Objective  To study the effects of cover treatment on the growth and death of fine root of Camellia oleifera.

Method  Using minirhizotron dynamic monitoring technology, and taking C. oleifera "Changlin 4" forest as test material, four treatments (black mulch film, Camellia shelll, peanut rod + straw, ecological film) and the control (no cover) were set up. The fine roots of C. oleifera in the 0~40 cm soil profile were observed for one year.

Result  The results indicated that the treatments of peanut stalk + straw and black mulching significantly increased the total root length, total root tip number and total surface area of the fine roots of C. oleifera, and peanut stalk + straw treatment was the best. However, the black mulch treatment had the most pronounced effects in promoting the average diameter of the live fine roots. The total root length, total root tip number and total surface area of fine roots treated with any of the four treatments were larger than that of the control. Compared with the control treatment, all the four cover treatments contributed to reducing the diameter of the dead fine roots, and the difference was significant. The total root length, total root tip number and total surface area of fine roots of C. oleifera peaked in March and June to July. The total root length, total root tip number and total surface area of the dead fine roots changed more gently in the spring and then slowly increased. The net growth rate of fine roots of C. oleifera increased at first and then decreased, peaked from May to June. The peanut stalk + straw treatment and black mulching treatment significantly increased the annual net (root length) productivity of fine roots of C. oleifera, while the treatment of peanut stalk + straw was the most obvious.

Conclusion  Summer is the peak period of fine root growth and death of C. oleifera. The peanut stalk + straw treatment has the most significant effect on promoting the fine root amount and annual net (root length) productivity of C. oleifera, and the black mulching treatment has the most obvious effect on promoting the diameter increase of fine roots of C. oleifera.