Analysis and Suggestions on the Current Status of Soybean Production in Huludao City

Soybean is one of the main crops in Huludao City and also a traditional crop. Soybean is both a protein crop and an oil crop. In recent years, soybean production has developed slowly, with no major breakthroughs. This article analyzes the current status of soybean production in Huludao City for reference.

1. Current status of soybean production. According to statistical data, from 1996 to 2005, the soybean planting area in Huludao City fluctuated considerably, hovering between 10,000 and 26,000 hectares. Among these, 2000 was the highest at 26,000 hectares, and 2005 was the lowest at 10,000 hectares. There were 5 years each in which the planting area exceeded 20,000 hectares and fell below 20,000 hectares. The soybean planting area accounted for about 11% of the total grain and soybean area. Soybean yield per unit was unstable; the lowest yield per unit was in 1999, only 613.0 kg/hectare; the highest yield per unit was in 2004, 2603.6 kg/hectare. Under normal circumstances, the yield per unit is 1700-2100 kg/hectare, which is at the lower-middle level in Liaoning Province.

2. Existing problems. (1) Slow variety renewal, with some varieties used for a long time. Soybean varieties are conventional varieties, and after a variety is bred it is often used for many years, with slow renewal. At present, there are more than 10 soybean varieties planted in the Huludao area, basically the Tiefeng series, Liaodou series, and Kaiyu series, including Tiefeng 29, Tiefeng 31, Tiefeng 35, Liaodou 15, Liaodou 16, and other old varieties such as Liaodou 10 and Kaiyu 10. Because they have been planted for many years, the seed characteristics have degenerated and disease resistance has decreased, resulting in low yields. (2) Excessive density. According to surveys, 50%-60% of soybean area has too many seedlings retained and excessive density, about 300,000-450,000 plants/hectare, seriously exceeding the suitable density. The reason is that under the traditional soybean planting method, the seeding rate is large, 120-150 kg/hectare, and no thinning is done after emergence. Excessive density causes the branches and leaves to close over, ridge closure occurs too early, ventilation and light transmission between plants are poor, photosynthetic efficiency decreases, causing a large number of flowers and pods to drop, and even lodging, resulting in reduced yield. (3) Little application of farmyard manure and unscientific fertilization. At present, the area of soybean receiving farmyard manure accounts for only 20%-30%, the area receiving chemical fertilizer applied with sowing is about 80%, and topdressing at the flowering stage accounts for only about 20%. During the soybean seedling stage, when the nitrogenous substances contained in the seed are exhausted and the root nodules have not yet begun nitrogen fixation, the plant may experience a short-term "nitrogen starvation period." If fertilizer is lacking at this time, seedling growth is inhibited, which is unfavorable for later nodule nitrogen fixation. At the late flowering stage, soybean nitrogen fixation reaches its peak. At the same time, because nitrogenous compounds in the soybean plant begin to flow in large amounts to the seeds, the rhizobia lack a supply of carbohydrates, and nitrogen fixation capacity begins to weaken. If fertilizer is lacking at this time, the impact on yield is relatively great. (4) Untimely pest control. Soybean aphids and red spiders occur relatively severely in most years. Because control is untimely and in some cases no control is carried out at all, severely damaged plants may have curled stems and leaves, disrupted physiological functions, poor root development, and plant development falling into a stagnant state, with branches and pods significantly reduced, causing about 10% yield loss each year. The soybean pod borer is the main pest affecting soybean yield and quality. In the late growth period, the larvae of the pod borer feed on the beans, causing insect-damaged beans. Each year only 50%-60% of the area is controlled. (5) Poor degree of large-scale production. High-quality varieties for dissemination and use are not planted according to regional planning, and large-scale production cannot be formed. High-protein and high-fat varieties are mixed with general varieties in planting, harvesting, storage, and sales, resulting in poor quality and high impurity content of commercial beans.

3. Development countermeasures. (1) Select high-yield and high-quality improved varieties and give play to their yield-increasing role. Excellent varieties are the main reason for increased yield. According to the results of introduction trials and demonstrations by agricultural technology extension departments, the main planted varieties in the Huludao area are Liaodou 15, Liaodou 16, Tiefeng 35, and Tiedou 37. (2) Implement equidistant dibbling and determine a reasonable density. Prepare the land finely and seize the suitable sowing period for sowing. The best sowing period is from April 25 to May 5. The reasonable density of soybean is intended to coordinate the development between individual soybean plants and the population, unify the contradiction between individual productivity and population production at a high-yield level, and obtain the highest population productivity. Different densities should be determined according to variety characteristics, soil fertility conditions, and management level. The planting form is pure sowing, with a row spacing of 50 cm, a hill spacing of 21.0-26.4 cm, and two seedlings retained per hill. According to trial results, the optimal density of Liaodou 15 is 177,000 plants/hectare, the optimal density of Liaodou 16 is 189,000 plants/hectare, and the optimal density of Tiefeng 35 is 162,000 plants/hectare. In production, according to the principle that fertile land is suitable for sparse planting and poor land is suitable for dense planting, and according to variety characteristics, it can be adjusted independently within a certain range. (3) Fertilize scientifically to meet soybean nutrient needs. Soybean is also a crop with relatively high fertilizer demand, and its absorption of the three elements nitrogen, phosphorus, and potassium continues until maturity. However, the nitrogen fixed by its rhizobia can only meet 1/3-1/2 of the nitrogen demand throughout the soybean growth period. Therefore, to obtain high yield, nitrogen fertilizer must be increased timely and appropriately, phosphorus and potassium fertilizers must be reasonably combined and applied, and trace element fertilizers must be sprayed. According to many years of trial results, the scientific fertilization formula is as follows: apply 15,000-22,500 kg/hectare of decomposed organic farmyard manure as base fertilizer, use 150-187.5 kg/hectare of nitrogen, phosphorus, and potassium compound fertilizer as seed fertilizer, topdress 45-75 kg/hectare of urea at the early flowering stage of soybean, and spray 0.225 kg/hectare of ammonium molybdate at the early flowering stage. (4) Control pests in a timely manner. Focus on controlling soybean aphids, red spiders, pod borers, and other pests. Soybean aphids generally occur in June and can be controlled by mixing 50 g of 40% dimethoate emulsifiable concentrate with poisoned soil or by spraying. For the soybean pod borer, the best control period is early to mid-August. Using 100 g of 80% dichlorvos emulsifiable concentrate to make 50 "slow-release cards" and hanging them evenly on the plants, or spraying 25% decis emulsifiable concentrate, can both achieve the control purpose. (5) Implement regionalized production and promote industrialized operation. Soybean has an irreplaceable role in the crop structure, and farmers have the habit and enthusiasm for planting it. On the one hand, a reasonable rotation system for corn, soybean, and other crops should be established. On the other hand, high-quality special-purpose soybean production bases should be established, with a certain region planting high-oil or high-protein varieties to ensure soybean quality grade. Through the leading role of processing enterprises, farmers plant corresponding special-purpose varieties, forming regionalized production bases for special-purpose varieties, and improving the overall market competitiveness of soybean.