The reference evapotranspiration was calculated using Penman-Monteith method proposed. This method was evaluated on data measured by lysimeter in Szarvas experimental station in Hungary. The results of the two methods...The reference evapotranspiration was calculated using Penman-Monteith method proposed. This method was evaluated on data measured by lysimeter in Szarvas experimental station in Hungary. The results of the two methods were in good agreement. However, this method requires an amount of data which is not available at all sites of meteorological measurement. Therefore it was necessary to investigate which elements influencing evapotranspiration are important and which elements are less important. With the help of investigation was indicated that radiation and vapor pressure deficit play important role in determination of reference evapotranspiration. Taking into account this there was two possibilities to calculate evapotranspiration. One of these is to use Penman-Monteith formula with constant wind speed as advised by Allen. Another one is to neglect wind speed data. Both methods were investigated and the method with constant wind speed was found better in a subhumid climatic condition of Hungary.展开更多
Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region. It is cdtical to quantify irrigation requirements during different growth stages under diverse climatic conditions. In t...Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region. It is cdtical to quantify irrigation requirements during different growth stages under diverse climatic conditions. In this study, the Hybrid-Maize model was calibrated and applied in a sub-humid Heilongjiang Province in Northeast China to estimate irrigation requirements for drip- irrigated maize during different crop physiological development stages and under diverse agro-climatic conditions. Using dimensionless scales, the whole growing season of maize was divided into diverse development stages from planting to maturity. Drip-irrigation dates and irrigation amounts in each irrigation event were simulated and summarized in 30-year simulation from 1981 to 2010. The maize harvest area of Heilongjiang Province was divided into 10 agro-climatic zones based on growing degree days, arid index, and temperature seasonality. The simulated results indicated that seasonal irrigation requirements and water stress during different growth stages were highly related to initial soil water content and distribution of seasonal precipitation. In the experimental site, the average irrigation amounts and times ranged from 48 to 150 mm with initial soil water content decreasing from 100 to 20% of the maximum soil available water. Additionally, the earliest drip-irrigation event might occur during 3- to 8-leaf stage. The water stress could occur at any growth stages of maize, even in wet years with abundant total seasonal rainfall but poor distribution. And over 50% of grain yield loss could be caused by extended water stress during the kernel setting window and grain filling period. It is estimated that more than 94% of the maize harvested area in Heilongjiang Province needs to be irrigated although the yield increase varied (0 to 109%) in diverse agro-climatic zones. Consequently, at least 14% of more maize production could be achieved through drip-irrigation systems in Heilongjiang Province compared to rainfed conditions.展开更多
Climate change will have a noteworthy bearing on survival, development, and population dynamics of insect pests. Therefore, we contemplated the survival and development of beet army worm, <em>Spodoptera exigua&l...Climate change will have a noteworthy bearing on survival, development, and population dynamics of insect pests. Therefore, we contemplated the survival and development of beet army worm, <em>Spodoptera exigua</em> under different temperatures, (15<span style="white-space:nowrap;">°</span>C, 25<span style="white-space:nowrap;">°</span>C, 35<span style="white-space:nowrap;">°</span>C, and 45<span style="white-space:nowrap;">°</span>C), CO<sub>2</sub> (350, 550, 750 ppm) and relative humidity (55%, 65%, 75% and 85%) regimes. Maximum larval and pupal weights were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C. The growth of <em>S. exigua</em> was faster at 35<span style="white-space:nowrap;">°</span>C (larval period 7.4 days and pupal period 4.5 days) than at lower temperatures. At 15<span style="white-space:nowrap;">°</span>C, the larval period was extended for 61.4 days and there was no adult emergence from the pupae till 90 days. The <em>S. exigua</em> hatchling was absent at 45<span style="white-space:nowrap;">°</span>C. The larval survival ranged from 31.6% - 57.2%, maximum survival was recorded at 25<span style="white-space:nowrap;">°</span>C, and minimum at 45<span style="white-space:nowrap;">°</span>C. The maximum (84.27%) and minimum adult emergence were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C and 35<span style="white-space:nowrap;">°</span>C respectively. Maximum fecundity (384.3 eggs/female) and egg viability (51.97%) were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C. Larval and pupal periods increased with an increase in CO<sub>2</sub> concentration. The highest pupal weights (128.6 mg/larva) were recorded at 550 ppm. The highest larval survival (73.50%) was recorded at 550 ppm and minimum (37.00%) at 750 ppm CO<sub>2</sub>. Fecundity was the highest in insects reared at 550 ppm CO<sub>2</sub> (657.4 eggs/female), and the lowest at 750 ppm. Maximum larval and pupal weights were recorded in insects reared at 75% relative humidity (RH). The growth rate of<em> S. exigua</em> was faster at 85% RH than at lower RH. The larval survival ranged between 40.0% - 58.5%. Maximum adult emergence (88.91%) was recorded in insects reared at 75% RH and minimum at 85% RH. Maximum fecundity (447.6 eggs/female) and the highest egg viability (72.95%) were recorded in insects reared at 75% and 65% RH respectively. Elevated temperatures and relative moistness will diminish the life cycle, while hoisted CO<sub>2</sub> will drag the life expectancy. Therefore, there is a need for thorough assessment of the impact of climatic factors on the population dynamics of insect pests, crop losses, and sustainability of crop production.展开更多
The present study was aimed to assess the growing stock of Timergara forest subdivision which was a part of Dir lower forest division (Pakistan). The study area was divided into two different climatic zones (i.e. sub-...The present study was aimed to assess the growing stock of Timergara forest subdivision which was a part of Dir lower forest division (Pakistan). The study area was divided into two different climatic zones (i.e. sub-tropical sub humid and sub-humid temperate zones) on the basis of altitudinal considerations. A total of 43 sample plots are taken in the forest area of 8480 hectare with random sampling technique representing 0.5% of the total forest area. Each sample plot size was of one hectare. In each 100 × 100 m (1 ha plot), number of trees, diameter, age, height, increment, form factor and volume were measured. An interrelation between the diameter (independent variable) and all the other dependent variables (volume, increment and height) were found. At the end, volume tables were made which suited the local conditions as the ones used before were not suited to the local conditions.展开更多
文摘The reference evapotranspiration was calculated using Penman-Monteith method proposed. This method was evaluated on data measured by lysimeter in Szarvas experimental station in Hungary. The results of the two methods were in good agreement. However, this method requires an amount of data which is not available at all sites of meteorological measurement. Therefore it was necessary to investigate which elements influencing evapotranspiration are important and which elements are less important. With the help of investigation was indicated that radiation and vapor pressure deficit play important role in determination of reference evapotranspiration. Taking into account this there was two possibilities to calculate evapotranspiration. One of these is to use Penman-Monteith formula with constant wind speed as advised by Allen. Another one is to neglect wind speed data. Both methods were investigated and the method with constant wind speed was found better in a subhumid climatic condition of Hungary.
基金supported by the Key Technology R&D Program of China during the 12th Five-year Plan period (2014BAD12B05)the National Natural Science Foundation of China (51479211, 51621061)the Chinese Scholarship Council (201506350059)
文摘Drip-irrigation is increasingly applied in maize (Zea mays L.) production in sub-humid region. It is cdtical to quantify irrigation requirements during different growth stages under diverse climatic conditions. In this study, the Hybrid-Maize model was calibrated and applied in a sub-humid Heilongjiang Province in Northeast China to estimate irrigation requirements for drip- irrigated maize during different crop physiological development stages and under diverse agro-climatic conditions. Using dimensionless scales, the whole growing season of maize was divided into diverse development stages from planting to maturity. Drip-irrigation dates and irrigation amounts in each irrigation event were simulated and summarized in 30-year simulation from 1981 to 2010. The maize harvest area of Heilongjiang Province was divided into 10 agro-climatic zones based on growing degree days, arid index, and temperature seasonality. The simulated results indicated that seasonal irrigation requirements and water stress during different growth stages were highly related to initial soil water content and distribution of seasonal precipitation. In the experimental site, the average irrigation amounts and times ranged from 48 to 150 mm with initial soil water content decreasing from 100 to 20% of the maximum soil available water. Additionally, the earliest drip-irrigation event might occur during 3- to 8-leaf stage. The water stress could occur at any growth stages of maize, even in wet years with abundant total seasonal rainfall but poor distribution. And over 50% of grain yield loss could be caused by extended water stress during the kernel setting window and grain filling period. It is estimated that more than 94% of the maize harvested area in Heilongjiang Province needs to be irrigated although the yield increase varied (0 to 109%) in diverse agro-climatic zones. Consequently, at least 14% of more maize production could be achieved through drip-irrigation systems in Heilongjiang Province compared to rainfed conditions.
文摘Climate change will have a noteworthy bearing on survival, development, and population dynamics of insect pests. Therefore, we contemplated the survival and development of beet army worm, <em>Spodoptera exigua</em> under different temperatures, (15<span style="white-space:nowrap;">°</span>C, 25<span style="white-space:nowrap;">°</span>C, 35<span style="white-space:nowrap;">°</span>C, and 45<span style="white-space:nowrap;">°</span>C), CO<sub>2</sub> (350, 550, 750 ppm) and relative humidity (55%, 65%, 75% and 85%) regimes. Maximum larval and pupal weights were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C. The growth of <em>S. exigua</em> was faster at 35<span style="white-space:nowrap;">°</span>C (larval period 7.4 days and pupal period 4.5 days) than at lower temperatures. At 15<span style="white-space:nowrap;">°</span>C, the larval period was extended for 61.4 days and there was no adult emergence from the pupae till 90 days. The <em>S. exigua</em> hatchling was absent at 45<span style="white-space:nowrap;">°</span>C. The larval survival ranged from 31.6% - 57.2%, maximum survival was recorded at 25<span style="white-space:nowrap;">°</span>C, and minimum at 45<span style="white-space:nowrap;">°</span>C. The maximum (84.27%) and minimum adult emergence were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C and 35<span style="white-space:nowrap;">°</span>C respectively. Maximum fecundity (384.3 eggs/female) and egg viability (51.97%) were recorded in insects reared at 25<span style="white-space:nowrap;">°</span>C. Larval and pupal periods increased with an increase in CO<sub>2</sub> concentration. The highest pupal weights (128.6 mg/larva) were recorded at 550 ppm. The highest larval survival (73.50%) was recorded at 550 ppm and minimum (37.00%) at 750 ppm CO<sub>2</sub>. Fecundity was the highest in insects reared at 550 ppm CO<sub>2</sub> (657.4 eggs/female), and the lowest at 750 ppm. Maximum larval and pupal weights were recorded in insects reared at 75% relative humidity (RH). The growth rate of<em> S. exigua</em> was faster at 85% RH than at lower RH. The larval survival ranged between 40.0% - 58.5%. Maximum adult emergence (88.91%) was recorded in insects reared at 75% RH and minimum at 85% RH. Maximum fecundity (447.6 eggs/female) and the highest egg viability (72.95%) were recorded in insects reared at 75% and 65% RH respectively. Elevated temperatures and relative moistness will diminish the life cycle, while hoisted CO<sub>2</sub> will drag the life expectancy. Therefore, there is a need for thorough assessment of the impact of climatic factors on the population dynamics of insect pests, crop losses, and sustainability of crop production.
文摘The present study was aimed to assess the growing stock of Timergara forest subdivision which was a part of Dir lower forest division (Pakistan). The study area was divided into two different climatic zones (i.e. sub-tropical sub humid and sub-humid temperate zones) on the basis of altitudinal considerations. A total of 43 sample plots are taken in the forest area of 8480 hectare with random sampling technique representing 0.5% of the total forest area. Each sample plot size was of one hectare. In each 100 × 100 m (1 ha plot), number of trees, diameter, age, height, increment, form factor and volume were measured. An interrelation between the diameter (independent variable) and all the other dependent variables (volume, increment and height) were found. At the end, volume tables were made which suited the local conditions as the ones used before were not suited to the local conditions.