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nutrient input and output
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  “nutrient input and output”译为未确定词的双语例句
     A Study on Nutrient Input and Output in Rice-wheat Rotation System in Huaian City, Jinagsu Province
     淮安稻麦生产养分投入与产出及其相互关系的研究
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  相似匹配句对
     Application of nutrient input-output relationships
     养分投入——产出关系的应用
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     The nutrient input was in order of N>Ca>K>Mg>Na>P.
     各养分归还量的大小依次为N >Ca>K >Mg >Na >P .
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     Forest nutrient input from rainfall in southern Sichuan
     川南地区森林养分输入量与大气降水的关系
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     Interlanguage and Input
     “过渡语”与输入
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     Changes of soil nutrient contents and input of nutrients in arable of China
     我国耕地土壤养分变化与肥料投入状况
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  nutrient input and output
Continuous study of watershed ecosystem processes regulating nutrient input and output budgets began in 1982.
      


The simulation model described in the first part of this paper is extrapolated into the whole study area in combination with the water balance data. Total nutrient input and output can be calculated from the model. Validation against field data indicated that the preliminary model is robust enough to simulate the nutrient distribution in the system (correlation coefficiency R TN = 0.717; R SRP = 0.821, higher than the significant value 0.708). But the process model used for the reed field...

The simulation model described in the first part of this paper is extrapolated into the whole study area in combination with the water balance data. Total nutrient input and output can be calculated from the model. Validation against field data indicated that the preliminary model is robust enough to simulate the nutrient distribution in the system (correlation coefficiency R TN = 0.717; R SRP = 0.821, higher than the significant value 0.708). But the process model used for the reed field is much too simple compared to the model used for the canal system. A more sophisticated linear regression model based on Mander and Mauring's work (1994) was finally adopted for the reed system. NitrogenY = -0.005 + 0.61X R 2 = 0.84, n= 41PhosphorousY = -0.013 + 0.85X R 2 = 0.98, n= 35Where Y is retention and X is load, both in g/m 2·d for N and mg/m 2·d for P. Compared to the field data based model, Mander-&-Mauring's model is less accurate in predicting the nutrient reduction at specific points, but good enough for estimating the total removal by the reed-canal system. It is also more general and can be easily adopted for other wetlands with similar situations. Moreover, it avoids the water data, which used to be a big pitfall in the former field data based model. According to the simulation results, about 3200~4000t of TN (total nitrogen), and 80 tons of SRP (soluble reactive phosphorous) can be removed by the 80,000 hm\+2 reed-canal system during the irrigation period in 1998. But the reduction capacity is 10 times higher than this value, according to the simulation based on the highest input concentration at the pumping station. Therefore, there is a great potential for the wetlands to remove nutrients. The limitation factor in the Liaohe delta is water, not the wetland's ability to remove nutrients.The simulation model also indicated a “mutual compensation” for the nutrient reduction in the reed system and canal system, so that the total reduction rate remains relatively stable in spite of the input concentration change at the pumping station. It is 66% for total nitrogen and 90% for soluble reactive phosphorus, respectively. There was no big change between the nutrient removal in 1988 and 1998, provided that the input water and nutrient load at the pumping station is the same. The main reason is that the total reed area did not change so much during the 10 years, though the area of each small irrigation plot changed differently. According to the estimated nutrient balance between input from irrigation water and output from reed cutting, the input is far lower than the output annually. Therefore, accumulation problem can be ignored from this irrigation system. The extensive reed marsh can be used for nutrient removal before the polluted water running directly into the sea. Thus eutrophication problem can be avoided to a large extent.

对以实验数据为基础建立的初步空间模型进行了验证 ,并用 Maunder和 Mauring的线性回归模型对苇田子模型进行了修正。模拟结果显示 ,辽河三角洲 8万 hm2 苇田每年灌期大约可以去除 32 0 0~ 4 0 0 0 t总氮和 80 t的活性磷 ,但这仅相当于其潜力的 1 /1 0。因此 ,运用河口湿地作为富含营养物质河水入海前的最后过滤屏障 ,对于防止近海水体的富营养化具有重要意义。

Based upon the concepts of ASSOD for soil degradation, the reality of China and some references, the paper presents the dynamic changes of different kinds of soil degradation in China while discussing the characteristics of the soil degradation, the problem and prospect of the related research in China. One sixth of Chinese national land is more or less eroded that is mainly distributed in the Yellow River drainage area, south China hilly area and northeast China. Land uses in some wrong ways and moveable dunes...

Based upon the concepts of ASSOD for soil degradation, the reality of China and some references, the paper presents the dynamic changes of different kinds of soil degradation in China while discussing the characteristics of the soil degradation, the problem and prospect of the related research in China. One sixth of Chinese national land is more or less eroded that is mainly distributed in the Yellow River drainage area, south China hilly area and northeast China. Land uses in some wrong ways and moveable dunes result in the desertification in north and northwest China especially the interlaced belt between agricultural and stock raising farms. Soil salinization resulted from irrigation is mainly located in the Huanghuaihai plain, west part of northeast China plain and northwest inland China. Almost all cultivated soils nationwide in China are declining in their fertility because of the bad balance between nutrient input and output. Soil gleyization can be found mainly in northeast China and Aba region in Sichuan province resulted from processes including freezing and thawing, surface waterlogging. Soil pollution and non-agricultural use of the soils are two problems caused by the quickly grown industrialization and urbanization in China.

根据ASSOD人为诱导下土壤退化的概念,结合中国的实际情况,分析了中国土壤侵蚀、荒漠化、盐碱化、贫瘠化、潜育化、土壤污染和土壤生产力丧失等主要土壤退化类型的动态变化,概括了中国人为诱导下土壤退化的特点及研究前景。到目前为止,中国土壤侵蚀的总面积约占全国土地面积的六分之一,主要分布在黄河流域、南方红色土壤丘陵地区和东北地区;土壤荒漠化主要分布在北部和西北部,特别是农牧交错地带,其原因主要包括不当的土地利用方式和沙丘移动占据农地或牧场而使之丧失生产功能;土壤盐碱化主要分布在黄淮海平原、东北平原西部、黄河河套地区、西北内陆地区,其原因主要是由于人为灌溉造成的土壤次生盐碱化所致;由于过度垦殖,土壤因有机质匮乏而导致养分失衡;土壤养分长期的低投入、高支出造成全国范围土壤肥力的下降;土壤潜育化主要分布在东北和四川阿坝地区,冻融造成土壤表层滞水是其主要成因;随着化学农业和城市化对农田的影响,土壤中的有毒物质不断积累,土壤大量被用于非农业,土壤性状、环境发生了显著变化,也对人类健康构成了严重的威胁。

The effects of grazing on physical properties (bulk density, water infiltration), chemical properties (soil organic matter, nitrogen) and soil microbes of grassland soils were reviewed based on published literature. The effects of grazing on soil properties were inconsistent, because of the complexity of the soil system, time lag after disturbance and resilience of soil system to perturbation. In general, because of the impact of animal trampling, there are changes in soil pore size distribution as well as total...

The effects of grazing on physical properties (bulk density, water infiltration), chemical properties (soil organic matter, nitrogen) and soil microbes of grassland soils were reviewed based on published literature. The effects of grazing on soil properties were inconsistent, because of the complexity of the soil system, time lag after disturbance and resilience of soil system to perturbation. In general, because of the impact of animal trampling, there are changes in soil pore size distribution as well as total porosity with increasing stocking rate. The decrease in macropores (>50μm) and larger mesopores (9~50μm) could lead to higher bulk density, greater penetration resistance and a decreased soil water holding capacity. However, bulk density may decrease in sandy soil with lower organic matter content, because overgrazing causes soil organic matter to decrease, influences the stability of soil aggregates and results in collapsed soil structure. There exists a complex interaction between grazing and soil organic matter. Many factors determine the response of soil organic matter to livestock grazing. These factors include the initial conditions of vegetation and soil, environmental factors, especially moisture and temperature, and grazing history (intensity, frequency, duration, and type of animal). Soils with inherently low soil organic matter are more prone to change in response to grazing than soils high in organic matter. Microbial biomass is the most labile C and N pool in soil and can be used as a rapid and sensitive indicator of change in the soil management system. Grazing at high stocking rates may have opposing effects on soil fertility depending on the time-scale considered. In the short term, benefits may occur because of increased nutrient cycling efficiency. But, in the long term, overgrazing without management may cause a decline in soil fertility due to imbalanced nutrient input and output, which finally leads to the degradation of grassland, especially in the more fragile arid and semi-arid regions.

介绍了放牧对草原土壤物理性质 (容重、渗透率 )、化学性质 (有机质、N素 )和微生物的影响。由于草原土壤系统本身的复杂性、滞后性和弹性 ,放牧对土壤性质的影响不尽相同。一般而言 ,随放牧强度的增大 ,动物践踏作用的增强 ,土壤孔隙分布的空间格局发生变化 ,土壤的总孔隙减少 ,特别是大孔隙 (>5 0μm)和较大中等孔隙 (9~ 5 0μm)减少 ,使土壤容重增加 ,土壤的渗透阻力加大 ,土壤的保水和持水能力下降。但在有机质含量很低的沙质土壤中 ,超载过牧 ,造成有机质含量降低 ,土壤的团粒结构减少 ,稳定性团聚体减少 ,土壤结构遭到破坏 ,使得土壤容重反而降低。土壤有机质和放牧之间存在复杂的相互关系 ,土壤有机质对放牧的响应受多种因素的影响 ,这些因素包括植被和土壤的初始状况 ;环境因素 ,特别是水分和温度 ;放牧历史 (强度、频率、持续时间和动物类型 )。同时 ,土壤有机质含量低的土壤比含量高的土壤更易受放牧的影响 ,而使有机质发生变化。土壤微生物量碳是最具活性的土壤碳库 ,对环境的变化敏感 ,能较早地指示生态系统功能的变化。当考虑时间尺度时 ,高强度放牧对土壤肥力有负面的影响 ,短期内 ,由于加速了养分...

介绍了放牧对草原土壤物理性质 (容重、渗透率 )、化学性质 (有机质、N素 )和微生物的影响。由于草原土壤系统本身的复杂性、滞后性和弹性 ,放牧对土壤性质的影响不尽相同。一般而言 ,随放牧强度的增大 ,动物践踏作用的增强 ,土壤孔隙分布的空间格局发生变化 ,土壤的总孔隙减少 ,特别是大孔隙 (>5 0μm)和较大中等孔隙 (9~ 5 0μm)减少 ,使土壤容重增加 ,土壤的渗透阻力加大 ,土壤的保水和持水能力下降。但在有机质含量很低的沙质土壤中 ,超载过牧 ,造成有机质含量降低 ,土壤的团粒结构减少 ,稳定性团聚体减少 ,土壤结构遭到破坏 ,使得土壤容重反而降低。土壤有机质和放牧之间存在复杂的相互关系 ,土壤有机质对放牧的响应受多种因素的影响 ,这些因素包括植被和土壤的初始状况 ;环境因素 ,特别是水分和温度 ;放牧历史 (强度、频率、持续时间和动物类型 )。同时 ,土壤有机质含量低的土壤比含量高的土壤更易受放牧的影响 ,而使有机质发生变化。土壤微生物量碳是最具活性的土壤碳库 ,对环境的变化敏感 ,能较早地指示生态系统功能的变化。当考虑时间尺度时 ,高强度放牧对土壤肥力有负面的影响 ,短期内 ,由于加速了养分的循环效率 ,产生有利的影响 ,但长期无管理的超载放牧必然造成系统物质 (资源 )输入和输?

 
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