Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water cond...Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water condition in dryland of dry subhumid area of the Loess Plateau were studied. The results suggested that a low precipitation satisfying ratio of 42.9%—58.8% appears in the growing period of winter wheat, and the yield, to a great extent depended on the water that was stored in deep soil layer in the previous rainy season. The filed trial results showed that tillage in the summer fallow period,straw cover, soil moisture regulation with adequate fertilization, crop rotation and proper cropping system could be the efficient ways for improving the water condition,and for the exploitation and utilization of natural water resources(both precipitation and soil water) in the winter wheat field of dryland.展开更多
Sunflower (Helianthus annuus L.) has emerged as an economically important crop in Pakistan due to its significant share in vegetable oil production. The plant metabolic processes require protein to increase the vegeta...Sunflower (Helianthus annuus L.) has emerged as an economically important crop in Pakistan due to its significant share in vegetable oil production. The plant metabolic processes require protein to increase the vegetative, reproductive growth and yield of the crop. The protein is wholly dependent upon the amount of nitrogen fertilization available for plant use. A two-year field study was conducted in 2008 and 2009. The objective was to determine the effect of different nitrogen (N) levels (N1 = 0 kg·ha–1, N2 = 60 kg·ha–1, N3 = 120 kg·ha–1, N4 = 180 kg·ha–1 and N5 = 240 kg·ha–1) on three sunflower hybrids (Hysun-33, Hysun-38 and Poineer-64A93) in agro-climatic conditions of Gujranwala, a sub-humid region in the centre of the Punjab province of Pakistan. A randomized complete block design split plot experiment was set-up with cultivars in the main plots and N levels in the subplots. Results showed that Hysun-38 gave maximum TDM (15815 kg·ha–1) and maximum grain yield (3389 kg·ha–1), while minimum TDM (14640 kg·ha–1) and grain yield (3125 kg·ha–1) was observed in Hysun-33. Among different N rates evaluated, N4 gave maximum TDM (17890 kg·ha–1) and grain yield (3809 kg·ha–1) compared to the other N rates. The maximum oil content (46.2%) was observed in Hysun-38 without application of N fertilizer (N1), while the minimum oil content (40.6%) was observed from N5 treatment. In conclusion, the application of 180 kg·ha–1 N to Hysun-38 provided the best combination for good yield in sunflower crop under the prevailing sub-humid conditions of Pakistan.展开更多
The temporal variations of the Gross Primary Productivity (GPP), the Total Ecosystem Respiration (TER) and the Net Ecosystem Exchange (NEE), and their responses to meteorological conditions (e.g. temperature, radiativ...The temporal variations of the Gross Primary Productivity (GPP), the Total Ecosystem Respiration (TER) and the Net Ecosystem Exchange (NEE), and their responses to meteorological conditions (e.g. temperature, radiative flux and precipitation) at Lamto, in wet savannah region across C?te d’Ivoire are analyzed using GFED-CASA and daily meteorological data recorded over the 2008-2015 period. The study shows the links between these carbon fluxes and climate variability at Lamto that is subject to high anthropogenic pressures and seasonal bushfires. The correlative statistics from multiple regression methods were used to assess the different relationships and show how they change in time. The results show important seasonal variability in the Gross Primary Productivity and the Total Ecosystem Respiration mainly associated with the changes in temperature and radiative flux. In addition, the statistical analysis suggests a high correlation between meteorological conditions and the GPP and TER. These climatic conditions may explain 83% and 79% of the variances of GPP and TER respectively. Moreover, the interannual variability of the Net Ecosystem Exchange indicates that around Lamto, in the subhumid savannah, the ecosystem behaves as a carbon sink similar to other West African ecosystems. On the other hand, there is no clear link between the NEE and temperature, radiative flux and precipitation. This lack of connection may suggest a limited response of the NEE interannual dynamics related to the changes in climatic features.展开更多
文摘Based on the soil moisture data from the locating experiments from 1986—1990, and using the water balance method, the water supply and demand state in the field of winter wheat, and the ways for improving water condition in dryland of dry subhumid area of the Loess Plateau were studied. The results suggested that a low precipitation satisfying ratio of 42.9%—58.8% appears in the growing period of winter wheat, and the yield, to a great extent depended on the water that was stored in deep soil layer in the previous rainy season. The filed trial results showed that tillage in the summer fallow period,straw cover, soil moisture regulation with adequate fertilization, crop rotation and proper cropping system could be the efficient ways for improving the water condition,and for the exploitation and utilization of natural water resources(both precipitation and soil water) in the winter wheat field of dryland.
文摘Sunflower (Helianthus annuus L.) has emerged as an economically important crop in Pakistan due to its significant share in vegetable oil production. The plant metabolic processes require protein to increase the vegetative, reproductive growth and yield of the crop. The protein is wholly dependent upon the amount of nitrogen fertilization available for plant use. A two-year field study was conducted in 2008 and 2009. The objective was to determine the effect of different nitrogen (N) levels (N1 = 0 kg·ha–1, N2 = 60 kg·ha–1, N3 = 120 kg·ha–1, N4 = 180 kg·ha–1 and N5 = 240 kg·ha–1) on three sunflower hybrids (Hysun-33, Hysun-38 and Poineer-64A93) in agro-climatic conditions of Gujranwala, a sub-humid region in the centre of the Punjab province of Pakistan. A randomized complete block design split plot experiment was set-up with cultivars in the main plots and N levels in the subplots. Results showed that Hysun-38 gave maximum TDM (15815 kg·ha–1) and maximum grain yield (3389 kg·ha–1), while minimum TDM (14640 kg·ha–1) and grain yield (3125 kg·ha–1) was observed in Hysun-33. Among different N rates evaluated, N4 gave maximum TDM (17890 kg·ha–1) and grain yield (3809 kg·ha–1) compared to the other N rates. The maximum oil content (46.2%) was observed in Hysun-38 without application of N fertilizer (N1), while the minimum oil content (40.6%) was observed from N5 treatment. In conclusion, the application of 180 kg·ha–1 N to Hysun-38 provided the best combination for good yield in sunflower crop under the prevailing sub-humid conditions of Pakistan.
文摘The temporal variations of the Gross Primary Productivity (GPP), the Total Ecosystem Respiration (TER) and the Net Ecosystem Exchange (NEE), and their responses to meteorological conditions (e.g. temperature, radiative flux and precipitation) at Lamto, in wet savannah region across C?te d’Ivoire are analyzed using GFED-CASA and daily meteorological data recorded over the 2008-2015 period. The study shows the links between these carbon fluxes and climate variability at Lamto that is subject to high anthropogenic pressures and seasonal bushfires. The correlative statistics from multiple regression methods were used to assess the different relationships and show how they change in time. The results show important seasonal variability in the Gross Primary Productivity and the Total Ecosystem Respiration mainly associated with the changes in temperature and radiative flux. In addition, the statistical analysis suggests a high correlation between meteorological conditions and the GPP and TER. These climatic conditions may explain 83% and 79% of the variances of GPP and TER respectively. Moreover, the interannual variability of the Net Ecosystem Exchange indicates that around Lamto, in the subhumid savannah, the ecosystem behaves as a carbon sink similar to other West African ecosystems. On the other hand, there is no clear link between the NEE and temperature, radiative flux and precipitation. This lack of connection may suggest a limited response of the NEE interannual dynamics related to the changes in climatic features.
