Effect of irrigation and nitrogen fertilizer on yield,oil content,nitrogen accumulation and water use of canola (Brassica napus L.)

Effects of N application and water supply on yield, oil content and N accumulation by canola, cultivar Marnoo, grown on a heavy clay soil in the Goulburn Murray Irrigation Region were investigated. Treatments were rainfed (R_f) or watered at a deficit of 50 mm (40–60 mm, I₅₀) beginning in the spring. N treatments were 0, 50, 100 or 200 kg N ha^–1 at sowing or as split applications of 20/80, and 50/50 kg N ha^–1 at sowing and rosette, respectively.Yield (Y_g) ranged from 170 to 520 g m^–2. Irrigation and N increased yield in both years. Grain yields were increased by N application on the irrigated treatments when 100 or 200 kg N ha^–1 was applied. Oil concentrations ranged from a maximum of 46.4% in treatment N₀ to a minimum of 40.6% in treatment N₂₀₀ and was inversely related to seed N concentration. Although fertilizer N decreased oil concentration, it increased the yield of oil.Nitrogen accumulation (N_b) limited yield of all treatments and was described by the equation, Y_g = 806[1-EXP(–0.039*N_b)]. This implied a decrease in yield per unit of N_b at the higher rates of fertilizer addition with consequent increases in grain N concentration.The efficiency of water use in the production of grain (WUE_g) and biomass (WUE_b) were 7.5 and 23 kg ha^–1 mm^–1 respectively. Nitrogen additions increased WUE_g and WUE_b in both seasons. Maximum values of 8.9 (WUE_g 1986) and 26.8 (WUE_b 1987) were measured from treatment N₂₀₀. These data suggest that the crops made efficient use of the applied water.     

Calculating soil nutrient balances in Africa at different scales

Nutrient balances were calculated for the arable soils of 38 sub-Saharan African countries. FAO production figures and forecasts for 35 crops for the period 1982–1984 and for 2000 were used to define land use systems, further characterized by fertility input through fertilizers, manure, rain and dust, biological N-fixation, and sedimentation, and fertility output through harvest of crops and removal of residues, leaching, denitrification, and erosion. The summarized output of the study is the sum of inputs minus the sum of outputs of nitrogen, phosphorus and potassium in the root zone. The alarming annual average nutrient loss for sub-Saharan Africa was 22 kg N, 2.5 kg P, and 15 kg K in 1982–84, and will be 26 kg N, 3 kg P, and 19 kg K in 2000. As the soil nutrient pool has to offset the negative balances each year, there is gross nutrient mining in sub-Saharan Africa. The need for integrated systems of nutrient management is emphasized, manipulating all inputs and outputs in a judicious way. Future scenarios of continued mining and conservation of soil fertility are discussed.     

珠江口门海堤堤型的选择

珠江口站地区面临南海、大陆岸线长４５７ｋｍ，遭受洪水。潮汐、台风的影响，河口滩涂 发育迅速，以约１００ｍ／ａ的速度向大海延伸。随着沿海地区的经济发展，滨海－２ｍ高程以上的滩涂的４万ｈｍ＾２正在和将要建堤围垦和开发利用，原有海堤也亟待加固提高，因此，对珠江口门坝有海堤堤型资料进行收集、整理，分析总结，选择经济可行的海堤堤型，具有重要的现实意义。文中收集了珠江口门的几种主要堤型，通过对各种堤基工程地质     

龙滩水电站工程融资和资金使用管理

龙滩水电站工程80％的建设资金来源于银行贷款,融资费用较高。因此,必须优化债务结构,减少利息支出;加速资金周转,提高资金使用效率;严格工程投资控制制度和工程预算管理制度;加强资金使用管理,以控制和降低工程造价。     

The water–energy nexus: energy use for water supply in China

China’s strategy to meet increasing water demand is to increase the use of inter-basin transfer water and unconventional water. This study evaluates the energy requirements of this strategy by disaggregating and quantifying the regional energy use for water supply in 2020 and 2030; the energy use in 2014 is calculated to represent the present situation. We find that the energy use for water supply in 2014 amounted to 81 billion kWh. This value is expected increase to 90 and 109 billion kWh by 2020 and 2030, respectively. In 2030, the urban domestic sector will overtake the agricultural sector as the most energy-intensive sector, with major contribution from inter-basin transfer water.     

论南昌市城区植物造景

通过对南昌城市绿化方面的现状和条件分析,在城市绿地系统的规划布局、植物配置、植物选用等方面进行论述,并提出了一系列措施和实施办法．     

巴彦县土地质量肥力评价

以巴彦县为研究区域,在研究区内安以4 km2标准格网均匀布点,并采集土壤样本,对表层土壤进行土地质量肥力评价。土壤肥力综合评价结果显示,巴彦县土壤肥力综合质量评价值分布的空间格局较弱,趋势不明显,质量中等区域占了较大比重,尽管质量中等区域零散地分布在各处,但是造成每个区域质量水平地下的原因不尽相同。综合了土壤中As、Cd、Hg元素含量与分布的土壤有害元素的土壤环境质量分布图显示,土壤环境质量存在较为明显的趋势,即西部相对质量较高,中部和东部较大范围内土壤环境质量水平相对较低。     

The Yellow River Basin: Water Accounting,Water Accounts,and Current Issues

Abstract

There is increasing recognition of the problems facing China in meeting the growing water demand in the Yellow River basin, the “cradle of Chinese Civilization” and a critically important agricultural and industrial region. Meaningful debate on the range and relative costs of options available to policy-makers in addressing the problem depend fundamentally on an accurate understanding of basin water resources. Unfortunately, the ability of outsiders to participate in the de bate and for Chinese, with their long history of water management, to contribute to similar discussions elsewhere in the world is hindered to some extent by a lack of understanding of differences in water accounting systems and concepts. This paper attempts to address this problem by describing the water accounting system used in the Yellow River basin and elsewhere in China. The paper shows that the primary difference between water accounting methodologies in the Yellow River and those typically applied elsewhere is related to supply accounting in general and groundwater accounting in particular. Although not currently included in its water accounting system, Chinese concepts of environmental water use, when included, will also differ substantially from those familiar to outside researchers. In terms of actual Yellow River balances, the paper highlights the apparent declining trend in basin rainfall and runoff and the dramatic growth in industrial and domestic water use. Together declining supply and rising demand will increasingly cause policy-makers to face hard choices in assessing their water planning options. These choices will only become more difficult as managers in the Yellow River, as elsewhere in the world, try to incorporate ecological needs in the water accounting equation.     

黄河三角洲河口地区土地利用及生态环境景观分析

通过人机交互解译1996年和2004年TM影像得到2期土地利用数据,求得到土地利用转移矩阵和各种生态环境景观指数。通过分析两期土地利用及景观结构指数之间的差异性,指出由自然和人为原因引起的生态环境的变化:研究区总面积有所减少,盐碱地改良后用于了鱼虾养殖,部分未利用地和水域盐碱化,区域景观类型丰富且均匀,局部破碎严重。     

张家口市工业用水特征与节水效益分析

通过对张家口市工业用水特征和用水效益分析,利用张家口市2001~2013年用水资料和国民经济统计资料,采用数理统计法,对工业用水结构、用水效益和用水指标进行分析计算。