A study was conducted to identify the causes of low crop yield on a large scale commercial farm in Zimbabwe. Soil and water samples were collected from fields （0-60 cm） and the dam used for irrigation, respectively....A study was conducted to identify the causes of low crop yield on a large scale commercial farm in Zimbabwe. Soil and water samples were collected from fields （0-60 cm） and the dam used for irrigation, respectively. Soil samples were analysed for soil fertility characteristics while the water was analysed for irrigation quality. The soils on the farm were heavy, ranging from sand loams to sand clays and fertile （〉 40 mg kgl N and 〉 20 mg kg1 available P） indicating high fertilizer utilization. It was also noted that 50% of the fields on the farm had soil pH below 5.0 despite having high basic cation （Ca = 10-18 meq% and Mg = 4-7 meq%）. A similar trend was observed down the soil profile （30-60 cm）. The soil also had extremely high concentration of iron （〉 200 ppm）, manganese （〉 400 ppm） and sulphate （〉 4000 ppm）. These findings suggest that the extreme acidity under these soils is the outcome of the exposure of pyrite to moisture and air by tillage of the land. The water used for irrigation was established to be medium saline and alkaline （pH 〉 7.6）. This pyrite induced acidity could not be neutralised by the water from the dam and the high exchangeable bases in the soil. Such problems can possibly be managed by growing tolerant crops. Soil testing on commercial farms is vital for identifying such problems in commercial farms in Zimbabwe.展开更多
Urban development has progressed with economic growth in various parts of Japan.However,there are concerns for the future with respect to severe population decline,aging population,and population concentration in metr...Urban development has progressed with economic growth in various parts of Japan.However,there are concerns for the future with respect to severe population decline,aging population,and population concentration in metropolitan areas.Therefore,it is required for effective urban development in localities for sustainability.One of the practical measures is to focus on pedestrians’activity in the area.It brings revitalizing the local economy,enhancing the region's attractiveness,and bringing about fiscal consolidation.Thus,it is required to understand walking characteristics based on the actual pedestrian activity in the walking space.However,a method for grasping pedestrian activity,including pedestrians'exploratory behavior such as free-purpose behavior,rambling activity in a narrow area has not been established.The study proposes a survey proportional distribution origin-destination survey method focused on the proportion of pedestrians’route selection and the distribution of pedestrians at the time in the area,and evaluation method for urban space using PdOD method.展开更多
文摘A study was conducted to identify the causes of low crop yield on a large scale commercial farm in Zimbabwe. Soil and water samples were collected from fields （0-60 cm） and the dam used for irrigation, respectively. Soil samples were analysed for soil fertility characteristics while the water was analysed for irrigation quality. The soils on the farm were heavy, ranging from sand loams to sand clays and fertile （〉 40 mg kgl N and 〉 20 mg kg1 available P） indicating high fertilizer utilization. It was also noted that 50% of the fields on the farm had soil pH below 5.0 despite having high basic cation （Ca = 10-18 meq% and Mg = 4-7 meq%）. A similar trend was observed down the soil profile （30-60 cm）. The soil also had extremely high concentration of iron （〉 200 ppm）, manganese （〉 400 ppm） and sulphate （〉 4000 ppm）. These findings suggest that the extreme acidity under these soils is the outcome of the exposure of pyrite to moisture and air by tillage of the land. The water used for irrigation was established to be medium saline and alkaline （pH 〉 7.6）. This pyrite induced acidity could not be neutralised by the water from the dam and the high exchangeable bases in the soil. Such problems can possibly be managed by growing tolerant crops. Soil testing on commercial farms is vital for identifying such problems in commercial farms in Zimbabwe.
文摘Urban development has progressed with economic growth in various parts of Japan.However,there are concerns for the future with respect to severe population decline,aging population,and population concentration in metropolitan areas.Therefore,it is required for effective urban development in localities for sustainability.One of the practical measures is to focus on pedestrians’activity in the area.It brings revitalizing the local economy,enhancing the region's attractiveness,and bringing about fiscal consolidation.Thus,it is required to understand walking characteristics based on the actual pedestrian activity in the walking space.However,a method for grasping pedestrian activity,including pedestrians'exploratory behavior such as free-purpose behavior,rambling activity in a narrow area has not been established.The study proposes a survey proportional distribution origin-destination survey method focused on the proportion of pedestrians’route selection and the distribution of pedestrians at the time in the area,and evaluation method for urban space using PdOD method.
