A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural producti...A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.展开更多
Conventional manufacturing techniques to fabricate microfluidic chips,such as soft lithography and hot embossing process,have limitations that include difficulty in preparing multiple-layered structures,cost-and labor...Conventional manufacturing techniques to fabricate microfluidic chips,such as soft lithography and hot embossing process,have limitations that include difficulty in preparing multiple-layered structures,cost-and labor-consuming fabrication process,and low productivity.Digital light processing(DLP)technology has recently emerged as a costefficient microfabrication approach for the 3D printing of microfluidic chips;however,the fabrication resolution for microchannels is still limited to sub-100 microns at best.Here,we developed an innovative DLP printing strategy for high resolution and scalable microchannel fabrication by dosing-and zoning-controlled vat photopolymerization(DZC-VPP).Specifically,we proposed a modified mathematical model to precisely predict the accumulated UV irradiance for resin photopolymerization,thereby providing guidance for the fabrication of microchannels with enhanced resolution.By fine-tuning the printing parameters,including optical irradiance,exposure time,projection region,and step distance,we can precisely tailor the penetration irradiance stemming from the photopolymerization of the neighboring resin layers,thereby preventing channel blockage due to UV overexposure or compromised bonding stability owing to insufficient resin curing.Remarkably,this strategy can allow the preparation of microchannels with cross-sectional dimensions of 20μm×20μm using a commercial printer with a pixel size of 10μm×10μm;this is significantly higher resolution than previous reports.In addition,this method can enable the scalable and biocompatible fabrication of microfluidic drop-maker units that can be used for cell encapsulation.In general,the current DZC-VPP method can enable major advances in precise and scalable microchannel fabrication and represents a significant step forward for widespread applications of microfluidics-based techniques in biomedical fields.展开更多
Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is ...Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.展开更多
基金supported by the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)the National Natural Science Foundation of China(U21A20218 and 32160765)+3 种基金the earmarked fund for China Agriculture Research System(CARS-22-G-12)the Science and Technology Project of Gansu Province,China(20JR5RA037 and 21JR7RA836)the Postdoctoral Research Start-up Foundation of Gansu Province,China(03824034)the Postdoctoral Research Start-up Foundation of Gansu Agricultural University,China(202403)。
文摘A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.
基金This study was supported by the National Key Research and Development Program of China(No.2018YFA0703000),the National Natural Science Foundation of China(No.31870957),the Fundamental Research Fundamental Funds for the Central Universities(DUT22LAB601),Guangdong Provincial Basic and Applied Basic Research(No.2019A1515110415),and the Shenzhen Basic Research Program general project(JCYJ20190808152211686 and JCYJ20190808120217133).
文摘Conventional manufacturing techniques to fabricate microfluidic chips,such as soft lithography and hot embossing process,have limitations that include difficulty in preparing multiple-layered structures,cost-and labor-consuming fabrication process,and low productivity.Digital light processing(DLP)technology has recently emerged as a costefficient microfabrication approach for the 3D printing of microfluidic chips;however,the fabrication resolution for microchannels is still limited to sub-100 microns at best.Here,we developed an innovative DLP printing strategy for high resolution and scalable microchannel fabrication by dosing-and zoning-controlled vat photopolymerization(DZC-VPP).Specifically,we proposed a modified mathematical model to precisely predict the accumulated UV irradiance for resin photopolymerization,thereby providing guidance for the fabrication of microchannels with enhanced resolution.By fine-tuning the printing parameters,including optical irradiance,exposure time,projection region,and step distance,we can precisely tailor the penetration irradiance stemming from the photopolymerization of the neighboring resin layers,thereby preventing channel blockage due to UV overexposure or compromised bonding stability owing to insufficient resin curing.Remarkably,this strategy can allow the preparation of microchannels with cross-sectional dimensions of 20μm×20μm using a commercial printer with a pixel size of 10μm×10μm;this is significantly higher resolution than previous reports.In addition,this method can enable the scalable and biocompatible fabrication of microfluidic drop-maker units that can be used for cell encapsulation.In general,the current DZC-VPP method can enable major advances in precise and scalable microchannel fabrication and represents a significant step forward for widespread applications of microfluidics-based techniques in biomedical fields.
基金supported by the National Key Research and Development Program of China(2021YFD1700204)the National Natural Science Foundation of China(U21A20218 and 32372238)+1 种基金the Modern Agro-Industry Technology Research System of China(CARS-22-G-12)the“Innovation Star”Program of Graduate Students in 2025 of Gansu Province,China(2025CXZX-749)。
文摘Enhancing soil organic carbon(SOC)stocks is a key aspect of modern agriculture,but whether this can be achieved by incorporating legume green manure crops in cereal production to substitute synthetic N fertilizers is unknown.This study used a six-year(2017-2022)field study to explore the impacts of intercropping green manure with maize and reducing nitrogen fertilization on SOC stocks,while specifically focusing on the relationship between aggregate composition and carbon sequestration.Maize intercropped with common vetch(M/V),maize intercropped with rapeseed(M/R),and sole maize(M),were each tested at conventional(N2,360 kg ha^(-1))and reduced(N1,270 kg ha^(-1),25% reduced)N application rates.Soil was sampled in 2020,2021,and 2022.Compared with sole maize,intercropping with green manure(M/V and M/R)significantly increased SOC stocks which compensated for any negative effect due to the 25% reduction in N application.Based on 3-year averages,intercropping with M/V and M/R increased the SOC content compared to sole maize(M)by 12.1 and 9.1%,respectively,with intercropping further mitigating the negative impact of reduced nitrogen application.There was no significant difference between M/V and M/R.The SOC content at N1 was reduced by 9.3-10.5%compared to that at N2 in sole maize,but the differences in SOC stocks between N1 and N2 were not significant in the intercropping patterns(M/V and M/R).The intercropped M/V and M/R showed 20.9 and 16.3% higher SOC contents compared to sole maize at N1,with no differences at N2.Intercropping green manure led to a 5.3% greater SOC in the 0-20 cm depth soil in 2022 compared to that in 2020,due to the cumulative effect of two years of green manure intercropping.Intercropping green manure(M/V and M/R)increased the proportion of macroaggregates(>0.25 mm)and aggregate stability while reducing the proportion of microaggregates compared to sole maize under the N1 application.Structural equation modeling indicated that cropping patterns and nitrogen application levels mainly affect SOC indirectly by regulating the composition of macroaggregates and aggregate organic carbon(AOC).Correlation analysis further revealed that the composition of macroaggregates is significantly and positively correlated with the SOC content(R^(2)=0.64).In addition,intercropping green manure can maintain high crop yields by increasing SOC under reduced chemical nitrogen application.The results of this study show that intercropping green manure with grain crops can be a viable measure for increasing SOC sinks and maize productivity by optimizing the aggregate composition with reduced N application in the Hexi Oasis Irrigation Area.
