Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch dr...Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch drip irrigation emitters,focusing on the anti-clogging performance through the experiment,were investigated.The dynamic variations in the clogging characteristics of emitters,specifically were subjected to statistical analysis.The movement mechanism of emitter clogging and discharging sediment was studied.The effects of emitter structure and position factors on emitter clogging were analyzed.The results show that the pressure-compensated emitter exhibits superior anti-clogging perfor-mance,with a service life that is 227.8%greater than that of the labyrinth channel emitter.A single structural factor cannot completely evaluate the anti-clogging performance of emitters.All factors causing emitter clogging should be considered comprehensively.Emitters contain sensitive sediment prone to clogging,however,significant blockage occurs primarily when the sediment content is elevated.The discharge of sediment,denoted as V90,from the emitter is affected by the accumulative effect of clogged sediment.These results may offer valuable insights for the application and advancement of drip irrigation technology.展开更多
The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI)...The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI) and fixed drip irrigation( FDI) on growth,photosynthetic characteristics,biomass accumulation and irrigation water use efficiency of Arabica coffee were investigated under three nitrogen levels,high nitrogen( NH),middle nitrogen( NM) and low nitrogen( NL). The results show that there was a significant Logistic curve between the plant height,the stem diameter of Arabica coffee and growth days. Compared with CDI,ADI had no significant effects on leaf net photosynthetic rate,stomatal conductance,instantaneous water use efficiency and biomass accumulation above ground of Arabica coffee,while FDI decreased significantly,ADI and FDI increased irrigation water use efficiency by 50. 59% and 32. 85%,respectively. Compared with NH,with the reduction of N application rate,net photosynthetic rate,stomatal conductance,biomass accumulation above ground and irrigation water use efficiency decreased by 6. 81%-12. 30%,13. 70%-22. 69%,9. 61%-16. 67% and 9. 78%-15. 64%,respectively. Compared with CDINH,ADINHdecreased net photosynthesis rate and the stomatal conductance not significantly,other treatments decreased by 9. 16%-19. 22%,14. 49%-32. 91%,and decreased biomass accumulation above ground by 8. 26%-27. 34% except ADINH,and increased irrigation water use efficiency by 16. 46%-60. 95% except CDINMand CDINL. Therefore,alternate drip irrigation under high N level( ADINH) is the best water and nitrogen coupling mode of young Arabica coffee tree for water efficiency.展开更多
Vacuum precision seed metering is the key part of vacuum seed planter. Planting performance of planter is affected by vacuum and air flow which are important parameters for choosing fan. Effects of qualification perce...Vacuum precision seed metering is the key part of vacuum seed planter. Planting performance of planter is affected by vacuum and air flow which are important parameters for choosing fan. Effects of qualification percent and miss percent on air chamber vacuum 3, 4, 5 and 6 kPa were studied at different operating speeds. The results showed that operating performance of the seed metering was excellent when air chamber vacuum was 5 and 6 kPa, which air flow was 7.4-8.0 m3·s-1 and 8.0-8.8 m3·s-1 , respectively.展开更多
基金National Natural Science Foundation of China(52269011,52469008)。
文摘Sediment particles,as one of the key components of drip irrigation technology,significantly affect the service life of emitters and restrict the popularization of drip irrigation technology.Hence,two types of patch drip irrigation emitters,focusing on the anti-clogging performance through the experiment,were investigated.The dynamic variations in the clogging characteristics of emitters,specifically were subjected to statistical analysis.The movement mechanism of emitter clogging and discharging sediment was studied.The effects of emitter structure and position factors on emitter clogging were analyzed.The results show that the pressure-compensated emitter exhibits superior anti-clogging perfor-mance,with a service life that is 227.8%greater than that of the labyrinth channel emitter.A single structural factor cannot completely evaluate the anti-clogging performance of emitters.All factors causing emitter clogging should be considered comprehensively.Emitters contain sensitive sediment prone to clogging,however,significant blockage occurs primarily when the sediment content is elevated.The discharge of sediment,denoted as V90,from the emitter is affected by the accumulative effect of clogged sediment.These results may offer valuable insights for the application and advancement of drip irrigation technology.
基金National Natural Science Foundation of China(51109102,51469010,51769010)the basic research project of Yunnan Province(2014FB130)key project of education department in Yunnan Province(2011Z035)
文摘The objective of this study was to obtain the water-saving and efficient production mode of Arabica coffee. The effects of three drip irrigation modes,conventional drip irrigation( CDI),alternate drip irrigation( ADI) and fixed drip irrigation( FDI) on growth,photosynthetic characteristics,biomass accumulation and irrigation water use efficiency of Arabica coffee were investigated under three nitrogen levels,high nitrogen( NH),middle nitrogen( NM) and low nitrogen( NL). The results show that there was a significant Logistic curve between the plant height,the stem diameter of Arabica coffee and growth days. Compared with CDI,ADI had no significant effects on leaf net photosynthetic rate,stomatal conductance,instantaneous water use efficiency and biomass accumulation above ground of Arabica coffee,while FDI decreased significantly,ADI and FDI increased irrigation water use efficiency by 50. 59% and 32. 85%,respectively. Compared with NH,with the reduction of N application rate,net photosynthetic rate,stomatal conductance,biomass accumulation above ground and irrigation water use efficiency decreased by 6. 81%-12. 30%,13. 70%-22. 69%,9. 61%-16. 67% and 9. 78%-15. 64%,respectively. Compared with CDINH,ADINHdecreased net photosynthesis rate and the stomatal conductance not significantly,other treatments decreased by 9. 16%-19. 22%,14. 49%-32. 91%,and decreased biomass accumulation above ground by 8. 26%-27. 34% except ADINH,and increased irrigation water use efficiency by 16. 46%-60. 95% except CDINMand CDINL. Therefore,alternate drip irrigation under high N level( ADINH) is the best water and nitrogen coupling mode of young Arabica coffee tree for water efficiency.
基金Supported by the Youth Science Foundation of Heilongjiang(QC2010119,QC2010028)the Science and Technology Innovation Person with Ability Study Special Foundation Project of Harbin(2011RFQXN054)+1 种基金the Graduate Student Innovative Scientific Research Project of Heilongjiang(YJSCX2011-064JHL)Division of Soybean Machinery,CARS(nycytx-004)
文摘Vacuum precision seed metering is the key part of vacuum seed planter. Planting performance of planter is affected by vacuum and air flow which are important parameters for choosing fan. Effects of qualification percent and miss percent on air chamber vacuum 3, 4, 5 and 6 kPa were studied at different operating speeds. The results showed that operating performance of the seed metering was excellent when air chamber vacuum was 5 and 6 kPa, which air flow was 7.4-8.0 m3·s-1 and 8.0-8.8 m3·s-1 , respectively.
