Soil salinization is a critical environmental issue restricting agricultural production.Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress.However,t...Soil salinization is a critical environmental issue restricting agricultural production.Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress.However,the legacy effects of straw added as an interlayer at different rates on soil organic carbon (SOC) and total nitrogen (TN) in saline soils still remain inconclusive.Therefore,a four-year (2015–2018) field experiment was conducted with four levels (i.e.,0,6,12and 18 Mg ha~(–1)) of straw returned as an interlayer.Compared with no straw interlayer (CK),straw addition increased SOC concentration by 14–32 and 11–57%in the 20–40 and 40–60 cm soil layers,respectively.The increases in soil TN concentration (8–22 and 6–34%in the 20–40 and 40–60 cm soil layers,respectively) were lower than that for SOC concentration,which led to increased soil C:N ratio in the 20–60 cm soil depth.Increases in SOC and TN concentrations in the 20–60 cm soil layer with straw addition led to a decrease in stratification ratios (0–20 cm:20–60 cm),which promoted uniform distributions of SOC and TN in the soil profile.Increases in SOC and TN concentrations were associated with soil salinity and moisture regulation and improved sunflower yield.Generally,compared with other treatments,the application of 12 Mg ha~(–1) straw had higher SOC,TN and C:N ratio,and lower soil stratification ratio in the2015–2017 period.The results highlighted that legacy effects of straw application as an interlayer were maintained for at least four years,and demonstrated that deep soil straw application had a great potential for improving subsoil fertility in salt-affected soils.展开更多
In the context of global efforts to reduce carbon(C)emissions,several studies have examined the effects of agricultural practices such as straw returning and fertilization on C sequestration by microorganisms.However,...In the context of global efforts to reduce carbon(C)emissions,several studies have examined the effects of agricultural practices such as straw returning and fertilization on C sequestration by microorganisms.However,our understanding of the specific microbial groups and their roles in long-term C increase remains limited.In this study,a 36-year(1984-2020)farmland experiment was conducted to investigate the impact of bacterial C metabolism on the augmentation of organic C in a Typic Hapludoll(Mollisol)in the black soil region of Jilin Province,Northeast China.Our results demonstrated a noteworthy increase in the diversity of microorganisms in the farmland as a result of long-term straw returning and application of mixed chemical fertilizers.However,by examining the functions of microorganisms involved in C metabolism,it was observed that the effects of fertilization on C metabolism were relatively consistent.This consistency was attributed to a deterministic competitive exclusion process,which minimized the differences between treatment groups.On the other hand,the influence of straw addition on C metabolism appeared to follow a more random pattern.These changes in microbial activity were closely linked to the downregulation of core metabolic pathways related to C metabolism.Notably,long-term fertilization had a negative impact on soil organic C levels,while long-term straw returning plus fertilization resulted in a positive increase in soil organic C.These findings have important implications for enhancing soil organic C and grain yield in the regions with typical black soil.展开更多
Straw return in situ,a common agronomic measure in China,has been widely used not only to increase crop yields and improve soil nutrients but also to remove polycyclic aromatic hydrocarbons(PAHs)from agricultural soil...Straw return in situ,a common agronomic measure in China,has been widely used not only to increase crop yields and improve soil nutrients but also to remove polycyclic aromatic hydrocarbons(PAHs)from agricultural soils.Nevertheless,the safety risks of food crops(i.e.,human health risk of wheat grains)grown in PAHs-contaminated agricultural soils amended with crop straw remain uncertain.A pot experiment was conducted in a PAHs-contaminated agricultural soil cultivated with winter wheat under different ratios of corn straw addition(0%(control,CK),1%,2.5%,and 5%,weight/weight).Results showed that corn straw addition significantly(P<0.05)decreased PAH concentrations in rhizosphere soil,roots,straws,and grains by 48.32%–50.01%,11.85%–42.67%,9.78%–28.03%,and 14.16%–31.67%,respectively,compared with CK,whereas the transfer factors of PAHs from roots to straws were significantly(P<0.05)increased.A correlation heatmap showed that PAH concentrations in roots,straws,and grains were positively(P<0.01)correlated with those in rhizosphere soil.These indicated that corn straw decreased PAH accumulation in winter wheat due to the increase of PAH dissipation in the rhizosphere soil,although it enhanced PAH transfer in winter wheat.The incremental lifetime cancer risk(ILCR)model indicated that corn straw significantly(P<0.05)decreased the human health risk of winter wheat grains by 29.73%–45.05%.Overall,corn straw apparently reduced PAH accumulation in winter wheat,ecological risk,and human health risk via enhancing PAH dissipation in the rhizosphere soil.These findings provide an important scientific basis and theoretical guidance for agricultural safety production.展开更多
基金funded by the National Natural Science Foundation of China (31871584)the Agricultural Science and Technology Innovation Program, Chinese Academy of Agricultural Sciences (CAAS-ZDRW202201)+2 种基金the Fundamental Research Funds for Central Non-profit Scientific Institution, China (1610132020011)the “Open the list” in charge of the Science and Technology Project of Ordos, Center for Agro-pastoral Ecology and Resource Conservation of Ordos City, Inner Mongolia, China (JBGS2021-001)the Inner Mongolia Autonomous Region Research Project (2021EEDSCXSFQZD011)。
文摘Soil salinization is a critical environmental issue restricting agricultural production.Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress.However,the legacy effects of straw added as an interlayer at different rates on soil organic carbon (SOC) and total nitrogen (TN) in saline soils still remain inconclusive.Therefore,a four-year (2015–2018) field experiment was conducted with four levels (i.e.,0,6,12and 18 Mg ha~(–1)) of straw returned as an interlayer.Compared with no straw interlayer (CK),straw addition increased SOC concentration by 14–32 and 11–57%in the 20–40 and 40–60 cm soil layers,respectively.The increases in soil TN concentration (8–22 and 6–34%in the 20–40 and 40–60 cm soil layers,respectively) were lower than that for SOC concentration,which led to increased soil C:N ratio in the 20–60 cm soil depth.Increases in SOC and TN concentrations in the 20–60 cm soil layer with straw addition led to a decrease in stratification ratios (0–20 cm:20–60 cm),which promoted uniform distributions of SOC and TN in the soil profile.Increases in SOC and TN concentrations were associated with soil salinity and moisture regulation and improved sunflower yield.Generally,compared with other treatments,the application of 12 Mg ha~(–1) straw had higher SOC,TN and C:N ratio,and lower soil stratification ratio in the2015–2017 period.The results highlighted that legacy effects of straw application as an interlayer were maintained for at least four years,and demonstrated that deep soil straw application had a great potential for improving subsoil fertility in salt-affected soils.
基金funded by the Science and Technology Cooperation Project Between Jilin Province and Chinese Academy of Sciences(No.2022000170)the National Natural Science Foundation of China(Nos.41920104008 and U22A20593)the Strategic Priority Research Program of CAS(No.XDA28020400)。
文摘In the context of global efforts to reduce carbon(C)emissions,several studies have examined the effects of agricultural practices such as straw returning and fertilization on C sequestration by microorganisms.However,our understanding of the specific microbial groups and their roles in long-term C increase remains limited.In this study,a 36-year(1984-2020)farmland experiment was conducted to investigate the impact of bacterial C metabolism on the augmentation of organic C in a Typic Hapludoll(Mollisol)in the black soil region of Jilin Province,Northeast China.Our results demonstrated a noteworthy increase in the diversity of microorganisms in the farmland as a result of long-term straw returning and application of mixed chemical fertilizers.However,by examining the functions of microorganisms involved in C metabolism,it was observed that the effects of fertilization on C metabolism were relatively consistent.This consistency was attributed to a deterministic competitive exclusion process,which minimized the differences between treatment groups.On the other hand,the influence of straw addition on C metabolism appeared to follow a more random pattern.These changes in microbial activity were closely linked to the downregulation of core metabolic pathways related to C metabolism.Notably,long-term fertilization had a negative impact on soil organic C levels,while long-term straw returning plus fertilization resulted in a positive increase in soil organic C.These findings have important implications for enhancing soil organic C and grain yield in the regions with typical black soil.
基金supported by the National Natural Science Foundation of China(Nos.41571456 and 42077325)the Natural Science Basic Research Program of Shaanxi,China(No.2023-JC-ZD-17).
文摘Straw return in situ,a common agronomic measure in China,has been widely used not only to increase crop yields and improve soil nutrients but also to remove polycyclic aromatic hydrocarbons(PAHs)from agricultural soils.Nevertheless,the safety risks of food crops(i.e.,human health risk of wheat grains)grown in PAHs-contaminated agricultural soils amended with crop straw remain uncertain.A pot experiment was conducted in a PAHs-contaminated agricultural soil cultivated with winter wheat under different ratios of corn straw addition(0%(control,CK),1%,2.5%,and 5%,weight/weight).Results showed that corn straw addition significantly(P<0.05)decreased PAH concentrations in rhizosphere soil,roots,straws,and grains by 48.32%–50.01%,11.85%–42.67%,9.78%–28.03%,and 14.16%–31.67%,respectively,compared with CK,whereas the transfer factors of PAHs from roots to straws were significantly(P<0.05)increased.A correlation heatmap showed that PAH concentrations in roots,straws,and grains were positively(P<0.01)correlated with those in rhizosphere soil.These indicated that corn straw decreased PAH accumulation in winter wheat due to the increase of PAH dissipation in the rhizosphere soil,although it enhanced PAH transfer in winter wheat.The incremental lifetime cancer risk(ILCR)model indicated that corn straw significantly(P<0.05)decreased the human health risk of winter wheat grains by 29.73%–45.05%.Overall,corn straw apparently reduced PAH accumulation in winter wheat,ecological risk,and human health risk via enhancing PAH dissipation in the rhizosphere soil.These findings provide an important scientific basis and theoretical guidance for agricultural safety production.
