Abstract
We investigated the changes of soil carbon content and the population of soil microorganisms, soil nematodes and soil animals in upland rice (Oryza. sativa L.) production following rye (Secale creale L.), crimson clover (Trifolium incamatum L.) and fallow (no cover) under different tillage systems (plow, rotary, and no-till) with 3 replications. The main results obtained for a 2 years field research were as follows.
No-till treatment enhanced soil respiration from 1 month after rice planting to July compared with plow and rotary plots. In 2001, the rye cover crop plot showed the highest soil respiration values for all tillage treatments, followed by crimson clover, and fallow treatment showed the lowest values for all tillage treatments.
Higher soil carbon content was observed in rye and crimson clover plots compared with the fallow plot in April, and this difference disappeared in May. However, that was also higher in the rye and crimson clover plots in September.
The population of soil microorganisms was strongly affected by tillage treatment, with the plow treatment having the lowest in most seasons. In all tillage and cover crop treatments, the population of soil animals was higher in May than in September, but no significant differences were observed among tillage and cover crop treatments.
The population of nematodes was strongly affected by cover crop and tillage treatments. For cover crop treatment, the population was higher in the rye and crimson clover plots than in the fallow plot, and for tillage treatment, the order was no-till>rotary>plow.
Cover crop treatments enhanced the soil respiration, the water holding capacity, soil carbon content and the population of nematodes. These results will be useful for enhancing the biological diversity of community in soils which is important for maintaining a healthy environment for plants.
