Effect of different seeding methods on green manure biomass, soil properties and rice yield in rice-based cropping systems
The cultivation of green manure crops plays an important role in soil quality and the sustainability of agricultural systems. Field experiments were conducted during one season (2007/2008) to evaluate the effects of different seeding methods on the biomass and N production of hairy vetch (Vicia villosa) and barley (Hordeum vuglare). The effects of treatments on rice yield and its components were also investigated. Specifically, the following four treatments were evaluated: broadcasting before rice harvesting (BBRH), partial tillage seeding (PTS), group seeding (GS) and drill seeding (DS). The overall results showed the following ranking of biomass and nitrogen production of hairy vetch by different seeding methods: BBRH > PTS > DS > GS. Additionally, biomass and nitrogen production of barley was lower than those of hairy vetch at all tested seeding treatments. BBRH and PTS treatments led to an increase in soil bulk density, porosity and soil organic content. The application of green manure with BBRH and PTS treatments led to a significant increase in rice yield (5,330 and 5,320 kg ha-1) when compared to conventional fertilization. Based on the results, BBRH and PTS are good practices for production of green manure in paddy soil. Chemical fertilizers can be replaced with hairy vetch as green manure in rice-based cropping systems.
Key words: Green manure, rice, biomass, soil property, seeding method.