Based on the MODIS NDVI data and Landsat TM/ETM data of 2002 and 2012, this paper extracts the planting area of winter wheat–summer maize, single spring maize, cotton and forest/fruit trees, vegetable and paddy, and ...Based on the MODIS NDVI data and Landsat TM/ETM data of 2002 and 2012, this paper extracts the planting area of winter wheat–summer maize, single spring maize, cotton and forest/fruit trees, vegetable and paddy, and made the agricultural land use map of the North China Plain(NCP). Agricultural land use area accounted for 63.32% compared to the total area of the NCP in 2002. And it increased to 65.66% in 2012, which mainly caused by the vegetables and forest/fruit trees increasing. Planting areas of winter wheat–summer maize, cotton, single spring maize, forest/fruit trees, vegetables and paddy were 5031.21×10~3, 865.90×10~3, 1226.10×10~3, 1271.17×10~3, 648.02×10~3, 216.51×10~3 ha in 2012. Rank of changes was: vegetables(+45%) > forest/fruit trees(+27.4%) > paddy(–23.7%) > cotton(–20.4%) > single spring maize(+17.3%) > winter wheat–summer maize(–0.6%). In developed region like Beijing and Tianjin, planting area of crops with high economic benefit(such as fruit trees and vegetables) increased significantly. Government policies for groundwater protection caused obvious decline of winter wheat cultivation in Hebei Province. Cotton planting in Shandong Province decreased more than 200,000 ha during 2002–2012. The data products will be published in the website: http://hydro.sjziam.ac.cn/Default.aspx. To clarify the agricultural land use in the NCP will be very helpful for the regional agricultural water consumption research, which is the serious problem in the NCP.展开更多
Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically...Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing factor.This study evaluated the changes in NO_(3)^(-)accumulation and transport in the deep vadose zone(DVZ,below the root zone),and the groundwater NO_(3)^(-)content associated with ALUC from grain to vegetable fields in the North China Plain(NCP).The ALUC from grain to vegetable resulted in nitrate–nitrogen(NO_(3)^(-)-N)accumulation in DVZ increased by 235.5 kg ha^(-1)m^(-1)(163.2%)in the piedmont plain and 224.9 kg ha^(-1)m^(-1)(102.7%)in the central plain,respectively.This change accelerated downward transport velocity in the DVZ(from 0.81±0.47 to 0.89±0.55 m yr^(-1)in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr^(-1)in the central plain)and increased NO_(3)^(-)leaching fluxes.High transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont plain.The impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.展开更多
The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of cro...The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of crop water consumption and net irrigation water consumption is crucial to guarantee the management of agricultural water resources. An actual crop evapotranspiration(ET) estimation model was proposed, by combining FAO Penman-Monteith method with remote sensing data. The planting area of winter wheat has a significant impact on water consumption; therefore, the planting area was also retrieved. The estimated ET showed good agreement with field-observed ET at four stations. The average relative bias and root mean square error(RMSE) for ET estimation were –2.2% and 25.5 mm, respectively. The results showed the planting area and water consumption of winter wheat had a decreasing trend in the Northern Hebei Plain(N-HBP) and Southern Hebei Plain(S-HBP). Moreover, in these two regions, there was a significant negative correlation between accumulated net irrigation water consumption and groundwater table. The total net irrigation water consumption in the N-HBP and S-HBP accounted for 12.9×10~9 m^3 and 31.9×10~9 m^3 during 2001–2016, respectively. Before and after 2001, the decline rate of groundwater table had a decreasing trend, as did the planting area of winter wheat in the N-HBP and S-HBP. The decrease of winter wheat planting area alleviated the decline of groundwater table in these two regions while the total net irrigation water consumption was both up to 28.5×10~9 m^3 during 2001–2016 in the Northwestern Shandong Plain(NW-SDP) and Northern Henan Plain(N-HNP). In these two regions, there was no significant correlation between accumulated net irrigation water consumption and groundwater table. The Yellow River was able to supply irrigation and the groundwater table had no significant declining trend.展开更多
Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study car...Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_(N)),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_(N) and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_(N) and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.展开更多
From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose z...From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose zone, evaluate the "time lag" effect of recharge, and underscore the role of thickening vadose zone in recharge. The results indicated that different agricultural land-use types need to be further considered in recharge rate estimate. Under the typical irrigation condition in the piedmont plain, the recharge rate under flood irrigated winter wheat and summer maize(W/M_F), maize(M), non-cultivation(NC), native vegetation(NV), vegetables(V), and orchards(O) is 206.4, 149.7, 194.1, 46.4, 320.0, and 48.6 mm/yr, respectively. In the central plain, the value under W/M_F, M, NC, V, and cotton(C) is 92.8, 50.8, 85.0, 255.5, and 26.5 mm/yr, respectively. Soil water residence time(several years) and groundwater level response time(several months) should be distinguished to further understand the processes of groundwater recharge, because the soil water displacement velocities range from 0.2 to 2.2 m/yr while the rate of wetting front propagation is approximately 47 m/yr in the piedmont plain. The thickening vadose zone would prolong residence time of soil water and contaminant, which could postpone the time of or alleviate groundwater pollution, but have no significant influence on the magnitude of recharge in a long time scale. Recharge coefficient based on shorter time span(e.g. 2 or 3 years) should be used with caution as a parameter for groundwater resources evaluation, because it varies with total water input and target soil depth. Uncertainties in evapotranspiration and other water balance components should be evaluated in recharge estimation and the impact of land-use types on recharge should be emphasized. The critical zone science would greatly improve the understanding of groundwater recharge processes. The results of the present study will be helpful in sustainable groundwater resources management.展开更多
As critical conduits for the dissemination of online public opinion,social media platforms offer a timely and effective means for managing emergencies during major disasters,such as earthquakes.This study focuses on t...As critical conduits for the dissemination of online public opinion,social media platforms offer a timely and effective means for managing emergencies during major disasters,such as earthquakes.This study focuses on the analysis of online public opinions following the Maduo M7.4 earthquake in Qinghai Province and the Yangbi M6.4 earthquake in Yunnan Province.By collecting,cleaning,and organizing post-earthquake Sina Weibo(short for Weibo)data,we employed the Latent Dirichlet Allocation(LDA)model to extract information pertinent to public opinion on these earthquakes.This analysis included a comparison of the nature and temporal evolution of online public opinions related to both events.An emotion analysis,utilizing an emotion dictionary,categorized the emotional content of post-earthquake Weibo posts,facilitating a comparative study of the characteristics and temporal trends of online public emotions following the earthquakes.The findings were visualized using Geographic Information System(GIS)techniques.The analysis revealed certain commonalities in online public opinion following both earthquakes.Notably,the peak of online engagement occurred within the first 24 hours post-earthquake,with a rapid decline observed between 24 to 48 hours thereafter.The variation in popularity of online public opinion was linked to aftershock occurrences.Adjusted for population factors,online engagement in areas surrounding the earthquake sites and in Sichuan Province was significantly high.Initially dominated by feelings of“fear”and“surprise”,the public sentiment shifted towards a more positive outlook with the onset of rescue operations.However,distinctions in the online public response to each earthquake were also noted.Following the Yangbi earthquake,Yunnan Province reported the highest number of Weibo posts nationwide;in contrast,Qinghai Province ranked third post-Maduo earthquake,attributable to its smaller population size and extensive damage to communication infrastructure.This research offers a methodological approach for the analysis of online public opinion related to earthquakes,providing insights for the enhancement of post-disaster emergency management and public mental health support.展开更多
The proportion of industrial livestock in China has increased over the past 30 years,which increases animal performance but causes the decoupling of crop and livestock production.Here,we aimed to quantify nutrient flo...The proportion of industrial livestock in China has increased over the past 30 years,which increases animal performance but causes the decoupling of crop and livestock production.Here,we aimed to quantify nutrient flows,nutrient use efficiency,and nutrient losses in different livestock systems in the North China Plain based on the NUFER-farm model.Activity data were collected by face-to-face surveys on pig and dairy(41 livestock farms)during 2016-2018.The two systems included industrial farms and mixed smallholdings.In mixed smallholdings,4.0%and 9.6%of pig and dairy feed dry matter(DM)were derived from household farmland,but 4.8%and 9.3%of manure DM recycled to household farmland.Nutrient use efficiency in industrial farms was higher than in mixed smallholdings at animal level,herd level,and system level.To produce 1 kg N and P in animal products,nutrient losses in industrial pig farms(2.0 kg N and 1.3 kg P)were lower than in mixed pig smallholdings,nutrient losses in industrial dairy farms(2.7 kg N and 2.2 kg P)were slightly higher than in mixed dairy smallholdings.Liquid manure discharge in industrial farms was the main losses pathway in contrast to mixed smallholdings.This study suggests that feed localization can reduce nutrient surpluses at the district level.It is necessary to improve manure management and increase the degree of integrated crop-livestock in smallholdings.In industrial farms,it is desirable to increase the liquid manure recycling ratio through cooperating livestock and crop production at the district level.展开更多
基金National Key Research and Development Plan,No.2016YFC0401403National Natural Science Foundation of China,No.41471027,No.31870422The Youth Innovation Promotion Association CAS,No.2017138
文摘Based on the MODIS NDVI data and Landsat TM/ETM data of 2002 and 2012, this paper extracts the planting area of winter wheat–summer maize, single spring maize, cotton and forest/fruit trees, vegetable and paddy, and made the agricultural land use map of the North China Plain(NCP). Agricultural land use area accounted for 63.32% compared to the total area of the NCP in 2002. And it increased to 65.66% in 2012, which mainly caused by the vegetables and forest/fruit trees increasing. Planting areas of winter wheat–summer maize, cotton, single spring maize, forest/fruit trees, vegetables and paddy were 5031.21×10~3, 865.90×10~3, 1226.10×10~3, 1271.17×10~3, 648.02×10~3, 216.51×10~3 ha in 2012. Rank of changes was: vegetables(+45%) > forest/fruit trees(+27.4%) > paddy(–23.7%) > cotton(–20.4%) > single spring maize(+17.3%) > winter wheat–summer maize(–0.6%). In developed region like Beijing and Tianjin, planting area of crops with high economic benefit(such as fruit trees and vegetables) increased significantly. Government policies for groundwater protection caused obvious decline of winter wheat cultivation in Hebei Province. Cotton planting in Shandong Province decreased more than 200,000 ha during 2002–2012. The data products will be published in the website: http://hydro.sjziam.ac.cn/Default.aspx. To clarify the agricultural land use in the NCP will be very helpful for the regional agricultural water consumption research, which is the serious problem in the NCP.
基金National Natural Science Foundation of China,No.41930865Project for Innovative Capacity Improvement in Hebei Province,No.225A4201D。
文摘Nitrate(NO_(3)^(-))accumulation and transport processes in the thick vadose zone affect the evolution of the groundwater NO_(3)^(-)content in intensive agricultural regions.Agricultural land-use change(ALUC),typically accompanied by substantial alterations in nitrogen fertilizer application and irrigation practices,is an important influencing factor.This study evaluated the changes in NO_(3)^(-)accumulation and transport in the deep vadose zone(DVZ,below the root zone),and the groundwater NO_(3)^(-)content associated with ALUC from grain to vegetable fields in the North China Plain(NCP).The ALUC from grain to vegetable resulted in nitrate–nitrogen(NO_(3)^(-)-N)accumulation in DVZ increased by 235.5 kg ha^(-1)m^(-1)(163.2%)in the piedmont plain and 224.9 kg ha^(-1)m^(-1)(102.7%)in the central plain,respectively.This change accelerated downward transport velocity in the DVZ(from 0.81±0.47 to 0.89±0.55 m yr^(-1)in the piedmont plain,and from 0.24±0.12 to 0.92±0.12 m yr^(-1)in the central plain)and increased NO_(3)^(-)leaching fluxes.High transport velocity and leaching fluxes resulted in chemical N-fertilizer entering the aquifer in several areas in the piedmont plain.The impact of the agricultural activity intensity changes,accompanied by the ALUC,on groundwater quantity and quality should be considered in similar regions.
基金National Natural Science Foundation of China,No.41471027National Key Research and Development Plan,No.2016YFC0401403
文摘The North China Plain is one of the most water-stressed areas in China. Irrigation of winter wheat mainly utilizes groundwater resources, which has resulted in severe environmental problems. Accurate estimation of crop water consumption and net irrigation water consumption is crucial to guarantee the management of agricultural water resources. An actual crop evapotranspiration(ET) estimation model was proposed, by combining FAO Penman-Monteith method with remote sensing data. The planting area of winter wheat has a significant impact on water consumption; therefore, the planting area was also retrieved. The estimated ET showed good agreement with field-observed ET at four stations. The average relative bias and root mean square error(RMSE) for ET estimation were –2.2% and 25.5 mm, respectively. The results showed the planting area and water consumption of winter wheat had a decreasing trend in the Northern Hebei Plain(N-HBP) and Southern Hebei Plain(S-HBP). Moreover, in these two regions, there was a significant negative correlation between accumulated net irrigation water consumption and groundwater table. The total net irrigation water consumption in the N-HBP and S-HBP accounted for 12.9×10~9 m^3 and 31.9×10~9 m^3 during 2001–2016, respectively. Before and after 2001, the decline rate of groundwater table had a decreasing trend, as did the planting area of winter wheat in the N-HBP and S-HBP. The decrease of winter wheat planting area alleviated the decline of groundwater table in these two regions while the total net irrigation water consumption was both up to 28.5×10~9 m^3 during 2001–2016 in the Northwestern Shandong Plain(NW-SDP) and Northern Henan Plain(N-HNP). In these two regions, there was no significant correlation between accumulated net irrigation water consumption and groundwater table. The Yellow River was able to supply irrigation and the groundwater table had no significant declining trend.
基金supported and funded by the National Key Research and Development Program of China(2016YFD0300105,2017YFD03002 and 2016YFD0300106)the Key Research and Development Program of Hebei Province,China(20326403D)。
文摘Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_(N)),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_(N) and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_(N) and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.
基金National Key Research and Development Plan,No.2016YFC0401403National Natural Science Foundation of China,No.41877169
文摘From a critical zone perspective, the present paper aims to present the magnitude of groundwater recharge under different agricultural land-use types, reveal the process of water and solute transport in thick vadose zone, evaluate the "time lag" effect of recharge, and underscore the role of thickening vadose zone in recharge. The results indicated that different agricultural land-use types need to be further considered in recharge rate estimate. Under the typical irrigation condition in the piedmont plain, the recharge rate under flood irrigated winter wheat and summer maize(W/M_F), maize(M), non-cultivation(NC), native vegetation(NV), vegetables(V), and orchards(O) is 206.4, 149.7, 194.1, 46.4, 320.0, and 48.6 mm/yr, respectively. In the central plain, the value under W/M_F, M, NC, V, and cotton(C) is 92.8, 50.8, 85.0, 255.5, and 26.5 mm/yr, respectively. Soil water residence time(several years) and groundwater level response time(several months) should be distinguished to further understand the processes of groundwater recharge, because the soil water displacement velocities range from 0.2 to 2.2 m/yr while the rate of wetting front propagation is approximately 47 m/yr in the piedmont plain. The thickening vadose zone would prolong residence time of soil water and contaminant, which could postpone the time of or alleviate groundwater pollution, but have no significant influence on the magnitude of recharge in a long time scale. Recharge coefficient based on shorter time span(e.g. 2 or 3 years) should be used with caution as a parameter for groundwater resources evaluation, because it varies with total water input and target soil depth. Uncertainties in evapotranspiration and other water balance components should be evaluated in recharge estimation and the impact of land-use types on recharge should be emphasized. The critical zone science would greatly improve the understanding of groundwater recharge processes. The results of the present study will be helpful in sustainable groundwater resources management.
基金funded by the Science Research Project of Hebei Education Department(No.BJK2023088).
文摘As critical conduits for the dissemination of online public opinion,social media platforms offer a timely and effective means for managing emergencies during major disasters,such as earthquakes.This study focuses on the analysis of online public opinions following the Maduo M7.4 earthquake in Qinghai Province and the Yangbi M6.4 earthquake in Yunnan Province.By collecting,cleaning,and organizing post-earthquake Sina Weibo(short for Weibo)data,we employed the Latent Dirichlet Allocation(LDA)model to extract information pertinent to public opinion on these earthquakes.This analysis included a comparison of the nature and temporal evolution of online public opinions related to both events.An emotion analysis,utilizing an emotion dictionary,categorized the emotional content of post-earthquake Weibo posts,facilitating a comparative study of the characteristics and temporal trends of online public emotions following the earthquakes.The findings were visualized using Geographic Information System(GIS)techniques.The analysis revealed certain commonalities in online public opinion following both earthquakes.Notably,the peak of online engagement occurred within the first 24 hours post-earthquake,with a rapid decline observed between 24 to 48 hours thereafter.The variation in popularity of online public opinion was linked to aftershock occurrences.Adjusted for population factors,online engagement in areas surrounding the earthquake sites and in Sichuan Province was significantly high.Initially dominated by feelings of“fear”and“surprise”,the public sentiment shifted towards a more positive outlook with the onset of rescue operations.However,distinctions in the online public response to each earthquake were also noted.Following the Yangbi earthquake,Yunnan Province reported the highest number of Weibo posts nationwide;in contrast,Qinghai Province ranked third post-Maduo earthquake,attributable to its smaller population size and extensive damage to communication infrastructure.This research offers a methodological approach for the analysis of online public opinion related to earthquakes,providing insights for the enhancement of post-disaster emergency management and public mental health support.
基金funded by the National Natural Science Foundation of China(31772393)the National Key Research and Development Program of China(2016YFD0200401)the National Key Research and Development Program of China funded by the Ministry of Science and Technology of the People's Republic of China(2016YFE0103100).
文摘The proportion of industrial livestock in China has increased over the past 30 years,which increases animal performance but causes the decoupling of crop and livestock production.Here,we aimed to quantify nutrient flows,nutrient use efficiency,and nutrient losses in different livestock systems in the North China Plain based on the NUFER-farm model.Activity data were collected by face-to-face surveys on pig and dairy(41 livestock farms)during 2016-2018.The two systems included industrial farms and mixed smallholdings.In mixed smallholdings,4.0%and 9.6%of pig and dairy feed dry matter(DM)were derived from household farmland,but 4.8%and 9.3%of manure DM recycled to household farmland.Nutrient use efficiency in industrial farms was higher than in mixed smallholdings at animal level,herd level,and system level.To produce 1 kg N and P in animal products,nutrient losses in industrial pig farms(2.0 kg N and 1.3 kg P)were lower than in mixed pig smallholdings,nutrient losses in industrial dairy farms(2.7 kg N and 2.2 kg P)were slightly higher than in mixed dairy smallholdings.Liquid manure discharge in industrial farms was the main losses pathway in contrast to mixed smallholdings.This study suggests that feed localization can reduce nutrient surpluses at the district level.It is necessary to improve manure management and increase the degree of integrated crop-livestock in smallholdings.In industrial farms,it is desirable to increase the liquid manure recycling ratio through cooperating livestock and crop production at the district level.
