肥料処理の種類の異なる水田における緑藻フシマダラの消長について

概要

論文の詳細を見る
Seasonal observations and culture experiments were made during a period from April 1977 to October 1979 in order to clarify the cause of the occurrence and growth of a filamentous green alga (Pitophora oedogonia) appearing in the surface water of four paddy fields subjected for a long period (52 years in 1979) to different fertilizer treatments (non-fertilizer, inorganic fertilizer, organic fertilizer and green manure). Before the midseason drainage done in summer, this alga appeared only in the organic fertilizer and green manure plots. In early autumn a fair amount of it appeared in the inorganic fertilizer plot. To investigate the effects of different levels of nutrient concentration on the algal growth, culture experiments were made twice with solutions simulated to the concentrations observed in the field plots under relative light intensities of 67,36,10,4 and 1%. The growth of this alga was generally optimum at a total nitrogen concentration of 50 μM, an average in the green manure plot in early summer, while it was independent of phosphate concentration. The difference of algal appearance and abundance in the four plots was explained mainly by the seasonal changes of the NH_4+ concentration in each paddy water. Some additive effects of light regime and competitive interference were discussed.
日本生態学会の論文
1985-09-30