The backbone of the coffee tree

Coffee is a shallow root crop, and the plants propagated with seeds have conical roots. Root system refers to the general name of root. The root morphological distribution and depth of shade varieties / soil conditions and agricultural technical measures are different. From the point of view of varieties, the roots of small / medium grain species are shallower, while those of large grain species are deeper. Under normal circumstances, there is a thick and short taproot and many developed lateral roots. Yunnan small-grained coffee is a 4-year-old fruiting tree with a depth of about 70 cm. The main roots beyond 70 cm tend to become slender and extend downward in the form of absorptive roots. The main root generally does not bifurcate, but if it is injured when digging seedlings, one or two roots grow down from the wound healing place to replace the severed main root after planting, the lateral root grows horizontally, the horizontal lateral root grows horizontally, and the downward lateral root is called vertical lateral root. the paper roots from the lateral roots are called secondary lateral roots and tertiary lateral roots respectively. The root system of coffee has an obvious layered structure, usually every 5 cm, but most of the absorbing roots are distributed in the soil layer of 30 cm, especially in the soil layer of more than 15 cm. A few of them are distributed in the soil layer of 30 cm and 60 cm, and there are only a few absorbing roots in the soil layer of 60 cm and 90 cm. The absorbing roots in the topsoil layer are thick and white, and the absorbing roots are yellow and delicate beyond 30 cm. The horizontal distribution of coffee root seconds exceeds 15-20 cm of the crown width in infancy, and there are many roots in the topsoil layer of coffee orchards covered or shaded by rows in the adult stage. The roots in the exposed surface layer of the soil are easy to burn, and the roots are deeply rooted during deep ploughing, and the coffee roots have a strong ability of regeneration, which recovers quickly after being damaged or cut off. Within 7 ~ 10 days, they grow good healing tissue and sprout many new lateral roots. The new lateral roots grow root rows for absorption, which is the most active root system.

The stem of coffee is erect, the tender stem is slightly square, green, corked and round and brown. The length of stem Internode is 4-7 cm, the length of shaded Internode is 20-30 cm, the length of overshaded Internode is 20-30 cm. A pair of leaves grow on each node, with overlapping buds in the axils, upper buds in the upper and lower buds in the lower. The upper bud develops into a branch and the lower bud develops into a straight branch. The upper segment sprouted at the same time as the terminal bud. Each upper bud can be produced only once, while the lower bud can be produced many times. When the terminal bud of the trunk is suppressed or the trunk is bent, the bud will germinate into a straight branch with the shape of trunk growth, and the direct branch can be cultured into the trunk.

The growth of coffee trunk has obvious apical dominance. The branches near the top of the trunk grow very vigorously. But this advantage weakens with the increase of the trunk. Its growth varies with varieties and natural climatic characteristics. When there are 6-9 pairs of true leaves in the main stem of small-seed coffee seedlings (8-12 pairs of medium-grain species), the first pair of branches will be drawn. In the year of planting, it generally grows 4-8 pairs of one minute, and the growth increases gradually in the second year, 7-12 pairs in the second year, and 14-15 pairs in the third year. If the management is good and the climate is suitable, it can be as high as 18-20 pairs. At the same time, two branches grow under the crown, open the stage to form a crown, and bear a small amount of fruit. Generally, the third year after planting is the year with the most vigorous vegetative growth / maximum growth. Management must be strengthened, especially the supply of water and fertilizer, in order to form a robust crown. In the fourth year, the growth of the trunk slowed down, the Internode became shorter, and entered the fruiting stage (there were also those with particularly exuberant vegetative growth, branching in large quantities in the second year, and entering the fruiting stage in the second or third year). If the trunk is allowed to grow naturally, all kinds of coffee can continue to grow according to its growth power. Small seeds up to 4 meters 6 meters, medium seeds 6 meters, large seeds up to more than 10 meters. The harvest is difficult and the yield can be reduced, so the height of the trunk is controlled. The small seed species were shaped in a cylindrical crown 3-4 years after planting by single-stem shaping / unroofing.

The growth of the trunk has seasonal variation, with smaller growth in the dry season, shorter internodes, larger growth in the rainy season and longer internodes, and the smallest growth and shortest internodes in winter. Therefore, according to this growth characteristic, we can know the plant age under natural growth.