A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning Sys...A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.展开更多
Climate change affected the agricultural expansion and the formation of farming-grazing transitional patterns during historical periods. This study analyzed the possible range of the boundary shift of the potential su...Climate change affected the agricultural expansion and the formation of farming-grazing transitional patterns during historical periods. This study analyzed the possible range of the boundary shift of the potential suitable agriculture area in the farming-grazing transitional zone in the northeastern China during the 20th century. Based on modem weather data, 1 km-resolution land cover data, historical climatic time series, and estimation by using similar historical climatic scenes, the following was concluded： 1） The climate conditions of suitable agriculture areas in the farming-grazing transitional zone in the northeastern China between 1971 and 2000 required an average annual temperature above 1℃ or ≥ 0℃ accumulated temperature above 2500℃-2700℃, and annual precipitation above 350 mm. 2） The northern boundary of the potential suitable agriculture area during the relatively warmer period of 1890-1910 was approximately located at the position of the 1961-2000 area. The northern boundary shifted back to the south by 75 km on average during the colder period of the earlier 20th century, whereas during the modem warm period of the 1990s, the area shifted north by 100 km on average. 3） The western and eastern boundaries of the suitable agricul^re area during the heaviest drought periods between 1920s and 1930s had shifted northeast by 250 km and 125 km, respectively, contrasting to the boundaries of 1951-2008. For the wettest period, that is, the 1890s to the 1910s, the shift of western and eastern boundaries was to the southwest by 125 km and 200 km, respectively, compared with that in the 1951-2008 period. This study serves as a reference for identifying a climatically sensitive area and planning future land use and agricultural production in the study area.展开更多
Cassava （Manihot esculenta Crantz） is a perennial woody shrub with an edible root, which grows in tropical and subtropical areas of the world. In Africa, cassava provides a basic daily source of dietary energy. It p...Cassava （Manihot esculenta Crantz） is a perennial woody shrub with an edible root, which grows in tropical and subtropical areas of the world. In Africa, cassava provides a basic daily source of dietary energy. It plays an important role in food security and incomes of many rural households in the southern Ethiopia. However, information available on production practices of cassava for the region is insufficient. Hence, field experiment was conducted at Awassa Agricultural Research Center for two successive cropping seasons from 2004 to 2006 to investigate the response of cassava to planting position and planting material. The treatments used were three planting positions （slant, vertical and horizontal） and five planting materials （main stem top part, main stem middle part, main stem bottom part, branch stake top part and branch stake bottom part） were combined in factorial arrangement and laid out in randomized complete block design with three replications. The result revealed that root yield was significantly （P 〈 0.05） affected by the interaction effects of the planting position and planting material. The highest yield （25.2 ton ha^-1） was obtained from the main stem top part planted in slant position whereas the least yield （6.5 ton ha^-1） was obtained from main stem bottom part planted in horizontal position. Based on the findings of this study, areas like Awassa with moderate rainfall slant and vertical planting of main stem top and middle parts could be used as planting material.展开更多
基金Project supported by the Tingthanathikul Foundation of Thailand, the Provincial Natural Science Foun- dation of Jiangxi (No. 0230025) the Open Research Foundation of Hubei Provincial Key Labaratory of Waterlogged Disaster and Wetland Agriculture (No. H
文摘A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.
基金Under the auspices of China Global Change Research Program(No.2010CB950103)National Natural Science Foundation of China(No.40901099)
文摘Climate change affected the agricultural expansion and the formation of farming-grazing transitional patterns during historical periods. This study analyzed the possible range of the boundary shift of the potential suitable agriculture area in the farming-grazing transitional zone in the northeastern China during the 20th century. Based on modem weather data, 1 km-resolution land cover data, historical climatic time series, and estimation by using similar historical climatic scenes, the following was concluded： 1） The climate conditions of suitable agriculture areas in the farming-grazing transitional zone in the northeastern China between 1971 and 2000 required an average annual temperature above 1℃ or ≥ 0℃ accumulated temperature above 2500℃-2700℃, and annual precipitation above 350 mm. 2） The northern boundary of the potential suitable agriculture area during the relatively warmer period of 1890-1910 was approximately located at the position of the 1961-2000 area. The northern boundary shifted back to the south by 75 km on average during the colder period of the earlier 20th century, whereas during the modem warm period of the 1990s, the area shifted north by 100 km on average. 3） The western and eastern boundaries of the suitable agricul^re area during the heaviest drought periods between 1920s and 1930s had shifted northeast by 250 km and 125 km, respectively, contrasting to the boundaries of 1951-2008. For the wettest period, that is, the 1890s to the 1910s, the shift of western and eastern boundaries was to the southwest by 125 km and 200 km, respectively, compared with that in the 1951-2008 period. This study serves as a reference for identifying a climatically sensitive area and planning future land use and agricultural production in the study area.
文摘Cassava （Manihot esculenta Crantz） is a perennial woody shrub with an edible root, which grows in tropical and subtropical areas of the world. In Africa, cassava provides a basic daily source of dietary energy. It plays an important role in food security and incomes of many rural households in the southern Ethiopia. However, information available on production practices of cassava for the region is insufficient. Hence, field experiment was conducted at Awassa Agricultural Research Center for two successive cropping seasons from 2004 to 2006 to investigate the response of cassava to planting position and planting material. The treatments used were three planting positions （slant, vertical and horizontal） and five planting materials （main stem top part, main stem middle part, main stem bottom part, branch stake top part and branch stake bottom part） were combined in factorial arrangement and laid out in randomized complete block design with three replications. The result revealed that root yield was significantly （P 〈 0.05） affected by the interaction effects of the planting position and planting material. The highest yield （25.2 ton ha^-1） was obtained from the main stem top part planted in slant position whereas the least yield （6.5 ton ha^-1） was obtained from main stem bottom part planted in horizontal position. Based on the findings of this study, areas like Awassa with moderate rainfall slant and vertical planting of main stem top and middle parts could be used as planting material.
