| Effects of CO2 concentration and temperature elevation on soil microbial biomass at different millet growth stages |
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| DOI：10.7606/j.issn.1000-7601.2022.01.12 |
| Key Words: elevated CO2 concentration warming millet belowground biomass soil microbial biomass mild drought |
| Author Name | Affiliation | | JIAO Jianyu | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China | | ZHENG Fenli | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China
Institute of Soil and Water Conservation, CAS & MWR, Yangling, Shaanxi 712100, China | | WANG Jing | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China | | WANG Xuesong | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China | | WEI Hanmei | State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| This study aimed at quantifying the effects of elevated CO2 concentration and temperature raising, and their interactions on soil microbial biomass at different growth stages of millet. A pot experiment was conducted within artificial climate chambers. Six treatments were designed with three climate scenarios under two water supply conditions. The three climate scenarios included one control experiment (400 μmol·mol-1 CO2 concentration and 22℃ temperature, CK), CO2 concentration elevation and temperature keeping the same as CK (700 μmol·mol-1 CO2 concentration and 22℃ temperature, EC), and both CO2 concentration and temperature elevation (700 μmol·mol-1 CO2 concentration and 26 ℃ temperature, EC+T). Meanwhile, two water conditions (adequate water supply of 70% field capacity; mild drought of 50% field capacity) were design under each climate scenario. The microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbial biomass phosphorus (MBP) contents were measured at four millet growth stages, i.e., anthesis, 10 d after anthesis, filling stage, maturity.The results indicated that under adequate water condition, the elevation of CO2 concentration increased contents of soil MBC, MBN and MBP by 27.01%~102.52%,27.02%~54.60% and 74.05%~161.42% (P＜0.05), respectively; but the effects of elevated CO2 concentration on soil microbial biomass showed decreasing trends with millet growth. Compared with the EC treatment, EC+T treatment reduced contents of soil MBC, MBN and MBP by 19.77%~28.22%, 8.56%~20.24% and 29.54%~39.70% (P＜0.05), respectively. Under the mild drought condition, there were no significant differences in soil MBC and MBN contents at four millet growth stages among three climate scenarios, and the content of soil MBP did not have an obvious changing trend. Compared with adequate water supply condition, mild drought condition decreased contents of soil MBC and MBN by 14.70%~38.53% and 37.06%~78.10% (P＜0.05), respectively,during the stages of anthesis, 10 d after anthesis and filling stage, but it had no significantly impacted on soil MBP.Under the adequate water condition, the interaction of elevated CO2 concentration and temperature rising significantly increased contents of soil MBC and MBN during the stages of anthesis and 10 d after anthesis, MBC and MBN contents increased 44.37%and 16.15% at anthesis, and 45.38% and 27.18% (P＜0.05) at 10 d after anthesis, while the interaction of CO2 concentration and growth stage had significant impacts on soil microbial biomass. In addition, the interaction of temperature increasing and millet growth stage had no significant influences on the contents of soil MBC, MBN and MBP. For millet belowground biomass, under adequate water condition, an elevation of CO2 concentration increased belowground biomass by 85.71% and 27.38% (P＜0.05) during the stages of anthesis and 10 d after anthesis, but there were no significant influences in the belowground biomass during filling stage and maturity.Compared with the EC treatment, EC+T treatment reduced the belowground biomass by 15.12%and 12.44% (P＜0.05) during the stages of anthesis and 10 d after anthesis, but it had no significant effects on the belowground biomass during the stages of falling stage and maturity. Under the mild drought condition, there were no significant differences in the belowground biomass at four millet growth stages among three climate scenarios. |
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