Effect of different fertilizer applications on sustainable soil fertility and rice production in red soil paddy ecosystem
长期不同养分投入对土壤养分和水稻生产持续性的影响

Based on a long-term field experiment started in 1990 in Taoyuan Experimental Station of Agriculture Ecosystem-CERN, the effects of fertilization on the fertility and productivity of paddy soil were analyzed, so as to discuss the sustainability of ecosystem of double-cropped paddy field in subtropical red earth region. Results showed that: chemical fertilizer input and recycling of organic matter in the ecosystem had the similar effects on soil fertility and system productivity. Organic matter recycling was better for the accumulation of soil organic matter (SOM) and total nitrogen (N). SOM and total N under different nutrient inputs presented an assurgent direction in cultivated soil layer (0-20cm) and annual amplitude varied from 1.5%-5.8% and 2.5%-9.4%, respectively. Contrast to previous experiment, nutrient phosphorus (P) content in soil cultivated layer under fertilization regime varied from -18.3% to 30%, potassium (K) was exhausting which decreased from 8.1% to 22.6%. The sustainability index indicated that, the sustainability of soil N was much more dependent on chemical fertilizer input, while P and K were relied on organic fertilizer. Paddy ecosystem has a strong ability of self-maintenance and the recycling of organic matter within the ecosystem could be benefit to the stability and sustainability of the system.