The effect of successive fertilization of the excess farmyard manure on the tomato yield, the occurrence of blossom-end rot and change of meso-faunas and microorganisms population in soil were studied under greenhouse condition. The results obtained were as follows.
The farmyard manure used in this study contained 2.8% nitrogen, 2.8% potassium and 2.4% calcium.
The fruit yield obtained from the plot which was supplied 5 t/10 a farmyard manure was 1.2 t/10 a more than that from 50 t/10 a at the first cropping. But, the yield from heavily manured plot and that from light manured plot were reversed at 2nd cropping.
In the 3rd cropping, the fruit yield reached the maximum during all croppings, even when blossom-end rot occurred. Outbreak and severity of blossom-end rot increased by fertilization of heavy manure and by accumulation of salts. Accordingly, in the 4th (1981) and the 5th (1982) croppings the fruit yields decreased markedly by blossom-end rot and Fusarium wilt.
Blossom-end rot and disorders of tomatoes increased with a decreasing K/Ca ratio in the culture soil. The K/Ca ratios in the soils of 2nd and 3rd cropping which supplied 50 t/10 a farmyard manure were 0.25 and 0.2, respectively.
It seems that the increase of blossomend rot was caused by the salts accumulation and ammonium production at early fruiting season.
The populations of bacteria and fungi in the soils which supplied 50 and 5 t/10 a farmyard manure and was disinfected and not-disinfected varied with the growth of crops.
The populations of Nematoda, Enchytraeidae and Acari increased remarkably from 1st to 2nd cropping, but decreased suddenly in 3rd one. It is not clear whether this sudden change was caused by a saltaccumulation or any other complex factors.

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Continuous and nondestructive measurement of plant growth in weight is considered to be one of the fundamental techniques used in studying mutual relations between plant growth and its environment. From these standpoints, this study directs to developing measurement systems of plant growth.
A cantilever beam was made by an elastic thin metal plate and a holder of plant stem is attached on its free end. Four strain gages were adhered to different cross sectional parts a distance apart on this beam and composed a bridge circuit. By this circuit, difference of bending moments caused on the beam by plant weight was converted into output voltage and measured. Detection of moment difference has a merit that it is not affected by a change of the acting position of loads. Therefore, it is possible to measure pure plant weight separately no matter how posture of plant changes. Using these weight beam sensors, total measurement systems have been developed and some experiments of cultivating plants in simple and community state have been made. These experimental results can be considered to have enough possibilities for measuring plant growth weight.

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Nineteen bean cultivars were grown from seed in a growth chamber and exposed to 0.6 ppm ozone for 2 hr at 12 days after sowing. The degree of foliar injury of primary leaves was measured by the chlorophyll reduction percentage, and was examined in relation to sugar content, osmotic potential, transpiration rate and leaf diffusion resistance, each parameter being measured prior to ozone exposure, to clarify the main factor controlling intraspecific response to ozone.
Several cultivars exposed to ozone showed no visible injury, while other cultivars exhibited 100% leaf injury.“Wonder Crop No. 2, ”“Green processor, ”and“Bronco”were the most sensitive to ozone ; “Provider”and“Bush Blue Lake 274” were the moderately sensitive; and“Bounty, ”“Goldrush, ”and“Masterpiece improved”were the most resistant.
The sensitive cultivars had less reducing sugar content, lower osmotic potential and higher transpiration rate than the resistant cultivars. However, the obvious relationship between non-reducing sugar content and the degree of foliar injury was not detected. And, ozone injury varied from 90% to 50% with little variation of leaf diffusion resistance.
These results may indicate that, although the role of sugars for the protection of plant from ozone injury is not clear, sugars play a part of detoxication of ozone and/or antioxidation in leaf tissues. And it is considerable to use the sugar content of leaf for an indicator of the sensitivity to ozone in bean cultivars.

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The effects of sulfur dioxide (SO₂) on the appearance of visible injury and photosynthesis in leaves of sunflower plants (Helianthus annuusL. cv. Russian Mammoth) grown in a phytotron greenhouse were examined with respect to leaf maturity. Five weeks old plants were exposed to 2.0 μl l^-1SO₂for 6 hr and the degree of visible injury was measured to demonstrate the leaf age/SO₂sensitivity variation. Young leaves were more SO₂-tolerant than old ones.
Studies were also conducted to elucidate the relationship between concentrations and leaf maturity with respect to the SO₂-induced inhibition of photosynthesis in sunflower leaves, when the relative rate of photosynthesis was logarithmically plotted against time, the line was separated into two straight lines. To describe the degree of inhibition of photosynthesis, the slopes of these lines (designated as the inhibition coefficients) were calculated. The initial coefficient was always higher than the second one, and both coefficients were leaf-age dependent.

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