it is best to use no-till strip sowers to no-till again, so that the soil is fully crushed.

Suitable for sowing

According to the soil moisture, one method is to fully irrigate the land before preparing the land, and sow the seeds when the moisture is suitable; the other method is to directly prepare the land for furrow or ridge sowing, and then fully irrigate the water to meet the water demand of carrot seeds. After sowing, pay attention to watering, and ensure that the soil does not dry before emerging.

Cover the greens for shade

Carrot seeds emerge slowly, and green cabbage seeds emerge quickly. When sowing, a small amount of green cabbage seeds can be mixed with sowing, using the characteristics of early emergence and rapid growth of green vegetables for shading, and pulling vegetables on the market in time after carrot emergence can not only play the role of shading seedlings, but also improve land utilization and increase income.

Cover grass moisturizing

After sowing, wheat straw is covered on the furrow or ridge surface, which has the effect of preserving moisture, cooling, preventing heavy rain erosion, soil compaction, which is conducive to seedling emergence.

Chemical weeding

Carrots are generally planted with a large density, and the sowing period is the high temperature and rainy season, there are more weeds, faster growth, artificial weeding is more difficult, and there are many flowers, sometimes due to untimely weeding and the formation of grass shortages, affecting the emergence of seedlings and seedling growth, so it must be weeded in time. The application of chemical herbicides eliminates the need for manual weeding. After sowing, use 50% grass net 100g per mu, spray with 69 to 75 kg of water, can remove a variety of annual weeds; 25% of the herbicide ether 0.75 to 1 kg per mu, diluted with water 100 to 200 times sprayed; per mu with 33% field emulsion oil 100 ~ 150ml, mixed with water 40 ~ 50 kg, after sowing seedlings sprayed on the surface; after emergence with cover grass can be sprayed, can prevent the removal of single leaf weeds.

(Zhengzhou Vegetable Research Institute Potato Project Wu Huanzhang)