Field Management of Cotton Bud stage

I. the reproductive characteristics of the bud stage.

Cotton bud period refers to the period from budding to flowering. It usually starts from late May to early June and lasts for 25-30 days. About 40 days after cotton emergence, when triangular buds up to 3 mm wide appear on the first fruit node of the first fruit branch on the cotton plant, it is called budding.

The emergence of buds marks the period from vegetative growth to vegetative growth and reproductive growth, but the vegetative growth is still dominant, mainly to expand the vegetative body. During this period, the dry matter accumulation of cotton plant increased continuously, and the carbon and nitrogen metabolism changed from nitrogen metabolism to carbon metabolism. Such as lack of fertilizer and water, nutritional growth is inhibited, carbon metabolism is not smooth, nutrients are too small, easy to cause premature senility. If there is too much nitrogen supply, too much sugar will be used to synthesize protein, resulting in excessive growth of nutrients, closed fields and poor ventilation in the lower parts, resulting in a large number of buds falling off. Because of the backwardness of bud, the nutrients originally transported to the middle and lower fruit branch buds are transported upward in large quantities, which further promotes the cotton plant to grow wildly, forming a vicious circle, unable to keep the early bud and sitting on the early bell, forming the so-called "high, big, empty".

The appearance of cotton plant at bud stage is as follows: compact plant type, stout stem, dense nodes, fruit branches extending flat around, large angle of birth, symmetrical distribution of internodes, moderate leaf size and large buds. If the plant type is loose, the stem is thick and the node is sparse, the fruit branch grows upward, the angle is small, the fruit branch is thin and the fruit node is long, the leaf is hypertrophy, the bud is small, and the bud is small. If the plant type is short, the stem is thin and the leaf is small, it is a weak seedling.

II. Field management

The management task of bud stage is to take fertilizer and water as the center, cooperate with mid-tillage, pruning, pest control and chemical control technology, coordinate the relationship between vegetative growth and reproductive growth, be strong but not crazy, steady but not decline, and steadily increase flower buds on the basis of strong seedlings and early emergence. The cotton field of water and fertilizer land is mainly controlled, and the dry and thin land is mainly promoted.

(1) Application of fertilizer and water

Fertilization in bud stage should not only meet the needs of strong trees, but also prevent excessive overgrowth, so as to apply steadily and skillfully.

In the northern cotton area, for the early maturing or barren cotton field, the fertilization effect is good at the bud stage; in the cotton field with sufficient base fertilizer and high density, the bud stage should be properly controlled, generally without the application of quick-acting nitrogen fertilizer, the fertilizer can be applied once at the early flowering stage; the medium fertility cotton field can be topdressing once at the full bud stage or early flowering stage, or twice at the early bud stage and early flowering stage. In the high-yield cotton field, under the premise of applying sufficient base fertilizer, organic fertilizer can be applied at the bud stage, which plays a great role in increasing yield.

The water demand of cotton in bud stage is relatively large, but in the northern cotton area, Rain Water is less in bud stage, coupled with serious evaporation, timely and appropriate watering plays an important role in increasing yield. In general, in order to alleviate the contradiction between the concentration of agricultural work in "three summers" and the use of water for summer seeds, high-yield cotton fields are often watered before wheat harvest; in order to prevent overgrowth, high-yield cotton fields often postpone watering, which can promote the root system and enhance the drought resistance of cotton plants. however, the watering time should be combined with the local climatic conditions.

(2) cultivating soil by ploughing

Mid-tillage at bud stage can resist drought and preserve soil moisture, eliminate weeds, promote root rooting and control overgrowth. The bud period requires ploughing 3-4 times to achieve "hoe after rain, hoe after watering, and grass hoe". The middle ploughing is deepened one by one, and the cotton field should be hoed deeply, up to 10-14 cm deep. Before the ridge closure, ploughing combined with soil cultivation, carried out in stages, ended before the arrival of the rainy season. The height of soil cultivation is about 17 cm. The advantages of soil cultivation are: small drought can preserve soil moisture, severe drought and furrow irrigation, good drainage, prevent cotton plant lodging, increase soil temperature, promote root development, inhibit weed growth, and so on.

(3) pruning

1. Remove leaf branches. When the cotton plant can clearly distinguish between fruit branch and leaf branch after budding, the leaf branch below the first fruit branch should be knocked off in time. The departure and retention of leaf branches and the number of leaf branches should be determined according to the density of remaining seedlings. For low density or dry and thin land, it can not be pruned completely, and when the leaf branch grows 1-2 fruit branches, it can be topped in time; in the stable cotton field with slightly higher density, 1-2 leaf branches can be retained, and then topped when the leaf branch has 1-2 fruit branches; for the cotton field with prosperous growth trend, all the leaf branches can be removed. The removal of leaf branches should be flexible and should not be forced. All in the ground, lack of seedlings to cut off ridges, can retain 1-2 leaf branches, the use of space more bolls.

2. Wipe the superfluous buds. In the leaf axils of the main stem and fruit branches, there are often buds that only consume nutrients and affect ventilation and light, which are called superfluous buds and should be removed in time. Wipe superfluous buds to achieve "buds but fingers, branches but inches, wipe a small wipe."

3. Go to Zaolai. For the mid-early maturing varieties and early sowing cotton fields, after the early buds are removed, the boll setting regulation and compensation ability of the cotton plant itself can be used to have the following effects: first, reduce the rotten bolls and stiff petals, and solve and slow down the premature senility. The second is to increase the number of Fu peach and early autumn peach, so that a large number of flowering period and the best boll setting period. The third is to increase the proportion of bolls in the inner circumference and middle fruit branches and increase the pre-frost flower. The fourth is to promote root development and root activity, prolong the functional period of leaves, and make cotton plants grow healthily.

There are many ways to get rid of early buds, usually when the cotton plant has 6-7 fruit branches. The effect of removing all buds of 2-3 fruit branches at the base is the best. This measure should be carried out in cotton fields with medium or above fertility and increase the application of flower and boll fertilizer.

(4) Prevention and control of diseases and pests

1. Disease. The bud stage is the peak period of Fusarium wilt of cotton. At present, there is no very effective prevention and control measures and agents for this disease. Only through agricultural measures to promote cotton seedlings strong roots and strong trees, increase resistance, prevent bacterial infection. Such as deep ploughing the land, increasing the application of organic fertilizer and potash fertilizer and so on.

2. Insect pests. With the planting of insect-resistant cotton, the bug bug has become the main pest. At this stage, the changes of insect situation in cotton field should be closely monitored and the initiative should be mastered. If black spots or brown spots are found on young leaves, they should be sprayed in time to prevent female adults from spawning and multiplying on cotton plants.

At present, pesticides such as lacewing bug (made in Tianjin), endosulfan, phoxim, malathion and so on have good control effect, and organophosphorus pesticides combined with pyrethroids pesticides are more effective.

(5) Chemical control at its discretion

For the prosperous and long cotton field, the lightweight control was carried out 1-2 times in the bud stage, each mu shrinking 0.3-0.5 grams per mu, which could maintain the stable growth of the aboveground part, promote the healthy growth of the root system, and be beneficial to the disease prevention of strong trees.