The work reports about the establishment and the development after two years of a Paulownia tree plantation in a large and homogeneous agricultural area, representative as a test site for climate, soil and land use ch...The work reports about the establishment and the development after two years of a Paulownia tree plantation in a large and homogeneous agricultural area, representative as a test site for climate, soil and land use characters of the countryside of Oristano, central Sardinia, Italy. The first results showed that the role assigned to Paulownia trees can be a beneficial system leading to a low carbon and high biomass productive agriculture in short time.展开更多
Immediate cutting and logging of mixed conifer/broadleaves species in a man-made forest crossed by fire in 2009 in the Arci Mountain in Sardinia can not guarantee as the best post-fire regeneration. The study case rep...Immediate cutting and logging of mixed conifer/broadleaves species in a man-made forest crossed by fire in 2009 in the Arci Mountain in Sardinia can not guarantee as the best post-fire regeneration. The study case reports the differences in the density and in the height of seedlings. The release of damaged Pinus halepensis Mill. stems seems to confirm the tree seeder role of this species.展开更多
The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area o...The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia （Northern Algeria Sahara）, since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces.展开更多
Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that...Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that new maize varieties must pass the tests for value for cultivation and use （VCU） and standardized tests for distinctness, uniformity and stability （DUS）. To meet the minimum requirements for variety release, public and private sector maize breeding programs routinely assemble breeding nurseries and evaluate variety performance in National and Regional Performance Trials （NRPT） with the objective of generating important agronomic data to identify the best maize varieties for release. In spite of intensive variety evaluation in regional and national trials, only few maize varieties have been registered and released annually in sub-Saharan Africa （SSA） denying farmers access to new improved varieties. The purpose of this study was to identify constraints hampering the registration and release of elite maize gennplasm and make recommends on how to quicken the deployment of elite germplasm to smallholders＇ farmers. A survey was conducted on the varietal testing and release systems in 14 selected countries （Angola, Benin, Ethiopia, Malawi, Ghana, Mali, Mozambique, Nigeria, Tanzania, Kenya, South Africa, Uganda, Zambia, and Zimbabwe） in SSA. The results from the study show that regulations on variety testing and release procedures in the various countries are overlapping and rigid hindering the deployment and commercialization of new improved maize germplasm. The study also showed that varietal release rates fluctuated between countries with South Africa having the highest number of varietal release rates per year and some countries failing to release a single variety per year.展开更多
Wind is among the most important environmental factors shaping birds＇ migration patterns. Birds must deal with the displacement caused by crosswinds and their behavior can vary according to different factors such as ...Wind is among the most important environmental factors shaping birds＇ migration patterns. Birds must deal with the displacement caused by crosswinds and their behavior can vary according to different factors such as flight mode, migratory season, experience, and distance to goal areas. Here we analyze the relationship between wind and migratory movements of three raptor species which migrate by soaring-gliding flight： Egyptian vulture Neophron percnopterus, booted eagle Aquila pennata, and short-toed snake eagle Circaetus gallicus. We analyzed daily migratory segments （i.e., the path joining consecutive roosting locations） using data recorded by GPS satellite telemetry. Daily movements of Egyptian vultures and booted eagles were significantly affected by tailwinds during both autumn and spring migrations. In contrast, daily movements of short-toed eagles were only significantly affected by tailwinds during autumn migration. The effect of crosswinds was signifi- cant in all cases. Interestingly, Egyptian vultures and booted eagles showed latitudinal differences in their behavior： both species compensated more frequently at the onset of autumn migration and, at the end of the season when reaching their wintering areas, the proportion of drift segments was higher. In contrast, there was a higher drift at the onset of spring migration and a higher compensation at the end. Our results highlight the effect of wind patterns on the migratory routes of soaring raptors, with different outcomes in relation to species, season, and latitude, ultimately shaping the loop migration patterns that current tracking techniques are showing to be widespread in many long distance migrants.展开更多
文摘The work reports about the establishment and the development after two years of a Paulownia tree plantation in a large and homogeneous agricultural area, representative as a test site for climate, soil and land use characters of the countryside of Oristano, central Sardinia, Italy. The first results showed that the role assigned to Paulownia trees can be a beneficial system leading to a low carbon and high biomass productive agriculture in short time.
文摘Immediate cutting and logging of mixed conifer/broadleaves species in a man-made forest crossed by fire in 2009 in the Arci Mountain in Sardinia can not guarantee as the best post-fire regeneration. The study case reports the differences in the density and in the height of seedlings. The release of damaged Pinus halepensis Mill. stems seems to confirm the tree seeder role of this species.
文摘The current study focuses on the contribution of the dromedary in the preservation and increase of spontaneous flora through seeds transfer by endozoochory. Thus dromedary faeces have been collected in selected area of region of Ghardaia （Northern Algeria Sahara）, since it is one of the three known cameline rangelands during the four successive seasons of the years 2009-2010, in order to examine their seed contents. Our investigation allowed us to invento 1,832 seeds representing 33 different types varying according to the seasons of harvest. The biggest density of seeds was present in summer with 986 seeds, against 424 seeds in winter, 366 seeds in fall and 56 seeds in spring, and of the same way, the biggest number of types was present in summer with 30 types, consistent of the fall season with 26 types, and arrived then the season of winter with 20 types and the one of spring with five types. The gotten results allowed us to appreciate the ecological role of this animal in the desertic ecosystem in the dissemination and the proliferation of the seeds of the spontaneous flora in its fragile and hostile desert environment to the survival of the seeds enveloped in its faeces.
文摘Before farmers can benefit from new improved maize varieties with novel genetic information, new maize varieties have to undergo performance testing, registration and approval. The registration procedures require that new maize varieties must pass the tests for value for cultivation and use （VCU） and standardized tests for distinctness, uniformity and stability （DUS）. To meet the minimum requirements for variety release, public and private sector maize breeding programs routinely assemble breeding nurseries and evaluate variety performance in National and Regional Performance Trials （NRPT） with the objective of generating important agronomic data to identify the best maize varieties for release. In spite of intensive variety evaluation in regional and national trials, only few maize varieties have been registered and released annually in sub-Saharan Africa （SSA） denying farmers access to new improved varieties. The purpose of this study was to identify constraints hampering the registration and release of elite maize gennplasm and make recommends on how to quicken the deployment of elite germplasm to smallholders＇ farmers. A survey was conducted on the varietal testing and release systems in 14 selected countries （Angola, Benin, Ethiopia, Malawi, Ghana, Mali, Mozambique, Nigeria, Tanzania, Kenya, South Africa, Uganda, Zambia, and Zimbabwe） in SSA. The results from the study show that regulations on variety testing and release procedures in the various countries are overlapping and rigid hindering the deployment and commercialization of new improved maize germplasm. The study also showed that varietal release rates fluctuated between countries with South Africa having the highest number of varietal release rates per year and some countries failing to release a single variety per year.
文摘Wind is among the most important environmental factors shaping birds＇ migration patterns. Birds must deal with the displacement caused by crosswinds and their behavior can vary according to different factors such as flight mode, migratory season, experience, and distance to goal areas. Here we analyze the relationship between wind and migratory movements of three raptor species which migrate by soaring-gliding flight： Egyptian vulture Neophron percnopterus, booted eagle Aquila pennata, and short-toed snake eagle Circaetus gallicus. We analyzed daily migratory segments （i.e., the path joining consecutive roosting locations） using data recorded by GPS satellite telemetry. Daily movements of Egyptian vultures and booted eagles were significantly affected by tailwinds during both autumn and spring migrations. In contrast, daily movements of short-toed eagles were only significantly affected by tailwinds during autumn migration. The effect of crosswinds was signifi- cant in all cases. Interestingly, Egyptian vultures and booted eagles showed latitudinal differences in their behavior： both species compensated more frequently at the onset of autumn migration and, at the end of the season when reaching their wintering areas, the proportion of drift segments was higher. In contrast, there was a higher drift at the onset of spring migration and a higher compensation at the end. Our results highlight the effect of wind patterns on the migratory routes of soaring raptors, with different outcomes in relation to species, season, and latitude, ultimately shaping the loop migration patterns that current tracking techniques are showing to be widespread in many long distance migrants.
