How to calculate the growth period of soybean?

Soybean growth period refers to the number of days between any two development periods of plants, indicating the time of continuous growth between the two development periods. For example, the duration of soybean from emergence to maturity represents the whole growth period of the crop.

Soybean is a thermophilic crop, which needs to absorb enough heat to grow fully, so the requirements for temperature in each growth stage are different. During the sowing period, the lowest temperature of soybean seed germination is 6-8℃, the seedling emergence is 8℃- 10℃, and the seedling is slightly frozen at -4℃. The optimum growth temperature of soybean in the whole growth period is 20℃-25℃, in which the optimum growth temperature of seedlings is 20℃-2 1℃, the flower bud differentiation stage is 2 1℃-23℃, the flowering stage is 22℃-25℃, and the pod setting and filling stage is 2 1℃-23℃. The accumulated temperature required for the whole growth period is generally required to be between 2400℃ and 3800℃.

Low temperature weather will delay the maturity of soybean and shorten the leaves of soybean plants, thus affecting the number of soybean pods and ultimately affecting the yield of soybean. In August 2009, the continuous low temperature and rainy weather in Northeast China led to poor growth of soybeans, which was one of the important reasons for soybean production reduction.

Frost weather will dry up and kill soybeans, and soybeans in the United States and China generally start harvesting at the end of September. If the sowing and harvesting of soybeans are delayed, frost weather may come in late September and June at 5438+ 10, which will do great harm to late-maturing soybeans. Frost weather is also an important speculation factor in the market.