干旱区生态环境知识资源中心(Arid): Insight into factors controlling formation rates of pedogenic carbonates: A combined geochemical and isotopic approach in dryland soils of the US Southwest

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DOI	10.1016/j.chemgeo.2017.10.014
	Insight into factors controlling formation rates of pedogenic carbonates: A combined geochemical and isotopic approach in dryland soils of the US Southwest
	Nyachoti, Syprose 1; Jin, Lixin 1; Tweedie, Craig E.2; Ma, Lin 1
通讯作者	Jin, Lixin
来源期刊	CHEMICAL GEOLOGY
ISSN	0009-2541
EISSN	1872-6836
出版年	2019
卷号	527
英文摘要	Natural accumulation of pedogenic carbonates has been well documented but few studies have focused on carbonate formation in agricultural drylands. This study aims to determine accumulation rates of pedogenic carbonates in intensively irrigated soils, and to define key linkages between flood irrigation, salt loading and soil-atmosphere CO2 exchange in cultivated drylands of the southwestern United States. We used a combination of elemental chemistry (CaO, soil organic and inorganic carbon contents), mineralogy, and U-series (U-238-U-234-Th-230) disequilibrium dating technique to investigate calcium sources, ages and formation rates of pedogenic carbonates. Study sites include an irrigated alfalfa field near El Paso in western Texas and a non-irrigated natural dryland site on the USDA Jornada Experimental Range of southern New Mexico. Our results showed that large amounts of dissolved calcium and inorganic carbon along with other soluble elements were loaded onto agricultural fields through irrigation waters in El Paso, TX while dust and rainfall were important for salt loading in natural soils of the Jornada. U-series activity ratios, (U-234/U-238) and (Th-230/U-238), in bulk soils suggested eolian deposits added U and modified U isotopes in shallow soils at both the irrigated and natural sites. Mobility of U-234 within the soil profile is related to leaching of U (and by inference other soluble ions) and carbonate accumulation at depth. The U-series dating technique in pedogenic carbonates revealed the presence of much younger carbonates at the irrigated site compared to the natural site. Pedogenic carbonate formation rates in the irrigated soils were also much higher than those in the non-irrigated soils, likely a result of influxes from dissolved Ca and inorganic carbon in water used for irrigation. This study demonstrates the potential for agricultural expansion and land use change in drylands to increase rate of pedogenic carbonate accumulation. Such changes may have important implications to global carbon cycling since drylands are forecast to become the most expansive terrestrial biome by mid-century and dryland agriculture is expanding quickly.
英文关键词	Dryland irrigation Salt loading Pedogenic carbonates U-isotopes
类型	Article
语种	英语
国家	USA
收录类别	SCI-E
WOS记录号	WOS:000501718200011
WOS关键词	RIO-GRANDE RIFT ; MOJAVE-DESERT ; WEATHERING PROFILES ; NEW-MEXICO ; BASIN ; RIVER ; MORPHOLOGY ; THORIUM ; GENESIS ; VALLEY
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
EI主题词	2019-11-20
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/310952
作者单位	1.Univ Texas El Paso, Dept Geol Sci, El Paso, TX 79968 USA; 2.Univ Texas El Paso, Dept Biol Sci, El Paso, TX 79968 USA
推荐引用方式 GB/T 7714	Nyachoti, Syprose,Jin, Lixin,Tweedie, Craig E.,et al. Insight into factors controlling formation rates of pedogenic carbonates: A combined geochemical and isotopic approach in dryland soils of the US Southwest[J],2019,527.
APA	Nyachoti, Syprose,Jin, Lixin,Tweedie, Craig E.,&Ma, Lin.(2019).Insight into factors controlling formation rates of pedogenic carbonates: A combined geochemical and isotopic approach in dryland soils of the US Southwest.CHEMICAL GEOLOGY,527.
MLA	Nyachoti, Syprose,et al."Insight into factors controlling formation rates of pedogenic carbonates: A combined geochemical and isotopic approach in dryland soils of the US Southwest".CHEMICAL GEOLOGY 527(2019).