[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei ho...[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.展开更多
Background The PandaX-4T experiment is a next-generation dark matter search program located in the China Jinping Underground Laboratory.To ensure the stability of the complex instrument during the planned operation,th...Background The PandaX-4T experiment is a next-generation dark matter search program located in the China Jinping Underground Laboratory.To ensure the stability of the complex instrument during the planned operation,the status of the facility should be monitored continuously.Purpose The paper reports the design of the slow control system for the experiment.The system is used to monitor the facility status and generate an alarm signal while the detector is in abnormal status.Methods Low-cost hardware is employed for the distributed data collection.Python-based data collection program was developed.We also used the open source software for data storage,visualization and anomaly detection,so that the development of the system is simplified.Conclusion We finally achieved a low-cost and robust slow control system for the prototype detector in short time.It is running well currently.The system will be integrated with the PandaX-4T facility in late 2019.展开更多
There is limited information about the influence of slow or controlled release fertilizer（S/CRF） on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three d...There is limited information about the influence of slow or controlled release fertilizer（S/CRF） on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs（polymer-coated urea（PCU）, sulfur-coated urea（SCU）, and urea formaldehyde（UF）） and two fertilization modes（both S/CRF and common urea（CU） as basal fertilizer, S/CRF as basal and CU as tillering fertilizer） on rice yield and quality. CU only was applied separately as control（CK）. Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF〉PCU〉SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer〉both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU〉PCU〉UF, and the trends of both S/CRF and CU as basal fertilizer〉S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.展开更多
Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea gran...Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.展开更多
This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer(UCRF)and the N uptake and N-use efficiency by rice plants.Water dissolution,soil leaching...This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer(UCRF)and the N uptake and N-use efficiency by rice plants.Water dissolution,soil leaching,and pot experiments were employed.The dynamics of N release from the UCRF could be quantitatively described by three equations:the first-order kinetics equation[N1=N0(1-e^-kt)],Elovich equation(N1=a+blnt),and parabola equation(N1=a+bt^0.5),with the best fitting by the first-order kinetics equation for different N(r=0.9569^**-0.9999^**).The release potentials(No values estimated by the first-order kinetics equation)of different N in the UCRF decreased in the order of total N〉DON〉urea-N〉NH4^+-N〉NO3^-N in water,and total N〉NH4^+-N〉DON〉urea-N〉NO3^--N in soil,respectively,being in accordance with cumulative amounts of N release.The constants of N release rate(k values and b values)for different N forms were in decreasing order of total N〉DON〉NH4^+-N〉NO3^--N in water,whereas the k values were urea-N〉DON〉NH4^+-N〉total N〉NO3^--N,and the b values were total N〉NH4^+-N〉DON〉NO3^--N〉urea-N in soil.Compared with a common compound fertilizer,the N-use efficiency,N-agronomy efficiency,and N-physiological efficiency of the UCRF were increased by 11.4%,8.32 kg kg^-1,and 5.17 kg kg^-1,respectively.The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants.The findings showed that the first-order kinetics equation[Nt=N0(l-e^kt)]could be used to describe the release characteristics of different N forms in the fertilizer.The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.展开更多
Lignin is the main by-product of pulp and papermaking and is not effectively utilized. Conversion of industrial lignins into value-added materials is beneficial for the effective utilization of resources as well as fo...Lignin is the main by-product of pulp and papermaking and is not effectively utilized. Conversion of industrial lignins into value-added materials is beneficial for the effective utilization of resources as well as for environmental protection. Because of their adsorptivity, slow-release property,biocompatibility, and biodegradability, lignin and its derivatives find potential applications as eco-friendly slow/controlled release materials in agricultural fields. This report reviews the recent research advances in lignin-based slow/controlled release fertilizers and pesticides.展开更多
Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tend...Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tends to reduce speed in the face of congestion thereby penalizing itself. In this group are the window based congestion control algorithms that use the size of congestion window to determine transmission speed. The two main algorithm of window based congestion control are the congestion avoidance and the slow start. The aim of this study is to survey the various modifications of window based congestion control. Much work has been done on congestion avoidance hence specific attention is placed on the slow start in order to motivate a new direction of research in network utility maximization. Mathematical modeling of the internet is discussed and proposals to improve TCP startup were reviewed. There are three lines of research on the improvement of slow start. A group uses the estimation of certain parameters to determine initial speed. The second group uses bandwidth estimation while the last group uses explicit request for network assistance to determine initial startup speed. The problems of each proposal are analyzed and a multiple startup for TCP is proposed. Multiple startups for TCP specify that startup speed is selectable from an n-arry set of algorithms. We then introduced the e-speed start which uses the prevailing network condition to determine a suitable starting speed.展开更多
In order to move tracked vehicles at an extremely slowspeed with automated mechanical transmission（ AMT）,slowdriving function was added in the original system. The principle and requirement of slowdriving function w...In order to move tracked vehicles at an extremely slowspeed with automated mechanical transmission（ AMT）,slowdriving function was added in the original system. The principle and requirement of slowdriving function were analyzed. Based on analysis of slow driving characteristic,identification of slowdriving condition and fuzzy control algorithm,a control strategy of the clutch was designed. In order to realize slowdriving,the clutch was controlled in a slipping mode as manual driving. The vehicle speed was increased to a required speed and kept in a small range by engaging or disengaging the clutch to the approximate half engagement point. Based on the control strategy,a control software was designed and tested on a tracked vehicle with AMT. The test results showthat the control of the clutch with the slowdriving function was smoother than that with original systemand the vehicle speed was slower and steadier.展开更多
By using field trials, the migration and transformation of coated controlled release nitrogen （YZS80） in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out...By using field trials, the migration and transformation of coated controlled release nitrogen （YZS80） in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly （P 〈0.05） in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate （10 -100 mg/kg） in 0 -80 d and 10 -60 cm soil layers, but increased significantly （ P 〈0.05） 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower （P〈0.05） before 45 d in 10 -30 cm soil layers, but significant higher（P〈0.05） after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^＋ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.展开更多
The effect of slow-release fertilizer application on reducing the fertilization times of ratooning rice was explored by carrying out plot experiments using different slow-release fertilizer formulas.The results showed...The effect of slow-release fertilizer application on reducing the fertilization times of ratooning rice was explored by carrying out plot experiments using different slow-release fertilizer formulas.The results showed that compared with conventional fertilization of farmers(TCK),there were no significant differences in plant heights of the first rice crop and ratoon rice crop and the number of tillers was slightly increased,by applying different ratios and types of slow-release fertilizers,indicating that reducing fertilization times did not affect rice growth.Compared with the TCK,the yields of treatments T1,T2,T3 and T4 of slow-release fertilizers increased to a certain extent.The yield of the first rice crop increased by 14.7%,16.7%,23.5% and 17.5%,respectively,the yields of the ratoon rice crop increased by 6.3%,5.8%,7.4% and 8.1%,respectively,and the yields of the two rice crops increased between 10.8% and 16.1%,indicating that reasonable combined application of slow-release nitrogen and fast-acting nitrogen fertilizer could meet the nutrient requirements of ratooning rice at different growth stages,and the application of slow-release fertilizers could reduce the fertilization times of ratooning rice.Based on the combination of rice yield and slow-release fertilizer cost in the first rice crop and ratoon rice crop,the T 3 formula was preferred,that is,urea-formaldehyde slow-release nitrogen fertilizer was used as the base and tillering fertilizer,and polyurethane-coated slow-release nitrogen fertilizer was used as the panicle-sprouting fertilizer.展开更多
Quantitative evaluation and analysis was made to the soil nutrients,rice yield,rice and fertilizer utilization rate,and economic and ecological benefits of the slow controlled release fertilizer in typical rice fields...Quantitative evaluation and analysis was made to the soil nutrients,rice yield,rice and fertilizer utilization rate,and economic and ecological benefits of the slow controlled release fertilizer in typical rice fields with middle-low yield by comparing the one-time application and split applications of slow-or controlledrelease fertilizer（ CRF） with farmers fertilizer practice as the control,with the aim to explore the effect of CRF. Results showed that compared with the control,the application of CRF could meet balance nutrients required for rice growth,and the effective panicles and seed-setting rate were higher in the treatment groups of FVOL,SVOL,LADVOLwhich applied CRF. As for soil nutrients,soil pH maintained balance in FVOL,FCAI,SVOL,LADVOL. In addition,differences in soil nutrient reduction amount reached the extremely significant level between FVOLand SXNK.SVOLwhich applied CRF provided reasonable regulation of N,P and K release rate,which showed advantages over blending fertilization and farmers fertilizer practice. Comprehensive analysis found that the application of CRF could make rice tillering growth and decline leveled off,which effectively improved the quality of rice population,and it also had higher input-output ratio than that of the control and good economic benefits. In general,CRF suits to be used widely on rice crop in the regions with medium-low yield.展开更多
The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like nor...The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like normalized advancing index (NAI) and complete transmission time (CTT). The simulations are done for a simple single-hop-topology (sender-router-receiver). The outcomes of this protocol are excellent and, in most cases, better than other approaches. The excellent properties of our proposed protocol were possible through tracking the available slow-start threshold. We achieved performance improvement, minimized end-to-end delay and large reduction in transmission time. DCM+ was able to combine many advantages at same time of the protocols NewReno and Westwood+. The results show, that DCM+ is extremely adequate for different types of networks. Feedback as main principle of control theory was used to control the congestion in the network. The parameters Round-Trip-Time (RTT) and Retransmission Timeout (RTO) are used as feedback signals to adjust the next congestion window (cwnd).展开更多
基金Supported by Special Fund for Agro-scientific Research in the Public Interest from Ministry of Agriculture(200903025-05)Fund from Kunming Municipal Science and Technology Committee(08S010201)~~
文摘[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.
基金the grants from National Science Foundation of China(Nos.11435008,11455001,11505112 and 11525522)a grant from the Ministry of Science and Technology of China(No.2016YFA0400301)+1 种基金We thank the support of a key laboratory grant from the Office of Science and Technology,Shanghai Municipal Government(No.11DZ2260700)the support from the Key Laboratory for Particle Physics,Astrophysics and Cosmology,Ministry of Education.This work is supported in part by the Chinese Academy of Sciences Center for Excellence in Particle Physics(CCEPP).
文摘Background The PandaX-4T experiment is a next-generation dark matter search program located in the China Jinping Underground Laboratory.To ensure the stability of the complex instrument during the planned operation,the status of the facility should be monitored continuously.Purpose The paper reports the design of the slow control system for the experiment.The system is used to monitor the facility status and generate an alarm signal while the detector is in abnormal status.Methods Low-cost hardware is employed for the distributed data collection.Python-based data collection program was developed.We also used the open source software for data storage,visualization and anomaly detection,so that the development of the system is simplified.Conclusion We finally achieved a low-cost and robust slow control system for the prototype detector in short time.It is running well currently.The system will be integrated with the PandaX-4T facility in late 2019.
基金the National Key R&D Program of China (2016YFD0300503)the Key Research Program of Jiangsu Province, China (BE2016344)+3 种基金the National Rice Industry Technology System, China (CARS01-27)the National Nature Science Foundation of China (31701350)the Program for Scientific Elitists of Yangzhou University, Chinaa Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘There is limited information about the influence of slow or controlled release fertilizer（S/CRF） on rice yield and quality. In this study, japonica rice cultivar Nanjing 9108 was used to study the effects of three different S/CRFs（polymer-coated urea（PCU）, sulfur-coated urea（SCU）, and urea formaldehyde（UF）） and two fertilization modes（both S/CRF and common urea（CU） as basal fertilizer, S/CRF as basal and CU as tillering fertilizer） on rice yield and quality. CU only was applied separately as control（CK）. Results showed that, rice grain yield, chalky kernel rate, chalky area, overall chalkiness, and the content of gliadin, glutenin, and protein, all showed the trends of UF〉PCU〉SCU within the same fertilization mode, and showed the trends of S/CRF as basal and CU as tillering fertilizer〉both S/CRF and CU as basal fertilizer within the same type of S/CRF. In contrast, the contents of amylose, amylopectin, and starch, as well as taste value, and peak and hot viscosity showed trends of SCU〉PCU〉UF, and the trends of both S/CRF and CU as basal fertilizer〉S/CRF as basal and CU as tillering fertilizer. Among S/CRF treatments and fertilization modes, taste values of cooked rice were positively correlated with amylose, amylopectin, and starch contents, as well as gel consistency, peak viscosity, hot viscosity, and cool viscosity, while negatively correlated with globulin, gliadin, glutenin, and protein contents. The types of S/CRF and fertilization modes are important for improving rice yield and quality. Compared to CK, higher yield and similar quality of rice was achieved with UF as basal and CU as tillering fertilizer, and similar yield with improved appearance and eating and cooking quality of rice was achieved with either both UF and CU as basal fertilizer, or PCU as basal and CU as tillering fertilizer.
基金the National Key Technology R&D Program of the 11th Five-Year Period (No.2006BAD10B08)
文摘Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.
文摘This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer(UCRF)and the N uptake and N-use efficiency by rice plants.Water dissolution,soil leaching,and pot experiments were employed.The dynamics of N release from the UCRF could be quantitatively described by three equations:the first-order kinetics equation[N1=N0(1-e^-kt)],Elovich equation(N1=a+blnt),and parabola equation(N1=a+bt^0.5),with the best fitting by the first-order kinetics equation for different N(r=0.9569^**-0.9999^**).The release potentials(No values estimated by the first-order kinetics equation)of different N in the UCRF decreased in the order of total N〉DON〉urea-N〉NH4^+-N〉NO3^-N in water,and total N〉NH4^+-N〉DON〉urea-N〉NO3^--N in soil,respectively,being in accordance with cumulative amounts of N release.The constants of N release rate(k values and b values)for different N forms were in decreasing order of total N〉DON〉NH4^+-N〉NO3^--N in water,whereas the k values were urea-N〉DON〉NH4^+-N〉total N〉NO3^--N,and the b values were total N〉NH4^+-N〉DON〉NO3^--N〉urea-N in soil.Compared with a common compound fertilizer,the N-use efficiency,N-agronomy efficiency,and N-physiological efficiency of the UCRF were increased by 11.4%,8.32 kg kg^-1,and 5.17 kg kg^-1,respectively.The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants.The findings showed that the first-order kinetics equation[Nt=N0(l-e^kt)]could be used to describe the release characteristics of different N forms in the fertilizer.The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.
基金financial support from the Independent Innovation and Achievements Transformation Project of Shandong Province (2014CGZH0302)
文摘Lignin is the main by-product of pulp and papermaking and is not effectively utilized. Conversion of industrial lignins into value-added materials is beneficial for the effective utilization of resources as well as for environmental protection. Because of their adsorptivity, slow-release property,biocompatibility, and biodegradability, lignin and its derivatives find potential applications as eco-friendly slow/controlled release materials in agricultural fields. This report reviews the recent research advances in lignin-based slow/controlled release fertilizers and pesticides.
文摘Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tends to reduce speed in the face of congestion thereby penalizing itself. In this group are the window based congestion control algorithms that use the size of congestion window to determine transmission speed. The two main algorithm of window based congestion control are the congestion avoidance and the slow start. The aim of this study is to survey the various modifications of window based congestion control. Much work has been done on congestion avoidance hence specific attention is placed on the slow start in order to motivate a new direction of research in network utility maximization. Mathematical modeling of the internet is discussed and proposals to improve TCP startup were reviewed. There are three lines of research on the improvement of slow start. A group uses the estimation of certain parameters to determine initial speed. The second group uses bandwidth estimation while the last group uses explicit request for network assistance to determine initial startup speed. The problems of each proposal are analyzed and a multiple startup for TCP is proposed. Multiple startups for TCP specify that startup speed is selectable from an n-arry set of algorithms. We then introduced the e-speed start which uses the prevailing network condition to determine a suitable starting speed.
基金Supported by the National Natural Science Foundation of China(51375053)
文摘In order to move tracked vehicles at an extremely slowspeed with automated mechanical transmission（ AMT）,slowdriving function was added in the original system. The principle and requirement of slowdriving function were analyzed. Based on analysis of slow driving characteristic,identification of slowdriving condition and fuzzy control algorithm,a control strategy of the clutch was designed. In order to realize slowdriving,the clutch was controlled in a slipping mode as manual driving. The vehicle speed was increased to a required speed and kept in a small range by engaging or disengaging the clutch to the approximate half engagement point. Based on the control strategy,a control software was designed and tested on a tracked vehicle with AMT. The test results showthat the control of the clutch with the slowdriving function was smoother than that with original systemand the vehicle speed was slower and steadier.
基金Supported by Beijing Science Committee Project"Science & TechnologyNew Star"(2008B38)"The Research and Establishmentof Agrochemical Service System for New Type of Fertilizer"(d0706004040431)The Foundation for Youth Scholars of BeijingAcademy of Agriculture and Forestry Sciences"The Developmentand Evaluation of Micro Water-soluble Cementation Coated Slow-releaseFertilizers Suitable for Semiand Areas"~~
文摘By using field trials, the migration and transformation of coated controlled release nitrogen （YZS80） in soil under the co-situs application mode were studied. The results indicated that YZS80 nitrogen dissolved out in average speed of about 0.4%/d and 32% totally in 80 d compared with common compound fertUizer. For YZS80, in the vertical downward direction of application points, urea nitrogen content increased significantly （P 〈0.05） in the 45 -80 d and the 30 -60 cm soil layers; nitrate nitrogen content was little change range and in moderate （10 -100 mg/kg） in 0 -80 d and 10 -60 cm soil layers, but increased significantly （ P 〈0.05） 45 -80 d compared to 0 -45 d; ammonium nitrogen content was significant lower （P〈0.05） before 45 d in 10 -30 cm soil layers, but significant higher（P〈0.05） after 45 d in 10 -60 cm soil layers; NO3^- -N/NH4^＋ -N meets gradually the needs of the crop with the extension of time. Under the co-situs application mode, the possibility of burning root and salt injury and loss dsk of nitrate leaching is a significant reduction.
基金Supported by National Key Research and Development Project(No.2018YFD0301302).
文摘The effect of slow-release fertilizer application on reducing the fertilization times of ratooning rice was explored by carrying out plot experiments using different slow-release fertilizer formulas.The results showed that compared with conventional fertilization of farmers(TCK),there were no significant differences in plant heights of the first rice crop and ratoon rice crop and the number of tillers was slightly increased,by applying different ratios and types of slow-release fertilizers,indicating that reducing fertilization times did not affect rice growth.Compared with the TCK,the yields of treatments T1,T2,T3 and T4 of slow-release fertilizers increased to a certain extent.The yield of the first rice crop increased by 14.7%,16.7%,23.5% and 17.5%,respectively,the yields of the ratoon rice crop increased by 6.3%,5.8%,7.4% and 8.1%,respectively,and the yields of the two rice crops increased between 10.8% and 16.1%,indicating that reasonable combined application of slow-release nitrogen and fast-acting nitrogen fertilizer could meet the nutrient requirements of ratooning rice at different growth stages,and the application of slow-release fertilizers could reduce the fertilization times of ratooning rice.Based on the combination of rice yield and slow-release fertilizer cost in the first rice crop and ratoon rice crop,the T 3 formula was preferred,that is,urea-formaldehyde slow-release nitrogen fertilizer was used as the base and tillering fertilizer,and polyurethane-coated slow-release nitrogen fertilizer was used as the panicle-sprouting fertilizer.
文摘Quantitative evaluation and analysis was made to the soil nutrients,rice yield,rice and fertilizer utilization rate,and economic and ecological benefits of the slow controlled release fertilizer in typical rice fields with middle-low yield by comparing the one-time application and split applications of slow-or controlledrelease fertilizer（ CRF） with farmers fertilizer practice as the control,with the aim to explore the effect of CRF. Results showed that compared with the control,the application of CRF could meet balance nutrients required for rice growth,and the effective panicles and seed-setting rate were higher in the treatment groups of FVOL,SVOL,LADVOLwhich applied CRF. As for soil nutrients,soil pH maintained balance in FVOL,FCAI,SVOL,LADVOL. In addition,differences in soil nutrient reduction amount reached the extremely significant level between FVOLand SXNK.SVOLwhich applied CRF provided reasonable regulation of N,P and K release rate,which showed advantages over blending fertilization and farmers fertilizer practice. Comprehensive analysis found that the application of CRF could make rice tillering growth and decline leveled off,which effectively improved the quality of rice population,and it also had higher input-output ratio than that of the control and good economic benefits. In general,CRF suits to be used widely on rice crop in the regions with medium-low yield.
文摘The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like normalized advancing index (NAI) and complete transmission time (CTT). The simulations are done for a simple single-hop-topology (sender-router-receiver). The outcomes of this protocol are excellent and, in most cases, better than other approaches. The excellent properties of our proposed protocol were possible through tracking the available slow-start threshold. We achieved performance improvement, minimized end-to-end delay and large reduction in transmission time. DCM+ was able to combine many advantages at same time of the protocols NewReno and Westwood+. The results show, that DCM+ is extremely adequate for different types of networks. Feedback as main principle of control theory was used to control the congestion in the network. The parameters Round-Trip-Time (RTT) and Retransmission Timeout (RTO) are used as feedback signals to adjust the next congestion window (cwnd).
