Experimental sand burial and precipitation enhancement alter plant and soil carbon allocation in a semi-arid steppe in north China

The Songnen grasslands were traditionally thought to be dominated by Artemisia and Chenopodiaceae plants as early as the late Pleistocene. However, increasing evidence has called that interpretation into question. To shed new light on the paleovegetation evolution of the arid and semi-arid steppe in North China, phytolith assemblages preserved in the region’s sand-paleosol sequence (section Daike) are used as a proxy for paleovegetation structure. Results show that both the sand and paleosol layers in the Songnen grassland sections contain well-preserved phytoliths attributed to different families of grass. This is the first direct evidence of the nature of the vegetation that existed during the sandy layer episodes. Moreover, the phytolith evidence represented in the samples indicates that plant successions happened within the subfamilies of Poaceae through the time. Referring to phytoliths in modern plants and topsoils, and using statistical analyses, we propose that phytolith assemblages in the section Daike originated from Poaceae-dominant communities rather than an Artemisia-Chenopodiaceae ecosystem. The phytoliths, and evidence from the historical and modern pollen-vegetation relationships, lead to rejection of the hypothesis of a past widespread Artemisia-Chenopodiaceae ecosystem in the Songnen grasslands. Using published radiocarbon and thermoluminescence data, it is proposed that the present Poaceae-dominated grasslands developed as early as the early Holocene. This study also highlights the usefulness of phytolith analysis in paleovegetation reconstruction in arid and semi-arid lands.

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Soil Carbon Dioxide Emissions from Sorghum–Sunflower Rotation in Rainfed Semi-arid Tropical Alfisols: Effects of Fertilization Rate and Legume Biomass Incorporation

Communications in Soil Science and Plant Analysis ◽

10.1080/00103624.2012.689399 ◽

2012 ◽

Vol 43 (14) ◽

pp. 1915-1929 ◽

Cited By ~ 1

Author(s):

V. Ramesh ◽

B. Venkateswarlu ◽

K. L. Sharma ◽

S. P. Wani

Keyword(s):

Carbon Dioxide ◽

Soil Carbon ◽

Carbon Dioxide Emissions ◽

Fertilization Rate ◽

Soil Carbon Dioxide ◽

Semi Arid

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Effects of defoliation timing on plant nutrient resorption and hay production in a semi-arid steppe

Journal of Plant Ecology ◽

10.1093/jpe/rtaa076 ◽

2020 ◽

Author(s):

Tongrui Zhang ◽

Frank Yonghong Li ◽

Hao Wang ◽

Lin Wu ◽

Chunjun Shi ◽

...

Keyword(s):

Nutrient Cycling ◽

Nutrient Resorption ◽

Plant Production ◽

Conservation Strategy ◽

Plant Nutrient ◽

Resorption Efficiency ◽

Nutrient Return ◽

Peak Biomass ◽

Arid Steppe ◽

Semi Arid

Abstract Aims Nutrient resorption is a key plant nutrient conservation strategy, and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems. Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands, while the effect of defoliation timing has not been unexplored. The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem. Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments: early defoliation, peak defoliation, late defoliation and non-defoliation. We measured plant nitrogen (N) and phosphorus (P) resorption at species and community levels, and quantified plant N and P fluxes in resorption, litter return and hay output. Plant production in the mowing system was assessed by hay production and quality. Important Findings Peak and late defoliation, but not early defoliation, reduced plant community N and P resorption proficiency (RP); and late defoliation reduced N resorption efficiency (RE) but not P resorption efficiency. Peak and late defoliation, but not early defoliation, reduced plant nutrient resorption flux and litter nutrient return flux. Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption. Peak defoliation had the highest hay production and quality, while early defoliation had the lowest. Our results provide new insights into the nutrient cycling in mowing grassland, and imply that the mowing timing can be used as a tool to mediate the balance between conservation and production of steppes, and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.

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