Nitrogen uptake and use of two contrasting maize hybrids differing in leaf senescence

被引:228
作者
Ma, BL [1 ]
Dwyer, LM [1 ]
机构
[1] Agr & Agri Food Canada, Cent Expt Farm, Eastern Cereal & Oilseed Res Ctr, Res Branch, Ottawa, ON K1A 0C6, Canada
关键词
dry matter partitioning; maize; N-15; nitrogen uptake; nitrogen use efficiency; senescence; Zea mays;
D O I
10.1023/A:1004397219723
中图分类号
S3 [农学(农艺学)];
学科分类号
0901 ;
摘要
In eastern Canada, the use of fertilizer N has been identified as the most energy-consuming component of maize (Zea mays L.) grain production. As the economic and environmental costs of excessive N fertilization rise, there is an increased emphasis on selection of hybrids with greater N use efficiency (NUE; defined as the ratio of the amount of N-15 recovered in grain or stover dry matter to the amount of fertilizer N-15 applied to the soil in this study). Using an N-15-labelling approach, a field study was conducted on a tile-drained Brandon loam soil (Typic Endoaquoll) on the Central Experimental Farm at Ottawa, Canada (45 degrees 22' N, 75 degrees 43' W) in 1993 and 1994. Fertilizer N uptake and partitioning within the plant in relation to dry matter changes were monitored during development of a current stay-green maize hybrid and an older early-senescing hybrid grown with three fertilizer N levels (0, 100, 200 kg N ha(-1)). Dry matter, N concentration and N-15 atom% enrichment of plant components were determined at five growth stages. The current stay-green hybrid, 'Pioneer 3902' had greater NUE than the old early-senescing hybrid, 'Pride 5', which was associated with 24% more dry matter production and 20% more N uptake during grain fill for Pioneer 3902. There was no indication of greater allocation of N to the grain in Pioneer 3902. Our data suggest that prolonged maintenance of green leaf area for photosynthate production during grain fill and the ability to take up available soil N later in grain filling are characteristics of maize hybrids with greater NUE.
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页码:283 / 291
页数:9
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