Minimum tillage is a soil conservation practice involving a reduction in soil disturbance and topsoil compaction, which could minimize environmental impact of the tobacco cultivation system. The objectives of this stu...Minimum tillage is a soil conservation practice involving a reduction in soil disturbance and topsoil compaction, which could minimize environmental impact of the tobacco cultivation system. The objectives of this study were to evaluate the development and growth responses of Nicotiana tabacum and the changes in the physical and hydrological soil properties after the application of two different treatments: minimum tillage (MT) and conventional tillage (CT). MT did not cause any pronounced differences in the crop yield compared to CT, instead it positively affected the physical and hydrological soil properties and the plants’ vegetative growth. Under MT, the soil showed a higher structural stability than CT with significantly lower compaction values. With MT the soil showed a higher capacity to maintain and store water during the drought periods, evidenced by soil moisture values significantly higher than CT. Tobacco on MT showed a good response, significantly prolonging the vegetative growth stage which at harvest determined a higher stem height, greater number of leaves and longer internodes.展开更多
Mt.Everest (27°54' N,86°54' E),the highest peak,is often referred to as the earth's 'third' pole,at an elevation of 8844.43 m. Due to the difficult logistics in the extreme high elevation...Mt.Everest (27°54' N,86°54' E),the highest peak,is often referred to as the earth's 'third' pole,at an elevation of 8844.43 m. Due to the difficult logistics in the extreme high elevation regions over the Himalayas,observational meteorological data are very few on Mt. Everest. In 2005,an automatic weather station was operated at the East Rongbuk glacier Col of Mt. Everest over the Himalayas. The observational data have been compared with the reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),and the reliability of NCEP/NCAR reanalysis data has been investigated in the Himalayan region,after the reanalyzed data were interpolated in the horizontal to the location of Mt. Everest and in the vertical to the height of the observed sites. The reanalysis data can capture much of the synoptic-scale variability in temperature and pressure,although the reanalysis values are systematically lower than the observation. Furthermore,most of the variability magnitude is,to some degree,underestimated. In addition,the variation extracted from the NCEP/NCAR reanalyzed pressure and temperature prominently appears one-day lead to that from the observational data,which is more important from the standpoint of improving the safety of climbers who attempt to climb Mt. Everest peak.展开更多
The objective of this research was to determine the capacity of a soil tillage system in soil conservation,in productivity and in energy efficiency.The minimum tillage and no-tillage systems represent good alternative...The objective of this research was to determine the capacity of a soil tillage system in soil conservation,in productivity and in energy efficiency.The minimum tillage and no-tillage systems represent good alternatives to the conventional(plough)system of soil tillage,due to their conservation effects on soil and to the good production of crops(Maize,96%-98%of conventional tillage for minimum tillage,and 99.8%of conventional tillage for no till;Soybeans,103%-112%of conventional tillage for minimum tillage and 117%of conventional tillage for no till;Wheat,93%-97%of conventional tillage for minimum tillage and 117%of conventional tillage for no till.The choice of the right soil tillage system for crops in rotation help reduce energy consumption,thus for maize:97%-98%energy consumption of conventional tillage when using minimum tillage and 91%when using no-tillage;for soybeans:98%energy consumption of conventional tillage when using minimum tillage and 93 when using no-tillage;for wheat:97%-98%energy consumption of conventional tillage when using minimum tillage and 92%when using no-tillage.Energy efficiency is in relation to reductions in energy use,but also might include the efficiency and impact of the tillage system on the cultivated plant.For all crops in rotation,energy efficiency(energy produced from 1 MJ consumed)was the best in no-tillage-10.44 MJ ha-1 for maize,6.49 MJ ha-1 for soybean,and 5.66 MJ ha-1 for wheat.An analysis of energy-efficiency in agricultural systems includes the energy consumed-energy produced-energy yield comparisons,but must be supplemented by soil energy efficiency,based on the conservative effect of the agricultural system.Only then will the agricultural system be sustainable,durable in agronomic,economic and ecological terms.The implementation of minimum and no-tillage soil systems has increased the organic matter content from 2%to 7.6%and water stable aggregate content from 5.6%to 9.6%,at 0-30 cm depth,as compared to the conventional system.Accumulated water supply was higher(with 12.4%-15%)for all minimum and no-tillage systems and increased bulk density values by 0.01%-0.03%(no significant difference)While the soil fertility and the wet aggregate stability have initially been low,the effect of conservation practices on the soil characteristics led to a positive impact on the water permeability in the soil.Availability of soil moisture during the crop growth period led to a better plant watering condition.Subsequent release of conserved soil water regulated the plant water condition and soil structure.展开更多
文摘Minimum tillage is a soil conservation practice involving a reduction in soil disturbance and topsoil compaction, which could minimize environmental impact of the tobacco cultivation system. The objectives of this study were to evaluate the development and growth responses of Nicotiana tabacum and the changes in the physical and hydrological soil properties after the application of two different treatments: minimum tillage (MT) and conventional tillage (CT). MT did not cause any pronounced differences in the crop yield compared to CT, instead it positively affected the physical and hydrological soil properties and the plants’ vegetative growth. Under MT, the soil showed a higher structural stability than CT with significantly lower compaction values. With MT the soil showed a higher capacity to maintain and store water during the drought periods, evidenced by soil moisture values significantly higher than CT. Tobacco on MT showed a good response, significantly prolonging the vegetative growth stage which at harvest determined a higher stem height, greater number of leaves and longer internodes.
基金the Strategic Study Foundation of Chinese Polar Science （Grant No. 2007228） the National Nature Science Foundation of China （Grant No. 40501015） the Chinese Academy of Science （Grant No. KZCX3-SW-354 and KZCX3-SW-344）.
文摘Mt.Everest (27°54' N,86°54' E),the highest peak,is often referred to as the earth's 'third' pole,at an elevation of 8844.43 m. Due to the difficult logistics in the extreme high elevation regions over the Himalayas,observational meteorological data are very few on Mt. Everest. In 2005,an automatic weather station was operated at the East Rongbuk glacier Col of Mt. Everest over the Himalayas. The observational data have been compared with the reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR),and the reliability of NCEP/NCAR reanalysis data has been investigated in the Himalayan region,after the reanalyzed data were interpolated in the horizontal to the location of Mt. Everest and in the vertical to the height of the observed sites. The reanalysis data can capture much of the synoptic-scale variability in temperature and pressure,although the reanalysis values are systematically lower than the observation. Furthermore,most of the variability magnitude is,to some degree,underestimated. In addition,the variation extracted from the NCEP/NCAR reanalyzed pressure and temperature prominently appears one-day lead to that from the observational data,which is more important from the standpoint of improving the safety of climbers who attempt to climb Mt. Everest peak.
基金performed under the frame of the Partnership in priority domains-PNII,developed with the support of MEN-UEFISCDI,project no.PN-II-PT-PCCA-2013-4-0015:Expert System for Risk Monitoring in Agriculture and Adaptation of Conservative Agricultural Technologies to Climate Change.
文摘The objective of this research was to determine the capacity of a soil tillage system in soil conservation,in productivity and in energy efficiency.The minimum tillage and no-tillage systems represent good alternatives to the conventional(plough)system of soil tillage,due to their conservation effects on soil and to the good production of crops(Maize,96%-98%of conventional tillage for minimum tillage,and 99.8%of conventional tillage for no till;Soybeans,103%-112%of conventional tillage for minimum tillage and 117%of conventional tillage for no till;Wheat,93%-97%of conventional tillage for minimum tillage and 117%of conventional tillage for no till.The choice of the right soil tillage system for crops in rotation help reduce energy consumption,thus for maize:97%-98%energy consumption of conventional tillage when using minimum tillage and 91%when using no-tillage;for soybeans:98%energy consumption of conventional tillage when using minimum tillage and 93 when using no-tillage;for wheat:97%-98%energy consumption of conventional tillage when using minimum tillage and 92%when using no-tillage.Energy efficiency is in relation to reductions in energy use,but also might include the efficiency and impact of the tillage system on the cultivated plant.For all crops in rotation,energy efficiency(energy produced from 1 MJ consumed)was the best in no-tillage-10.44 MJ ha-1 for maize,6.49 MJ ha-1 for soybean,and 5.66 MJ ha-1 for wheat.An analysis of energy-efficiency in agricultural systems includes the energy consumed-energy produced-energy yield comparisons,but must be supplemented by soil energy efficiency,based on the conservative effect of the agricultural system.Only then will the agricultural system be sustainable,durable in agronomic,economic and ecological terms.The implementation of minimum and no-tillage soil systems has increased the organic matter content from 2%to 7.6%and water stable aggregate content from 5.6%to 9.6%,at 0-30 cm depth,as compared to the conventional system.Accumulated water supply was higher(with 12.4%-15%)for all minimum and no-tillage systems and increased bulk density values by 0.01%-0.03%(no significant difference)While the soil fertility and the wet aggregate stability have initially been low,the effect of conservation practices on the soil characteristics led to a positive impact on the water permeability in the soil.Availability of soil moisture during the crop growth period led to a better plant watering condition.Subsequent release of conserved soil water regulated the plant water condition and soil structure.
