Variation of 15N in Corn and Soil Following Application of Fertilizer Nitrogen

作者：Daniel H. Kohl, GEORGIA B. SHEARER, B. Commoner · 发表于：Soil Science Society of America Journal · 年份：1973 · DOI：10.2136/sssaj1973.03615995003700060028x · 被引用次数：64 · 研究领域：Soil and Water Nutrient Dynamics、Agriculture, Soil, Plant Science、Soil Carbon and Nitrogen Dynamics

Abstract Samples of corn ( Zea mays L.) plant tissue (grain and leaf) were obtained from the University of Illinois South Farm plots and from the University of Illinois Morrow plots. Soil samples were also obtained from each of the South Farm plots. The 15 N: 14 N ratio of the nitrogen in these corn plants is shown to be sensitive to the source of nitrogen taken up by the plants. A systematic decline in δ 15 N (per mill excess 15 N) was observed within a narrow range of variation (about 4 δ 15 N units) with increasing applications of commercial nitrogen fertilizer. This result is consistent with increasing contributions of fertilizer nitrogen to the plant, as the fertilizer had a δ 15 N value close to zero. Similarly, the influence of a small amount of manure nitrogen (40 kg nitrogen/ha) applied over many years was detected in samples grown on the University of Illinois' historic Morrow plots. The results indicate that the nitrogen of grain and the leaf tissue of young plants is derived at least in part from different pools reflecting different proportions of fertilizer and soil nitrogen or fertilizer nitrogen of different δ 15 N, due to the time course of its fractionation. Unexplained differences between the influence of soybeans and clover on δ 15 N were also observed. Neither the quantity nor the δ 15 N of the total nitrogen was influenced by short term (3 years) addition of large quantities of nitrogen (448 kg/ha) to the soil on the South Farm plots. A relatively high va...