Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried ou...Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.展开更多
This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a us...This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a user can easily produce appropriate landform data for simulations using standard laser profiler data,and visualize the results using a GIS.Hyper KANAKO was applied to the streams around Kiyomizu-dera in Kyoto,Japan.Kiyomizu-dera is a famous temple in Japan which is visited by numerous tourists throughout the year.We simulated a disaster scenario of debris flow caused by torrential rain.We set the hydrograph using rainfall intensity data,and set the landform data using information from the Geospatial Information Authority of Japan(GSI) and a digital elevation model(DEM).We evaluated different mesh sizes and also used a digital surface model(DSM) to consider the building heights.The simulation results showed that with small mesh size,the debris flowmoved through the roads,which seems realistic for a disaster situation.When buildings were considered,the flow direction changed,and a 1-m flow depth,which was deeper than in other cases,appeared in the flow path.This may pose a dangerous situation for evacuations.展开更多
Dry season water application and conservation were studied for two years in Ado Ekiti to evaluate their effects on the performance of plantain Musa spp.. The treatments were： morning watering （MW）, evening watering...Dry season water application and conservation were studied for two years in Ado Ekiti to evaluate their effects on the performance of plantain Musa spp.. The treatments were： morning watering （MW）, evening watering （EW）, morning and evening watering （MEW）, morning watering ＋ mulch （MW ＋ ML）, evening watering ＋ mulch （EW ＋ ML）, morning and evening watering ＋ mulch （MEW ＋ ML）, mulch （ML） and Control. Height and girth increase, number of green leaves, yield and yield parameters were the highest in the MEW ＋ ML which were identical to those of Evening watering ＋ mulch and morning ＋ evening watering. The evening or morning watering with mulch was identical but showed better performance than those without mulch. The mulched plants and the control showed the least performance. It is therefore recommended that proper water conservation in plantain plantation will improve banana survival during dry season and subsequently increase yield in the study area.展开更多
The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated b...The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria （WIN）. And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.展开更多
This paper analyzed the effect of flood and socio-economic problems on fish farming in Ibadan Metropolis, Oyo State, Nigeria. A multistage random sampling technique was used to select 80 fish farmers in the state. Bot...This paper analyzed the effect of flood and socio-economic problems on fish farming in Ibadan Metropolis, Oyo State, Nigeria. A multistage random sampling technique was used to select 80 fish farmers in the state. Both primary and secondary data were collected and analyzed using descriptive statistics to analyze the socio-economic characteristics of the fish farmers, cost and returns analysis was done to determine the profitability ratios of the fish farming in the study areas. The mean age analyzed was 45%. The result of the cost and returns analysis showed that Average Total Cost CATC） of N1, 500,517.5 was incurred, Total Revenue （TR） of N, 138,659,400 was realized and a returning Gross Margin （GM） of N was 64,885,800 by fish farmers. The major constraints encountered by fish farmers were flooding that wash away fish, deposit heavy metals such as ammonia （NH4）, lead, copper, cadmium, arsenic, etc., that can result to the death of fish in the fishponds and rivers when flood overflowing. The methodology applied for the flood examination includes site visits, interviews of affected fish farmers, and analyses of flood data collected during the field examination.展开更多
Understanding the interactions between salinity and fertilizers is of significant importance for enhancing crop yield and fertilizeruse efficiency. In this study a complete block design experiment was performed in the...Understanding the interactions between salinity and fertilizers is of significant importance for enhancing crop yield and fertilizeruse efficiency. In this study a complete block design experiment was performed in the Hetao Irrigation District of Inner Mongolia,China, to evaluate the effects of interactions between soil salinity and nitrogen(N) application rate on sunflower photosynthesis and growth and to determine the optimum N application rate for sunflower growth in the district. Four levels of soil salinity expressed as electrical conductivity(0.33–0.60, 0.60–1.22, 1.2–2.44, and 2.44–3.95 dS m-1) and three application rates of N fertilization(90, 135,and 180 kg ha-1) were applied to 36 micro-plots. Soil salinity inhibited the photosynthetic rate, stomatal conductance, transpiration rate, plant height, leaf area, and aboveground dry matter of sunflowers. The intercellular CO2 concentration first decreased and then increased with increasing soil salinity in the seedling stage, and the instantaneous leaf water-use efficiency fluctuated with soil salinity. The stomatal and non-stomatal limitations of sunflowers alternated in the seedling stage; however, in the bud, blooming,and mature stages, the stomatal limitation was prevalent when the salinity level was lower than 2.44 dS m-1, whereas the nonstomatal limitation was predominant above the salinity level. The application of N fertilizer alleviated the adverse effects of salinity on sunflower photosynthesis and growth to some extent. During some key growth periods, such as the seedling and bud stages, a moderate N application rate(135 kg ha-1) resulted in the maximum photosynthetic rate and yielded the maximum dry matter. We suggest a moderate N application rate(135 kg ha-1) for the Hetao Irrigation District and other sunflower-growing areas with similar ecological conditions.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.30390082 and 3027079)the Science and Technology Committee of Jiangsu Province,China(No.BE2005369).
文摘Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.
基金supported by JSPS KAKENHI Grant No.24710206,Grant-in-Aid for Young Scientists (B)
文摘This paper presents debris-flow numerical simulations using the Hyper KANAKO system,developed by the authors.The system uses the debris flow simulator KANAKO 2D equipped with a graphical user interface(GUI);hence,a user can easily produce appropriate landform data for simulations using standard laser profiler data,and visualize the results using a GIS.Hyper KANAKO was applied to the streams around Kiyomizu-dera in Kyoto,Japan.Kiyomizu-dera is a famous temple in Japan which is visited by numerous tourists throughout the year.We simulated a disaster scenario of debris flow caused by torrential rain.We set the hydrograph using rainfall intensity data,and set the landform data using information from the Geospatial Information Authority of Japan(GSI) and a digital elevation model(DEM).We evaluated different mesh sizes and also used a digital surface model(DSM) to consider the building heights.The simulation results showed that with small mesh size,the debris flowmoved through the roads,which seems realistic for a disaster situation.When buildings were considered,the flow direction changed,and a 1-m flow depth,which was deeper than in other cases,appeared in the flow path.This may pose a dangerous situation for evacuations.
文摘Dry season water application and conservation were studied for two years in Ado Ekiti to evaluate their effects on the performance of plantain Musa spp.. The treatments were： morning watering （MW）, evening watering （EW）, morning and evening watering （MEW）, morning watering ＋ mulch （MW ＋ ML）, evening watering ＋ mulch （EW ＋ ML）, morning and evening watering ＋ mulch （MEW ＋ ML）, mulch （ML） and Control. Height and girth increase, number of green leaves, yield and yield parameters were the highest in the MEW ＋ ML which were identical to those of Evening watering ＋ mulch and morning ＋ evening watering. The evening or morning watering with mulch was identical but showed better performance than those without mulch. The mulched plants and the control showed the least performance. It is therefore recommended that proper water conservation in plantain plantation will improve banana survival during dry season and subsequently increase yield in the study area.
文摘The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria （WIN）. And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.
文摘This paper analyzed the effect of flood and socio-economic problems on fish farming in Ibadan Metropolis, Oyo State, Nigeria. A multistage random sampling technique was used to select 80 fish farmers in the state. Both primary and secondary data were collected and analyzed using descriptive statistics to analyze the socio-economic characteristics of the fish farmers, cost and returns analysis was done to determine the profitability ratios of the fish farming in the study areas. The mean age analyzed was 45%. The result of the cost and returns analysis showed that Average Total Cost CATC） of N1, 500,517.5 was incurred, Total Revenue （TR） of N, 138,659,400 was realized and a returning Gross Margin （GM） of N was 64,885,800 by fish farmers. The major constraints encountered by fish farmers were flooding that wash away fish, deposit heavy metals such as ammonia （NH4）, lead, copper, cadmium, arsenic, etc., that can result to the death of fish in the fishponds and rivers when flood overflowing. The methodology applied for the flood examination includes site visits, interviews of affected fish farmers, and analyses of flood data collected during the field examination.
基金Supported by the National Natural Science Foundation of China(Nos.51279142 and 51379151)the Fundamental Research Fund for the Central Universities,China(No.204206020201)
文摘Understanding the interactions between salinity and fertilizers is of significant importance for enhancing crop yield and fertilizeruse efficiency. In this study a complete block design experiment was performed in the Hetao Irrigation District of Inner Mongolia,China, to evaluate the effects of interactions between soil salinity and nitrogen(N) application rate on sunflower photosynthesis and growth and to determine the optimum N application rate for sunflower growth in the district. Four levels of soil salinity expressed as electrical conductivity(0.33–0.60, 0.60–1.22, 1.2–2.44, and 2.44–3.95 dS m-1) and three application rates of N fertilization(90, 135,and 180 kg ha-1) were applied to 36 micro-plots. Soil salinity inhibited the photosynthetic rate, stomatal conductance, transpiration rate, plant height, leaf area, and aboveground dry matter of sunflowers. The intercellular CO2 concentration first decreased and then increased with increasing soil salinity in the seedling stage, and the instantaneous leaf water-use efficiency fluctuated with soil salinity. The stomatal and non-stomatal limitations of sunflowers alternated in the seedling stage; however, in the bud, blooming,and mature stages, the stomatal limitation was prevalent when the salinity level was lower than 2.44 dS m-1, whereas the nonstomatal limitation was predominant above the salinity level. The application of N fertilizer alleviated the adverse effects of salinity on sunflower photosynthesis and growth to some extent. During some key growth periods, such as the seedling and bud stages, a moderate N application rate(135 kg ha-1) resulted in the maximum photosynthetic rate and yielded the maximum dry matter. We suggest a moderate N application rate(135 kg ha-1) for the Hetao Irrigation District and other sunflower-growing areas with similar ecological conditions.
