Management of herbicide usage in rubber plantations with help of modelling erosion and crop growth
- Publikations-Art
- Arbeitspapier/Diskussionspapier
- Autoren
- Hongxi Liu, Xueqing Yang, Sergey Blagodatskiy, Carsten Marohn, Georg Cadisch
- Erscheinungsjahr
- 2016
- Tagungsname
- Sustainable Rubber Conference
Land use in Xishuangbanna, SW China, a typical tropical rain forest region, has dramatically changed over the past 30 years as forest was converted into rubber plantations. This land use change induced soil loss. Reduced herbicide management has proven an efficient way to reduce plot level erosion by increasing plant and litter cover. However, efficiency of land management (reduced herbicide) regarding erosion mitigation at watershed level as well as long-term effects of land management (e.g. on latex production) remain unclear. In order to provide a comprehensive assessment, we firstly calibrated and validated a physical-based crop-erosion model (Land Use Change Impact Assessment, LUCIA) by simulating short-term (one year) effects of weed management on runoff and soil loss in an established rubber plantation (12 year age). The model was further validated to simulate long-term (20 years) growth of rubber plantations under standard weed management (twice spraying per year). Then scenarios were created to simulate soil erosion under different herbicide managements in the long run (23 years): i) totally cleared understory (H+); ii) twice weeding per year (Hs); iii) once weeding per year (H-). It was found that total soil loss in one rotation length was reduced under H- by 60% compared to Hs and 70% compared to H+. Once weeding per year (H-) can efficiently control annual soil loss below 2 t ha-1 year-1 with no negative impact on latex production. To evaluate effect of reduced herbicide on watershed scale, LUCIA was further applied to a mixed land use watershed with 11% rubber plantation. Reduced herbicide use (H-) was found to decrease total sediment export by 15% at watershed level.