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141.
The OECD has introduced a water pricing mechanism and listed eight categories gleaned from experience in OECD countries. However, in the Asian humid tropics, it is too early to apply water pricing because there is seldom a concept of water right, or practical organization of water management. In almost all irrigation projects in Japan, area charge has been applied, and collected fees have recovered entire operation and maintenance costs. Although effective volumetric charge is employed in several regions in Japan, most farmers pay area-based annual charges at several times of the year via Land Improvement Districts. In the Asian humid tropics, it is important to facilitate the establishment of sound management organizations of irrigation water before introducing a strict water pricing mechanism to levy the charge. 相似文献
142.
中原油田耕地污染分析 总被引:2,自引:0,他引:2
通过对中原油田污染耕地的现场调查和几种污染因素的比较,发现油田高矿化度产出水腐蚀穿孔是造成弃耕地土壤污染的主要原因。污染土壤含盐量为7.07g·kg-1、可溶性Na+和Cl-为9.39和11.56cmol·kg-1,是未污染土壤的6.0、7.8和18.1倍。由于土壤盐分和可溶性Na+含量高,造成了土壤板结、紧实,使土壤生态环境退化和恶化。 相似文献
143.
本文根据二次正交旋转组合设计的特点和局部控制理论,提出了中心点数据处理法。此法是先求出各区组的矫正系数,即各区组中心点总平均值与本区组中心点平均值之比,然后将小区原始数据分别乘本区组的矫正系数。用此法排除非试验因子干扰的效果明显地优于飘移处理法,不仅计算简单,而且有拟合程度高、便于模拟选优的优点。 相似文献
144.
滇中亚热带山地主要森林群落取样的最小面积:常绿阔叶林 400m~2(20×20m)~361m~2(19×19m);云南松林 324m~2(18×18m);华山松林 289m~2(17×17m)~324m~2(18×18m);滇油衫林 289m~2(17×17m)~324m~2(18×18m)。采用400m~2(20×20m)的样方面积可满足该地区一切森林群落取样的需要。 相似文献
145.
The distributions of free oxides along profiles of some dry rice fields were set forth in the previous reports2,3,4,6), In this paper, the distribution of free oxides in dry rice field5) in polder lands of Kojima-Basin, Okayama pref. is reported. Localities, years elapsed since the planting of rice began in each field and the characteristic of soil profiles are given in Table 1. All the fields are dry rice fields except Soil A, and carry barley or wheat in winter season. Parent materials are similar in all horizons of all soils and rich in fine particles. Fine sands (0.2-0.02 mm) are mainly composed of quartz somewhat accompanied with feldspars, mica, augite and amphibolite. Clays (< 0.002 mm) are mainly composed of halloysite accompanied with a small proportion of montmorillonite. The structure develops well in all the soils. 相似文献
146.
Parthenium hysterophorus is a weed of global significance causing severe economic, environmental, human and animal health problems in Asia, Africa, Australia and the Pacific. In South Asia, P. hysterophorus occurs in India, Pakistan, Sri Lanka, Bangladesh and Nepal. A host-specific leaf-feeding beetle Zygogramma bicolorata from México was introduced into India in 1984, as a biological control agent for P. hysterophorus . In this study, a GIS-based distribution map of P. hysterophorus and its biological control agent Z. bicolorata in South Asia based on meta-analysis is presented. The map highlights the limited published information on P. hysterophorus incidence in many of the states and territories in India, as well as in neighbouring Bangladesh, Bhutan, Nepal and Pakistan. Incidence of Z. bicolorata was recorded as three distinct clusters, covering many states in India. In Pakistan, Z. bicolorata was recorded in the Punjab region bordering India. A CLIMEX model based on the current distribution of Z. bicolorata in India suggests that the geographic range of this agent in India and Pakistan can extend to other P. hysterophorus -infested areas in the region. The CLIMEX model also suggests that all of Bangladesh and Sri Lanka, and parts of Nepal are climatically suitable for Z. bicolorata. 相似文献
147.
Experiments were conducted to evaluate the effects of light, seed burial depth, and flooding on germination, emergence and growth of Ludwigia hyssopifolia. Germination was strongly stimulated by light, suggesting that seeds of this species are positively photoblastic. Seeds sown on the soil surface gave the greatest percentage of seedling emergence in plastic trays, and no seedlings emerged from seeds buried in soil at depths of ≥1 cm. Intermittent or shallow flooding suppressed emergence and growth of L. hyssopifolia. Flooding to a depth of 2 cm for 4 days out of 7 days reduced seedling emergence by more than 71% and seedling dry matter by 97% compared to where the soil had not been flooded. Flooding up to a depth of 10 cm however, when delayed to 21 days after sowing, did not significantly suppress growth of this species. This study illustrates the role of seed burial by tillage and flooding as two important tools for the management of L. hyssopifolia. 相似文献
148.
Katharine McKinnon 《Asia Pacific viewpoint》2008,49(3):281-293
Emerging post‐development literatures consider how post‐structural and post‐colonial critiques of development could form the basis for new kinds of development practices. Much of the search for such post‐development possibilities draws on new theories of discourse. This paper considers the challenges of bringing together empirical research and the experience of doing development with the often ethereal and deeply speculative work of discourse theorists. I reflect on the course taken by my own research in Northern Thailand, and discuss the possibilities that can emerge as theory confronts empirics, and conceptual frameworks are transformed through the daily politics of fieldwork. 相似文献
149.
Qi Jing Bas Bouman Herman van Keulen Huib Hengsdijk Weixing Cao Tingbo Dai 《Agricultural Systems》2008
Rice yield is the result of the interaction between genotype (cultivar characteristics), environment (climate and soil conditions), and management. Few studies have attempted to isolate the contribution of each of these factors. Here the rice growth model ORYZA2000 was used to analyse the variation in yield, nitrogen (N) uptake, and internal N use efficiency (INUE, grain yield per unit total crop N uptake) of rice in different environments. First, ORYZA2000 was calibrated and evaluated using an empirical data set that spanned three varieties, three years, and eight locations in Asia. Next, we used the model to investigate the relative contribution of indigenous soil N and external N supply and of the weather factors temperature and radiation to observed variation in yield. 相似文献
150.
Gundolf Kohlmaier Luita Kohlmaier Elke Fries Wolfgang Jaeschke 《European Journal of Forest Research》2008,127(2):133-147
With the analytical tool, Frankfurt Harvested Wood Products Model, FPM, the carbon stocks and carbon stock changes of Harvested
Wood Products, HWP, either in USE or in LANDFILLS L-F, have been evaluated, each separately, from the readily available statistical
data base of the FAO, FAOSTAT, on the wood commodities: “Sawnwood and Wood-based Panels, SWP” and the paper commodities, “Paper
and Paperboard, PAP”. The focus was on the newly founded Asia-Pacific Partnership countries for Clean Development and Climate
(in short AP6), including Canada, which wants to join the AP6, in relation to the countries of the European Union EU-25. It
could be shown that the stocks and stock changes of the HWP in USE follow a simple algorithm of the annual consumption or
production and their mean annual growth, for the categories SWP and PAP, provided the mean residence times of the HWP in USE
can be estimated. With the information on the fraction of residues entering the landfills and their estimated residence times
an equivalent simple expression has been derived for stocks and stock changes of the HWP in LANDFILLS L-F. Their values have
been calculated to be approximately 0.5 to 0.7 times smaller than those of the HWP in USE. Still, all stock changes of the
HWP in L-F were positive and thus accumulating carbon. However, when methane outgasing within the HWP in L-F had been considered,
the calculated Greenhouse Gas Balance was zero or negative under the estimated parameters thus to at least partly compensate
the positive storage of carbon in HWP in USE. The percentage of CO2 removed by the HWP in USE in comparison to the annual greenhouse gas emissions varied from 0.3 to 1.7%, with a mean value
of 0.8% for the AP6 countries including Canada, in contrast to 1.0% of the EU-25 countries. Despite of the relative small
magnitude in relation to the total emission of all GHG this contribution should not be neglected in the GHG Budget of a country. 相似文献