Studies on the Germination of Barnyardgrass Seeds : 1. On the germination of barnyardgrass seeds sown in the irrigated and non-irrigated soils.

Abstract

The germination (emergence) of one wild species and four cultivated variety barnyardgrass seeds was examined under the different soil conditions. The results obtained are as follows: 1. Any difference of the velocity of germination could not be found between 60% soil moisture (by weight) plot and moistened plot to soil capacity. But the velocity was recognized to be decreased with the depth of irrigation. At the early stage of germination period, the remarkable decrease of velocity was not caused by the low daily mean soil temperature but by the irrigation. But, the reverse relationship of the decrease observed latter was thought to be mainly based on the slight rising of the daily mean soil temperature and the increased amount of the accumulated daily mean soil temperature during several days. On the other hand, the decrease of velocity by the application of inorganic fertilizer on the non-irrigated plots was slight. But, the application on the irrigated plots caused the comparatively great decrease and especially remarkable decrease in the irrigated low soil temperature plots. As the results of these, the velocity with the application of inorganic fertilizer resulted in the slight decrease. Except very late variety Daruma showing specially great decrease of germination velocity due to irrigation, low soil temperature and application of inorganic fertilizer, there was no relationships between the velocity of germination of any variety and the heading date. 2. The greatest decrease of germination percentage was caused by the irrigation and the decrease by the application of inorganic fertilizer was not so remarkable. Moreover, the decrease by the low soil temperature was very slight. The decrease of the germination percentage caused by the application of ammonium sulphate was greater than the case of ammonium nitrate. As to the non-irrigated plots, the arrangement of plots in sequence from the low soil temperature plot without any application of fertilizer showing the highest germination percentage, is as follows; the low soil temperature plot with application of inorganic fertilizer, the high soil temperature plot with the application and the high ones without any application. As to the irrigated plots, the arrangement of plots in sequence from the high soil temperature plot without any application of fertilizer showing the highest germination percentage, is as follows; the low soil temperature plot without any application, the high ones with the application and the low ones with the application. The decreasing effect of germination percentages due to irrigation, soil temperature and application of inorganic fertilizer was found to be differed with materials.