Long-term Research on Red Soil Degradation and Remediation Promotes Development of Ecological Recycling Agriculture in Hilly Region of Southeast China

The degradation problems of soil erosion, soil acidification, soil fertility attenuation, soil heavy metal pollution, and seasonal drought in the red soil hilly region of Southeast China have resulted in the degradation of the red soil ecosystem and the decline of the land productivity, which restricts the sustainable development of regional agriculture. Since the establishment of Yingtan Red Soil Ecological Experiment Station in 1985, the long-term observation and ecological basic research of red soil ecosystems have been carried out, the application research and demonstration have been implemented on soil degradation and restoration, soil quality evolution and improvement, nutrient cycling and efficient utilization, soil pollution and remediation, and ecological agriculture model and regional development strategy in red soil hilly region. For the red soil development, it was found that the process of modern desilication and realuminizing was continuing, and the natural soil acidification rate in the small watershed was low. For the accelerated acidification of red soil under agricultural utilization, the new methods of inhibiting proton production and improving acid resistance capacity were developed, the new aluminum-tolerant plant resources are excavated, and the molecular biology mechanisms for plant aluminum-resistance was revealed. The multi-scale methods for soil erosion monitoring were established, the spatial distribution of soil erodibility factor was mapped, the development mechanisms of soil erosion and slope collapse in the red soil region were identified, and the development-management model for red soil erosion control was established. The occurrence regularity of seasonal drought in red soil region was found out, the mechanism of pore formation and the hydrologic flux at different scales were revealed, a high precision remote data collection system for soil moisture status was developed, and a high efficient and water-saving agricultural model in the low-hilly red soil region was established. For heavy metal and rare earth element, the prediction models for migration in soil-crop systems were established, the safety threshold values for red soil and paddy soil were put forward, and the remediation technology system for heavy metal polluted red soil and paddy soil was integrated. The changes of soil fertility and nutrient balance in red soil region were investigated and mapped, the driving mechanism of biological network for carbon and nitrogen turnover in red soils was revealed, and the principle for biological fertility cultivation of large soil aggregate was put forward. The modern high efficient agricultural technology system for farmland conservation in Jiangxi Province was established, and the ecological recycling agriculture model for integrated governance of "mountain-water-farmland-forest-lake-grass" system was developed at the small watershed scale in red soil region, which made a great contribution to the farmland quality development, the ecological environment protection, and the development of a new generation of ecological recycling agriculture in red soil region.