As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions...As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon (SOC), nitrogen (N) and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium (Ca), magnesium (Mg), and potassium (K), and cation exchange capacity (CEC) were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium (Na) neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly (P〈0.001) and positively correlated with SOC, total N, pH and electrical conductivity (EC). Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.展开更多
The long-term productivity of a soil is greatly influenced by cation exchange capacity(CEC).Moreover,interactions between dominant base cations and other nutrients are important for the health and stability of grass...The long-term productivity of a soil is greatly influenced by cation exchange capacity(CEC).Moreover,interactions between dominant base cations and other nutrients are important for the health and stability of grassland ecosystems.Soil exchangeable base cations and cation ratios were examined in a 11-year experiment with sheep manure application rates 0–1,500 g/(m2?a) in a semi-arid steppe in Inner Mongolia of China,aiming to clarify the relationships of base cations with soil p H,buffer capacity and fertility.Results showed that CEC and contents of exchangeable calcium(Ca2+),magnesium(Mg2+),potassium(K+) and sodium(Na+) were significantly increased,and Ca2+ saturation tended to decrease,while K+ saturation tended to increase with the increases of sheep manure application rates.The Ca2+/Mg2+ and Ca2+/K+ ratios decreased,while Mg2+,K+ and Na+ saturations increased with increasing manure application rates.Both base cations and CEC were significantly and positively correlated with soil organic carbon(SOC) and soil p H.The increases of SOC and soil p H would be the dominant factors that contribute to the increase of cations in soil.On a comparison with the initial soil p H before the experiment,we deduced that sheep manure application could partly buffer soil p H decrease potentially induced by atmospheric deposition of nitrogen and sulfur.Our results indicate that sheep manure application is beneficial to the maintenance of base cations and the buffering of soil acidification,and therefore can improve soil fertility in the semi-arid steppes of northeastern China.展开更多
Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated ...Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought.Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought,whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought.The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species,and the community biomass resistance and recovery were also greatly driven by the stability of grasses.Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability.Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects.Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.展开更多
Aims We aimed to improve the understanding of the carbon and nutri-ent physiological responses and adaptation of semi-arid grassland plants to environmental changes.Methods We investigated plant leaf non-structural ca...Aims We aimed to improve the understanding of the carbon and nutri-ent physiological responses and adaptation of semi-arid grassland plants to environmental changes.Methods We investigated plant leaf non-structural carbohydrate(NSC=solu-ble sugars+starch),nitrogen(N)and phosphorus(P)levels in an Inner Mongolian semi-arid grassland community treated with water,N and P additions for 8 years.Two dominant grasses(Agropyron cris-tatum(L.)Gaertn.,Stipa krylovii Roshev.)and two forbs(Artemisia frigida Willd.,Potentilla bifurca L.)were analyzed.Important Findings Water addition decreased plant leaf N and P concentrations,whereas N and P addition increased them,indicating that the semi-arid grassland studied suffers from a shortage of N and P sup-ply.Both N and P addition decreased the levels of soluble sugars,starch and thus also NSC in plant leaves,which may be attributed to(i)increased carbohydrate consumption associated with a higher growth rate,and(ii)a dilution effect of greater plant size under N and P addition.Water addition tended to increase the leaf NSC levels both in the grasses(+9.2%)and forbs(+0.6%only),which may be a result of increased photosynthesis of plants with increased water availability.Under conditions of ambient and increased water supply in the present study,N addition resulted in an N/P ratio of>16 in the grasses but a significantly lower N/P ratio of<11 in the forb species.This finding implies that growth of the two grass spe-cies will be limited mainly by P availability but the forbs will still be mainly limited by N supply if N deposition,alone or in combination with summer precipitation,continues to increase as predicted in Inner Mongolia.展开更多
基金supported by the National Key Basic Research Program of China (2011CB403204)the Natural Science Foundation of China (31000200)
文摘As a pioneer leguminous shrub species for vegetation re-establishment, Caragana microphylla is widely distributed in the semi-fixed and fixed sandy lands of the Horqin region, North China. C. microphylla planta- tions modify organic carbon (SOC), nitrogen (N) and phosphorus dynamics, bulk density and water-holding capacity and biological activities in soils, but little is known with regard to soil exchange properties. Variation in soil ex- changeable base cations was examined under C. microphylla plantations with an age sequence of 0, 5, 10, and 22 years in the Horqin Sandy Land, and at the depth of 0-10, 10-20, and 20-30 cm, respectively. C. microphylla has been planted on the non-vegetated sand dunes with similar physical-chemical soil properties. The results showed that exchangeable calcium (Ca), magnesium (Mg), and potassium (K), and cation exchange capacity (CEC) were significantly increased, and Ca saturation tended to decrease, while Mg and K saturations were increased with the plantation years. No difference was observed for exchangeable sodium (Na) neither with plantation years nor at soil depths. Of all the base cations and soil layers, exchangeable K at the depth of 0-10 cm accumulated most quickly, and it increased by 1.76, 3.16, and 4.25 times, respectively after C. microphylla was planted for 5, 10, and 22 years. Exchangeable Ca, Mg, and K, and CEC were significantly (P〈0.001) and positively correlated with SOC, total N, pH and electrical conductivity (EC). Soil pH and SOC are regarded as the main factors influencing the variation in ex- changeable cations, and the preferential absorption of cations by plants and different leaching rates of base cations that modify cation saturations under C. microphylla plantation. It is concluded that as a nitrogen-fixation species, C. microphylla plantation is beneficial to increasing exchangeable base cations and CEC in soils, and therefore can improve soil fertility and create favorable microenvironments for plants and creatures in the semi-arid sandy land ecosystems.
基金funded by the National Natural Science Foundation of China (41371251,31370009)the National Basic Research Program of China (2011CB403204)
文摘The long-term productivity of a soil is greatly influenced by cation exchange capacity(CEC).Moreover,interactions between dominant base cations and other nutrients are important for the health and stability of grassland ecosystems.Soil exchangeable base cations and cation ratios were examined in a 11-year experiment with sheep manure application rates 0–1,500 g/(m2?a) in a semi-arid steppe in Inner Mongolia of China,aiming to clarify the relationships of base cations with soil p H,buffer capacity and fertility.Results showed that CEC and contents of exchangeable calcium(Ca2+),magnesium(Mg2+),potassium(K+) and sodium(Na+) were significantly increased,and Ca2+ saturation tended to decrease,while K+ saturation tended to increase with the increases of sheep manure application rates.The Ca2+/Mg2+ and Ca2+/K+ ratios decreased,while Mg2+,K+ and Na+ saturations increased with increasing manure application rates.Both base cations and CEC were significantly and positively correlated with soil organic carbon(SOC) and soil p H.The increases of SOC and soil p H would be the dominant factors that contribute to the increase of cations in soil.On a comparison with the initial soil p H before the experiment,we deduced that sheep manure application could partly buffer soil p H decrease potentially induced by atmospheric deposition of nitrogen and sulfur.Our results indicate that sheep manure application is beneficial to the maintenance of base cations and the buffering of soil acidification,and therefore can improve soil fertility in the semi-arid steppes of northeastern China.
基金supported by the National Natural Science Foundation of China(32060284,31870441)the Natural Science Foundation of Inner Mongolia,China(2019JQ04)+2 种基金the Central Government Guides the Local Science and Technology Development Foundation(2020ZY0027)the National Science Foundation of the United States(DEB-1856318,CBET-1833988)the Natural Science Foundation of Hebei Province(C2022201042)。
文摘Nitrogen enrichment and land use are known to influence various ecosystems,but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood.Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought.Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought,whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought.The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species,and the community biomass resistance and recovery were also greatly driven by the stability of grasses.Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability.Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects.Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.
基金The National Natural Science Foundation of China(41371076,31370009)the National Key Basic Research Program of China(2011CB403204)the State Key Laboratory of Forest and Soil Ecology(LFSE2013-01).
文摘Aims We aimed to improve the understanding of the carbon and nutri-ent physiological responses and adaptation of semi-arid grassland plants to environmental changes.Methods We investigated plant leaf non-structural carbohydrate(NSC=solu-ble sugars+starch),nitrogen(N)and phosphorus(P)levels in an Inner Mongolian semi-arid grassland community treated with water,N and P additions for 8 years.Two dominant grasses(Agropyron cris-tatum(L.)Gaertn.,Stipa krylovii Roshev.)and two forbs(Artemisia frigida Willd.,Potentilla bifurca L.)were analyzed.Important Findings Water addition decreased plant leaf N and P concentrations,whereas N and P addition increased them,indicating that the semi-arid grassland studied suffers from a shortage of N and P sup-ply.Both N and P addition decreased the levels of soluble sugars,starch and thus also NSC in plant leaves,which may be attributed to(i)increased carbohydrate consumption associated with a higher growth rate,and(ii)a dilution effect of greater plant size under N and P addition.Water addition tended to increase the leaf NSC levels both in the grasses(+9.2%)and forbs(+0.6%only),which may be a result of increased photosynthesis of plants with increased water availability.Under conditions of ambient and increased water supply in the present study,N addition resulted in an N/P ratio of>16 in the grasses but a significantly lower N/P ratio of<11 in the forb species.This finding implies that growth of the two grass spe-cies will be limited mainly by P availability but the forbs will still be mainly limited by N supply if N deposition,alone or in combination with summer precipitation,continues to increase as predicted in Inner Mongolia.