The influences of the application of organic matters as the substitution of chemical fertilizers and the reduction of agricultural chemicals on the growth and yield of rice [Oryza sativa] plant and the growing wings of red dragonflies [Sympetrum sp.]
2006
Yajima, Y.(Fukushima-ken. Agricultural Experiment Station, Koriyama (Japan)) | Sato, N. | Kanke, B.
The influences of the chemical fertilizers, the agricultural chemicals and the organic matters on the growth and yield of rice plant and the growing wings of red dragonflies were investigated in the cold and highland areas, especially Inawashiro Town, where the resident has an interest in the environment. The yield of brown rice in the use of organic matters, such as cattle or chicken manures and strained lees of rapeseed oil, as the substitution chemical fertilizers decreased around 10% compared with those of the popular cultivation. The reduction of yield was associated with a lower number of ears, which was caused by the suppression of tiller number on the initial growing stage. The reduction of agricultural chemicals did not affect the growth and yield of rice plant except to herbicide. However, the yield of brown rice in the field not applied herbicide was almost 30% less than that of the popular cultivation by the propagation of weed on the 3 years later. Red dragonflies grew wings from the beginning to end in July, and the peak of the number of growing wings was shown in the mid-July. The number of red dragonflies grown wings evidently decreased by the midterm drainage, and it decreased by the surface spread of the dried cattle manure used for the purpose of the constraint of weed. Then, it was suggested that the growing wings of red dragonflies was not affected by the application of chemical fertilizer and agricultural chemicals except to insecticide, but decreased by the application of an insecticide.
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