The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical mod...The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical models based on partial least squares （PLS） regression were defined from the measured reflectance spectra （0.4 to 2.4 μm）. Here, reliable estimates were obtained for nitrogen content, but prediction accuracy was only moderate for organic carbon. For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy. The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon, and therefore an appropriate alternative to time- and cost-intensive chemical analysis in the laboratory.展开更多
[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonab...[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonable control period and the application amount of DPC. [Method] The new machine-harvested cotton variety Hengmian HD008 was used as the test material, and 3 different DPC treatments were set. [Result] DPC significantly reduced plant height and branch length, reduced branch angle and leaf area, so the rational control can effectively shape the ideal plant type of machine-harvested cotton. DPC had significant effects on yield and yield components, and the proper amount of DPC could increase the number of bolls during hot days, the number bolls in autumn and the total number of bolls. It increased the boll weight and seed index, but decreased lint percentage decreased, and proper amount of DPC could increase the yield. DPC significantly increased the specific breaking strength of fibers, and proper control could improve the uniformity of fibers, but other indexes had no significant influence. [Conclusion] According to the requirements of machine harvest to the agronomic traits of cotton and the growth characteristics of cotton plant, chemical control could begin after floral bud emergence in cotton about every 10 d, and the spraying amount can be controlled according to the growth amount of the main stem. The daily growth amount of plant height should be controlled at 1.5-1.8 cm, and the plant height should be within 75-90 cm.展开更多
文摘The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements （n = 52） performed with an ASD FieldSpee-Ⅱ spectroradiometer. For parameter prediction, empirical models based on partial least squares （PLS） regression were defined from the measured reflectance spectra （0.4 to 2.4 μm）. Here, reliable estimates were obtained for nitrogen content, but prediction accuracy was only moderate for organic carbon. For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy. The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon, and therefore an appropriate alternative to time- and cost-intensive chemical analysis in the laboratory.
基金Supported by the Fundamental Research Funds of the Heibei Academy of Agriculture and Forestry Sciences(A2015040201)the Cotton Industry Technology System of Hebei Province+1 种基金the Key Research and Development Planning Program of Hebei Province(16226303D)the Financial Program of Hebei Province(F17C10005)~~
文摘[Objective] The aim was to investigate the effects of DPC chemical controlling technique on agronomic traits, yield and quality of machine-harvested cotton in the Yellow River Valley of China, and clarify the reasonable control period and the application amount of DPC. [Method] The new machine-harvested cotton variety Hengmian HD008 was used as the test material, and 3 different DPC treatments were set. [Result] DPC significantly reduced plant height and branch length, reduced branch angle and leaf area, so the rational control can effectively shape the ideal plant type of machine-harvested cotton. DPC had significant effects on yield and yield components, and the proper amount of DPC could increase the number of bolls during hot days, the number bolls in autumn and the total number of bolls. It increased the boll weight and seed index, but decreased lint percentage decreased, and proper amount of DPC could increase the yield. DPC significantly increased the specific breaking strength of fibers, and proper control could improve the uniformity of fibers, but other indexes had no significant influence. [Conclusion] According to the requirements of machine harvest to the agronomic traits of cotton and the growth characteristics of cotton plant, chemical control could begin after floral bud emergence in cotton about every 10 d, and the spraying amount can be controlled according to the growth amount of the main stem. The daily growth amount of plant height should be controlled at 1.5-1.8 cm, and the plant height should be within 75-90 cm.
