Studies on the Growing Process of Potato Plant : VI. Effects of heavy application of stable manure and phosphorus on the growth and yield of potato plant in deeply plowed field

[摘要] The experiment was performed to make clear the effects of stable manure and phosphorus on the growth and yield of potato plants which were planted on the virgin volcanic ash soil plowed to the depth of 30 cm. Various treatments are designated by the symbols P, P+M, 3 P and 3 P+M, where P shows phosphorus, 3 P shows heavy application of phosphorus and M shows stable manure. The results obtained are summerized as follows: 1) The elongation of stem length was more higher at 3 P and 3 P+M plots than at P and P+M plots during the early stage of growth, while after the flowering time the length of stem became higher at P+M and 3 P+M plots than at 3 P and P plots. 2) Number of leaves and branches of plants on each treatments were same in order with stem length; that is 3P+M>P+M>3P>P. Fallen leaves were counted many at P+M and 3P+M plots during early stage growth, because the increase of the leaf area was remarkable in these treatments. But after the end of flowering time, leaving leaves were counted more at P+M and 3 P+M plots than at P and 3 P plots, therefore growing period was delayed about 10 days at P+M and 3 P+M plots. 3) The leaf areas were greater at 3 P and 3 P+M plots during growing period before flowering time, and since then they became greater at P+M and 3 P+M plots. Net asssimilation rate was inversly proported to the leaf area till the end of flowering time, but after this time they become higher at P+M and 3 P+M plots than at P and 3 P plots. Total production of dry matter by plants was arranged in order P+M>3 P>3 P+M>P. 4) At P plot the tuber development of potato plant in early stage was better and starch accumulation in the stem was decreased rapidly. The translocation of nutrient from shoots to tubers at 3 P plot after the end of flowering time was very smooth. 5) The content of N, P2O5 and K2O in the leaf at P+M and 3 P+M plots was higher than at P and 3 P plots after the flowering time, especially with K2O. The plant nutrient during early stage of growth was higher at 3 P plot than the others and decreased rapidly after the flowering time above all, the decrease of K2O was remarkable. 6) The starch value of tuber was higher at 3 P plot than the others. The yield of tuber was in the following ranking; P+M>3 P>3 P+M>P. And that of starch was 3 P>P+M>3 P+M>P.

[学科分类] 农业科学（综合）