On the Micrometeorology of the Cultivated Pot

Abstract

There have been only a few reports which demonstrated the micrometeorology of the cultivated pot. The objective of this study is to elucidate the effect of albedo of the pot wall on soil environment in pot. For this purpose, four different wall conditions were prepared using Wagner pots (1/2000a). The outer surface of pots were coated with black lacquer, covered with aluminum film by vaporization, respectively, while one pot was buried almost in a level with the ground. On May 13, 1977, the seedlings of carrot (cultivar ‘MS yonsun’) were planted at the center and at four positions off the center towards east, west, south and north in each pot. Observations terminated on July 16. The features of the distribution of direct solar radiation on the pot wall, of soil temperature, soil moisture and the growth of carrot in the pot were investigated.The diurnal course of direct solar radiation on the pot wall varied according to directions of the pot wall. The daily amount was greatest at the east and west walls, and 52 percent as much as that on a horizontal surface. At the north and south walls the ratios were calculated to be 19 and 10 percent, respectively. The directional distribution of solar radiation affected greatly the soil temperature in the pot.Soil temperature and soil moisture in each pot were affected by albedo of the pot wall, and its effect was more remarkable in the black pot. The range of variation of the soil heat quantity at the center of the black pot was 1.37 times as large as those of the control and the aluminum-covered pots, and was about 5.5 times that of the buried one on June 9. Soil moisture was lowermost in the black pot, in which the moisture decreased markedly in the daytime and recovered only slightly at night.Dry matter weights of carrot roots at the south position and east position of the control pot and at the center of the black pot were relatively larger than those in the other conditions. Differences in the dry matter weight of root were recognized as significant only in the black pot, in which the accumulated soil temperature (May 13-July 16) was negatively correlated with top and root dry matter weights, it almost of the same experimental results in other reports.