Ecological restoration by Taman＇x plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations ...Ecological restoration by Taman＇x plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations of soil water content and salinity around natural individual Tamarix ramosissiraa Ledeb. were invetigated in a semi-arid saline region of the upper Yellow River, Northwest China. Specifically, soil water content, electrical conductivity （EC）, sodium adsorption ratio （SARa）, and salt ions （including Na＋, K＋, Ca2＋, Mg2＋ and 8042-） were measured at different soil depths and at different distances from the trunk of T. ramasissima in May, July, and September 2016. The soil water content at the 20-80 cm depth was significantly lower in July and September than in May, indicating that T. ramosissima plants absorb a large amount of water through the roots during the growing period, leading to the decreasing of soil water content in the deep soil layer. At the 0-20 cm depth, there was a salt island effect around individual T. ramosissima, and the ECe differed significantly inside and outside the canopy of T. ramosissima in May and July. Salt bioaccumulation and stemflow were two major contributing factors to this difference. The SAR at the 0-20 cm depth was significantly different inside and outside the canopy of T. ramosissima in the three sampling months. The values of SAR~ at the 60-80 cm depth in May and July were significantly higher than those at the 0-60 cm depth and higher than that at the corresponding depth in September. The distribution of Na＋ in the soil was similar to that of the SAI, while the concentrations of K＋, Ca2＋, and Mg2＋ showed significant differences among the sampling months and soil depths. Both season and soil depth had highly significant effects on soil water content, ECe and SARa, whereas distance from the trunk of T. ramosissima only significantly affected ECe. Based on these results, we recommend co-planting of shallow-rooted salt-tolerant species near the Tamarx plants and avoiding planting herbaceous plants inside the canopy of T. ramodssima for afforestation in this semi-arid saline region. The results of this study may provide a reference for appropriate restoration in the semi-arid saline regions of the upper Yellow River.展开更多
Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under ...Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under continuous water stress (50% field capacity) and control (80% field capacity) conditions in a net house covered with polyethylene sheet at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Under water stress condition, the susceptible genotype namely BB04 exhibited more negative leaf water potential (LWP) which was followed by that of BARI bushbean-2 in all the time of the day except at noon. The tolerant genotype namely BB24 exhibited less negative LWP at noon. The tolerant genotypes maintained higher relative water content (WRC) than the susceptible ones from dawn to dusk. The relationship between RWC and LWP was examined separately for four genotypes under water stress condition. The genotype BB24 showed a smaller decrease in RWC with more negative LWP than BB04. Water stress reduced pod setting ratio. The relationship between the leaf water status and reproductive responses showed that the genotype with a little reduction in mid-day drop of RWC or with high mid-day RWC displayed a high pod setting ratio.展开更多
This study aims to predict the undrained shear strength of remolded soil samples using non-linear regression analyses,fuzzy logic,and artificial neural network modeling.A total of 1306 undrained shear strength results...This study aims to predict the undrained shear strength of remolded soil samples using non-linear regression analyses,fuzzy logic,and artificial neural network modeling.A total of 1306 undrained shear strength results from 230 different remolded soil test settings reported in 21 publications were collected,utilizing six different measurement devices.Although water content,plastic limit,and liquid limit were used as input parameters for fuzzy logic and artificial neural network modeling,liquidity index or water content ratio was considered as an input parameter for non-linear regression analyses.In non-linear regression analyses,12 different regression equations were derived for the prediction of undrained shear strength of remolded soil.Feed-Forward backpropagation and the TANSIG transfer function were used for artificial neural network modeling,while the Mamdani inference system was preferred with trapezoidal and triangular membership functions for fuzzy logic modeling.The experimental results of 914 tests were used for training of the artificial neural network models,196 for validation and 196 for testing.It was observed that the accuracy of the artificial neural network and fuzzy logic modeling was higher than that of the non-linear regression analyses.Furthermore,a simple and reliable regression equation was proposed for assessments of undrained shear strength values with higher coefficients of determination.展开更多
基金funded by the Fundamental Research Funds for the Central Universities (2016ZCQ06)the Forestry Industry Research Special Funds for Public Welfare Projects (201504402)the Application Technology of Seaweed Fertilizer Based on Desertification Control and Saline-alkili Soil Improvement (2016HXFWSBXY002)
文摘Ecological restoration by Taman＇x plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations of soil water content and salinity around natural individual Tamarix ramosissiraa Ledeb. were invetigated in a semi-arid saline region of the upper Yellow River, Northwest China. Specifically, soil water content, electrical conductivity （EC）, sodium adsorption ratio （SARa）, and salt ions （including Na＋, K＋, Ca2＋, Mg2＋ and 8042-） were measured at different soil depths and at different distances from the trunk of T. ramasissima in May, July, and September 2016. The soil water content at the 20-80 cm depth was significantly lower in July and September than in May, indicating that T. ramosissima plants absorb a large amount of water through the roots during the growing period, leading to the decreasing of soil water content in the deep soil layer. At the 0-20 cm depth, there was a salt island effect around individual T. ramosissima, and the ECe differed significantly inside and outside the canopy of T. ramosissima in May and July. Salt bioaccumulation and stemflow were two major contributing factors to this difference. The SAR at the 0-20 cm depth was significantly different inside and outside the canopy of T. ramosissima in the three sampling months. The values of SAR~ at the 60-80 cm depth in May and July were significantly higher than those at the 0-60 cm depth and higher than that at the corresponding depth in September. The distribution of Na＋ in the soil was similar to that of the SAI, while the concentrations of K＋, Ca2＋, and Mg2＋ showed significant differences among the sampling months and soil depths. Both season and soil depth had highly significant effects on soil water content, ECe and SARa, whereas distance from the trunk of T. ramosissima only significantly affected ECe. Based on these results, we recommend co-planting of shallow-rooted salt-tolerant species near the Tamarx plants and avoiding planting herbaceous plants inside the canopy of T. ramodssima for afforestation in this semi-arid saline region. The results of this study may provide a reference for appropriate restoration in the semi-arid saline regions of the upper Yellow River.
文摘Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under continuous water stress (50% field capacity) and control (80% field capacity) conditions in a net house covered with polyethylene sheet at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Under water stress condition, the susceptible genotype namely BB04 exhibited more negative leaf water potential (LWP) which was followed by that of BARI bushbean-2 in all the time of the day except at noon. The tolerant genotype namely BB24 exhibited less negative LWP at noon. The tolerant genotypes maintained higher relative water content (WRC) than the susceptible ones from dawn to dusk. The relationship between RWC and LWP was examined separately for four genotypes under water stress condition. The genotype BB24 showed a smaller decrease in RWC with more negative LWP than BB04. Water stress reduced pod setting ratio. The relationship between the leaf water status and reproductive responses showed that the genotype with a little reduction in mid-day drop of RWC or with high mid-day RWC displayed a high pod setting ratio.
文摘This study aims to predict the undrained shear strength of remolded soil samples using non-linear regression analyses,fuzzy logic,and artificial neural network modeling.A total of 1306 undrained shear strength results from 230 different remolded soil test settings reported in 21 publications were collected,utilizing six different measurement devices.Although water content,plastic limit,and liquid limit were used as input parameters for fuzzy logic and artificial neural network modeling,liquidity index or water content ratio was considered as an input parameter for non-linear regression analyses.In non-linear regression analyses,12 different regression equations were derived for the prediction of undrained shear strength of remolded soil.Feed-Forward backpropagation and the TANSIG transfer function were used for artificial neural network modeling,while the Mamdani inference system was preferred with trapezoidal and triangular membership functions for fuzzy logic modeling.The experimental results of 914 tests were used for training of the artificial neural network models,196 for validation and 196 for testing.It was observed that the accuracy of the artificial neural network and fuzzy logic modeling was higher than that of the non-linear regression analyses.Furthermore,a simple and reliable regression equation was proposed for assessments of undrained shear strength values with higher coefficients of determination.
