TY  - BOOK
AU  - Jusheng Jiang
AU  - Guishui Xie
AU  - Junming Chen
AU  - Mingdao Cai
AU  - Weifu Lin
AU  - Xianhai Zeng
AU  - Yuekun Wang
TI  - Comparison of functional properties of ecosystems for rubber plantations under different tapping systems
PB  - Proceedings of IRRDB Symposium 1999, Hainan, Peoples Republic of China. pp.131-146.
KW  - Contrast research
KW  - Functional properties
KW  - New tapping system
KW  - Old tapping system
KW  - Rubber plantation ecosystem
N2  - The ecosystems of rubber plantations of clone PR 107 under S/2 D/2 (old or traditional tapping system) and S/2 D/4 + ET (new tapping system) were designed for positional observation of soil nutrients, leaf nutrients, physiological parameters of latex, meteorological factors and yield. Comparative analysis of single and multi-factors of the resultant data derived from two years observation manifested that the material recycle and energy metabolism under similar environmental conditions and management were obviously higher in the rubber plantations under new tapping system than under the old system. The plantations under new system consumed more soil organic matter (6.6;), soil nitrogen (9.8;), soil available potassium (2;) and soil water (1091.69 kg/ha) annually than those under old system but less soil available phosphorous. The plantations under new tapping system contained soil available phosphorous 115;higher than those under old tapping system, which was likely due to improved energy metabolism responsible for enhanced utilization efficiency of phosphorous and hence for less soil available phosphorous, or due to improved availability of soil phosphorous by changing root-system ecological environment after ethylene stimulation. The principal factors influencing physiological functions of the two rubber plantation ecosystems (new and old tapping systems) were different in some way. The effect of Mg+2 content of leaf on DRC of latex and the effect of maximum temperature on R-SH of latex were similar in the plantations under both new and old systems, whereas the ecological factors affecting Pi, Mg+2 and sucrose content of the latex were different under both ecosystems. The physio-ecological factors comprehensively influencing the latex producing function of the two ecosystem were different. The main factors affecting average yield per unit area and per tree included Mg+2 content of leaf and raining days per month for the new tapping system, whilst DRC of latex and the content of soil organic matter for the old tapping system. The above suggested that the environmental condition adapted to growth of the rubber tree had changed greatly after the new tapping system was adopted. The control techniques for the rubber plantation ecosystem of the new tapping system should include improvement of components of fertilizer and changing of the frequency and date of fertilizer application, application of organic fertilizer for improvement of soil organic matter, and establishment of plant covers of rubber plantations for conserving water and increasing fertility. The phosphorous metabolism observed in the rubber plantation under the new tapping system needs further research
ER  -