Cultivation and management of spring sowing of rape

Rape, also known as rape, sowthistle, Cruciferae, Brassica plants, native to China, its stem color is dark green, such as cabbage, is a variety of cruciferous cabbage, flowers are yellow. In agronomy, a number of species with oily seeds in plants are collectively referred to as rape. At present, the main cultivation types of rapeseed are Brassica napus, Brassica napus and Brassica napus. Mainly distributed in Anhui, Henan, Sichuan and other places. Rape is rich in nutrition, in which vitamin C content is very high. Rape generally grows in places where the climate is relatively humid, such as southern China. Rapeseed also has many uses, such as rape flowers can be eaten when they are not in bud; rape flowers are also a beautiful scenic spot when they are in full bloom (Hanzhong City, Shaanxi Province, China); after the flowers have withered, rapeseed can extract oil.

Growth conditions of rapeseed

Temperature: rape is a crop that likes cold and has strong cold resistance. According to the experiment, the lowest temperature of seed germination is 4 ℃, which can emerge in 4 days under the condition of 20 ℃, flowering stage 15 ℃, pod development period 12 ℃, and the temperature difference between day and night is large, which is beneficial to flowering and pod development, and increases the accumulation of dry matter and oil.

Water: rape has a long growth period, a large vegetative body, and a large number of organs, so it needs more water. The requirements for water in each growth stage are as follows: the general soil moisture in the germination and seedling stage should be kept at about 65% of the field capacity; the flowering stage is 76% to 85% of the field capacity, and the pod development stage is 60% to 80% of the field capacity.

Fertilizer: it is determined that for every 100 kilograms of rapeseed produced, the ratio of nitrogen, phosphorus and potassium is 0.95, and the demand for the three elements is more than 3 times that of cereal crops. In addition, rape is sensitive to trace element boron, and the lack of boron is easy to cause flowers and unfruitful.

Soil: rapeseed is a straight-root crop with developed root system, deep main root, many branches and fine roots, which requires deep soil layer, good structure, rich organic matter, fertilizer and water conservation, loose and aerated loam soil, in weak acid or neutral soil, it is more beneficial to increase the yield and increase the oil content of rapeseed.

Cultivation and management of spring sowing of rape

After the beginning of spring, rape enters the period of vegetative growth and reproductive growth, at this time, it is very important to do a good job in field management. In the management of rape after the beginning of spring, the first thing is to re-apply bolting fertilizer.

After budding, rape began to change from vegetative growth to reproductive growth. At this time, the rape root system is developed, a large number of nutrients are absorbed, if the fertilizer is insufficient, it will affect the stem and leaf growth and flowering and fruiting, so it is necessary to apply more fertilizer. This is called bolting fat. Especially for Brassica campestris, because of its short flowering and fruiting period and poor fertilizer tolerance, bolting fertilizer should be applied earlier, and fertilizer should be applied to the field before bolting. It is not suitable to apply fertilizer after flowering to prevent green trees and diseases.

During the flowering period of rape, it is necessary to prevent stains. Rape needs a lot of water during bolting, and the agricultural proverb says, "if you want oil, the ditch water flows in February." If the lower rape leaves are found to wilt at noon on a sunny day, it should be irrigated with fertilization. When irrigating, it is necessary to pay attention to the wet state of the soil. It is not appropriate to pour too much water.

Field management

The main results are as follows: 1) do a good job of ditch drainage and reduce the humidity in the field.

2) remove the weeds in the field, remove the lower disease, old and yellow leaves in time and take them out of the field for centralized treatment, so as to reduce the number of diseases and insect pests.

Spring is the main season of rape diseases and insect pests, and the common diseases are white rust. The most suitable temperature for white rust is 10 ℃. The disease is most likely to occur when it is overcast and rainy in spring and poor drainage in the field, and rape is most susceptible to the disease at bolting and flowering stage. Rapeseed suffered frost injury, the disease resistance was weakened, the disease of early-maturing varieties was serious, and the increase of bacterial sources in continuous cropping rape field was also serious. In addition to selecting Brassica napus with strong disease tolerance. Strengthen cultivation management, pay attention to clearing ditches and drainage, and reduce field humidity. Do a good job in pastoral cleaning, thoroughly remove the disease and disability, and avoid continuous cropping with cruciferous crops. In the early stage of the disease, ① 75% chlorothalonil wettable powder was sprayed with 100g / mu and 60kg water; ② 80 mancozeb wettable powder was sprayed with 100g / mu and 60kg water; ③ 70 methyl thiophanate wettable powder was sprayed with 60g / mu and 60kg water. During the dry season, aphids often occur in large numbers. After discovery, 200 jin per mu is sprayed with 40% dimethoate emulsion at a concentration of 100%.

When sowing rape in spring, we should pay attention to the following points:

1. Sowing at the right time, according to soil moisture and ground temperature in March, pay attention to grasp the sowing time.

two。 Sowing: the average temperature of the day is stable at 2 ℃ and the soil is thawed for 5-6cm. Sowing quantity 500-800g/667m2. Diammonium phosphate 4-5kg/667m2, urea 1-2kg/667m2. So that the sowing rate is accurate and the seed is uniform, the sowing end is straight, the soil cover is tight, and there is no replay or omission.

3. The sowing depth should be controlled at a depth of 3 to 5 centimeters. Sowing quality reaches three evenness (row spacing, plant spacing and sowing depth)

4. Irrigation: the budding stage is the critical period of water in spring rape, especially in the flowering stage. Depending on the growth and field capacity of spring rape, it is generally irrigated twice. After bolting, rape was irrigated once before flowering, and running horse water was watered once at the later stage of flowering.