The optimum soil water content for the growth of Cymbidium

Since Cymbidium is a drought-tolerant plant, what is its optimum soil content? This is closely related to cultivation management. We plant Cymbidium in orchid pots with different soil water content, and the soil water content is expressed by the maximum soil water holding capacity. The maximum water holding capacity of 100% of the tested soil is equivalent to 51.66% of the soil content (wet weight%). The changes of plant growth rate, fresh weight and dry weight were measured every 30 days, and the photosynthetic rate was also measured.

From the tested data, it can be seen that in the treatment of 90% and 70% maximum soil water holding capacity, the growth rate is similar and the growth is relatively normal. When the soil water content decreased to 1/3 of the maximum water holding capacity, the growth was slow, and half of the seedlings died in 90 days. When the maximum soil water holding capacity was 30%, the plant growth stopped at the beginning, and all the seedlings died in 90 days. The changes of fresh weight and dry weight of aboveground parts in different treatments were also the same as the growth rate.

The photosynthetic rates of all kinds of soil maximum water holding capacity treatments were measured 20 days and 60 days after planting, respectively. It was also found that 90% and 70% soil maximum water holding capacity treatments had the highest photosynthetic rate, and the two treatments were similar. However, when the soil water content decreased to 50% of the maximum soil water holding capacity, photosynthesis decreased, especially in 60 days treatment. If the orchid grows in drier conditions (30% of the maximum soil water holding capacity), the photosynthetic rate decreases in 20 days and loses its photosynthetic capacity at 60 days.

Combined with the results of growth rate and photosynthetic rate, we believe that the most suitable soil water content for the growth of Cymbidium is that the maximum soil water holding capacity is 70% 90%, less than 50%, the growth will be blocked or even die. (Ye Qingsheng, Pan Ruichi)