Sustainability of traditionally cultivated rice in the rice-wheat cropping zone(RWCZ)of Pakistan is dwindling due to the high cost of production,declining water resources and escalating labour availability.Thus,farmer...Sustainability of traditionally cultivated rice in the rice-wheat cropping zone(RWCZ)of Pakistan is dwindling due to the high cost of production,declining water resources and escalating labour availability.Thus,farmers and researchers are compelled to find promising alternatives to traditional transplanted rice(TPR).A field study was conducted in Punjab,Pakistan,in 2017 and 2018 to explore the trade-offs between water saving and paddy yield,water productivity and economics of two aromatic rice varieties under dry direct seeded rice(DDSR)and TPR.The experiment was comprised of three irrigation regimes on the basis of soil moisture tension(SMT)viz.,continuous flooded(>–10 kPa SMT),alternate wetting and drying(AWD)(–20 kPa SMT)and aerobic rice(–40 kPa SMT),maintained under TPR and DDSR systems.Two aromatic rice verities:Basmati-515 and Chenab Basmati-2016 were used during both years of study.In both years,DDSR produced higher yields(13–18%)and reduced the total water inputs(8–12%)in comparison to TPR.In comparison to traditional continuous flooded(CF),AWD under DDSR reduced total water input by 27–29%and improved the leaf area index(LAI),tillering,yield(7–9%),and water productivity(44–50%).The performance of AWD with regard to water savings and increased productivity was much higher in DDSR system as compared to AWD in TPR system.Cultivation of DDSR with aerobic irrigation improved water savings(49–55%)and water productivity(22–30%)at the expense of paddy yield reduction(36–39%)and spikelet sterility.With regard to variety,the highest paddy yield(6.6 and 6.7 t ha–1)was recorded in DDSR using Chenab Basmati-2016 under AWD irrigation threshold that attributed to high tiller density and LAI.The economic analysis showed DDSR as more beneficial rice establishment method than TPR with a high benefit-cost ratio(BCR)when the crop was irrigated with AWD irrigation threshold.Our results highlighted that with the use of short duration varieties,DDSR cultivation in conjunction with AWD irrigation can be more beneficial for higher productivity and crop yield.展开更多
Over the past decades, the Arctic Ocean has experienced rapid warming under climate change, which has dramatically altered its physical and biogeochemical properties. Reduction in the sea-ice cover is one of the most ...Over the past decades, the Arctic Ocean has experienced rapid warming under climate change, which has dramatically altered its physical and biogeochemical properties. Reduction in the sea-ice cover is one of the most important driving forces of biogeochemical changes in the Arctic Ocean. Between 1999 and 2016, seven Chinese National Arctic Research Expeditions have taken place in the Bering and Chukchi seas, allowing assessment of the biogeochemical response of the western Arctic Ocean to global warming. Herein, we summarize advances in Chinese and international marine biogeochemistry research in the western Arctic Ocean, reviewing results from the Chinese expeditions and highlighting future trends of biogeochemistry in the Pacific Arctic region. The findings reported in this paper contribute towards a better understanding of water masses, greenhouse gases, nutrients, ocean acidification, and organic carbon export and burial processes in this region.展开更多
In order to obtain the optimal input of water and nitrogen(W&N)suitable for the jujube trees in Northern Shaanxi,12 treatments had been set in the demonstration base of micro-irrigation jujube tree of Mizhi County...In order to obtain the optimal input of water and nitrogen(W&N)suitable for the jujube trees in Northern Shaanxi,12 treatments had been set in the demonstration base of micro-irrigation jujube tree of Mizhi County in 2014-2015 through field experiment of jujube trees under surge root irrigation(SRI),in which three soil moisture levels(high moisture level W1:60%-85%θ,middle moisture level W2:50%-75%θ,low moisture level W3:40%-65%θ)and four nitrogen input levels(high nitrogen F75:0.75 kg/plant,middle nitrogen F50:0.50 kg/plant,low nitrogen F25:0.25 kg/plant,no nitrogen F0:0.00 kg/plant)were set.Through analyzing the effects of different W&N inputs on the yield,net income(NI)and W&N utilization efficiency(WUE and NUE)of jujube trees and establishing a weighted grey correlation model,the optimization of W&N input for jujube trees could be achieved under SRI.Results showed that different W&N inputs had significant influences on yield,NI,WUE and NUE.Along with the increase of soil moisture content,the yield and NUE increased,while WUE decreased gradually,and the NI had the tendency to increase first and then decrease.Along with the increase of nitrogen input,the yield,NI and WUE had the tendency to increase first and then decrease while the NUE decreased significantly,and the yield,NI,WUE and NUE could not reach the maximum at the same time.Through the study on the grey correlation model of jujube tree’s comprehensive benefit based on the yield,NI,WUE and NUE,results showed the comprehensive benefit of jujube trees was significantly different when W&N input was different,and the gray correlation degree of W2F25 treatment was the highest in two years,which means that the soil moisture content of 50%-75%θand nitrogen input of 0.25 kg/plant was the optimal W&N input for jujube trees under SRI in Northern Shaanxi area.展开更多
文摘Sustainability of traditionally cultivated rice in the rice-wheat cropping zone(RWCZ)of Pakistan is dwindling due to the high cost of production,declining water resources and escalating labour availability.Thus,farmers and researchers are compelled to find promising alternatives to traditional transplanted rice(TPR).A field study was conducted in Punjab,Pakistan,in 2017 and 2018 to explore the trade-offs between water saving and paddy yield,water productivity and economics of two aromatic rice varieties under dry direct seeded rice(DDSR)and TPR.The experiment was comprised of three irrigation regimes on the basis of soil moisture tension(SMT)viz.,continuous flooded(>–10 kPa SMT),alternate wetting and drying(AWD)(–20 kPa SMT)and aerobic rice(–40 kPa SMT),maintained under TPR and DDSR systems.Two aromatic rice verities:Basmati-515 and Chenab Basmati-2016 were used during both years of study.In both years,DDSR produced higher yields(13–18%)and reduced the total water inputs(8–12%)in comparison to TPR.In comparison to traditional continuous flooded(CF),AWD under DDSR reduced total water input by 27–29%and improved the leaf area index(LAI),tillering,yield(7–9%),and water productivity(44–50%).The performance of AWD with regard to water savings and increased productivity was much higher in DDSR system as compared to AWD in TPR system.Cultivation of DDSR with aerobic irrigation improved water savings(49–55%)and water productivity(22–30%)at the expense of paddy yield reduction(36–39%)and spikelet sterility.With regard to variety,the highest paddy yield(6.6 and 6.7 t ha–1)was recorded in DDSR using Chenab Basmati-2016 under AWD irrigation threshold that attributed to high tiller density and LAI.The economic analysis showed DDSR as more beneficial rice establishment method than TPR with a high benefit-cost ratio(BCR)when the crop was irrigated with AWD irrigation threshold.Our results highlighted that with the use of short duration varieties,DDSR cultivation in conjunction with AWD irrigation can be more beneficial for higher productivity and crop yield.
基金the National Natural Science Foundation of China (Grant nos. 41506222, 41776205, 41606052, 41606211)Chinese Polar Environment Comprehensive Investigation & Assessment Programs (Grant nos. CHINARE2017-03-04, 2017-04-03)the Fundamental Research Funds for the Second Institute of Oceanography, SOA (Grant nos. JG1611, JG1502)
文摘Over the past decades, the Arctic Ocean has experienced rapid warming under climate change, which has dramatically altered its physical and biogeochemical properties. Reduction in the sea-ice cover is one of the most important driving forces of biogeochemical changes in the Arctic Ocean. Between 1999 and 2016, seven Chinese National Arctic Research Expeditions have taken place in the Bering and Chukchi seas, allowing assessment of the biogeochemical response of the western Arctic Ocean to global warming. Herein, we summarize advances in Chinese and international marine biogeochemistry research in the western Arctic Ocean, reviewing results from the Chinese expeditions and highlighting future trends of biogeochemistry in the Pacific Arctic region. The findings reported in this paper contribute towards a better understanding of water masses, greenhouse gases, nutrients, ocean acidification, and organic carbon export and burial processes in this region.
基金This study was financially supported by the National Key R&D Program(No.2016YFC0400204)by the National Natural Science Foundation of China(No.51279157).
文摘In order to obtain the optimal input of water and nitrogen(W&N)suitable for the jujube trees in Northern Shaanxi,12 treatments had been set in the demonstration base of micro-irrigation jujube tree of Mizhi County in 2014-2015 through field experiment of jujube trees under surge root irrigation(SRI),in which three soil moisture levels(high moisture level W1:60%-85%θ,middle moisture level W2:50%-75%θ,low moisture level W3:40%-65%θ)and four nitrogen input levels(high nitrogen F75:0.75 kg/plant,middle nitrogen F50:0.50 kg/plant,low nitrogen F25:0.25 kg/plant,no nitrogen F0:0.00 kg/plant)were set.Through analyzing the effects of different W&N inputs on the yield,net income(NI)and W&N utilization efficiency(WUE and NUE)of jujube trees and establishing a weighted grey correlation model,the optimization of W&N input for jujube trees could be achieved under SRI.Results showed that different W&N inputs had significant influences on yield,NI,WUE and NUE.Along with the increase of soil moisture content,the yield and NUE increased,while WUE decreased gradually,and the NI had the tendency to increase first and then decrease.Along with the increase of nitrogen input,the yield,NI and WUE had the tendency to increase first and then decrease while the NUE decreased significantly,and the yield,NI,WUE and NUE could not reach the maximum at the same time.Through the study on the grey correlation model of jujube tree’s comprehensive benefit based on the yield,NI,WUE and NUE,results showed the comprehensive benefit of jujube trees was significantly different when W&N input was different,and the gray correlation degree of W2F25 treatment was the highest in two years,which means that the soil moisture content of 50%-75%θand nitrogen input of 0.25 kg/plant was the optimal W&N input for jujube trees under SRI in Northern Shaanxi area.
