1. Surface runoff and soil erosion, soil temperature, soil moisture and the growth of peach seedlings under five systems of culture, were compared in the clayey orchard, of which slope 28 per cent, during May to October in 1951. The results were as follows; 2. On runoff and erosion control, the effects of the cultivation under straw mulch, sod culture and winter cover crops (grass mulch during peach tree growing season), were distinguished on the same rate, but summer cover crops was less. Runoff soil did not always follow runoff water and it seemed that the proportion of soil to water varied by system of culture, property of rain and soil, seasonal transfiguration of treat meats and others. The class of runoff soil was not so different as to distinguish the difference of soil managements, but the runoff soil was remarkably less in the percentage of pebble than that of the surface soil of test field. 3. The difference of the shoot linear growth of peach seedlings between systems of culture, appeared evidently during the end of July to the beginning of September and the total length wes classified as following order ; straw mulch> winter cover crops> clean culture> summer cover crops> sod culture. The same effect was noted on the total top and root fresh weight. In all systems of culture, the root penetrated deeper than 60cm, and the concentration of root was greatest at 5 to 10cm in depth, but the greatest concentration of fine root was different in depth between systems. 4. The influence of systems of culture on the soil temperature was distinguished still at 30cm in depth. Under straw mulch, sod culture and winter cover crops, the temperature was too low to growth of peach tree during May to June. In midsummer, it was too high under clean culture and winter cover crops. On and after September, the soil temperature fell early under straw mulch, summer cover crops and sod culture. The influence of soil temperature for top and root growth of peach tree was not evident, but for the distribution of roots in upper 10cm of soil, especially of fine root, was fairly distinct. 5. The influence of soil managements on the soil moisture was visible at 30cm in depth. Under straw mulch, the soil moisture was optimum always at all depth and winter cover crops was next suitable. Lack of soil moisture was limited within 20cm depth of surface soil under clean culture, but it was considerably great still 20-30cm in depth under sod culture and summer cover crops. The influence of soil moisture for growth of peach seedlings seemed fairly distingiushed.
The studies on the requirement of oxygen of the roots as a part of the studies on the physiology of root in vegetable crops were carried out concerning the following items. (1) The measuring method of the amount of oxygen absorbed by the roots of vegetables. (2) The comparing of the amount of oxygen absorbed by the roots of various vegetables in the water. (3) The influence of temperature on the oxygen absorption of the roots of vegetables. The results obtained were as follows. 1. It is a convenient and exact method for comparing the amount of oxygen absorbed by the roots of various kinds of vegetables to measure the amounts of oxygen absorbed by the excised roots in the water. 2. Absorbing oxygen of the roots in the water is about 1/2 to 1/3 of that in the air. 3. According to the investigations on 6 species of summer vegetables and 14 species of autumn and winter vegetables, the amount of oxygen absorbed by the roots of kidney beans and strawberries is greater and that of eggplants is less than that of the other species of summer vegetables, and wthin the autumn and winter vegetables, strawberries and broad beans come first in the amount of oxygen their roots absorb, peas, chinese cabbages, spinaches, lettuces and radishes rank next and leaf beet, mitsuba (Cryptotaenia japonica) are lowest in oxgen absorption of the roots. 4. The amount of absorbed oxygen per unit weight of dry matter is not so great in the roots of strawberries, but in kidney beans and broad beans it is as great as supposed by. grading in fresh roots. The cause of these facts may be the abundance of hydrogen giving materials such as carbohydrates or enzymes related to the respiration of the roots. 5. The vegetables of which roots absorb a large amount of oxygen are generally weak against submersion. 6. In the roots of 7 species of vegetables, investigated on the amounts of oxygen absorbed at every 5°C from 0°to 60°C, all of the root but not with eggplants absorb oxygen even at 0°-2°C temperature, and the strawberries which can grow in a cooler season absorb fair amount of oxygen at 0°C, and kidney beans absorb oxygen abundantly at relatively low temperatures. The greatest amount of oxygen are absorbed by the roots at the following temperatures. Eggplants, tomatoes, peppers……50°C Cucumbers……40°C Kidney beans……35°C Strawberries……60°C 7. The amount of oxygen absorbed by the roots, at 35°C is about 1.9-4.5 times and at 45° C about 2.1-5.3 times as great as that at 15°C
1. Data presented, which are conducted by the continuous aerating system, show effect of soil oxygen concentration in the soil atmosphere upon the growth of Satsuma orange, Trifoliate orange and peach seedlings and grape cuttings. 2. The growth of Satsuma orange, Trifoliate orange and grape was vigorous in low oxygen level and shoot growth of Satsuma and Trifoliate oranges, which was normal in about 4% or more oxygen, was interrupted by about 1% oxygen concentration. Grapes which made normal growth in 7% oxygen died in about 0.5% oxygen as Trifoliate orange. Satsuma orange did not die during the experimental procedure. The shoot growth of peach seedlings used for check was decreased in about 6% oxygen and died in little less than 2% oxygen. 3. Results of experiments of last 6 years on oxygen relation to the growth of the young seedlings of common fruit trees and stock plants are classified as follows. I Good growth group for low oxygen concentration: persimmon (D. Lotus LINN.), Satsuma orange, Trifoliate orange, grape. II Intermediate growth group for low oxygen concentration : apple, Japanese pear. III Weak growth group for low oxygen concentration: peach.
1. On account of flower forcing of the stocks, studies on flower bud differentiation and development were conducted at Nagano 1951 and 1952, using the seedlings which were grown on the regions of the high altitude and received different growing temperatures. 2. Flower clusters differentiated aside the growing point axis which were developing. Flower clusters which had been differentiated developed to flower buds and flowered when the circumstances were favorable. 3. Stock seedlings which were moved to high temperature suddenly soon after the flower clusters differentiation, developed imperfect flower buds e. g. aborted, or deformed flower, etc. 4. To avoid of these imperfect flower buds, the seedlings which had differentiated to the flower clusters perfectly should be used. 5. For this reason, the seedlings should be received low temperature over 35-40 days below 13°C min. 6. Seedlings which had been grown at the regions of high altitude, might be forced of the flowers ahead 30 days compared to the ones grown at the low altitude. The seedlings of Non-Branching strains were forced 50 days ahead. 7. Flower stalks were too dwarf for cut flowers when the seedlings had been grown at too cool region of high altitude. The length of flower stalks was correlated to the dimensions of seedlings at the time the flower buds differentiated. It should be sown 50 to 60 days ahead the time of flower cluster differentiation and grown up to longer seedlings to secure tall flower stalks. 8. To secure the cut flowers of stocks at X-mas, it should be sown in July 10 to 20 at 700 to 800 meters altitude and then moved the seedlings to warm regions or house early in October.
Surveys of the sod apple orchard were practiced during from April, 1949 to May, 1952 in the Aomori Apple Experiment Station and 95 sod apple orchards which are scattered all over Aomori Prefecture. The results obtained are summarized as follows: 1. The red clover in the sod apple orchards grew very vigorously and produced above 14.5 tons of the green matter per acre, based on the average of three years. The best growth of the red clover was obtained in the second growing year. The growth, however, lost vigor in haste from the third growth of the third growing year. 2. From the soil moisture determinations, the apple orchards are classified into two types-or-chards in which differences of the soil moisture content between the sod plot and tilled one were very scarce and those in which the soil moisture content of the sod plot was smaller than the tilled one greatly in the dry season, then it seemed that such difference for the soil moisture content was based largely on the soil properties pf the apple orchards, especially soil types. 3. One of the best assurances that the sod will not unduly compete with the apple trees for soil moisture was obtained from mowing the apple orchard frequently and mulching the cut cover crops around the tree or where the rover crops fell. 4. The distinct effects of the sod upon the tree vigor, yield of fruit, or fruits were not found out in these surveys. It was certain, however, that the tree in the sod of the dry land showed reduced vigor after the long drought, being attended with the yellowing of foliage color especially in May and July as compared with the tilled tree and that the fruit color of the sod was generally superior to that of the tilled tree. 5. During these surveys, it seemed that there was no outbreak of pests and diseases of the apples to be attributed in particular to the sod culture. 6. In the sod apple orchards investigated, roots of the red clover have penetrated the deep layer of the soil and were traced up to the depths of 90cm, about ninety percent of the whole being found out within about 30cm soil depths from the surface layer.
Cabbage varieties and strains were grown on the three regions of different altitude in Nagano prefecture (Nagano or Suzaka 360m, Fujisato 760m, and Sugadaira 1, 390m above the sea-level) in 1948, 49, and 50, and were tested for their adaptability to the different ecological conditions of the three regions during summer seasons. The experimental results obtained were as follows : 1. Although cabbage was rather an insensitive crop to high temperature, its most favourable growing temperature range was from 15 to 20°C in daily mean. In the region of low altitude, where the summer temperature exceeded the optimum temperature range, cabbage growth was retarded during summer season, and severely checked when mean daily temperature exceeded 25°C. In the region higher than 1, 000m above the sea level, where mean daily temperature was about 20°C even in hottest season, cabbage grew up very vigorously during summer seasons. 2. In the cool region of high altitude, the differences in the times of maturity or the weight of head between the early varieties and late ones were rather small, while in the regions of low altitude where the summer temperature exceeded the optimum range for cabbage growth, the diffences between the two groups were large. 3. Some varieties and strains were less sensitive to high temperature than the others.
Three artificially induced tetraploid flowers were created by seed treatment with colchicine solution in 1950-1951. (1) Coral flower is a kind of garden annuals. It has a peculiar habit of flowering, that is, small five pink petals of each floret open slowly in the twilight of evening and soon fade till darkness of night comes. The name maybe refers to bearing a plenty of small coral colored fruit-pods on the stems. Tetraploid coral flower grows vigorously with longer stems, larger leaves and much enlarged florets, furthermore, having longer flower season due to lowered seed fertility than diploid. (2) Viscaria is a well-known biennial garden plant like Pinks. Tetraploid one grows rather slowly at the young stage in winter and then becomes more vigorously and higher-habited in warm spring, producing so enlarged flowers but fewer seeds than diploid. (3) Edging lobelia is a pretty deep-violet flowered garden ribbon plant. Especially, Crystal Palace which was used for the trial is a good compact-habited variety. The tetraploid plant produced by chromosomal doubling was much dwarfened and had thicker leaves, bearing the same flowers as large as diploid. This plant was sterile completely and damaged severely to death by winter cold. It is presumed that such“polyploid feebleness”as the above lobelia is possibly caused by surplus duplication of the genetically similar chromosomes which are affecting plant growth respectively.