At present, the shortage of agricuItural water resources is worsening. In order to reduce the rice irrigation water and improve the utiIization of fertiIizers so as to achieve the high and stabIe yielding of rice, thi...At present, the shortage of agricuItural water resources is worsening. In order to reduce the rice irrigation water and improve the utiIization of fertiIizers so as to achieve the high and stabIe yielding of rice, this report reviewed the research advances in water and fertiIizer coupIing, the conception of water and fertiIizer cou-pIing and its three kinds of effects （synergy, antagonism, superposition）, mechanism of water and fertiIizer coupIing, effects of water and fertiIizer coupIing on growth, deveIopment, yield and quality of rice and effects of water and fertiIizer coupIing on utiIization rate of nitrogen in rice. In addition, the deveIopment prospects of water and fertiIizer coupIing in China were described. It was proposed that the water and fertiIizer coupIing mode is an effective measure to achieve the high yield and quality of rice. According to actual demand, referring to the ideas of promoting fertiIizer with water and reguIating water with fertiIizer, reasonabIe water and fertiIizer cou-pIing mode can be estabIished, thereby improving the utiIization efficiencies of water and fertiIizer. In the premise of saving irrigation water and no increasing fertiIization amount, both high yielding and Iess poI ution can be achieved, providing theoretical and technical basis for water-saving agricuIture and cuItivation and management of rice in future.展开更多
Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models f...Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models for climate change.In this study,a nitrogen model,based on nitrogen transformation processes and nitrogen fluxes exchange between the atmosphere and terrestrial ecosystem,was incorporated into the Atmosphere–Vegetation Interaction Model(AVIM)to simulate the carbon cycle under nitrogen limitation.This new model,AVIM-CN,was evaluated against site-scale eddy covariance–based measurements of an alpine meadow located at Damxung station from the FLUXNET 2015 dataset.Results showed that the annual mean gross primary production simulated by AVIM-CN(0.7073 gC m^-2 d^-1)was in better agreement with the corresponding flux data(0.5407 gC m^-2 d^-1)than the original AVIM(1.1403 gC m^-2 d^-1)at Damxung station.Similarly,ecosystem respiration was also down-regulated,from 1.7695 gC m^-2 d^-1 to 1.0572 gC m^-2 d^-1,after the nitrogen processes were introduced,and the latter was closer to the observed vales(0.8034 gC m^-2 d^-1).Overall,the new results were more consistent with the daily time series of carbon and energy fluxes of observations compared to the former version without nitrogen dynamics.A model that does not incorporate the limitation effects of nitrogen nutrient availability will probably overestimate carbon fluxes by about 40%.展开更多
Water and nitrogen fertilizer are two essential factors for quality and yield formation of rice.Experimental study was carried out to investigate the effects of water and nitrogen fertilizer coupling on yield-related ...Water and nitrogen fertilizer are two essential factors for quality and yield formation of rice.Experimental study was carried out to investigate the effects of water and nitrogen fertilizer coupling on yield-related factors,such as growth(height),physiological indicators(chlorophyll and leaf area index(LAI))and yield composition indicators(productive panicles,thousand grain weight and total grains per panicle).Results showed that,the height difference under two irrigation regimes was not significant,and it showed no difference until the tillering stage(p>0.05).The water control method for controlled and mid-gathering irrigation(CMI)was favorable for nutrients converting to rice grain.Meanwhile the height difference for CMI and conventional irrigation(CVI)was the biggest at 80 d after rice transplantation.Variance analysis showed the effect of fertilization on height was significant(p<0.05).With organic fertilizer application,it could control plant growth and promote the nutrients converting to the panicle.The change curve of LAI was similar to chlorophyll content.Organic fertilizer application could not only promote chlorophyll content and LAI,but also delay leaf fading and promote yield.Nitrogen fertilizer factors showed significant difference on rice yield,compared to irrigation regimes showing no significance.Considering the irrigation and fertilizer factors together,the interaction was significant.The descending orders for the effects of water and nitrogen on rice yield were fertilizer,water and fertilizer,water.Regression analysis showed that the productive panicles and total grains per panicle of rice were extremely significant on rice yield,and the direct effect of total grains per panicle on yield was greater than that of productive panicle.This study results could provide theoretical basis for water and nitrogen management to improve rice production.展开更多
我国是世界上最大的猪肉生产国,同时也是最大的消费国。猪肉的品质影响着人们摄取蛋白质的质量,目前缺乏有效的快速无损检测方法应对巨大的检测需要。为快速测定冷藏猪肉挥发性盐基氮(TVB-N)、pH值和含水率,提出一种新的猪肉品质检测方...我国是世界上最大的猪肉生产国,同时也是最大的消费国。猪肉的品质影响着人们摄取蛋白质的质量,目前缺乏有效的快速无损检测方法应对巨大的检测需要。为快速测定冷藏猪肉挥发性盐基氮(TVB-N)、pH值和含水率,提出一种新的猪肉品质检测方法,利用近红外光谱技术结合化学计量学方法建立冷藏猪肉TVB-N、pH值和含水率的数学模型。以不同种类的白条猪肉为研究对象,选择排酸完成后的猪最长背部肌肉的切块,采集相应猪肉近红外光谱数据并结合化学计量学试验获取TVB-N、pH和含水率的测量值,对比分析采集到的光谱信息和理化指标,发现在8600~8450、7160~6950、5300~5000 cm^(-1)区域出现显著的吸收峰,而8600~8450 cm^(-1)附近吸收峰的峰值却明显小于其他吸收峰。使用SPXY(sample set partitioning based on joint X-Y distances)算法进行数据集划分,将数据集按照3∶1的比例划分成训练集和测试集。使用蒙特卡罗交叉验证法(MCCV)剔除异常数据,通过偏最小二乘法回归(PLSR)建立TVB-N、pH值、含水率和全波段光谱信息的回归关系。利用数据中心化、Savitzky-Golay(S-G)一阶求导、S-G二阶求导、直接差分二阶求导和多元散射校正等方法对原始光谱进行预处理,探寻合适的预处理方式。结果显示:数据中心化、直接差分二阶求导、二阶求导取得较优的试验效果;故结合竞争性自适应重加权算法(CARS)、非信息变量剔除(UVE)、连续投影算法(SPA)等特征波长提取算法建立PLSR特征波段模型并进行分析。结果显示,TVB-N、pH值、含水率的预测模型结构分别为数据中心化-CARS-PLSR、直接差分二阶求导-CARS-PLSR、二阶求导-CARS-PLSR时具有优异的性能,其中训练集相关系数RC分别为0.9471、0.9988、0.9971,均方根误差(RMSE)分别为1.2088、0.0087、0.0015;测试集相关系数RP分别为0.9275、0.9630、0.9459,RMSE分别为1.6836、0.0517、0.0056。综上可知,近红外波段区域与猪肉TVB-N、pH值、含水率存在显著相关性,利用近红外光谱可以准确预测猪肉中TVB-N、pH值和含水率。展开更多
基金Supported by National Key Technology Research and Development Program(2011BAD16B01,2012BAD04B10,2013BAD07B11)~~
文摘At present, the shortage of agricuItural water resources is worsening. In order to reduce the rice irrigation water and improve the utiIization of fertiIizers so as to achieve the high and stabIe yielding of rice, this report reviewed the research advances in water and fertiIizer coupIing, the conception of water and fertiIizer cou-pIing and its three kinds of effects （synergy, antagonism, superposition）, mechanism of water and fertiIizer coupIing, effects of water and fertiIizer coupIing on growth, deveIopment, yield and quality of rice and effects of water and fertiIizer coupIing on utiIization rate of nitrogen in rice. In addition, the deveIopment prospects of water and fertiIizer coupIing in China were described. It was proposed that the water and fertiIizer coupIing mode is an effective measure to achieve the high yield and quality of rice. According to actual demand, referring to the ideas of promoting fertiIizer with water and reguIating water with fertiIizer, reasonabIe water and fertiIizer cou-pIing mode can be estabIished, thereby improving the utiIization efficiencies of water and fertiIizer. In the premise of saving irrigation water and no increasing fertiIization amount, both high yielding and Iess poI ution can be achieved, providing theoretical and technical basis for water-saving agricuIture and cuItivation and management of rice in future.
基金supported by a project of the National Key Research and Development Program of China [grant number2016YFA0602501]a project of the National Natural Science Foundation of China [grant numbers 41630532 and41575093]
文摘Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models for climate change.In this study,a nitrogen model,based on nitrogen transformation processes and nitrogen fluxes exchange between the atmosphere and terrestrial ecosystem,was incorporated into the Atmosphere–Vegetation Interaction Model(AVIM)to simulate the carbon cycle under nitrogen limitation.This new model,AVIM-CN,was evaluated against site-scale eddy covariance–based measurements of an alpine meadow located at Damxung station from the FLUXNET 2015 dataset.Results showed that the annual mean gross primary production simulated by AVIM-CN(0.7073 gC m^-2 d^-1)was in better agreement with the corresponding flux data(0.5407 gC m^-2 d^-1)than the original AVIM(1.1403 gC m^-2 d^-1)at Damxung station.Similarly,ecosystem respiration was also down-regulated,from 1.7695 gC m^-2 d^-1 to 1.0572 gC m^-2 d^-1,after the nitrogen processes were introduced,and the latter was closer to the observed vales(0.8034 gC m^-2 d^-1).Overall,the new results were more consistent with the daily time series of carbon and energy fluxes of observations compared to the former version without nitrogen dynamics.A model that does not incorporate the limitation effects of nitrogen nutrient availability will probably overestimate carbon fluxes by about 40%.
基金This work was funded in part by the High-level Talent Research Project of North China University of Water Resources and Electric Power(No.201705017)partly by Key Laboratory of Efficient Irrigation-drainage and Agricultural Soil-water Environment in Southern China(Hohai University),Ministry of Education(2017B20414-2)+2 种基金partly by Water Conservancy Science and Technology Project of Nanjing Water Bureau(20130317-1)partly by Science and Technology Project of Nantong(201716004)Zhejiang Basic Public Welfare Research Plan(No.LGN18E090002)。
文摘Water and nitrogen fertilizer are two essential factors for quality and yield formation of rice.Experimental study was carried out to investigate the effects of water and nitrogen fertilizer coupling on yield-related factors,such as growth(height),physiological indicators(chlorophyll and leaf area index(LAI))and yield composition indicators(productive panicles,thousand grain weight and total grains per panicle).Results showed that,the height difference under two irrigation regimes was not significant,and it showed no difference until the tillering stage(p>0.05).The water control method for controlled and mid-gathering irrigation(CMI)was favorable for nutrients converting to rice grain.Meanwhile the height difference for CMI and conventional irrigation(CVI)was the biggest at 80 d after rice transplantation.Variance analysis showed the effect of fertilization on height was significant(p<0.05).With organic fertilizer application,it could control plant growth and promote the nutrients converting to the panicle.The change curve of LAI was similar to chlorophyll content.Organic fertilizer application could not only promote chlorophyll content and LAI,but also delay leaf fading and promote yield.Nitrogen fertilizer factors showed significant difference on rice yield,compared to irrigation regimes showing no significance.Considering the irrigation and fertilizer factors together,the interaction was significant.The descending orders for the effects of water and nitrogen on rice yield were fertilizer,water and fertilizer,water.Regression analysis showed that the productive panicles and total grains per panicle of rice were extremely significant on rice yield,and the direct effect of total grains per panicle on yield was greater than that of productive panicle.This study results could provide theoretical basis for water and nitrogen management to improve rice production.
文摘我国是世界上最大的猪肉生产国,同时也是最大的消费国。猪肉的品质影响着人们摄取蛋白质的质量,目前缺乏有效的快速无损检测方法应对巨大的检测需要。为快速测定冷藏猪肉挥发性盐基氮(TVB-N)、pH值和含水率,提出一种新的猪肉品质检测方法,利用近红外光谱技术结合化学计量学方法建立冷藏猪肉TVB-N、pH值和含水率的数学模型。以不同种类的白条猪肉为研究对象,选择排酸完成后的猪最长背部肌肉的切块,采集相应猪肉近红外光谱数据并结合化学计量学试验获取TVB-N、pH和含水率的测量值,对比分析采集到的光谱信息和理化指标,发现在8600~8450、7160~6950、5300~5000 cm^(-1)区域出现显著的吸收峰,而8600~8450 cm^(-1)附近吸收峰的峰值却明显小于其他吸收峰。使用SPXY(sample set partitioning based on joint X-Y distances)算法进行数据集划分,将数据集按照3∶1的比例划分成训练集和测试集。使用蒙特卡罗交叉验证法(MCCV)剔除异常数据,通过偏最小二乘法回归(PLSR)建立TVB-N、pH值、含水率和全波段光谱信息的回归关系。利用数据中心化、Savitzky-Golay(S-G)一阶求导、S-G二阶求导、直接差分二阶求导和多元散射校正等方法对原始光谱进行预处理,探寻合适的预处理方式。结果显示:数据中心化、直接差分二阶求导、二阶求导取得较优的试验效果;故结合竞争性自适应重加权算法(CARS)、非信息变量剔除(UVE)、连续投影算法(SPA)等特征波长提取算法建立PLSR特征波段模型并进行分析。结果显示,TVB-N、pH值、含水率的预测模型结构分别为数据中心化-CARS-PLSR、直接差分二阶求导-CARS-PLSR、二阶求导-CARS-PLSR时具有优异的性能,其中训练集相关系数RC分别为0.9471、0.9988、0.9971,均方根误差(RMSE)分别为1.2088、0.0087、0.0015;测试集相关系数RP分别为0.9275、0.9630、0.9459,RMSE分别为1.6836、0.0517、0.0056。综上可知,近红外波段区域与猪肉TVB-N、pH值、含水率存在显著相关性,利用近红外光谱可以准确预测猪肉中TVB-N、pH值和含水率。
