Why does planting second-generation seeds reduce production?

 Why does planting second-generation seeds reduce production?

Modern corn production uses the heterosis of the first hybrid to obtain high yield and stress resistance. Heterosis refers to the phenomenon that the growth potential, viability, fecundity, adaptability, yield, quality and other traits of the hybrids produced by the cross of two parents with different relationship traits surpass their parents. The opposite of heterosis is the so-called inbreeding decline. Due to the decline of inbreeding, the growth potential, viability, stress resistance and yield of the second generation of hybrids were significantly reduced compared with the first generation. Generally, the yield of the second generation of hybrids is reduced by more than 50% compared to the first generation.

 

2 What are genetically modified varieties?

Transgenic varieties refer to new varieties of maize cultivated by transgenic technology. Transgenic breeding is based on a pre-designed blueprint. With the help of laboratory operation technology, a specific gene of a certain organism is transferred to another organism, so that the latter can obtain new genetic traits in a targeted manner. Before genetically modified varieties are approved for use, they must pass the national safety evaluation of genetically modified varieties. My country has not yet approved genetically modified corn for agricultural production.

3

The benefits of deep plowing of corn fields in autumn?

Deep plowing in autumn can improve the physical and chemical properties of corn field soil, thicken the active soil layer, improve soil permeability, water storage and moisture retention capacity and fertility, which is conducive to root growth and expands the range of nutrient and water absorption. Deep ploughing also turns the pests and germs hidden in the soil to the surface to freeze to death or sun death to reduce pests and diseases.

4

What techniques should be mastered when returning corn stalks to the field?

(1) Crush in time. When the ears of corn are harvested or when the straw is recovered, crush them in time, and the crushing length should not exceed 10 cm, so as to prevent the soil from being too long and causing the soil to be unreliable.

(2) Increase the application of nitrogen fertilizer. Soil microorganisms need a certain amount of nitrogen to decompose crop stalks, so there is a problem of competing with crop seedlings for available nitrogen in the soil. Appropriate amount of nitrogen fertilizer should be added to speed up the decay of straw, so that it can transform effective nutrients as soon as possible.

(3) Plowing in time. After the corn stalks are crushed and returned to the field, they must be immediately rotary tilled or harrowed to eliminate stubble, and deep ploughing is required. The ploughing depth is 20-25 cm. Through plowing and capping, the problem of excessive soil pores caused by returning the straw to the field is eliminated.

(4) Return soil moisture to the field. The soil moisture status has become an important factor in determining the rate of straw decay and decomposition. If conditions permit, timely irrigation is required.

(5) Prevent and control diseases and insect pests. Prevent and control various pests and diseases in time, and do not return straw to fields on plots with serious corn borer and smut. Diseased straw should be burned or composted at high temperature before returning to the field.

5

What is conservation tillage?

It is a new type of farming technology compared to traditional farming.

Conservation farming includes four technical contents: ① Reform the traditional farming method of plowing the soil with the plow plow, and implement no-tillage or less-tillage. No-tillage means that no farming is carried out except for sowing. Less tillage includes subsoiling and topsoil tillage. Deep loosening loses the deep soil, basically does not damage the soil structure and ground vegetation, can increase the natural rainfall infiltration rate and increase the soil water content; ② Cover the ground with more than 30% of crop straws and stubble, while improving fertility , Use straw to cover the soil, root stubble to consolidate the soil, protect the soil, reduce wind erosion, water erosion and ineffective evaporation of water, and improve the utilization of natural rainfall; Compound operations such as pesticide application, soil covering and suppression, simplify the process, reduce the number of mechanical access to the ground, and reduce the cost; ④ Change tillage to control weeds by spraying herbicides or mechanical topsoil operations to control weeds.

6

What is corn no-tillage technology?

Refers to a kind of farming and corn planting technology that uses chemical weeding technology under suitable conditions, without plowing and raking the field, opening holes (ditches), fertilizing, and sowing directly on the previous stubble field.

7

How to overcome the difficulties of corn stubble soil preparation and poor soil preparation quality?

Before planting corn, the ground preparation should be based on the principles of finely crushing, leveling, moisture-preserving, and high-efficiency, and land preparation operations should be carried out in a timely manner to prepare for planting and seedling protection. After the corn is harvested, the soil preparation should be carried out when the soil moisture content is suitable (the moisture content of the soil layer of 10-20 cm is 15%-20%), and the large-scale rotary tiller is used to treat it again. If the required state is not reached, it can be used again. Comprehensive soil preparation machinery (deep loosening and shallow turning, heavy rake, leveling completed in one time) work once. After corn is harvested, the land is not prepared directly. For example, in the spring land preparation of spring corn in the north, the root stubble undergoes a long period of degradation, differentiation, precipitation and other processes, and the water content is low. It is based on comprehensive consideration of factors such as farming time, weather, soil and planting plan At the appropriate time before sowing, use a large rotary tiller to prepare the ground. If corn is planted with wide and narrow rows, there is no need to deal with the root stubble after the corn is harvested, and only the wide rows can be leveled with a rotary tiller. This way, autumn soil preparation is easier, the number of mechanical operations is small, the cost is low, and the effect is good. The specific method is: change the current uniform ridge (65 cm) into wide (90 cm) narrow (40 cm) row planting, and deep loosen the corn in the 90 cm wide row during the big bell-mouth period, and perform rotary tillage on the wide row after harvest. In the next season, only sown corn on the wide rows that have been rotary tilled. If soybeans are planted, sown both in the wide rows and in the narrow rows. Natural conditions and production conditions vary greatly from place to place, and should be flexibly controlled according to the situation.

8

Why can increasing density increase production?

The yield of corn is composed of the number of effective ears per unit area, the number of ears per ear, and the weight of a thousand kernels. Within a certain range, when the planting density per unit area increases, the number of effective panicles increases, and the number of grains per panicle and 1000-grain weight decreases. However, according to the variety characteristics and soil fertility conditions, the density has increased reasonably, and the number of panicles and grain weight is relatively stable or the decline rate is small. The significant increase in the total number of grains due to the increase in the number of ears has a large compensation effect, and ultimately increases the yield. The current prominent problem in corn production is the low planting density, which seriously affects the yield.

The principle of reasonable dense planting is that plots with high fertility can be planted appropriately, plots with low fertility should be appropriately dilute, and fertilizer should be kept secret; if water is sufficient, it can be planted appropriately, and water should be dilute, and water should be kept secret; early-maturing varieties should be properly densely planted and late-maturing Large ear-type varieties should be sparsely valued; sufficient fertilizers can be properly planted, and fertilizers should be sparsely valued if they are insufficient.

9

How to determine the row spacing of corn planting according to locality and variety?

The row spacing planting method of corn is an important adjustment way to improve the group structure and increase the utilization rate of light energy. Practice has proved that when the density increases, the appropriate planting method can be used to increase the yield of dense planting. The arrangement of corn row spacing varies with varieties and soil fertility levels. For the dense-tolerant varieties with small stem and leaf angles, upward rushing leaves, and deep root development, the row spacing should be narrower on the fertile plots; the row spacing for tall stalks and flat leaves should be wider. Generally, corn planting methods include horizontal sowing in equal rows, dense planting in wide and narrow rows, and ridge cultivation. The advantages of equal-row flat sowing are that the plants are evenly distributed and can make full use of light energy to produce more photosynthetic substances; wide and narrow row planting can improve the ventilation and light conditions of the group, which is convenient for field management and operation; ridge cultivation is beneficial to early corn sowing and seedling growth. In the rainy season, ridge cultivation is easier to drain than sitting flat; in drought, ridges and furrows can also be used for irrigation, which is conducive to centralized fertilization.

10

What are the key points of corn mulching planting technology?

(1) Grasp the whole seedlings. Film mulching planting must ensure that there are no weeds and root stubble on the ground, the topsoil is finely fragmented and soft, and the row spacing is moderate; it can be planted earlier than the open field with timely enough moisture, equidistant hole planting, shallow planting and thin cover, staggered planting fertilizer.

(2) Cover the film. The low-pressure polyethylene linear film with high light transmittance, good warming effect, strong tensile force, tear resistance, and not easy to aging should be selected. The quality of the film directly affects the effect of seedling emergence, moisture preservation and warming. To prevent the mulch from being damaged by wind.

(3) Apply enough fertilizer. Plastic film mulching makes it difficult to apply fertilizers, so it is necessary to apply foot fertilizers and increase organic fertilizers to meet the plant's greatest demand for nutrients throughout the life.

(4) Choose seeds. It is necessary to choose corn varieties with proper growth period, leaf upswing and strong stress resistance.

(5) Reasonable dense planting. Plastic film mulching planting density is generally 20%-40% higher than that of open field planting, depending on the characteristics of the variety, soil fertility and fertilization level.

(6) Medication to kill weeds. Weed control is the key. Before mulching, use chemicals to kill weeds, usually 38% Atlas 0.2-0.25 kg per mu plus 150-200 ml of acetochlor EC, 60 kg of water, spray evenly on the bed surface when the soil is dry, and immediately cover the film. .

(7) Prevent and control diseases and insect pests. Use seed coating to prevent and control underground pests, and choose high-efficiency and low-toxic pesticides to timely control the second-generation armyworm and corn borer.

(8) Strengthen management. For the corn field planted in the film, if it is sowed first and then covered with the film, the seedlings should be opened in time after the seedlings are ready to prevent high-temperature burning of the seedlings. Before placing the seedlings, let the air blow for 2 to 3 days, and then follow the principles of magnification and no small size, green and no yellow, assault out on cloudy days, and avoid noon on sunny days. After the seedlings are put out, the seedling holes should be sealed with soil. If it is mulching and then sowing, check it in time. When it is found that there are seedlings under the film, the seedlings should be lifted out of the film in time, and the seedling holes should be sealed tightly. For the corn field planted on the side of the film, sow as close to the film as possible. It is necessary to make full use of the advantages of planting on the side of the film, topdressing during the critical period when corn needs fertilizer, and give full play to the effect of increasing the yield of film-covered corn.

11

How to achieve high-yield and efficient water-saving irrigation of corn?

(1) Change the traditional corn irrigation method-ground irrigation. In the late 1980s, some new irrigation methods were promoted, such as horizontal border (ditch) irrigation, wave irrigation, and long border section irrigation, which greatly improved the water-saving effect.

(2) Sprinkler irrigation and drip irrigation. Sprinkler irrigation technology has the characteristics of high water delivery efficiency, strong terrain adaptability and improvement of the field microclimate, and can be combined with agricultural technical measures such as spraying and weeding, and has a good effect of saving water and increasing production. It is especially suitable for areas with insufficient water resources and strong water permeability. Drip irrigation is the use of drippers or other micro-water devices to directly transport water to the roots of crops, with high irrigation uniformity, and can be combined with fertilization and pesticide application. It is currently the most efficient water-saving irrigation technology.

(3) Apply other water-saving irrigation techniques. In the arid and semi-arid areas of Northwest my country, irrigation with membranes is used. Different from the general irrigation method, the irrigation on the film is to transport the water through the mulching film, and infiltrate the corn root system through the seedling hole. As the water flow resistance of the mulching film is small, the irrigation speed is fast, and the deep leakage is less. Moreover, the mulching film can reduce the evaporation between trees, and the water saving effect is remarkable. In Xinjiang, Shandong, Jiangsu and other sloping fields without irrigation conditions, dish irrigation can be used. Dish irrigation is to use unglazed clay pots to store water. The pot is buried in the soil, and the mouth of the pot is lower than the field surface. It is usually tied with a lid with a hole or a plastic film to prevent the water from evaporating in the pot. You can add water to the tank, or you can collect rainfall.

12

For non-irrigated dry fields and drought from sowing to seedling, how to achieve drought resistance, seedling protection, and root increase in yield?

(1) Choose drought-tolerant varieties. Breeding and popularizing drought-tolerant varieties is the main way to increase crop yields under drought conditions.

(2) Reasonable fertilization. Increasing the application of organic fertilizer is not only full of nutrients and long-lasting fertilizer, but also improves the soil structure, coordinates water, fertilizer, gas, and heat, plays a role in regulating water with fertilizer, and is therefore an effective measure to improve the ability of soil to store water and maintain moisture. The best method of fertilization is to apply all nitrogen, phosphorus, potassium and organic fertilizers at one time, which is not only good for moisture retention, but also good for fertilizer infiltration, attracting roots, and increasing the drought tolerance of crops.

(3) Deep plowing and meticulous cultivation to absorb rain and protect moisture. Reconstructing sloping farmland with soil water storage and carrying out mechanical tillage and deep plowing are important measures to absorb rain and preserve moisture. In practical applications, we should insist on early harvest and early plowing to preserve moisture, deep plowing and fine raking, and fine land preparation.

(4) Sowing early at the right time to cultivate strong seedlings. According to the growth habit of the crop, after entering the suitable sowing period, the seedlings should be sown without waiting for water, fertilizer, and time. When drought is encountered, mechanical furrow sowing can be used to prevent dry seeding and wet seedlings. Make full use of the effective accumulated temperature, light and soil moisture to ensure early rooting of crops and form strong seedlings to improve drought tolerance.

13

How to prevent empty stalks in corn?

(1) Choose improved varieties. If there are problems with the internal factors of corn seeds, after sowing, empty stalks cannot be prevented, which will inevitably cause losses. Therefore, we must check the seed selection. At present, there are many corn hybrid varieties that are suitable for planting in various places. You should choose the best from the best and buy from the reputable seed department. You should not buy cheap, inferior or even fake seeds.

(2) Reasonable dense planting. The planting density of corn should be determined according to the ground, fertilizer, and species.It is best to use wide and narrow rows for planting.

(3) Strengthen the management during the growth period of corn. If it is time for seedlings and fixed seedlings, choose strong seedlings; do a good job in cultivating and weeding; seriously prevent and control diseases and insect pests; increase fertilizers, especially for fields with low soil fertility, should reapply basal fertilizers, and topdressing should be heavier and lighter, nitrogen, phosphorus, In combination with potassium, micro-fertilizer should also be applied appropriately, zinc sulfate 0.5-1 kg per mu; reasonable irrigation, controlled watering during the seedling stage, and appropriate irrigation at the right time after jointing, etc.

(4) Implement artificial auxiliary pollination. Before flowering, emasculation can be performed alternately. If the bracts are too long, the top 3-7 cm can be cut off to make the filaments emerge early and increase the chance of pollination.

(5) Topdressing young ear differentiation fertilizer and attacking ear fertilizer. The time is 5 to 7 days before the growth and development of the plant enters the fetus and the ears, so as to raise the fetus.

14

How to prevent corn from being bald and missing seeds?

The lack of corn kernels is closely related to variety, soil, fertilizer and water, climate, cultivation management, pests and diseases.

The main countermeasures to prevent baldness and lack of granules are:

(1) Plant good varieties. Plant disease-resistant, insect-resistant and adaptable varieties.

(2) Improve the soil and enhance the ability of soil to retain water and fertilizer. Advocate the use of fermented compost and deep tillage and intertillage techniques to improve the soil structure, promote the growth and development of corn, and enhance the resistance of corn to adverse environments.

(3) Reasonable water for fertilization. It is necessary to increase the application of organic fertilizers, combined with the application of nitrogen, phosphorus, and potassium, to prevent the lack of phosphorus and boron fertilizers in the field; to prevent drought and waterlogging disasters, the water supply after the jointing of corn should be timely and appropriate to promote the development of male and female ears.

(4) Strengthen cultivation management. ① The density should be determined according to the variety, soil fertility and planting method, in order to create good ventilation and light conditions, meet the light requirements of the middle and upper leaves, and promote the development of female ears. ②Strengthen cultivating weeding and soil cultivation. ③ Use wide and narrow ridge planting techniques to improve the ventilation and light transmission conditions in the field. ④ When encountering bad climatic conditions that affect normal pollination, artificial auxiliary pollination technology should be adopted.

(5) Strengthen the prevention and control of plant diseases and insect pests.

15

How to prevent corn lodging?

(1) Choose short-stem lodging resistant varieties.

(2) Properly deepen the ploughing layer, promote the development of the root system, increase the number of roots and the depth of soil.

(3) Nursery and transplant. After the slow seedling period, the stems are firmer and stronger.

(4) Squat seedlings on the fat ground. In fields with higher water and fertilizer, control the water and fertilizer to squat the seedlings before the joints to promote roots and stalks.

(5) Reasonable dense planting. Usually, there are 4500 seedlings per mu for compact varieties and about 3,500 for flat varieties.

(6) Implement nitrogen, phosphorus, and potassium formula fertilization.

(7) Chemical control. Spray anti-lodging regulators such as Jindele or Kangfengli according to the medication instructions.

(8) Control corn borer, stem rot, etc.

16

Why should corn be chemically regulated?

Generally, corn varieties are prone to lodging when the density exceeds 4500 plants/mu. Applying chemical control technology, spraying 300 microliters/liter of Kindle or Zhuang Feng Ling on the leaf surface of the corn at the jointing stage can reduce the corn vegetative body, thin stalks, and resist lodging without changing the corn. Ear traits, the purpose of constructing high-yield populations.

17

What are the key links to increase corn production?

In order to obtain high yields of corn, the following two links should be paid attention to and seized:

One is to prevent the problem of base fertilizer from burning buds during the seedling stage.

High-nitrogen compound fertilizer should not be used as base fertilizer, and urea should be used with caution to prevent burning buds and roots.

The second is to prevent the problem of defertilization in the later stage.

Corn is the best