Author: Feng Yao-zong, Wang Hui-hai, Zhang Jia-he, Zhang Ke-ying, Ma Wei-jun and Long Yi-ming
J Integr Plant Biol 1982, 24 (2): -.
This paper sums up the ecological data recorded in the south of Yunnan on our experiment of the rubber-tea artificial community during 1960 to 1980. It is a part of our studies of the tropical artificial ecosystem. The following results concern its dynamic productivity, stability, interspecific relationships, structure and function. 1. By the introduction of tea into the rubber plantation, its annual productive period has been prolonged from seven to ten months, while the non-productive period of young plants has also been shortened by three to four years. Its monthly productivity curve shows a change corresponding to the monthly variation of local solar radiation. In contrast, the monthly productivity curve of the monocultural tea plantation is not so. This is due to the fact that a tea-plantation must possess a certain amount of shade before it can grow well. 2. The rubber-tea community has a comparatively high stability in productivity. Low temperature is the major problem of rubber plantations in the south of Yunnan. It often causes cracks in the root collar barks of rubber trees and may even cause the death of the trees. We believe that the problem is caused by lack of heat from sun light, and have found that the critical least amount of heat necessary is 123 calories/sq em per day. In order to obtain more amount of heat, during the past twenty years, we have compared the annual productivity variations of various rubber-tea community structures, and are convinced that the cold-resistant ability of one kind of rubber-tea community structure has been greatly improved. This is achieved by discovering and applying two kinds of heat effects; namely, the directional heat effect of side rows and the lower story heat effect in the community. By adopting the wide row and thick planting structure of rubbertea community, arable land suitable for the rubber tree has been raised from 800 m. to 1000 m. in altitude. 3. The rubber-tea community possesses a high environmental protection capability. Owing to the introduction of the tea plants in the lower story, the annual rate of water loss in the community decreases by 42%, and that of soil erosion by 23.8%. Before the dry season sets in, the rubber-tea community contains 150 tons more water per hectare than that of a rubber plantation, and 322.5 tons more than that of a tea plantation (2.2 m thickness of Soil). The content of the organic matter in the soil of the rubber-tea community is 0.15% higher than that of a rubber plantation, and 0.2% higher than that of a tea plantation. Moreover, the soil unit weight of the rubber-tea community is comparatively lighter. 4. A corresponding relationship of the underground story-formation has been found in rubber-tea community; for example, rootlets of the rubber trees are concentrated in soil 0–20 cm below the surface, and those of the tea trees in soil 20–50 cm in depth. This shows the possibility of mutual aceomodation of the two species. 5. In conformity with the changes in altitute and latitude, the proportion of rubber and tea should also be changed accordingly. In the plains, the rubber trees will play a dominant part in the community. As the altitude rises, tea trees will gradually replace the rubber trees in playing the dominant role. Finally, the rubber trees entirely disappear from the scene and are replaced by plants such as camphor tree (Cinnamomum porrectum (Roxb.) Kosterm.). A camphor-tea community is formed. In fact, it is a type of artificial community welcomed by people in the south of Yunnan. Now, rubber-tea community is being rapidly spread in the southern part of our country, amounting to more than 10,000 hectares in area.