Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized...Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.展开更多
采用超声波处理活性污泥,利用其释放出的有机质作为电子供体.摇瓶实验表明,喹啉的生物降解速率与处理或未处理的污泥量成正比,将25%未处理污泥和75%处理过的污泥混合用于降解喹啉时,喹啉的降解速率最快.在此过程中,处理的污泥主要起着...采用超声波处理活性污泥,利用其释放出的有机质作为电子供体.摇瓶实验表明,喹啉的生物降解速率与处理或未处理的污泥量成正比,将25%未处理污泥和75%处理过的污泥混合用于降解喹啉时,喹啉的降解速率最快.在此过程中,处理的污泥主要起着电子供体的作用,而未处理的污泥主要起着生物催化剂的作用.对喹啉生物降解过程进行电子平衡计算,结果表明,18 m L处理污泥的上清液作为电子供体相当于3.65 mmol/L草酸的作用.展开更多
Dew is an important water source for plants in arid and semi-arid regions. However, information on dew is scarce in such regions. In this study, we explored dew formation, amount, and duration of rain-fed jujube（Zizy...Dew is an important water source for plants in arid and semi-arid regions. However, information on dew is scarce in such regions. In this study, we explored dew formation, amount, and duration of rain-fed jujube（Zizyphus jujube Mill） trees in a semi-arid loess hilly region of China（i.e., Mizhi County）. The data included dew intensity and duration, relative humidity, temperature, and wind speed measured from 26 July to 23 October, 2012 and from 24 June to 17 October, 2013 using a micro-climate system（including dielectric leaf wetness sensors, VP-3 Relative Humidity/Temperature Sensor, High Resolution Rain Gauge, and Davis Cup Anemometer）. The results show that atmospheric conditions of relative humidity of 〉78% and dew point temperature of 1°C–3°C are significantly favorable to dew formation. Compared with the rainfall, dew was characterized by high frequency, strong stability, and long duration. Furthermore, heavy dew accounted for a large proportion of the total amount. The empirical models（i.e., relative humidity model（RH model） and dew point depression model（DPD model）） for daily dew duration estimation performed well at 15-min intervals, with low errors ranging between 1.29 and 1.60 h, respectively. But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model. For rain-fed jujube trees in the semi-arid loess hilly regions of China, the optimal threshold of relative humidity was 78%, and the optimal upper and lower thresholds of dew point depression were 1°C and 5°C, respectively. The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales.展开更多
The authors studied the effects using three different levels of irrigation on the growth and biomass allocation in H. ammodendron and T. ramosissima seedlings in the shelterbelt along the Tarim Desert Highway. The thr...The authors studied the effects using three different levels of irrigation on the growth and biomass allocation in H. ammodendron and T. ramosissima seedlings in the shelterbelt along the Tarim Desert Highway. The three irrigation amounts were 35 (CK), 24.5 (treatment 1), and 14 (treatment 2) kg·ind. plant-1·once-1, respectively. The results show that (1) the vertical depth of the two seedlings’ root increased with lower levels of irrigation showing that the two species adapted to decreased irrigation by root elongation in the hinterland of the Taklimakan Desert, and the vertical root depth of H. ammodendron under treatment 2 was notably higher than CK. (2) Compared with CK, the belowground biomass of treatment 1 and 2 both showed a significant increase as follows: H. ammodendron seedlings in- creased by 14.51% and 37.03% under treatment 1 and 2, respectively, while T. ramosissima seedlings increased by 68.19% and 25.78% under treatment 1 and 2, respectively. This means that H. ammoden- dron seedlings were more adapted to the conditions in treatment 2 while T. ramosissima seedlings were better adapted to treatment 1 conditions. (3) When compared with CK, the fine root bomass of these two species all exhibited some increase under both treatments, and ANOVA analysis showed that the biomass of deep layer root of the two species under treatment 2 was notably higher than CK and treatment 1. This should help seedlings to more effectively absorb soil water from deep layers during dry conditions. (4) The root-shoot ratio was different for these two species. For H. ammodendron seed- lings, the root-shoot ratio was less than 1, while for T. ramosissim seedlings it was larger than 1. The root-shoot ratio of H. ammodendron seedlings increased with decreasing levels of irrigation, and that of T. ramosissim seedlings also increased under treatment 2. (5) With decreasing levels of irrigation, due to the difference of species, the growth variation of aboveground indexes was also different, while compared with CK, it was not significant.展开更多
Jujube is widely cultivated in the semi-arid region of the Loess Plateau in Northwest China due to its high water deficit tolerance.In such an ecologically vulnerable area,it is critical to explore the water consumpti...Jujube is widely cultivated in the semi-arid region of the Loess Plateau in Northwest China due to its high water deficit tolerance.In such an ecologically vulnerable area,it is critical to explore the water consumption processes of key tree species and their responses to driving factors.Sap flow data gathered during a two-year field study in a jujube plantation were analyzed as a surrogate for transpiration measurements.The measured sap flows were related to changes in the soil water content,meteorological factors(the vapor pressure deficit and the level of photosynthetically active radiation),and plant physiological factors(the sap wood area,leaf area and leaf area index).The factors that govern sap flow were found to vary depending on the growing season,and on hourly and daily timescales.The plants’drought tolerance could be predicted based on their peak sap flows and the variation in their sap flow rates at different soil water levels.The sap flow was most strongly affected by the water content of the topmost(0-20 cm)soil layer.Of the studied meteorological factors,the photosynthetically active radiation had a greater effect on sap flow than the vapor pressure deficit.The correlation we found could be applied to predict jujube tree water consumption and assist the design of irrigation scheme.展开更多
基金supported by the China National Support Program(2015BAC01B03)the Shaanxi Co-ordination Program(2016KTZDNY0105)the National Key Research and Development Program of China(2016YED0300201)
文摘Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.
文摘采用超声波处理活性污泥,利用其释放出的有机质作为电子供体.摇瓶实验表明,喹啉的生物降解速率与处理或未处理的污泥量成正比,将25%未处理污泥和75%处理过的污泥混合用于降解喹啉时,喹啉的降解速率最快.在此过程中,处理的污泥主要起着电子供体的作用,而未处理的污泥主要起着生物催化剂的作用.对喹啉生物降解过程进行电子平衡计算,结果表明,18 m L处理污泥的上清液作为电子供体相当于3.65 mmol/L草酸的作用.
基金funded by the National Key Technology R&D Program (2015BAC01B03)the Science and Technology Coordination and Innovation Project of Shaanxi Province (2014KTCG01-03)
文摘Dew is an important water source for plants in arid and semi-arid regions. However, information on dew is scarce in such regions. In this study, we explored dew formation, amount, and duration of rain-fed jujube（Zizyphus jujube Mill） trees in a semi-arid loess hilly region of China（i.e., Mizhi County）. The data included dew intensity and duration, relative humidity, temperature, and wind speed measured from 26 July to 23 October, 2012 and from 24 June to 17 October, 2013 using a micro-climate system（including dielectric leaf wetness sensors, VP-3 Relative Humidity/Temperature Sensor, High Resolution Rain Gauge, and Davis Cup Anemometer）. The results show that atmospheric conditions of relative humidity of 〉78% and dew point temperature of 1°C–3°C are significantly favorable to dew formation. Compared with the rainfall, dew was characterized by high frequency, strong stability, and long duration. Furthermore, heavy dew accounted for a large proportion of the total amount. The empirical models（i.e., relative humidity model（RH model） and dew point depression model（DPD model）） for daily dew duration estimation performed well at 15-min intervals, with low errors ranging between 1.29 and 1.60 h, respectively. But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model. For rain-fed jujube trees in the semi-arid loess hilly regions of China, the optimal threshold of relative humidity was 78%, and the optimal upper and lower thresholds of dew point depression were 1°C and 5°C, respectively. The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales.
基金Supported by Major Orientation Foundation of the CAS Innovation Program (Grant No. KZCX3-SW-342)Research Developing Planning Program of National High and New Technology of China (Grant No. 2004BA901A21-1)
文摘The authors studied the effects using three different levels of irrigation on the growth and biomass allocation in H. ammodendron and T. ramosissima seedlings in the shelterbelt along the Tarim Desert Highway. The three irrigation amounts were 35 (CK), 24.5 (treatment 1), and 14 (treatment 2) kg·ind. plant-1·once-1, respectively. The results show that (1) the vertical depth of the two seedlings’ root increased with lower levels of irrigation showing that the two species adapted to decreased irrigation by root elongation in the hinterland of the Taklimakan Desert, and the vertical root depth of H. ammodendron under treatment 2 was notably higher than CK. (2) Compared with CK, the belowground biomass of treatment 1 and 2 both showed a significant increase as follows: H. ammodendron seedlings in- creased by 14.51% and 37.03% under treatment 1 and 2, respectively, while T. ramosissima seedlings increased by 68.19% and 25.78% under treatment 1 and 2, respectively. This means that H. ammoden- dron seedlings were more adapted to the conditions in treatment 2 while T. ramosissima seedlings were better adapted to treatment 1 conditions. (3) When compared with CK, the fine root bomass of these two species all exhibited some increase under both treatments, and ANOVA analysis showed that the biomass of deep layer root of the two species under treatment 2 was notably higher than CK and treatment 1. This should help seedlings to more effectively absorb soil water from deep layers during dry conditions. (4) The root-shoot ratio was different for these two species. For H. ammodendron seed- lings, the root-shoot ratio was less than 1, while for T. ramosissim seedlings it was larger than 1. The root-shoot ratio of H. ammodendron seedlings increased with decreasing levels of irrigation, and that of T. ramosissim seedlings also increased under treatment 2. (5) With decreasing levels of irrigation, due to the difference of species, the growth variation of aboveground indexes was also different, while compared with CK, it was not significant.
基金the Special Foundation of National Science&TechnologySupporting Plan(No.2011BAD29B04&No.2013BAD20B03).
文摘Jujube is widely cultivated in the semi-arid region of the Loess Plateau in Northwest China due to its high water deficit tolerance.In such an ecologically vulnerable area,it is critical to explore the water consumption processes of key tree species and their responses to driving factors.Sap flow data gathered during a two-year field study in a jujube plantation were analyzed as a surrogate for transpiration measurements.The measured sap flows were related to changes in the soil water content,meteorological factors(the vapor pressure deficit and the level of photosynthetically active radiation),and plant physiological factors(the sap wood area,leaf area and leaf area index).The factors that govern sap flow were found to vary depending on the growing season,and on hourly and daily timescales.The plants’drought tolerance could be predicted based on their peak sap flows and the variation in their sap flow rates at different soil water levels.The sap flow was most strongly affected by the water content of the topmost(0-20 cm)soil layer.Of the studied meteorological factors,the photosynthetically active radiation had a greater effect on sap flow than the vapor pressure deficit.The correlation we found could be applied to predict jujube tree water consumption and assist the design of irrigation scheme.
