Let's learn about the growth habits of sweet potatoes and their requirements for the environment.
First, the growth habits of sweet potatoes
1. growth period
The growth period of spring potato is 160-200 days, and that of summer potato is about 1 10- 120 days. According to the growth characteristics of Chiquan in the wild and its relationship with climate conditions, it can be roughly divided into three growth periods:
(1) prophase (from seedling raising to pot sealing)
60-70 days for spring potato and 40 days for summer potato.
At this stage, the stems and leaves grow slowly and the roots develop rapidly, mainly in the period of long fiber roots.
(2) Mid-term (from pot sealing to the peak of stem and leaf growth)
Spring potatoes last about 50 days, and summer potatoes last about 30 days.
At this stage, the root tuber expands slowly, and the stems and leaves grow rapidly, which is a period of mainly growing stems and leaves.
(3) Late stage (stem and leaf decline to harvest)
Spring potato is after late August, and summer potato is after early September.
This period is the main period of root enlargement.
Second, the growth environment of sweet potato
(1) temperature
Sweet potatoes like temperature and are afraid of cold. When planting, it does not take root at 5- 10 cm, the ground temperature is about 10℃, 15℃ takes 5 days, 17- 18℃, 20℃ takes 3 days, and 27-30℃ takes normal rooting.
When the temperature is 25-28℃, the stem and leaf grow faster, and when the temperature is above 30℃, the stem and leaf grow faster, but the tuber expands slowly.
Above 38℃, the respiratory consumption is high and the growth of stems and leaves is slow. Below 20℃, the stems and leaves grow rapidly and stop growing at 15℃. If it lasts too long below 10℃, the stems and leaves will freeze and die.
The higher the ground temperature is between 2 1-29℃, the faster and more tubers are formed, but the potato tubers are smaller.
The ground temperature of 22-24℃ is beneficial to the formation of tuberous roots.
The ground temperature of 20-25℃ is most suitable for root swelling, and the swelling is slow when it is lower than 20℃ or higher than 30℃. When the temperature is lower than 18℃, some varieties stop swelling, and when the temperature is lower than 10℃, they are vulnerable to chilling injury, and the root tuber is frozen at -2℃.
The larger temperature difference between day and night during root tuber expansion period is beneficial to root tuber expansion and nutrient accumulation.
(2) Lighting
Sweet potatoes like light. Under the condition of sufficient light, its leaves are thicker, older, stronger and stronger, and its conduction tissue is developed, so its yield is higher.
When the light is insufficient, the leaves will turn yellow, with many fallen leaves, short leaf age, slender stems and vines, underdeveloped transportation organization, less transportation of organic nutrients assimilated into root tubers and low yield.
Long illumination time every day is beneficial to the growth of stems and leaves, the length of stems and vines and the increase of branches.
12.5- 13 hours a day is more suitable for root swelling.
Illumination for 8-9 hours a day is beneficial to bud flowering, but not suitable for root swelling.
(3) Moisture
Sweet potato is a drought-tolerant crop, but too much water is not conducive to increasing production.
Sweet potato is afraid of flooding, especially after it comes out, which has a great influence on yield.
The uneven growth rate inside and outside the root tuber is caused by the uncertainty of soil moisture, and the phenomenon of skin cracking often occurs.
In short, sweet potatoes are afraid of both waterlogging and drought. The masses said, "The dry roots are long, the wet roots are long, and the dry roots are long.
"In order to obtain high yield of sweet potato, we should timely and properly irrigate, timely and thoroughly drain water, and strengthen intertillage and soil and water conservation in dry land.
(4) nutrients
Sweet potato has strong fertilizer absorption ability and barren tolerance, but sufficient fertilizer must be applied to obtain high yield.
Besides nitrogen, phosphorus and potassium, sulfur, iron, magnesium and calcium also play an important role.
Among the three elements, sweet potato has the greatest demand for potassium, followed by nitrogen and phosphorus.
According to the analysis, per 1000 kg sweet potato contains 3.5 kg nitrogen, 5.6 kg phosphorus 1.75 kg potassium.
Therefore, increasing potassium fertilizer and timely and appropriate application of nitrogen and phosphorus fertilizer can significantly increase production.
(5) Soil
Sandy loam and sandy soil with deep soil layer, rich organic matter and good ventilation and drainage performance are better.
When the soil is sticky, the root bark is bad and rough, the potato shape is irregular, the yield is low, and it is not resistant to storage.
However, sandy loam and sandy soil generally have low fertility and poor water retention capacity, so measures such as fertilization should be taken to gradually improve soil fertility in order to obtain high yield.
Sweet potato is more resistant to acid and alkali, and its PH value is about 4.5-8.5, but 5.2-6.7 is suitable.
When the soil salt content exceeds 0.2%, sweet potatoes should not be planted.
To sum up, it is the growth habits and environmental requirements of sweet potatoes. Friends who want to grow sweet potatoes can actually learn more about the growth habits of sweet potatoes, so as to know how to manage them at ordinary times.