• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.699-707
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• 1992

Three goats were fed with $^{15}N$-labelled rice straw to study the characteristics of digestion, assimilation, metabolism and excretion of C and N compounds from rice straw. It was shown that the amount of $^{15}N$ assimilated into the bodies of the two slaughtered goats accounted for 38.5 and 23.6% of the total amount of $^{15}N$ ingestion in the experimental diet by each goat. The $^{15}N$ excreted via the feces and urine for the three goats accounted for 34.8, 33.2 and 33.9% of the total amount of $^{15}N$ ingested in the feed of the 3 goats. The recoveries of $^{15}N$ from the two slaughtered goats were 73.3 and 57.5%, with the corresponding rates of $^{15}N$ loss 26.7 and 42.5% respectively. The amino acids digestibilities were 68.7 and 54.0%, while the digestibilities of carbohydrates were 74.8 and 67.7% respectively for goats 1 and 3.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.142-149
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• 1982

Use efficiency of top-dressed labelled nitrogen(30% at ear formation stage) ranged 23 to 61%(five fields) with no clear difference between varieties. In high yield soil the use efficiency of top-dressed nitrogen was higher and more than 50% of fertilizer nitrogen in plant seemed to be taken up after ear formation, $^{15}N$ excess was greatest in grain indicating that top-dressed nitrogen translocates easily to grain. The difference of $^{15}N$ excess between grain and straw was greater in Tonsil line than in the local indicating faster nitrogen translocation in Tangil. Percent nitrogen derived from top-dressed nitrogen ranged 14 to 27% in aerial part. Two 3-hill plots per treatment could be enough for $^{15}N$ experiment under field condition if there is specific care.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.113-118
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• 1974

A study was carried out to investigate the effect of application time of fertilizer nitrogen on its rate of uptake and its distribution in rice plant. The rate of applied fertilizer was 100kg/ha, as a single application at transplanting time and four equal split applications of 25kg/ha was applied at transplanting time, 3 weeks after transplanting, 1 week before the primodial initiation stage of growth and at the flag leaf stage of growth, respectively. The ammonium sulfate was labelled with N-15, as 1% atom excess for single application and 4.4% atom excess for split applications. The results are sumarized as follows: 1. The effect of split application of nitrogen on yield was observed. The yield of brown rice of the single application at transplanting time was 3.1 ton/ha and the split application was 3.4 ton/ha. However, without nitrogen the yield was reduced to 1.9 ton/ha. 2. The number of grains per panicle and 1000 grains weight were increased as split application of nitrogen, but for the number of panicles per hill and maturing rate, the single application of nitrogen revealed favorable results. 3. The rate of uptake of applied fertilizer nitrogen showed a tendency that the efficiency of fertilizer nitrogen increased by top dressing. The rate of uptake of applied nitrogen as basal application, first top dressing, second top dressing and third top dressing was 28%, 33% 51% and 63%, respectively. 4. After shooting stage of the growth, nitrogen in straws transfered to grains. The nitrogen applied at flag leaf stage was absorbed by root and easily accumulated in grains rather than straw.