Growth and yield of seed potatoes after application of gibberellic acid to the tubers before planting.

The influence of GA on growth and yield of potato seed tubers (size 28-45 mm) was studied in field experiments on sandy soil in the late cv. Alpha. Different GA conc. were applied to seed tubers with or without sprouts by both dipping and spraying. The main purpose was to find a more suitable method of preparing seed tubers than the laborious presprouting in light method. This other method would allow mechanical planting, should not be laborious and should give a high yield of seed tubers. The application of GA accelerated emergence. GA also significantly increased the yield of the seed tuber fraction, probably by increasing the number of stems and thus the number of tubers/plant. GA accelerated tuberization, decreased the total tuber yields in one experiment, whereas in the other experiment an increase occurred. The best results were obtained if sprouted tubers were treated and under favourable growing conditions. Spraying was equally effective as dipping also in the 'spraying just before planting' treatment after heat shock. This means that application during mechanical planting seems to be possible, on the understanding that the GA conc. is not too high to prevent the occurrence of phytotoxic effects (45 mg GA/l caused small leaflets with yellow discolouration). The application of GA to seed tubers seems to be attractive especially in slowly emerging cv. or in cv. with a high proportion of large tubers. (Abstract retrieved from CAB Abstracts by CABI’s permission

Palaeobotanical investigations in the vicinity of the sneeker meer (Province of Friesland, The Netherlands)

This paper deals with the investigation of soil samples taken near Terhorne on the North-East shore of the “Sneeker Meer”, an expanse of water in the province of Friesland. (see fig. I) According to the geological map, the peat around this large body of water is covered by an 1—4 dm thick layer of young marine clay, but at the place where our samples were taken, the peat reaches the surface. A series of samples were collected from the whole depth of this peat-deposit (see diagram I). The surface lies here 0.35 m below the level of the sea. (As the sealevel is taken the N.A.P., the average height of the water level at Amsterdam.) At a depth of 2.15 or 2.20 m the borer reached the underlying sand. It proved impossible to penetrate with the borer used by us more than 5 to 10 cm into the sand. This sand (diagram 1a, which shows the lowest part of diagram I on an enlarged scale) proved to be of a red-brown colour