Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in...Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in dry-hot valley regions,where extreme hydrothermal conditions pose significant challenges.This study presents a novel framework that integrates microclimatic variables,such as temperature lapse rates,to enhance the spatial precision of revegetation efforts.The Reshuihe watershed in Southwest China,a representative dry-hot valley,was chosen as the study area.By analyzing hourly temperature and rainfall across an elevation gradient,a quadratic relationship between temperature lapse rates and weak rainfall events was identified,underscoring the role of microclimatic processes in influencing rainfall distribution and plant-available water.Rainfall peaks were observed when the temperature lapse rate was approximately 4.5°C/km.This relationship was incorporated into a cost-based restoration framework using the Marxan model,optimizing the spatial allocation of priority areas for revegetation.Results demonstrated that integrating microclimatic variables significantly improved the effectiveness of revegetation strategies,particularly for reducing debris flow risks.The lowest restoration costs were observed between elevations of 3200 m and 3300 m,where strong correlations between temperature lapse rates and rainfall were recorded.Priority restoration areas covered 41 km^(2),targeting zones with high debris flow risks.These findings highlight the value of incorporating microclimatic data into revegetation planning,enabling cost-effective and ecologically sustainable hazard mitigation in regions vulnerable to hydrological hazards.展开更多
Microclimate characteristics and related environmental energy mechanisms were examined based on the long term located observations in the mature, thinned and young Cunninghamia lanceolata plantation ecosystems in...Microclimate characteristics and related environmental energy mechanisms were examined based on the long term located observations in the mature, thinned and young Cunninghamia lanceolata plantation ecosystems in western Hunan Province, China. The results show that the mature plantation ecosystem can improve the microclimate significantly by regulating the amount and spatial distribution of environmental energy, which delineates the pattern of the microclimate in forest ecosystems in the process of ecological restoration. Compared with the young plantation, the mature plantation ecosystem decreased annual mean air temperature by 0 4℃. The maximum decrease in monthly mean air temperature was 2 3℃. The mature plantation ecosystem decreased annual mean ground temperature by 1 2℃ with a maximum decrease in monthly mean ground temperature of 2 3℃. Mainly due to the dense canopy, the mature forest ecosystem regulates the distribution of radiation energy, and expenditure ratios of heat budget and principal energy components to decrease temperature or make it even.展开更多
Objective The aim was to elucidate the effects of N rates on rice canopy microclimate and community health so as to provide a sci- entific basis for studying the production potential in irrigated rice with healthy can...Objective The aim was to elucidate the effects of N rates on rice canopy microclimate and community health so as to provide a sci- entific basis for studying the production potential in irrigated rice with healthy canopy. Method The effects of rice population structure traits under different N rates on rice canopy temperature, relative humidity （ RH）, light transmittance and sheath blight were studied by using Sunscan canopy analysis system and HOBO（ Pro Temp/RH IS logger）. Result The results showed that leaf area index, plant height and tiller number had significant effects on canopy cooling, RH enhancing and light reducing. Extremely significant multiple linear regression relationships existed among canopy day temperature, day RH, LAI and tiller number, and among light transmittance, tiller number and plant height. At flowering stage, per unit LAI could result in a day-maximum-temperature （Tmax） deceasing of 0.87℃ and a day-minimum-RH （RHmin） enhancing of 2.5% within canopy. Similarly, 100 plants per ms could respectively cause a Tmax deceasing of 1.23℃ and an RHmin enhancing of 3.3% in rice canopy. And per 10 cm plant height and 100 plants per m^2 could respectively reduce 9.3% and 7.8% of light in canopy. Conclusion Sheath blight disease index was significantly enhanced as the canopy day temperature decreased, day RH increased and light transmittance reduced. Bigger canopy from higher nitrogen level treatment leads to a more stable canopy microclimate with little changes in temperature and RH during day and night, which has the risk of worsening canopy health. Thus, moderately controlling the space development of canopy is the basis of constructing healthy canopy in rice.展开更多
Objective] This study aimed to explore the biological basis and microcli-mate effects in intercropping jujube orchard. [Method] From 2009 to 2011, jujube was intercroped with wheat, peanut, soybean, garlic, watermelon...Objective] This study aimed to explore the biological basis and microcli-mate effects in intercropping jujube orchard. [Method] From 2009 to 2011, jujube was intercroped with wheat, peanut, soybean, garlic, watermelon, vegetables etc. By fixed observation and simultaneous mobile observation, the field microclimate factors such as the air temperature, surface temperature, air relative humidity, wind speed, etc. were measured, with mono-crop farmland as the control. [Result] The competi-tion relationship existed between jujube trees and the intercropped plants for re-sources such as il umination, fertilizer, and water; however there were differences in phenological phases and the critical periods in needing for water, fertilizer and il u-mination between jujube and intercropped plants. Meanwhile, there was significant difference （P〈0.05） in the variation of agricultural microclimate environment in jujube field compared with that in control farmland. Compared with the control, the air tem-perature in intercropping jujube orchard was reduced by 0.2 to 0.7 ℃, the earth surface temperature reduction ranged from 2.1 to 2.5 ℃, the relative air humidity increased by 3.7% to 6.8% and the wind speed decreased by 0.2 to 0.4 m/s. [Conclusion] Al above results showed that intercropping in jujube orchard could be promoted in central China and northern China areas.展开更多
Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment ...Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment and physiological activities of tomato seedlings in seedbeds by controlled experiments.The results indicated that airflow could enhance CO_(2) concentration near the seedling canopy,accelerate water evaporation from the seedling substrate,and reduce fluctuations in the temperature and humidity in microclimate.The photosynthetic rates of leaves at the 4th,7th,and 10th positions in seedlings subjected to airflow increased by 25.04%,8.23%,and 8.47%,respectively,whereas the transpiration rates increased by 15.59%,22.28%,and 13.26%,respectively when compared to the control group.Additionally,the strong seedling index of seedlings treated with airflow and exogenous iron element increased by 26.02%and 31.5%,respectively.Compared to seedlings treated with exogenous iron element,the geometric mean diameter of the pith tissue cells in the stems of seedlings subjected to airflow disturbance was reduced by approximately 18.66%,while the elastic modulus and bending strength of the stems increased by 10.01%and 5.89%,respectively.Similarly,the volume of root tissue cells decreased by 19.22%,but the elastic modulus of the roots increased by 6.46%.This study confirms that airflow significantly enhances seedling resilience to abiotic stress,yielding similar or better outcomes than exogenous iron application.It provides both theoretical and practical support for using airflow disturbance as a green technology for cultivating robust seedlings.展开更多
In order to improve the understanding of the role of a canopy opening/gap on the physical environments in a secondary forest in Northeastern China, a case study was conducted in and around a small irregular gap in a m...In order to improve the understanding of the role of a canopy opening/gap on the physical environments in a secondary forest in Northeastern China, a case study was conducted in and around a small irregular gap in a montane secondary forest. The secondary forest, which was severely disturbed by human beings about 50 years ago, was dominated by Quercus mongolica and Fraxinus rhynchophyllaan. Temporal variation in photosynthetic photon flux density （PPFD）, air temperature （TA） at 10 cm above the ground, soil temperature （Ts） and soil water content （SWC） at top-layer （0-15 cm） and sub-layer （15-30 cm） were measured from May to September after the second year since the formation of the small gap （the ratios of gap diameter to stand height were less than 0.5） in 2006 respectively. Results indicated that the highest value of PPFD occurred at the northern edge of the gap, particularly at the beginning of the growing season in May. On sunny days, the highest value of PPFD appeared earlier than that on overcast days. Maximum and mean values of TAwere higher in the northern part of the gap, and the minimum values of TAwere at the southern edge of the gap. Soil temperature varied obviously in the gap with the range from 1 to 8 ℃. Maximum values of Ts occurred at the northern part of the gap, which was significantly correlated with the maximum values of TA （R = 0.735, P〈0.05）. SWC was higher in the top-layer （0-15 cm） than that in sub-layer （15-30 cm）, but the difference of them was not significant （p〉0.05）, which might be attributed to the small gap size and the effects of aboveground vegetations. From these results, the maximum of PPFD in the study area occurred at the northern part of the gap, which was consistent with the results observed in north hemisphere, but the occurrence time varied with the differences of the latitudes. The highest values of air and soil temperatures also occurred in the northern part of the gap because they were affected by the radiation. However, the variation of temperature in July was different from other months due to the influence of gap size. And the values of soil water content were neither higher in the gap in the wet season nor lower in the dry season, which might be affected by the gap size and topography the gap located. The variations of light, soil and air temperatures, and soil moisture in this small irregular gap might be related to the effects of the micro-site, which affects the regeneration of plant species.展开更多
基金supported by the National Natural Science Foundation of China for General Program(42171118)the National Natural Science Foundation of China for Distinguished Young Scholars(41925030)the Special Funding Projects of Talents of Yunnan Province(YNWR-QNBJ-2020-099).
文摘Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in dry-hot valley regions,where extreme hydrothermal conditions pose significant challenges.This study presents a novel framework that integrates microclimatic variables,such as temperature lapse rates,to enhance the spatial precision of revegetation efforts.The Reshuihe watershed in Southwest China,a representative dry-hot valley,was chosen as the study area.By analyzing hourly temperature and rainfall across an elevation gradient,a quadratic relationship between temperature lapse rates and weak rainfall events was identified,underscoring the role of microclimatic processes in influencing rainfall distribution and plant-available water.Rainfall peaks were observed when the temperature lapse rate was approximately 4.5°C/km.This relationship was incorporated into a cost-based restoration framework using the Marxan model,optimizing the spatial allocation of priority areas for revegetation.Results demonstrated that integrating microclimatic variables significantly improved the effectiveness of revegetation strategies,particularly for reducing debris flow risks.The lowest restoration costs were observed between elevations of 3200 m and 3300 m,where strong correlations between temperature lapse rates and rainfall were recorded.Priority restoration areas covered 41 km^(2),targeting zones with high debris flow risks.These findings highlight the value of incorporating microclimatic data into revegetation planning,enabling cost-effective and ecologically sustainable hazard mitigation in regions vulnerable to hydrological hazards.
文摘Microclimate characteristics and related environmental energy mechanisms were examined based on the long term located observations in the mature, thinned and young Cunninghamia lanceolata plantation ecosystems in western Hunan Province, China. The results show that the mature plantation ecosystem can improve the microclimate significantly by regulating the amount and spatial distribution of environmental energy, which delineates the pattern of the microclimate in forest ecosystems in the process of ecological restoration. Compared with the young plantation, the mature plantation ecosystem decreased annual mean air temperature by 0 4℃. The maximum decrease in monthly mean air temperature was 2 3℃. The mature plantation ecosystem decreased annual mean ground temperature by 1 2℃ with a maximum decrease in monthly mean ground temperature of 2 3℃. Mainly due to the dense canopy, the mature forest ecosystem regulates the distribution of radiation energy, and expenditure ratios of heat budget and principal energy components to decrease temperature or make it even.
基金Supported by Oversea Project of National Natural and Science Foundationof China(30528005)RTOP Project of International RiceResearch Institute(IRRI)+1 种基金Grain High-yield Project of China(2004BA520A12)And 948 Introduction Project of the Ministry ofAgriculture(2003-Z53)~~
文摘Objective The aim was to elucidate the effects of N rates on rice canopy microclimate and community health so as to provide a sci- entific basis for studying the production potential in irrigated rice with healthy canopy. Method The effects of rice population structure traits under different N rates on rice canopy temperature, relative humidity （ RH）, light transmittance and sheath blight were studied by using Sunscan canopy analysis system and HOBO（ Pro Temp/RH IS logger）. Result The results showed that leaf area index, plant height and tiller number had significant effects on canopy cooling, RH enhancing and light reducing. Extremely significant multiple linear regression relationships existed among canopy day temperature, day RH, LAI and tiller number, and among light transmittance, tiller number and plant height. At flowering stage, per unit LAI could result in a day-maximum-temperature （Tmax） deceasing of 0.87℃ and a day-minimum-RH （RHmin） enhancing of 2.5% within canopy. Similarly, 100 plants per ms could respectively cause a Tmax deceasing of 1.23℃ and an RHmin enhancing of 3.3% in rice canopy. And per 10 cm plant height and 100 plants per m^2 could respectively reduce 9.3% and 7.8% of light in canopy. Conclusion Sheath blight disease index was significantly enhanced as the canopy day temperature decreased, day RH increased and light transmittance reduced. Bigger canopy from higher nitrogen level treatment leads to a more stable canopy microclimate with little changes in temperature and RH during day and night, which has the risk of worsening canopy health. Thus, moderately controlling the space development of canopy is the basis of constructing healthy canopy in rice.
基金Supported by Science and Technology Development Program of Department of Science and Technology of Henan Province(2006220001)~~
文摘Objective] This study aimed to explore the biological basis and microcli-mate effects in intercropping jujube orchard. [Method] From 2009 to 2011, jujube was intercroped with wheat, peanut, soybean, garlic, watermelon, vegetables etc. By fixed observation and simultaneous mobile observation, the field microclimate factors such as the air temperature, surface temperature, air relative humidity, wind speed, etc. were measured, with mono-crop farmland as the control. [Result] The competi-tion relationship existed between jujube trees and the intercropped plants for re-sources such as il umination, fertilizer, and water; however there were differences in phenological phases and the critical periods in needing for water, fertilizer and il u-mination between jujube and intercropped plants. Meanwhile, there was significant difference （P〈0.05） in the variation of agricultural microclimate environment in jujube field compared with that in control farmland. Compared with the control, the air tem-perature in intercropping jujube orchard was reduced by 0.2 to 0.7 ℃, the earth surface temperature reduction ranged from 2.1 to 2.5 ℃, the relative air humidity increased by 3.7% to 6.8% and the wind speed decreased by 0.2 to 0.4 m/s. [Conclusion] Al above results showed that intercropping in jujube orchard could be promoted in central China and northern China areas.
基金supported by an International Cooperation Key Plan of Shaanxi Province(Grant No.2022KWZ-12)an Agricultural Science Innovation and Transformation Project of Shaanxi Province[Grant No.NYKJ-2022-YL(XN)12]a High-End Foreign Expert Recruitment Program(Grant No.G2022172006L).
文摘Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment and physiological activities of tomato seedlings in seedbeds by controlled experiments.The results indicated that airflow could enhance CO_(2) concentration near the seedling canopy,accelerate water evaporation from the seedling substrate,and reduce fluctuations in the temperature and humidity in microclimate.The photosynthetic rates of leaves at the 4th,7th,and 10th positions in seedlings subjected to airflow increased by 25.04%,8.23%,and 8.47%,respectively,whereas the transpiration rates increased by 15.59%,22.28%,and 13.26%,respectively when compared to the control group.Additionally,the strong seedling index of seedlings treated with airflow and exogenous iron element increased by 26.02%and 31.5%,respectively.Compared to seedlings treated with exogenous iron element,the geometric mean diameter of the pith tissue cells in the stems of seedlings subjected to airflow disturbance was reduced by approximately 18.66%,while the elastic modulus and bending strength of the stems increased by 10.01%and 5.89%,respectively.Similarly,the volume of root tissue cells decreased by 19.22%,but the elastic modulus of the roots increased by 6.46%.This study confirms that airflow significantly enhances seedling resilience to abiotic stress,yielding similar or better outcomes than exogenous iron application.It provides both theoretical and practical support for using airflow disturbance as a green technology for cultivating robust seedlings.
基金This research was supported by National Natural Science Foundation of China （30671669） and ＂the 100-Young-Researcher Project＂ of Chinese,Academy of Sciences.
文摘In order to improve the understanding of the role of a canopy opening/gap on the physical environments in a secondary forest in Northeastern China, a case study was conducted in and around a small irregular gap in a montane secondary forest. The secondary forest, which was severely disturbed by human beings about 50 years ago, was dominated by Quercus mongolica and Fraxinus rhynchophyllaan. Temporal variation in photosynthetic photon flux density （PPFD）, air temperature （TA） at 10 cm above the ground, soil temperature （Ts） and soil water content （SWC） at top-layer （0-15 cm） and sub-layer （15-30 cm） were measured from May to September after the second year since the formation of the small gap （the ratios of gap diameter to stand height were less than 0.5） in 2006 respectively. Results indicated that the highest value of PPFD occurred at the northern edge of the gap, particularly at the beginning of the growing season in May. On sunny days, the highest value of PPFD appeared earlier than that on overcast days. Maximum and mean values of TAwere higher in the northern part of the gap, and the minimum values of TAwere at the southern edge of the gap. Soil temperature varied obviously in the gap with the range from 1 to 8 ℃. Maximum values of Ts occurred at the northern part of the gap, which was significantly correlated with the maximum values of TA （R = 0.735, P〈0.05）. SWC was higher in the top-layer （0-15 cm） than that in sub-layer （15-30 cm）, but the difference of them was not significant （p〉0.05）, which might be attributed to the small gap size and the effects of aboveground vegetations. From these results, the maximum of PPFD in the study area occurred at the northern part of the gap, which was consistent with the results observed in north hemisphere, but the occurrence time varied with the differences of the latitudes. The highest values of air and soil temperatures also occurred in the northern part of the gap because they were affected by the radiation. However, the variation of temperature in July was different from other months due to the influence of gap size. And the values of soil water content were neither higher in the gap in the wet season nor lower in the dry season, which might be affected by the gap size and topography the gap located. The variations of light, soil and air temperatures, and soil moisture in this small irregular gap might be related to the effects of the micro-site, which affects the regeneration of plant species.
