畑地における雑草種子群の檢出について

抄録

A knowledge of the seed population present in the soil beneath different types of vegetation is of great value in the consideration of some of the ecological problems with regard to agricultural practice. BLENCHLEY and WARINGTON investigated the seed content of arable soils in considerable detail and found an association between the seeds present and the treatment (by manures and cultivation) which the land had received. Such comprehensive studies of the buried seed population of arable soils in our country have not yet produced satisfying results. The present study closely follows the methods initiated by AKAZA, with some modification of which are given details of reexaminations. Numerical estimations were made of the number of seeds, as shown by the morphological features, in numerous soil samples of known area taken from the uncropped(a)and the cropped lands(forage crops land(b), soy bean land(c)). Further, the structural analysis of the buried seed population is reported by using the "occurrence probability method"and MOTOMURA's theory. From the results summarized in Tables 8,9,10 and Figures 1,2,3,it will be seen that the six types of seed population were divided into ; (a) Digitaria ascendens-Stellaria neglecta type, Persicaria nodosa-Rorippa atrovirens type, (b) Stellaria neglecta type, Portulaca oleracea-Euxolus ascendens type, (c) Digitaria ascendens type, Exolus ascendens-Stellaria neglecta type.