[Objective] This study aimed to investigation the effects of straw covering and different types of potassium fertilizer on salinity accumulation in surface layer of tobacco-planted paddy soil in southern China. [Metho...[Objective] This study aimed to investigation the effects of straw covering and different types of potassium fertilizer on salinity accumulation in surface layer of tobacco-planted paddy soil in southern China. [Method] Tobacco variety ‘Yunyan87’ was used as the experimental material to investigate the effects of salinity accumulation in surface layer of tobacco-planted paddy soil on the growth and development of flue-cured tobacco using different types of potassium fertilizer and mulching cultivation methods. [Result] The results showed that K+ , Ca2+ , SO42and NO3-were the major salt ions in topsoil at different growth stages of flue-cured tobacco, Na + and Mg2+ contents were also relatively high at vigorous growth stage, indicating that these salt ions were easily accumulated in surface layer of soil; to be specific, the absolute increase of salt ion concentration showed a decreasing order of K+ SO42- NO3-Ca2+ Mg2+ Na+ Cl-, while the relative increase of salt ion concentration showed a decreasing order of Ca2+ K+ Na+ NO3-SO42-Mg2+ Cl-. At 60 d posttransplanting, total salt content in topsoil reached the minimum of 359.1 mg/kg in Treatment 2, total salt content in topsoil reached the maximum of 536.1 mg/kg in Treatment 5 (CK), which was significantly higher than that in other treatments. At 90 d post-transplanting, no significant difference was observed in total salt content among various treatments. At harvesting period, total salt content in topsoil reached the maximum of 3 278.4 mg/kg in Treatment 1, which was significantly higher than that in other treatments. Topsoil pH showed no significant differences among various treatments at three different periods, ranging from 5.39 to 5.59. Straw covering could effectively reduce salt content in topsoil, accelerate vigorous growth of tobacco, shorten vigorous growth period and increase plant height, leaf number and lead area; at vigorous growth stage, root vitality and root volume of tobacco were improved, but the yield and output value were relatively low. Major agronomic traits and yield of tobacco showed no significant difference among various treatments. Output value of tobacco reached the maximum of 24 196.8 yuan/hm2 in Treatment 3, which was significantly higher than that in other treatments. [Conclusion] Appropriate types and proportions of potassium fertilizer and straw covering can effectively reduce the total salt content in tobacco-planted paddy soil and increase the effective supply amount of K+ , Ca2+ , SO42-and NO3-, thereby promoting and improving the root vitality of tobacco, which is conducive to the growth and development of tobacco and will eventually enhance the yield, quality and economic benefits of flue-cured tobacco.展开更多
Many leading experts agree on the importance of monitoring the "concrete skin" as the most loaded area affected by the external environment. Surfacing, concrete mixture composition and curing are of great importance...Many leading experts agree on the importance of monitoring the "concrete skin" as the most loaded area affected by the external environment. Surfacing, concrete mixture composition and curing are of great importance for the concrete surface resistance. The paper introduces an experimental program focused on the monitoring of de-icing salts resistance, depending on surface roughness. Quantitative evaluation of the concrete surface was performed by using confocal laser scanning microscopy, which is the new generation of optical systems that are able to make all measurements in 3D resolution. These measurements are supplemented by results of mechanical and absorption tests.展开更多
The use of landscape covariates to variability of soil properties in similar estimate soil properties is not suitable topographic and vegetation conditions. for the areas of low relief due to the high A new method wa...The use of landscape covariates to variability of soil properties in similar estimate soil properties is not suitable topographic and vegetation conditions. for the areas of low relief due to the high A new method was implemented to map regional soil texture (in terms of sand, silt and clay contents) by hypothesizing that the change in the land surface diurnal temperature difference (DTD) is related to soil texture in case of a relatively homogeneous rainfall input. To examine this hypothesis, the DTDs from moderate resolution imagine spectroradiometer (MODIS) during a selected time period, i.e., after a heavy rainfall between autumn harvest and autumn sowing, were classified using fuzzy-c-means (FCM) clustering. Six classes were generated, and for each class, the sand (〉 0.05 mm), silt (0.002-0.05 mm) and clay (〈 0.002 mm) contents at the location of maximum membership value were considered as the typical values of that class. A weighted average model was then used to digitally map soil texture. The results showed that the predicted map quite accurately reflected the regional soil variation. A validation dataset produced estimates of error for the predicted maps of sand, silt and clay contents at root mean of squared error values of 8.4%, 7.8% and 2.3%, respectively, which is satisfactory in a practical context. This study thus provided a methodology that can help improve the accuracy and efficiency of soil texture mapping in plain areas using easily available data sources.展开更多
基金Supported by Project of Guangdong Zhongyan Industry Limited Liability Company[YYG15JO-QK(2011)-004]~~
文摘[Objective] This study aimed to investigation the effects of straw covering and different types of potassium fertilizer on salinity accumulation in surface layer of tobacco-planted paddy soil in southern China. [Method] Tobacco variety ‘Yunyan87’ was used as the experimental material to investigate the effects of salinity accumulation in surface layer of tobacco-planted paddy soil on the growth and development of flue-cured tobacco using different types of potassium fertilizer and mulching cultivation methods. [Result] The results showed that K+ , Ca2+ , SO42and NO3-were the major salt ions in topsoil at different growth stages of flue-cured tobacco, Na + and Mg2+ contents were also relatively high at vigorous growth stage, indicating that these salt ions were easily accumulated in surface layer of soil; to be specific, the absolute increase of salt ion concentration showed a decreasing order of K+ SO42- NO3-Ca2+ Mg2+ Na+ Cl-, while the relative increase of salt ion concentration showed a decreasing order of Ca2+ K+ Na+ NO3-SO42-Mg2+ Cl-. At 60 d posttransplanting, total salt content in topsoil reached the minimum of 359.1 mg/kg in Treatment 2, total salt content in topsoil reached the maximum of 536.1 mg/kg in Treatment 5 (CK), which was significantly higher than that in other treatments. At 90 d post-transplanting, no significant difference was observed in total salt content among various treatments. At harvesting period, total salt content in topsoil reached the maximum of 3 278.4 mg/kg in Treatment 1, which was significantly higher than that in other treatments. Topsoil pH showed no significant differences among various treatments at three different periods, ranging from 5.39 to 5.59. Straw covering could effectively reduce salt content in topsoil, accelerate vigorous growth of tobacco, shorten vigorous growth period and increase plant height, leaf number and lead area; at vigorous growth stage, root vitality and root volume of tobacco were improved, but the yield and output value were relatively low. Major agronomic traits and yield of tobacco showed no significant difference among various treatments. Output value of tobacco reached the maximum of 24 196.8 yuan/hm2 in Treatment 3, which was significantly higher than that in other treatments. [Conclusion] Appropriate types and proportions of potassium fertilizer and straw covering can effectively reduce the total salt content in tobacco-planted paddy soil and increase the effective supply amount of K+ , Ca2+ , SO42-and NO3-, thereby promoting and improving the root vitality of tobacco, which is conducive to the growth and development of tobacco and will eventually enhance the yield, quality and economic benefits of flue-cured tobacco.
文摘Many leading experts agree on the importance of monitoring the "concrete skin" as the most loaded area affected by the external environment. Surfacing, concrete mixture composition and curing are of great importance for the concrete surface resistance. The paper introduces an experimental program focused on the monitoring of de-icing salts resistance, depending on surface roughness. Quantitative evaluation of the concrete surface was performed by using confocal laser scanning microscopy, which is the new generation of optical systems that are able to make all measurements in 3D resolution. These measurements are supplemented by results of mechanical and absorption tests.
基金Supported by the Basic Research Program of Jiangsu Province,China (No. BK2008058)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-409)
文摘The use of landscape covariates to variability of soil properties in similar estimate soil properties is not suitable topographic and vegetation conditions. for the areas of low relief due to the high A new method was implemented to map regional soil texture (in terms of sand, silt and clay contents) by hypothesizing that the change in the land surface diurnal temperature difference (DTD) is related to soil texture in case of a relatively homogeneous rainfall input. To examine this hypothesis, the DTDs from moderate resolution imagine spectroradiometer (MODIS) during a selected time period, i.e., after a heavy rainfall between autumn harvest and autumn sowing, were classified using fuzzy-c-means (FCM) clustering. Six classes were generated, and for each class, the sand (〉 0.05 mm), silt (0.002-0.05 mm) and clay (〈 0.002 mm) contents at the location of maximum membership value were considered as the typical values of that class. A weighted average model was then used to digitally map soil texture. The results showed that the predicted map quite accurately reflected the regional soil variation. A validation dataset produced estimates of error for the predicted maps of sand, silt and clay contents at root mean of squared error values of 8.4%, 7.8% and 2.3%, respectively, which is satisfactory in a practical context. This study thus provided a methodology that can help improve the accuracy and efficiency of soil texture mapping in plain areas using easily available data sources.