Topsoils and subsoils from 4 sandy soils and 2 clayey soils were placed into 12 concrete frames in 1985. In 1986, after preliminary growth tests using soybean, rainfed corn with the recommended doses of fertilizers, followed by irrigated sorghum and rice bean (Vigna Umbellata) without fertilization, was grown to identify the crop productivity of the soils. The corn in sandy soils showed more tolerance to drought than that in clayey soils. The following sorghum in sandy soils, however, gave a scanty harvest becasue of nitrogen deficiency, while the rice bean bore a harvest of nearly the same level as that in clay soils.

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Micropropagation of peanut plant was examined through cultured seeds in vitro. Multiple shoot buds were induced from peanut seedlings by BAP in vitro. Multile shoot buds formed from nodal region. Shoots were continuously multiplied by using combinations of BAP and IBA. One can calculate that more than 1, 600, 000 shoots could be obtained from a single shoot in a year using the present technique. Plant regeneration was achieved by rooting single shoots. The rooting rate was 50% at IBA free and 100% at all concentrations of IBA used. Regenerated plantlets were successfully planted out in soil via semi-aquaculture condition.

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[in Japanese]

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The purpose of this paper is to report the results of experiment conducted on the utilization of useful tropical and sub-tropical woody plants as feeding resources of animals, and to contribute the establish-ment of agro-foretry systems in the tropical and sub-tropical farmings.
Four species of tropical and sub-tropical woody plants were selected to compare several characteristics of adaptability, productivity and resistance to cuttings.
Species selected and studied in the experiment of frequency of harvesting (Experiment 1.) are as follows:
Todaigusa-ka (Euphorbiaceae) ; Akamegashiwa (Mallotus japonicus Muell. -Arg.), Urajiroakamegashiwa (Mallotus paniculatus Muell.-Arg.), Oobagi (Macaranga tanarius Muell.-Arg.) . Nire-ke (Ulmaceae) ; Urajiroenoki (Trema orientalis Blume var. orientalis) .
Akamegashiwa (Mallotus japonicus Muell.-Arg.) was used in the experiment designed to study the effect of cutting method and intensity on the dry matter yield (Experiment 2) .
The summary of two experiments are as follows:
1. From the results of experiment 1., it was clear that the regrowth of these woody plants were considered fairly slow as compared with herbaceous forage plants such as pasture grasses. Except Urajiroakamegashiwa which showed maximum yield at 3 times harvesting in a year (3.5 months intervals), the maximum dry matter yield of plants was recorded in the plot harvested twice in a year (7 months intervals) . With increase of harvest frequency, dry matter yield decreased.
Oobagi seems to be the weakest in the regrowth after harvesting. Some of plants died after cutting of 3 to 4 times in a year.
2. With Akamegashiwa, different method and intesity of harvesting were compared. The most efficient method and high yield of dry matter was recorded in the plot harvested from newly grown shoot including growing point of shoot and undeveloped leaves. When plants were harvested from trunks at 1.2 m above ground level, regrowth of plants was not vigorus, and dry matter yield showed the lowest results.
Akamegashiwa seems to be fairly tolerable to frequent cuttings, though yield was decreased sharply after frequent cuttings, regrowth was observed normal and even in the experiment plot harvested 3 times in a year at the height of 1.2 m of trunks, dead plants were not observed.
3. The results of this experiment indicate that there seems to be different response to cutting among defferent tree species. In order to get further informations on this point, the selection of species for cutting resistance is obviously needed.
It is also suggested that since the regrowth of woody plants are fairly slow when compared with herbaceous forage plants such as grasses, it is important to establish the systems of long-range utilization, fitted to be able to gain full capacity of productivity of woody plants in the farming system of Agro-forestry.

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[in Japanese]

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This study was carried out to examine the effects of aluminum toxicity on maize and also to evaluate the toxicity mechanism in acid soils. The results indicated that a decrease in both exchangeable-Al and Al-saturation had a significant positive effect on the growth of maize. Whereas a change in exchangeable-Al, while keeping Al-saturation levels almost constant, had no apparent effect on the crop.
Al-toxicity is one of the major contributing factors to poor crop growth in acid soils. Under an acidic condition, the degree of Al-saturation appears more important than the absolute amount of exchangeable-Al in affecting crop growth.
We considered that the difference in the crop growth was caused, among others, by the difference in charge properties of the soils; for acid soil with permanent negative charge, the effect of liming on the crop growth was prominent due to a sharp decrease in Al-saturation, whereas that was not the case for the soils dominated by variable negative charge.

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Impact properties of long grain rice kernel (KDML 105 and IR60) were determined through drop-weight impact tests in comparison with short grain rice kernel (Koshihikari and Nipponbare) under controlled atmospheric conditions (20°C, 33.3, 54.6 and 75.5 percent r. h.)
The impact phenomena of rice kernel were also analyzed by using an impact model considering the effect of load cell deflection. Runge Kutta method was applied to solve the nonlinear equations of motions. Impact force-time curves obtained from the experiments were similar to the simulated deflection-time curves of load cell.
The mean value of impact breaking energy was determined by applying Weibull probability distribution to the applied energy and breaking frequency and then recalculated by the above model. Other related properties, e. g., impact breaking load, impact breaking deformation, impact strength were also determined.
It was found that impact breaking energy was about 2.5 times the compressive breaking energy, impact breaking load was about 1.8 times the compressive breaking load and impact strength was about 1.2 times the compressive strength.

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[in Japanese]

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[in Japanese]

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