干旱区生态环境知识资源中心(Arid): An isotopic proxy for nitrogen redistribution from Alnus acuminata to wheat intercrop

Arid

DOI	10.1017/S0014479721000284
	An isotopic proxy for nitrogen redistribution from Alnus acuminata to wheat intercrop
	Ukozehasi, Celestin; Griffiths, Howard
通讯作者	Ukozehasi, C (corresponding author)，Univ Rwanda, Sch Agr & Food Sci, Kigali 6605, Rwanda.
来源期刊	EXPERIMENTAL AGRICULTURE
ISSN	0014-4797
EISSN	1469-4441
出版年	2022-02
英文摘要	Direct belowground nitrogen (N) transfer has often been reported where plants with contrasting nutrients acquisition strategies (N-2-fixing and non-fixing) co-occur, and there is still a gap in the knowledge of the extent of this transfer in the top soil under the field conditions. However, assessment under field conditions is challenging. We hypothesized a practical application of the analysis of natural abundance of delta N-15 supplemented with an isotopic mixing model 'IsoSource' to understand the relative direct contribution of N-2-fixing Alnus acuminata to wheat intercrop (non-fixing) N isotopic signatures. A field experiment was conducted in an andic soil of high lands in northern Rwanda to quantitatively determine the proportional contribution of nitrogen by Alnus acuminata to wheat vegetative tissue isotope signatures at different distances from the trees (1 m, 3 m, 5 m, and 7 m). The study involved the measurements and analyses of natural abundance of stable isotopes delta N-15 and isotopic mixing modeling by IsoSource. Leaf samples were collected from twigs of 10 years old Alnus acuminata grown on the terrace-risers, along with soil samples (0-20 cm) and wheat flag leaf samples across terrace at 1 m, 3 m, 5 m, and 7 m from trees for isotopic measurement. The chlorophyll content index of wheat flag leaf at the four points across terrace was estimated by means of SPAD meter 502. The delta N-15 proportional contribution by Alnus acuminata to wheat was obtained through IsoSource analysis. We noted a significant (p < 0 center dot 01) gradient in depletion of wheat delta N-15 signatures moving further away from the tree line of Alnus acuminata. The wheat at 1 m from the trees exhibited the delta N-15 values closer to that of the tree, while at 7 m, the crop delta N-15 signature was significantly different from that of the tree. An isotopic mixing model 'IsoSource' indicated that the tree N may have provided 33 center dot 6 +/- 4 center dot 3 % of the wheat intercrop N at 1 m distance from the trees. Therefore, this study shows that the understanding of field-based crop N and nutrient transfer in agroforestry may be enhanced by analysis of the physiological basis of stable isotopes signatures.
英文关键词	Intercropping Isotopic proxy N transfer IsoSource Wheat Alnus acuminata Rwanda
类型	Article ; Early Access
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000757761500001
WOS关键词	N-15 NATURAL-ABUNDANCE ; SONORAN DESERT ; STABLE-ISOTOPES ; SOIL PROPERTIES ; LEGUME TREE ; PLANT ; AGROFORESTRY ; GRASS ; SYSTEMS ; CARBON
WOS类目	Agronomy
WOS研究方向	Agriculture
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/377266
作者单位	[Ukozehasi, Celestin] Univ Rwanda, Sch Agr & Food Sci, Kigali 6605, Rwanda; [Griffiths, Howard] Univ Cambridge, Dept Plant Sci, Cambridge CB2 3EA, England
推荐引用方式 GB/T 7714	Ukozehasi, Celestin,Griffiths, Howard. An isotopic proxy for nitrogen redistribution from Alnus acuminata to wheat intercrop[J],2022.
APA	Ukozehasi, Celestin,&Griffiths, Howard.(2022).An isotopic proxy for nitrogen redistribution from Alnus acuminata to wheat intercrop.EXPERIMENTAL AGRICULTURE.
MLA	Ukozehasi, Celestin,et al."An isotopic proxy for nitrogen redistribution from Alnus acuminata to wheat intercrop".EXPERIMENTAL AGRICULTURE (2022).