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101.
姜德文 《中国水土保持科学》2006,4(5):103-106
科学发展观是我们统领发展的指导思想。国家提出加快建设资源节约型社会和环境友好型社会的目标,开发建设项目水土保持方案的审批应成为转变经济增长方式、实现社会转型的重要手段。在新形势和新的历史发展时期,应根据国家“十一五”规划纲要确定的产业发展政策、区域主体功能定位,从注重单个项目水土流失防治技术的战术层面向注重流域或区域的资源环境保护的战略层面转变,针对不同情况给予审批、暂缓审批或不予审批,发挥水土保持调节经济发展的作用。水行政主管部门要加强水土保持方案的技术评估机构建设,强化水土保持监测工作,为国家掌握水土资源、生态环境、水土流失动态变化,调整经济发展政策,提供技术支撑和科学依据。 相似文献
102.
黄泛区潮土-冬小麦系统中尿素的转化和化肥氮去向 总被引:24,自引:5,他引:24
在田间条件下,用~(15)N标记的微区试验法研究了潮土-冬小麦系统中尿素的转化和化肥氮的去向。结果表明:土壤中尿素水解后,主要进行硝化和生物固定,而被粘土矿物固定的量很少;小麦返青后,随着气温上升,生物固定的标记氮不断分解,其量可达总生物固定量的60%。作为基肥条施的尿素,其损失略高于作返青肥或拔节肥表施后随即灌水的处理。氮素损失主要发生在春季气温回升后的生长期间,当季的淋洗损失极微。在较为适宜的用量和施用技术下,化肥氮的损失仍达33—45%,其中以碳酸氢铵为最高,次为硫酸铵和硝酸铵,而尿素和硝酸铵中的硝态氮损失最低。 相似文献
103.
The mechanism of atmospheric,surface and soil water interactions( water transformation) in hillslope under natural conditions was analyzed,and a dynamic model was developed to simulate infiltration,overland flow and soil water movement during natural rainfall in hillslope,by bringing froward concepts such as rainfall intensity on slope and a correction coefficient of saturated soil water content for soil surface seal.Some factors,including slope angle,slope orientation and raindrop inclination,which affect the rainfall amount on slope, were taken into account while developing the dynamic model.The effect of surface seal on infiltration and water balance under a boundary condition of the second kind was aslo considered. Application of the model in a field experiment showed that the model simulated precisely the infiltration,overland flow and sol water monvement in hillsope under natural rainfall conditions. 相似文献
104.
A neutral and an acidic soil were treated with different doses (0–3,000 mg Cu kg–1 soil as CuSO4) of copper. The percentages of inhibition of nitrification in both soils varied from 5 to 97%, but for the N mineralization
these percentages varied from 8 to 65%. The toxic effect of Cu for basal nitrification and N mineralization was assessed as
critical. Nitrification was more sensitive than ammonification to copper toxicity. It appears that an ecological dose of inhibition
for nitrification and N mineralization higher than 10% is suitable as an indicator for Cu contamination. Soil resiliency assessed
by N mineralization in the lime treatments varied from 11 to 154% in the sandy soil and from 70 to 168% in the sandy loam
soil. A combined application of lime and compost significantly increased soil resiliency. The percentage increase varied from
904 to 1,390% in the sandy soil and from 767 to 2,230% in the sandy loam soil. It appears that compost was a powerful agent
for recovering the soil fertility of Cu-contaminated soils as assessed by N transformation. The acidic sandy soil showed a
lower capacity for recovery after Cu toxicity stress.
Received: 27 February 1999 相似文献
105.
板栗疫病菌一低毒病毒系统.是一个优良的研究植物病原真菌致病和病毒一宿主相互作用分子机制的模型。随着研究的深入,原有的苯菌灵和潮霉素两个遗传转化筛选标记已不能满足研究需要。文章报道构建一个由构巢曲trpC启动子驱动的G418抗性Neo基因盒,并成功应用于板栗疫病菌的遗传转化研究。 相似文献
106.
水分淋洗下菜园土壤各形态锌的迁移转化特征 总被引:3,自引:1,他引:3
采用室内模拟降雨淋溶土柱的方法,研究了经过1年降雨的淋溶后,菜园土壤垂直方向上各形态锌的迁移转化规律。结果表明:锌的大多数形态很难随水分运动发生迁移,~年的降雨至多能使占总量0.57%的水溶态锌发生淋溶损失。水分淋洗和施磷锌平均能使分别占总量3%和4%的难溶态RES—Zn和OX-Zn向易被植物利用的EX—Zn、CABS—Zn和OM—Zn形态转化。随施锌量的增加,土壤锌的有效性指数增加30%~78%.有效锌总量增加3.12~10.07mg/kg。当施磷50mg/kg时,土壤Zn的有效性指数增加3%~28%,有效锌总量增加0.04~0.28mg/kg,磷锌在土壤中表现为协同作用。 相似文献
107.
通过柱花草Stylosanthes guianensis转化过程中预培养时间、农杆菌Agrobacterium侵染浓度、乙酰丁香酮、植物组织浸提液、脯氨酸、硝酸银和农杆菌浸入法对农杆菌、外植体及共培养基的处理,研究了提高柱花草基因转化率的方法.试验结果:用预培养2 d处理外植体,10 μmol/L乙酰丁香酮和稀释5倍的番木瓜Carica papaya浸提液预处理农杆菌,1.5 mg/L的脯氨酸处理共培养基及采用农杆菌浸入法侵染外植体可以明显地提高柱花草的转化率;对农杆菌进行稀释,用柱花草浸提液预处理农杆菌及硝酸银处理共培养基对转化率无明显的影响.用SAS软件进行2×2的卡平方(x2)检验在最佳条件下的遗传转化表明:子叶和真叶的出芽率与对照相比差异都达到极显著. 相似文献
108.
109.
Although water and energy resources are well-recognized concerns regarding economic and social development sustainability, little specific research has focused on both water and energy problems at the same time. This study analyzed the water and electricity-use patterns in Shenzhen, South China during 2001-2009. A curve regression method was used to examine the relationship between water and electricity use per gross domestic product (GDP) in Shenzhen and its three sectors, i.e., agriculture, industry & construction, and residential life & services. Results showed that agriculture only covered less than 10% of water and electricity use in Shenzhen, while industry & construction and residential life & services accounted for more than 90% of water and electricity use in Shenzhen, which coincided with the city’s industrial structure. The water and electricity use per GDP in agriculture was the biggest among three sectors in Shenzhen during 2001-2009, which means inefficiency of water and electricity use in agriculture. Due to transitioning to advanced materials and manufacturing, both water and electricity use per GDP in industry & construction decreased during 2001-2009 and their utilization efficiencies gradually increased over time. The same held true for those in residential life & services transformed toward modern business, creative culture, finance services, etc. Derived from the survival of the fittest in competing for limited water and electricity resources, agriculture in Shenzhen has been gradually substituted by industry & construction and residential life & services, with much higher efficiencies of water and electricity use. And traditional agriculture will not be sustainable in the process of urbanization and industrialization, except high-tech intensive agriculture with low water and energy cost. Furthermore, by means of curve regression, we found that there was a significant quadratic relationship between water use per GDP and electricity use per GDP in the entire city and its three sectors. Suitable industrial transformation and advancement was a very effective way to save water and energy for modern cities. This can provide some reference for systematic planning and design of water and electricity allocation and use in agriculture, industry & construction and residential life & services in a city. 相似文献
110.
Transformation of Upland Cotton (Gossypium hirsutum L.) with gfp Gene as a Visual Marker 总被引:1,自引:0,他引:1
The green-fluorescent protein (gfp) gene was evaluated as a screening marker during cotton (Gossypium hirsutum L.) transforming and plant regeneration.High expression of GFP (green-fluorescent protein)... 相似文献