Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,t...Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.展开更多
Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was ...Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was to examine the effect of liming on rice production,yield and P uptake in a three-year field experiment in a double rice cropping system in subtropical China.We also conducted an incubation experiment to investigate the direct effect of liming on soil available P and phosphatase activities on paddy soils in the absence of plants.In the incubation experiment,liming reduced soil P availability(measured as Olsenextractable P)by 14–17%and inhibited the activity of soil acid phosphatase.Nonetheless,lime application increased grain yield,biomass,and P uptake in the field.Liming increased grain yield and P uptake more strongly for late rice(26 and 21%,respectively)than for early rice(15 and 8%,respectively).Liming reduced the concentration of soil available P in the field as well,reflecting the increase in rice P uptake and the direct negative effect of liming on soil P availability.Taken together,these results suggest that by stimulating rice growth,liming can overcome direct negative effects on soil P availability and increase plant P uptake in this acidic paddy soil where P is not the limiting factor.展开更多
基金supported by the National Key Research and Development Program of China(2017YFD0300104,2016YFD0300903,2015BAC02B02)the National Natural Science Foundation of China(32022061)+3 种基金the Special Fund for Agroscientific Research in the Public Interest(201503118,201503122)the Agricultural Science and Technology Innovation Program of CAAS(Y2016PT12,Y2016XT01)the Modern Agricultural Development of Jiangsu Province(2019-SJ-039-07)the GEF Project of Climate Smart Staple Crop Production in China(P144531)。
文摘Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.
基金This work was supported by the National Key Research and Development Program of China(2018YFD0301102)the National Natural Science Foundation of China(31701383).
文摘Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was to examine the effect of liming on rice production,yield and P uptake in a three-year field experiment in a double rice cropping system in subtropical China.We also conducted an incubation experiment to investigate the direct effect of liming on soil available P and phosphatase activities on paddy soils in the absence of plants.In the incubation experiment,liming reduced soil P availability(measured as Olsenextractable P)by 14–17%and inhibited the activity of soil acid phosphatase.Nonetheless,lime application increased grain yield,biomass,and P uptake in the field.Liming increased grain yield and P uptake more strongly for late rice(26 and 21%,respectively)than for early rice(15 and 8%,respectively).Liming reduced the concentration of soil available P in the field as well,reflecting the increase in rice P uptake and the direct negative effect of liming on soil P availability.Taken together,these results suggest that by stimulating rice growth,liming can overcome direct negative effects on soil P availability and increase plant P uptake in this acidic paddy soil where P is not the limiting factor.