[Effect of different tillage methods on rice growth and soil ecology].

Field experiments were conducted in double-cropping rice field in South China during 1998-1999 to study the effect of different tillage methods on rice growth and soil ecology. The results showed that with rice scattering planting, no-tillage method caused a reduction of rice tillering, effective panicle, and filled grains of rice. Grain yield under no-tillage was 13.40% lower than that under conventional tillage, and the economic benefits decreased by 10.9%. Soil analysis showed that in no-tillage fields, soil bulk density and hardness were increased, soil porosity and available P and K were decreased, the amount of actinomyces and fungi was reduced, while that of soil bacteria was increased, and the enzyme activity was promoted. Minimum tillage and conventional tillage had similar soil physical and chemical properties, soil microbial quantity and enzyme activity. Minimum tillage could produce a 2.1% higher grain yield than conventional tillage, and increase the economic benefits by 11.0%.