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P^32 ̿ ԫ μϿ

Effects of Green Manures on Rice using P^32

ѱĹȸ 1968 11 3ȣ p.1 ~ 7
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Abstract

Ѧ ϼ٥ϱ Ͽ ԫ Wagner pot(1/20,000) Ͽ ϴ ߫ μ P-32 Ͽ ̿ .
1. Ѧ ڪ , ڪ, г, , ѷ Ÿ ʾҴ.
2. ⦴ ϡ Ͽ pot 10g20g ϡ .
3. /쵵 Ѧ ϡ ϡ Ͽ 󬸦 .
4. Ү P Ѧ Φɼ .
5. ۵ κ Ѧ Φɼ .
6. κ 5ʹ ̸ ̷ μ pot A-value 籵ȴ.
7. Ŀ ԫ ׹ .

Organic matter in rice-paddy soils exercises two antagonistic effects on the rice plant under water-logged conditions in growing season in the course of its decompositioh: It liberates mineral nutrients and promotes soil fertility. On the other hand, however, it demands oxygen for its decay and therefore competes with rice roots for this element, when applied in large quantify of fresh status. For the practical end of rice culture, it is most desirable that these two effects should not contend with each other. To determine the proper content of organic materials to be applied, the influences of varied amounts of a homogeneous mixture of dried green manure, ranging from 0 to 20 g/pot (1/20,000 tanbo), upon the growth of rice was investigated in a sand culture. Labeled phosphorus fertilizer was also used in the form of KH_2^(32)P0_4 to evaIuate the availability of this nutrient in the soil.
Under the present experimental conditions, green manure seems to have influenced little on the growth of rice, except on number of grains produced and grains/straw ratio. Moreover, no sympton of growth inhibition is observable even by the largest amount of its application. The available phosphorus, as estimated by A-value, appears to have increased, as the amount of organic materials applied increases. In view of the fact that pure sand instead of a paddy soil is used in this culture, the present results would not be directly applicable to practical rice faming. Besides, the estimated A-value is in need of further study, since it varies according to method of application, as suggested by Nishigaki et. al. (1958).

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