Application of plant growth regulators in soybean farming

The use of plant regulators helps control the growth rate of soybeans, prevent overgrowth, and improve the stress resistance and yield of soybeans. ‌
1. Improve nitrogen fixation ability
DA-6 (Diethyl aminoethyl hexanoate):
Soak the seeds with DA-6 at a concentration of 8-15 mg/L for 8 hours, and spray once at the beginning of flowering and pod-setting stages of the seedling stage to achieve the effects of improving germination rate, increasing the number of flowers, improving the nitrogen fixation ability of rhizobia, plump pods, increased dry matter, early maturity, and increased yield.

2. Reduce soybean flower and pod drop
Naphthalene acetic acid (NAA):
Spray the pods with 5-10 mg/L Naphthalene acetic acid solution during the peak pod-setting period of soybeans, which can regulate the transfer of photosynthetic products from leaves to pods, inhibit the formation of abscission layers, reduce flower and pod drop, and increase yield early.

3. Promote rooting
Use 1.8% Compound Sodium Nitrophenolates (Atonik) to prepare a 6,000-fold solution and soak soybean seeds for 3 hours, which has a good root-promoting effect.

Kinetin + Gibberellic acid
Soaking seeds with 3.5mg/L Gibberellic acid solution or 1mg/L Kinetin solution can effectively accelerate the initial germination speed of spring-sown soybeans at 10-15℃, significantly accelerate the growth rate of young roots, and increase the fresh weight and dry weight of young roots. The promoting effect of Gibberellic acid is particularly obvious. This shows that both solutions can transfer more substances stored in seeds to the developing seedlings. The promoting effect of these two solutions at 10℃ is greater than that at 15℃; at 25℃, there is no obvious promoting effect.

Uniconazole
Using 10mg/LU uniconazole to mix seeds or spray seedlings when cotyledons are open can significantly reduce seedling height, increase stem thickness, root length and number of fibrous roots, and significantly improve the root-crown ratio. However, after transplanting, plant height, number of leaves, survival rate and stem thickness increased, and the root-crown ratio still exceeded the control.

4. Increase yield
Forchlorfenuron (KT-30/CPPU)
Spraying 5-10mg/L KT-30 solution at the beginning of flowering can increase photosynthetic rate, protein content, total nitrogen content, and significantly increase yield.

Brassinolide (BRs):
It can increase the activity of nitrate reductase in soybean seedlings, increase the absorption and conversion of nitrate fertilizers, increase plant height and material accumulation, and improve crop resistance to adverse environments.

Triacontanol:
Triacontanol has application forms of milk powder, emulsifiable concentrate, suspension and microgranules, among which milk powder has stable efficacy. For foliar spraying, 0.5 mg/L of milk powder solution can be sprayed during the flowering period, which can make the leaves greener, improve photosynthesis and material accumulation, increase the fruit set rate and 100-grain weight, and mature a few days earlier. If other dosage forms are used, 0.5 mg/L of liquid medicine can also be used, and sprayed once at the beginning of flowering and once at the peak of flowering.

5. Preventing leggy growth and lodging
Paclobutrazol (Paclo)
Generally used for crops with vigorous growth, inhibiting cell elongation, reducing plant height, improving field density, preventing plant leggy growth and lodging; increasing the number of main stem nodes and stem thickness, increasing the number of effective branches and pods; deepening leaf color, increasing photosynthetic capacity, and promoting the transportation of photosynthetic products to grains, thereby increasing yield. Use it during the row closure period for spring soybeans and 100-200 mg/L during the flowering period for summer soybeans. If the soil is fertile and the plants are leggy, the concentration can be appropriately increased, but it should not exceed 300 mg/L.

Mepiquat chloride:
Spraying 100-200 mg/L on the leaves from flowering to pod setting can effectively inhibit plant height, promote pod setting, and increase yield.

Uniconazole:
Uniconazole can inhibit the biosynthesis of Gibberellic acid in plants, slow down the cell elongation rate, and has a significant inhibitory effect. At the beginning of soybean flowering, spray 30-50L of 50mg/L solution per 667㎡. After treatment, the plant height can be reduced, lodging resistance can be achieved, and the number of pods and yield can be increased.

Chlormequat Chloride (CCC):
It can promote the growth of soybean roots, improve the water absorption capacity of the roots, increase the accumulation of proline in the body, and enhance the plant's drought resistance, cold resistance, salt and alkali resistance and disease resistance. If 1000mg/L Chlormequat Chloride (CCC) is sprayed on the leaves during the flowering period, the stems can be made thick and strong, which can prevent lodging, increase the number of pods and grains, and significantly increase the yield.

Ethephon:
After being absorbed by the plant, Ethephon releases ethylene in the body, causing physiological changes, promoting fruit ripening, making soybean plants short and strong, and increasing yield. When soybeans have 9 to 12 leaves, use 40% ethephon water to prepare 0.3 to 0.5g/L Ethephonsolution, and spray 30 to 40L of diluted solution per 667㎡.

6. Improve stress resistance
abscisic acid:
abscisic acid is a plant hormone in plants. Its main physiological function is to induce plants to produce drought resistance, cold resistance, disease resistance and salt tolerance. For example, when the soil is under drought stress, abscisic acid can close the stomata of the leaves, reduce the transpiration loss of water in the plant body, and improve the plant's ability to resist drought. In the reproductive growth stage of soybeans, spraying the leaves with 2mg/Lab of abscisic acid can increase the number of soybean pods, grains and yields under moderate drought or non-drought conditions.