[Objective] The aim of this study was to investigate the dry matter accumulation,moisture content in maize kernel and their influences on mechanical harvesting.[Methods] Using Zhengdan 958,Xianyu 335,Hongda 8 and Liyu...[Objective] The aim of this study was to investigate the dry matter accumulation,moisture content in maize kernel and their influences on mechanical harvesting.[Methods] Using Zhengdan 958,Xianyu 335,Hongda 8 and Liyu 16 as experimental materials,we preliminarily measured the dynamic changes of dry matter accumulation and moisture content with the days after pollination lasted,and investigated the effect of moisture content in kernels on mechanical harvesting of Zhengdan 958 and Liyu 16.[Results] During summer growing season,Zhengdan 958 and Liyu 16 became physiologically mature and suitable for harvesting at about 51 days after pollination,Xianyu 335 and Hongda 8 required 58 days to become physiologically mature and suitable for harvesting after pollination.At physiologically mature stage,the moisture contents in kernels of Zhengdan 958,Xianyu 335,Hongda 8 and Liyu 16 were respectively 33.74%,28.86%,32.05% and 35.24%,respectively.Adopting mechanical harvesting at physiologically mature stage,the kernel loss rate of Zhengdan 958 and Liyu 16 was consistent with the range of mechanical operation index(kernel loss rate of 0.84%≤2%),while the percentage of broken kernels did not accord with the range of mechanical operation index(kernel crashing rate of 10.12%≧1%).The results indicate that Zhengdan 958 and Liyu 16 are not suitable for mechanical harvesting using full feeding combine havester.[Conclusion] This study provided theoretical basis for improving the maize harvest index under delayed harvesting.展开更多
[Objective] The paper aimed to discuss the relationship between sulfur contents of mosses and the concentration of SO2-4 and the source of Atmospheric sulfur in Nanchang.[Method] 29 moss samples (Bryohaplocladium mic...[Objective] The paper aimed to discuss the relationship between sulfur contents of mosses and the concentration of SO2-4 and the source of Atmospheric sulfur in Nanchang.[Method] 29 moss samples (Bryohaplocladium micriophyllum (Hedw.) R.Watanabe et Iwats) were collected from four sampling points,including North campus and Qianhu campus of Nanchang Power Station were determined.[Result] The results showed that sulfur contents of mosses tissues in North campus of Nanchang University (0.45±0.059%) were higher than Qianhu campus of Nanchang University (0.26±0.002%),which coincided with the changing law of the concentration of SO2-4.Sulphur isotope of mosses tissues was-0.64‰-9.71‰.Sulphur isotope of mosses tissues in Meling (4.02‰-9.71‰) was higher than Qianhu campus of Nanchang University (0.55‰-0.56‰) and power plant (-0.64‰-0.45‰).[Conclusion] Relationship between sulphur contents and sulphur isotopes of mosses tissues showed sulfur source of sulphur deposition in Nanchang city was mainly affected by 34S-enriched sulphur transported from northerly air masses and biogenic sulfur.展开更多
[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with ...[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco nitrogen,free amino acid nitrogen as indicators,the effect of nitrogen application on contents of different forms of nitrogen in rice plants were studied.[Result] The contents of total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco-N,free amino nitrogen of rice plant during heading and maturity stage increased with the increasing application amount of nitrogen,and their contents would be high under heavy application of spike fertilizer when the application amount of nitrogen was the same.However,application of nitrogen had different impact on different forms of nitrogen,which showed obvious impact on the contents of Rubisco-N and free amino nitrogen.The differences of Rubisco-N and free amino nitrogen content of two varieties during heading and maturity stage under different nitrogen application modes all reached significant or extremely significant level.Correlation analysis showed that total nitrogen content of rice plant had extremely significant correlation with protein nitrogen content during heading and maturity stage in both early and late seasons.[Conclusion] The study provided a theoretical basis for clarifying the regulatory role of nitrogen application on nitrogen absorption and utilization.展开更多
In order to assess the performance of the embankment soil under various climate conditions during the period of service, the modulus behaviour of an unsaturated compacted soil is evaluated using the constant water con...In order to assess the performance of the embankment soil under various climate conditions during the period of service, the modulus behaviour of an unsaturated compacted soil is evaluated using the constant water content triaxial test. Since the water content measurement method is simple and economical and it is used widely in engineering, the soil suction is replaced by the water content and the relationship between the water content and the modulus is developed. The compacted samples are prepared with different compacted water contents, and samples with a similar water content subjected to drying or wetting procedures prior to the triaxial test are also investigated. The effect of the water content and the confining pressure on the modulus is analyzed. The results show that the modulus decreases with the increase in the water content and a power function can be proposed to quantitatively describe the relationship between the modulus and the water content in the range of the measured water content. The modulus increases with the increase in the confining pressure of the compacted soil. However, the effect of the water content on the modulus is more pronounced than that of the confining pressure. This research can be referenced for the compacted embankment soil assessment in-service period.展开更多
Under the condition of high temperature, the effects of five cover patterns (clean tillage, film mulching, weed covering, branches and leaves covering and growing grass covering) on soil properties in young Phoebe b...Under the condition of high temperature, the effects of five cover patterns (clean tillage, film mulching, weed covering, branches and leaves covering and growing grass covering) on soil properties in young Phoebe boumei forest were in- vestigated. The results showed that the five cover patterns all showed significant ef- fects on soil properties in young Phoebe bournei forest under the condition of high temperature. Land cover increased land temperature in Phoebe boumei forest. Un- der the film mulching, the land temperature was increased most rapidly with the largest increment. However, weed covering, branches and leaves covering and growing grass covering decreased land temperature. Among them, growing grass covering showed the best cooling effect. The film mulching, weed covering, branch- es and leaves covering and growing grass covering all increased land humidity. The film mulching showed the best moisture-preserving effect in the early period, but in the late period, the humidity in the film mulching treatment group was lower than that in the clean tillage treatment group. Among the five mulching patterns, moisture loss in the film mulching treatment group was slowest and least, followed by those in the weed covering and branches and leaves covering treatment groups, and moisture loss in the growing grass covering treatment group was fastest and most.展开更多
A surface soil moisture model with improved spatial resolution was developed using remotely sensed apparent thermal inertia(ATI).The model integrates the surface temperature derived from TM/ETM+ image and the mean ...A surface soil moisture model with improved spatial resolution was developed using remotely sensed apparent thermal inertia(ATI).The model integrates the surface temperature derived from TM/ETM+ image and the mean surface temperature from MODIS images to improve the spatial resolution of soil temperature difference based on the heat conduction equation,which is necessary to calculate the ATI.Consequently,the spatial resolution of ATI and SMC can be enhanced from 1 km to 120 m(TM) or 60m(ETM+).Moreover,the enhanced ATI has a much stronger correlation coefficient(R^2) with SMC(0.789) than the surface reflectance(0.108) or the ATI derived only from MODIS images(0.264).Based on the regression statistics of the field SMC measurement and enhanced ATI,a linear regression model with an RMS error of 1.90%was found.展开更多
[Objective] The aim was to study the regression relationship between water index (WI) and fuel moisture content (FMC) of different growth periods of sawtooth oaks leaf.[Method] Taking sawtooth oaks in Huaguo Mount...[Objective] The aim was to study the regression relationship between water index (WI) and fuel moisture content (FMC) of different growth periods of sawtooth oaks leaf.[Method] Taking sawtooth oaks in Huaguo Mountain,Lianyungang City as research object,the sensitivity of WI to leaf FMC was studied at leaf level,and statistical characteristics were analyzed.[Result] The WI of sawtooth oaks leaves was sensitive to the changes of FMC,and the line regression level between them was significant.A fitting curve between leaf FMC and WI was obtained.[Conclusion] The research provides reference for acquisition methods of vegetation water remote sensing within the range of study area.展开更多
Self assembled monolayers (SAMs) of 1-tetradecylphosphonic acids (TDPA, CH3(CH2)13P(O)(OH)2 ) were formed on the 2024 aluminum alloy surface in TDPA-containing ethanol-water solutions with different water co...Self assembled monolayers (SAMs) of 1-tetradecylphosphonic acids (TDPA, CH3(CH2)13P(O)(OH)2 ) were formed on the 2024 aluminum alloy surface in TDPA-containing ethanol-water solutions with different water content. The adsorption and corrosion protection properties of the SAMs for 2024 alloy in 0.1 mol/L H2SO4 solution were examined and characterized by potentiodynamic polarization, electrochemical impedance spectrum (EIS), Fourier transformed infrared spectroscopy (FTIR), Auger electron spectra (AES) and atomic force microscopy (AFM). FTIR and AES results show that the TDPA molecules were successfully adsorbed on the 2024 aluminum alloy surface, and the density of the SAMs increased with the increasing water content in the assembly solution. The results of electrochemical studies and corrosion morphologies observed by AFM show that a 4 h modification resulted in maximal inhibition efficiency, and the higher the water content in the assembly solution is, the better the inhibition performance of the SAMs can be achieved. The effect of water content in TDPA solutions on the performance of the SAMs is related to the hydration reaction of the metal surface.展开更多
In modern agriculture, accurate and effective measurements of soil water content lays foundation for promotion on precision irrigation technology and improvement on water use efficiency. The research reviewed soil moi...In modern agriculture, accurate and effective measurements of soil water content lays foundation for promotion on precision irrigation technology and improvement on water use efficiency. The research reviewed soil moisture indices at home and abroad and classified the indices into two categories in order to make prediction on soil moisture and take measures. Specifically, single indices included precipitation index, soil moisture index, and crop drought index and overall indices included supply/demand water index of crops, overall water index, PDSI, crop water shortage index. Soil moisture index was analyzed in terms of advantages and disadvantages,as well as adaptability in agriculture, providing references for relieving and predicting adverse effects on agriculture and formulating scientific policies.展开更多
[Objective] This research aimed at studying the effects of application amount of DCD and physics and chemistry characteristics of soil such as temperature,moisture content,organic matter content and pH on the inhibiti...[Objective] This research aimed at studying the effects of application amount of DCD and physics and chemistry characteristics of soil such as temperature,moisture content,organic matter content and pH on the inhibition of nitrification when applying nitrification inhibitor DCD in latosol.[Method] The experiment was carried out under aerobic incubated conditions.[Result] A significant delay period of nitrification was observed when the application amount of DCD was 10 mg/kg soil,and the inhibition can at least last for 56 d.When the cultural temperature had increased from 10 to 30 ℃,the duration of nitrification inhibition was shortened from 90 to 30 d.The nitrification inhibition of DCD was reduced with the increasing soil moisture content,organic matter content and soil pH,while the duration of nitrification inhibition was prolonged with the decreasing soil moisture content,organic matter content and soil pH.[Conclusion] Nitrification inhibition of DCD can be improved by increasing the application amount or reducing soil temperature,moisture content,organic matter content and pH.展开更多
[Objective] The effects of different plastic films mulching on soil temperature and moisture, and growth and yield of sugarcane were discussed in order to provide references for using different plastic film in sugarca...[Objective] The effects of different plastic films mulching on soil temperature and moisture, and growth and yield of sugarcane were discussed in order to provide references for using different plastic film in sugarcane pro-duction. [Method]Four kinds of plastic films viz., normal colorless transparent plastic film, milky photodegradation weeding plastic film, black plastic film and gray-black plastic film were used in sugarcane cultivation by using no film mulching as the control. Soil temperature and moisture were measured during plastic film mulching period, and sugarcane agronomic traits such as emergence rate, tillering rate, plant hight, stalk diameter and effective stalk number were investigated during growth period, the cane yield and economic benefits were calculated during harvest period. [Result] The results showed that plastic film mulching could significantly increase soil temperature and moisture. Com-pared with the control, soil temperature was increased by 0.3-0.8 ℃ in three plastic films mulching treatment except for gray-black plastic film mulching. The soil moisture of all mulching treatments was 10.1%-17.4% higher than the control. Furthermore, the seedling emergence rate, tillering rate, effective stalk number and cane yield also could be improved using plastic film mulching,which were increased by 0.8%-9.9%, 20.6%-34.9%, 5190-10980 stalks/hm^2and6.4%-14.9% as compared to the control,while plant height and stalk diameter were found to be no significant effect by plastic film mulching. The results of benefit analysis indicated that, milky photodegradation weeding film mulching had the highest economic benefit, the second were normal colorless transparent plastic film mulching and black plastic film mulching, which were 5 987.2, 1 876.5 and 1 813.5 Yuan/hm^2 higher than the control. The gray-black film mulching treatment had poor benefit.[Conclusion] The milky photodegradation weeding plastic film could be vigorously extended in sugarcane production. Normal colorless transparent plastic film and black plastic film could be ex-tended gradually as a new kind of plastic film. The grayblack film should not be used for its higher cost and more thickness.展开更多
Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hyg...Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hygrophytes. We surveyed the composition, delta(13)C values and proline concentration of PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGs occurred variously in eight steppe communities with different soil moisture status. In wetter habitats, hygromesophytes and hygrophytes were more abundant and accounted for the majority of aboveground biomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) the numerical order of the mean delta(13)C values of PFGs is as follows: xerophytes (-26.38parts per thousand) = mesoxerophytes (-26.51parts per thousand) > xeromesophytes (-27.02parts per thousand) > mesophytes (-27.56parts per thousand) = hygromesophytes and hygrophytes (-27.80parts per thousand); (3) xerophytes maintained relative higher delta(13)C values and water use efficiency (WUE) in habitats of different water availability, whereas delta(13)C values of xeromesophytes were more sensitive to change in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly increased. Significantly positive correlations existed between proline and biomass or delta(13)C values of different water ecological groups.展开更多
[Objective] The aim was to build spectral diagnosis model for nitrogen nutrition in rice leaf.[Method] Through determination of transmission,absorption spectra and nitrogen content on rice leaves of different rice var...[Objective] The aim was to build spectral diagnosis model for nitrogen nutrition in rice leaf.[Method] Through determination of transmission,absorption spectra and nitrogen content on rice leaves of different rice varieties(Xiangyou 109 and Shanyou 98),different growth periods and different nitrogen levels,we analyzed the correlation between leaf spectra and their nitrogen contents,and built prediction model of spectral index for nitrogen content in rice leaf.[Result] The detection precision of this model was above 80% that can be used on diagnosing of rice nitrogen nutrition.[Conclusion] The study provided evidence for monitoring nitrogen nutrition status of rice.展开更多
A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being high...A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase (SOD) activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde (MDA) content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.展开更多
[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water res...[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows: conventional ridge tillage, loosening the cm in spring (deep loosening in spring), and depth of 30 cm in autumn (deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn). Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.展开更多
A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula plaophylla forest in Changbai Mountain from May to September in 2004....A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula plaophylla forest in Changbai Mountain from May to September in 2004. Results indicated that the total soil respiration, root-severed soil respiration and the root respiration followed a similar seasonal trend, with a high rate in summer due to wet and high temperature and a low rate in spring and autumn due to lower temperature. The mean rates of total soil respiration, root-severed soil respiration and root respiration were 4.44, 2.30 and 2.14 μmol.m^-2.s^-1, respectively during the growing season, and they were all exponentially correlated with temperature. Soil respiration rate had a linear correlation with soil volumetric moisture. The Q10 values for total soil respiration, root-severed soil respiration and root respiration were 2,82, 2.59 and 3. 16, respectively. The contribution rate of root respiration to the total soil respiration was between 29.3% and 58.7% during the growing season, indicating that root is a major component of soil respiration. The annual mean rates of total soil respiration, root-severed soil respiration and root respiration were 1.96, 1.08, and 0.87 μmol.m^-2.s^-1, or 741.73 408.71, and 329.24 g.m^-2.a^-1, respectively. Root respiration contributed 44.4% to the annual total soil respiration. The relationship proposed for soil respiration with soil lemperature was useful for understanding and predicting potential changes in Changbai Mountain B. platyphylla forest ecosystem in response to forest management and climate change.展开更多
基金Supported by Supporting Program for Sci & Tech Research of China(2009BADA6B01)Natural Science Foundation of Anhui Province(090411017)~~
文摘[Objective] The aim of this study was to investigate the dry matter accumulation,moisture content in maize kernel and their influences on mechanical harvesting.[Methods] Using Zhengdan 958,Xianyu 335,Hongda 8 and Liyu 16 as experimental materials,we preliminarily measured the dynamic changes of dry matter accumulation and moisture content with the days after pollination lasted,and investigated the effect of moisture content in kernels on mechanical harvesting of Zhengdan 958 and Liyu 16.[Results] During summer growing season,Zhengdan 958 and Liyu 16 became physiologically mature and suitable for harvesting at about 51 days after pollination,Xianyu 335 and Hongda 8 required 58 days to become physiologically mature and suitable for harvesting after pollination.At physiologically mature stage,the moisture contents in kernels of Zhengdan 958,Xianyu 335,Hongda 8 and Liyu 16 were respectively 33.74%,28.86%,32.05% and 35.24%,respectively.Adopting mechanical harvesting at physiologically mature stage,the kernel loss rate of Zhengdan 958 and Liyu 16 was consistent with the range of mechanical operation index(kernel loss rate of 0.84%≤2%),while the percentage of broken kernels did not accord with the range of mechanical operation index(kernel crashing rate of 10.12%≧1%).The results indicate that Zhengdan 958 and Liyu 16 are not suitable for mechanical harvesting using full feeding combine havester.[Conclusion] This study provided theoretical basis for improving the maize harvest index under delayed harvesting.
基金Supported by National Natural Science Foundation (40573006)~~
文摘[Objective] The paper aimed to discuss the relationship between sulfur contents of mosses and the concentration of SO2-4 and the source of Atmospheric sulfur in Nanchang.[Method] 29 moss samples (Bryohaplocladium micriophyllum (Hedw.) R.Watanabe et Iwats) were collected from four sampling points,including North campus and Qianhu campus of Nanchang Power Station were determined.[Result] The results showed that sulfur contents of mosses tissues in North campus of Nanchang University (0.45±0.059%) were higher than Qianhu campus of Nanchang University (0.26±0.002%),which coincided with the changing law of the concentration of SO2-4.Sulphur isotope of mosses tissues was-0.64‰-9.71‰.Sulphur isotope of mosses tissues in Meling (4.02‰-9.71‰) was higher than Qianhu campus of Nanchang University (0.55‰-0.56‰) and power plant (-0.64‰-0.45‰).[Conclusion] Relationship between sulphur contents and sulphur isotopes of mosses tissues showed sulfur source of sulphur deposition in Nanchang city was mainly affected by 34S-enriched sulphur transported from northerly air masses and biogenic sulfur.
基金Supported by Natural Science Foundation of Guangxi Province(0728062)Natural Science Foundation of Guangxi Province(0832008Z)~~
文摘[Objective]The paper was to study the effect of different nitrogen application levels and modes on contents of different forms of nitrogen in rice plants.[Method] Using Guichao 2 and Diejiazhan as test materials,with total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco nitrogen,free amino acid nitrogen as indicators,the effect of nitrogen application on contents of different forms of nitrogen in rice plants were studied.[Result] The contents of total nitrogen,protein nitrogen,chlorophyll nitrogen,soluble protein nitrogen,Rubisco-N,free amino nitrogen of rice plant during heading and maturity stage increased with the increasing application amount of nitrogen,and their contents would be high under heavy application of spike fertilizer when the application amount of nitrogen was the same.However,application of nitrogen had different impact on different forms of nitrogen,which showed obvious impact on the contents of Rubisco-N and free amino nitrogen.The differences of Rubisco-N and free amino nitrogen content of two varieties during heading and maturity stage under different nitrogen application modes all reached significant or extremely significant level.Correlation analysis showed that total nitrogen content of rice plant had extremely significant correlation with protein nitrogen content during heading and maturity stage in both early and late seasons.[Conclusion] The study provided a theoretical basis for clarifying the regulatory role of nitrogen application on nitrogen absorption and utilization.
基金The Natural Science Foundation of Jiangsu Province(No. BK2011618)
文摘In order to assess the performance of the embankment soil under various climate conditions during the period of service, the modulus behaviour of an unsaturated compacted soil is evaluated using the constant water content triaxial test. Since the water content measurement method is simple and economical and it is used widely in engineering, the soil suction is replaced by the water content and the relationship between the water content and the modulus is developed. The compacted samples are prepared with different compacted water contents, and samples with a similar water content subjected to drying or wetting procedures prior to the triaxial test are also investigated. The effect of the water content and the confining pressure on the modulus is analyzed. The results show that the modulus decreases with the increase in the water content and a power function can be proposed to quantitatively describe the relationship between the modulus and the water content in the range of the measured water content. The modulus increases with the increase in the confining pressure of the compacted soil. However, the effect of the water content on the modulus is more pronounced than that of the confining pressure. This research can be referenced for the compacted embankment soil assessment in-service period.
基金Supported by Forestry Science and Technology Program of Hunan Province(XLK201406)~~
文摘Under the condition of high temperature, the effects of five cover patterns (clean tillage, film mulching, weed covering, branches and leaves covering and growing grass covering) on soil properties in young Phoebe boumei forest were in- vestigated. The results showed that the five cover patterns all showed significant ef- fects on soil properties in young Phoebe bournei forest under the condition of high temperature. Land cover increased land temperature in Phoebe boumei forest. Un- der the film mulching, the land temperature was increased most rapidly with the largest increment. However, weed covering, branches and leaves covering and growing grass covering decreased land temperature. Among them, growing grass covering showed the best cooling effect. The film mulching, weed covering, branch- es and leaves covering and growing grass covering all increased land humidity. The film mulching showed the best moisture-preserving effect in the early period, but in the late period, the humidity in the film mulching treatment group was lower than that in the clean tillage treatment group. Among the five mulching patterns, moisture loss in the film mulching treatment group was slowest and least, followed by those in the weed covering and branches and leaves covering treatment groups, and moisture loss in the growing grass covering treatment group was fastest and most.
基金Project (2013CB227904) supported by the National Basic Research Program of ChinaProject (2012QNB09) supported by the Fundamental Research Funds for the Central University,ChinaProject (NCET-12-0956) supported by the Program for New Century Excellent Talents
文摘A surface soil moisture model with improved spatial resolution was developed using remotely sensed apparent thermal inertia(ATI).The model integrates the surface temperature derived from TM/ETM+ image and the mean surface temperature from MODIS images to improve the spatial resolution of soil temperature difference based on the heat conduction equation,which is necessary to calculate the ATI.Consequently,the spatial resolution of ATI and SMC can be enhanced from 1 km to 120 m(TM) or 60m(ETM+).Moreover,the enhanced ATI has a much stronger correlation coefficient(R^2) with SMC(0.789) than the surface reflectance(0.108) or the ATI derived only from MODIS images(0.264).Based on the regression statistics of the field SMC measurement and enhanced ATI,a linear regression model with an RMS error of 1.90%was found.
基金Supported by Natural Science Foundation of Jiangsu Province(BK2009627)~~
文摘[Objective] The aim was to study the regression relationship between water index (WI) and fuel moisture content (FMC) of different growth periods of sawtooth oaks leaf.[Method] Taking sawtooth oaks in Huaguo Mountain,Lianyungang City as research object,the sensitivity of WI to leaf FMC was studied at leaf level,and statistical characteristics were analyzed.[Result] The WI of sawtooth oaks leaves was sensitive to the changes of FMC,and the line regression level between them was significant.A fitting curve between leaf FMC and WI was obtained.[Conclusion] The research provides reference for acquisition methods of vegetation water remote sensing within the range of study area.
基金Project(Q20120110)supported by Youth Foundation of Hubei Provincial Education Bureau,ChinaProject(2009CDB347)supported by the Hubei Provincial Natural Science Foundation,ChinaProject(51001045)supported by the National Natural Science Foundation of China
文摘Self assembled monolayers (SAMs) of 1-tetradecylphosphonic acids (TDPA, CH3(CH2)13P(O)(OH)2 ) were formed on the 2024 aluminum alloy surface in TDPA-containing ethanol-water solutions with different water content. The adsorption and corrosion protection properties of the SAMs for 2024 alloy in 0.1 mol/L H2SO4 solution were examined and characterized by potentiodynamic polarization, electrochemical impedance spectrum (EIS), Fourier transformed infrared spectroscopy (FTIR), Auger electron spectra (AES) and atomic force microscopy (AFM). FTIR and AES results show that the TDPA molecules were successfully adsorbed on the 2024 aluminum alloy surface, and the density of the SAMs increased with the increasing water content in the assembly solution. The results of electrochemical studies and corrosion morphologies observed by AFM show that a 4 h modification resulted in maximal inhibition efficiency, and the higher the water content in the assembly solution is, the better the inhibition performance of the SAMs can be achieved. The effect of water content in TDPA solutions on the performance of the SAMs is related to the hydration reaction of the metal surface.
基金Supported by Key Programs for Science and Technology Development(1501031102)~~
文摘In modern agriculture, accurate and effective measurements of soil water content lays foundation for promotion on precision irrigation technology and improvement on water use efficiency. The research reviewed soil moisture indices at home and abroad and classified the indices into two categories in order to make prediction on soil moisture and take measures. Specifically, single indices included precipitation index, soil moisture index, and crop drought index and overall indices included supply/demand water index of crops, overall water index, PDSI, crop water shortage index. Soil moisture index was analyzed in terms of advantages and disadvantages,as well as adaptability in agriculture, providing references for relieving and predicting adverse effects on agriculture and formulating scientific policies.
基金Supported by Scientific Research Project for Young Teachers of Qiongzhou University(QYQN201123)National Science and Technology Support Program(2011BAD11B04)~~
文摘[Objective] This research aimed at studying the effects of application amount of DCD and physics and chemistry characteristics of soil such as temperature,moisture content,organic matter content and pH on the inhibition of nitrification when applying nitrification inhibitor DCD in latosol.[Method] The experiment was carried out under aerobic incubated conditions.[Result] A significant delay period of nitrification was observed when the application amount of DCD was 10 mg/kg soil,and the inhibition can at least last for 56 d.When the cultural temperature had increased from 10 to 30 ℃,the duration of nitrification inhibition was shortened from 90 to 30 d.The nitrification inhibition of DCD was reduced with the increasing soil moisture content,organic matter content and soil pH,while the duration of nitrification inhibition was prolonged with the decreasing soil moisture content,organic matter content and soil pH.[Conclusion] Nitrification inhibition of DCD can be improved by increasing the application amount or reducing soil temperature,moisture content,organic matter content and pH.
基金Supported by National State Supporting Program(2012BAD40B04-3)Guangxi Bagu Scholar Program(No.[2013]3)~~
文摘[Objective] The effects of different plastic films mulching on soil temperature and moisture, and growth and yield of sugarcane were discussed in order to provide references for using different plastic film in sugarcane pro-duction. [Method]Four kinds of plastic films viz., normal colorless transparent plastic film, milky photodegradation weeding plastic film, black plastic film and gray-black plastic film were used in sugarcane cultivation by using no film mulching as the control. Soil temperature and moisture were measured during plastic film mulching period, and sugarcane agronomic traits such as emergence rate, tillering rate, plant hight, stalk diameter and effective stalk number were investigated during growth period, the cane yield and economic benefits were calculated during harvest period. [Result] The results showed that plastic film mulching could significantly increase soil temperature and moisture. Com-pared with the control, soil temperature was increased by 0.3-0.8 ℃ in three plastic films mulching treatment except for gray-black plastic film mulching. The soil moisture of all mulching treatments was 10.1%-17.4% higher than the control. Furthermore, the seedling emergence rate, tillering rate, effective stalk number and cane yield also could be improved using plastic film mulching,which were increased by 0.8%-9.9%, 20.6%-34.9%, 5190-10980 stalks/hm^2and6.4%-14.9% as compared to the control,while plant height and stalk diameter were found to be no significant effect by plastic film mulching. The results of benefit analysis indicated that, milky photodegradation weeding film mulching had the highest economic benefit, the second were normal colorless transparent plastic film mulching and black plastic film mulching, which were 5 987.2, 1 876.5 and 1 813.5 Yuan/hm^2 higher than the control. The gray-black film mulching treatment had poor benefit.[Conclusion] The milky photodegradation weeding plastic film could be vigorously extended in sugarcane production. Normal colorless transparent plastic film and black plastic film could be ex-tended gradually as a new kind of plastic film. The grayblack film should not be used for its higher cost and more thickness.
文摘Major plant species in the Xilin River Basin were grouped into six plant functional groups (PFGs) based on their water ecological groups: xerophytes, mesoxerophytes, xeromesophytes, mesophytes, hygromesophytes and hygrophytes. We surveyed the composition, delta(13)C values and proline concentration of PFGs in eight different plant communities along a soil moisture gradient. Results show that: (1) PFGs occurred variously in eight steppe communities with different soil moisture status. In wetter habitats, hygromesophytes and hygrophytes were more abundant and accounted for the majority of aboveground biomass, whereas xerophytes and mesoxerophytes became more conspicuous in dryer habitats; (2) the numerical order of the mean delta(13)C values of PFGs is as follows: xerophytes (-26.38parts per thousand) = mesoxerophytes (-26.51parts per thousand) > xeromesophytes (-27.02parts per thousand) > mesophytes (-27.56parts per thousand) = hygromesophytes and hygrophytes (-27.80parts per thousand); (3) xerophytes maintained relative higher delta(13)C values and water use efficiency (WUE) in habitats of different water availability, whereas delta(13)C values of xeromesophytes were more sensitive to change in soil water availability; (4) From xerophytes to hygrophytes, their proline content markedly increased. Significantly positive correlations existed between proline and biomass or delta(13)C values of different water ecological groups.
基金Supported by National Natural Science Foundation(10664001,41061039)National 863 Project(2007AA10Z205)+1 种基金Project for Excellent Young Scientists and Technicians of GuizhouNational Project for Innovative Experiments of College Students(Guizhou University200820)~~
文摘[Objective] The aim was to build spectral diagnosis model for nitrogen nutrition in rice leaf.[Method] Through determination of transmission,absorption spectra and nitrogen content on rice leaves of different rice varieties(Xiangyou 109 and Shanyou 98),different growth periods and different nitrogen levels,we analyzed the correlation between leaf spectra and their nitrogen contents,and built prediction model of spectral index for nitrogen content in rice leaf.[Result] The detection precision of this model was above 80% that can be used on diagnosing of rice nitrogen nutrition.[Conclusion] The study provided evidence for monitoring nitrogen nutrition status of rice.
文摘A study was conducted to determine the physiological characteristics changes of Aesculus chinensis seeds during natural dehydration in 2003. The results showed that A. chinensis seeds were recalcitrant with being highly desiccation-sensitive. The seed moisture content of fresh fruits was higher than 60%. When the seeds were naturally dried for 30 days, their moisture content declined to 30.2% and their viability was completely lost. The seed germination percentage had a small increase at the beginning of desiccation and then decreased rapidly. The relative electrical conductivity of the A. chinensis seeds increased along with a decrease in seed moisture content. However, there was an abnormal increase in relative electrical conductivity when the seed moisture content was between 53.7% and 50.9%. Superoxide dismutase (SOD) activity decreased rapidly in the period of desiccation except for an abnormality when the seed moisture content was between 53.7% and 50.9%. Malondialdehyde (MDA) content increased slowly at the early stage of desiccation and then rose rapidly after the moisture content was below 50.9%. The soluble sugar content in seeds slowly increased with the increasing period of desiccation. The seed germination percentage was at the high level when seed moisture content was in range of 47%- 60%, which suggests that this was the optimum moisture content for maintaining A. chinensis seed viability.
基金Supported by National Maize Industry Technology System(CARS-02-38)Science and Technology Development Project of Jilin Province(LFGC14308)Special Fund for Scientific Research in the Public Interest(201303125-03)
文摘[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows: conventional ridge tillage, loosening the cm in spring (deep loosening in spring), and depth of 30 cm in autumn (deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn). Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure.
基金supported by the Knowledge Inno-vation Project of the Chinese Academy of Sciences (KZCX2-YW-416)the National Natural Science Foundation (90411020)
文摘A stdudy was conducted to determine the seasonal changes of soil respiration and the contribution of root respiration to soil respiration in Betula plaophylla forest in Changbai Mountain from May to September in 2004. Results indicated that the total soil respiration, root-severed soil respiration and the root respiration followed a similar seasonal trend, with a high rate in summer due to wet and high temperature and a low rate in spring and autumn due to lower temperature. The mean rates of total soil respiration, root-severed soil respiration and root respiration were 4.44, 2.30 and 2.14 μmol.m^-2.s^-1, respectively during the growing season, and they were all exponentially correlated with temperature. Soil respiration rate had a linear correlation with soil volumetric moisture. The Q10 values for total soil respiration, root-severed soil respiration and root respiration were 2,82, 2.59 and 3. 16, respectively. The contribution rate of root respiration to the total soil respiration was between 29.3% and 58.7% during the growing season, indicating that root is a major component of soil respiration. The annual mean rates of total soil respiration, root-severed soil respiration and root respiration were 1.96, 1.08, and 0.87 μmol.m^-2.s^-1, or 741.73 408.71, and 329.24 g.m^-2.a^-1, respectively. Root respiration contributed 44.4% to the annual total soil respiration. The relationship proposed for soil respiration with soil lemperature was useful for understanding and predicting potential changes in Changbai Mountain B. platyphylla forest ecosystem in response to forest management and climate change.