What causes green-stay in soybeans? A detailed explanation of the causes and prevention methods
Green-stay in soybeans is a phenomenon that appears when soybeans enter the maturity stage, and it can seriously affect soybean yield and quality. So what causes green-stay in soybeans? How can it be prevented? Follow along with the editor to learn about the causes of green-stay in soybeans and the preventive measures.
I. Causes of green-stay in soybeans
1. Improper variety selection
Soybean varieties differ in pod-setting habit, and the degree of green-stay also differs. Varieties with an indeterminate pod-setting habit show more severe green-stay, while conversely, varieties with a determinate pod-setting habit show milder green-stay. This is because determinate pod-setting varieties shift to reproductive growth after vegetative growth reaches a certain point, whereas indeterminate pod-setting varieties carry out vegetative growth and reproductive growth simultaneously, making them highly prone to green-stay when nitrogen fertilizer is applied excessively.
2. Improper climate and environment
Under continuous cropping and repeated cropping, pests and diseases are severe, which affects the reproduction of soybean rhizobia, reduces their nitrogen-fixation capacity, and with repeated cropping causes an imbalance between vegetative growth and reproductive growth, resulting in green-stay. The flowering and podding stage of soybeans is the peak period of water demand; water shortage at this time affects normal flowering and podding, slows normal reproductive growth, and keeps vegetative growth lingering with delayed maturity. High temperatures during the flowering stage affect pollination of the plants, forming empty pods. Soybeans themselves are a short-day crop, so if the light period is too long, flowering is also delayed, leading to green-stay.
II. Preventive measures
1. Reasonable irrigation
If drought and poor soil moisture occur before soybean sowing, watering the subsoil moisture can ensure timely sowing and lay a solid foundation for a high yield. During the soybean seedling stage, that is, within 15 days after emergence, the soil should be slightly dry to encourage the roots to grow downward and prevent lodging later; unless it is excessively dry, watering is generally unnecessary. From 15-35 days after emergence, watering during drought can increase plant height and promote flower bud differentiation. During the flowering and podding stage, watering when drought occurs and draining when water accumulates can meet the water demand for seed filling.
2. Combined use of nitrogen, phosphorus, potassium and boron
Soil available boron content shows a highly significant positive exponential correlation with relative soybean yield. For boron fertilizer application, seed dressing gives the best effect, reducing the empty pod rate by 10% and increasing yield by about 20%.
3. Pay attention to pest and disease control
Aphids must be taken seriously starting from the seedling stage, and control should be carried out early. When the rate of aphid-infested plants reaches 20%-30% and a few show leaf curling, control should be carried out immediately, while also controlling cotton spider mite scale insects, dwarf virus disease, and others.
4. Use plant growth regulators
In production, plant growth regulators can be used to reduce the incidence of pods without seeds and correspondingly increase yield. Commonly used plant growth regulators include triacontanol, 784-1, and ABT rooting powder No. 5, but attention must be paid to the concentration.
The above is an introduction to the causes of green-stay in soybeans and prevention methods. We hope it can help you. To learn more related knowledge, please stay tuned to us.