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1.
中国新农村建设中的能源保障问题分析   总被引:9,自引:1,他引:8  
能源是社会主义新农村建设的基础条件。从中国农村能源的供求现状分析,农村能源保障存在着供应、生态和投入的危机,不加节制的用能习惯和传统的用能技术将会使农村能源需求超过中国全部可供的常规能源量,农村能源问题将成为制约农村经济与社会发展的主要因素。必须寻求可持续发展的途径。根据农村可再生资源的潜力和利用途径分析,生物质能与太阳能相结合的综合利用方式,特别是培育生物质能产业可能是解决农村能源保障问题的根本出路。  相似文献   

2.
Today, food security depends on very few major grain crops, actually an outcome of breeding success and globalization. This will not change in the near future. But action must be taken to stop the unprecedented pace of the erosion of biodiversity on arable fields; this is a prerequisite to ensure robust cropping systems as well as complementary food production for coming generations. Although this has been discussed for decades, little progress has been made. Most underutilized crops are no longer suitable for today’s agriculture. Success can be achieved only by planning long‐term breeding programmes instead of screening underutilized crops again and again. This cannot be realized, however, by market‐driven private breeders. State funding is mandatory to launch a programme of a set of well‐chosen crops. Guidelines are provided, based on case examples from cool temperate regions, where promising crops undergo stepwise selection process. In Europe, a programme could be established in the frame of a virtual institute, wisely investing a small part of the direct payments that go to farmers today, thereby safeguarding their future.  相似文献   

3.
The long-term effects of undersowing a ryegrass catch crop in cereals was analysed with the FASSET simulation model. The model was tested on a 28-year field experiment with ryegrass catch crops in spring barley. The experiment included treatments with nitrogen (N) fertiliser rates, catch crop use and timing of tillage. The modelled effects of these treatments generally agreed with observations on crop production, soil carbon, soil nitrogen and nitrate leaching. Both the observations and the simulations predicted a yield increase of 7 kg N ha−1 and an increase in nitrate leaching of 13 kg N ha−1 due to a prehistory of 24 years with continuous use of catch crops compared to a prehistory without catch crops.

A range of scenarios was constructed to evaluate the fate of the reduced nitrate leaching on crop N uptake, N leaching, gaseous emissions and change in soil organic N, and how this fate interacts with soils and climate and management. These scenarios showed that 22–30% of the reduced nitrate leaching was subsequently leached during the following decades after termination of catch crop use. Between 35 and 40% of the reduced nitrate leaching was harvested in cereals. The exact distribution depended primarily on the soil texture. The scenarios showed that effects of catch crops should be evaluated on the long-term rather than consider short-term effects only.  相似文献   


4.
中国热带作物产业发展的战略思考   总被引:2,自引:1,他引:1  
为科学、高效和可持续发展热带作物产业提供参考依据,主要分析中国热带作物产业发展概况,并与世界热带作物产业进行比较,进而探讨热带作物产业发展的思路、目标,提出发展热带作物产业的3个路径选择:(1)国内适度规模发展,做精做强,建立和完善现代热带作物产业体系;(2)实施“引进来”战略,着力提高热带作物产业的综合生产能力;(3)实施“走出去”战略,合作开发境外热带作物资源,积极开辟国际贸易市场。  相似文献   

5.
Herbicide-tolerant crops in agriculture: oilseed rape as a case study   总被引:3,自引:0,他引:3  
Oilseed rape has been modified extensively by conventional breeding for the production of varieties useful for human consumption (blended vegetable oil and margarine) and industrial processes (rubber additives and high‐temperature lubricants). Because much is now known about its genetic and biochemical composition, it has been an obvious choice for genetic modification and is now at the forefront of the commercial development of genetically modified (GM) or transgenic crops. Around the world, the increase in commercial plantings of all transgenic crops has been rapid. In 1996, 1.7 million hectares were planted, but by 1998 this figure had jumped to 27.8 million ha. The area in the year 2001 is likely to be about 50 million ha. With the possible introduction of transgenic varieties into European agriculture, it is essential that the associated farming practices employed are appropriate for their growth, both from a commercial and an environmental viewpoint. Some of the first transgenic crops are those carrying agronomic traits, e.g. herbicide tolerance transgenes. However, before full commercialization occurs, important agronomic and environmental questions need to be answered. How are these new crops to be incorporated into existing cropping practices? How will this change the current herbicide use profile for a given crop? Do herbicide‐tolerant varieties enhance or impede integrated pest management schemes? What is the likely uptake of such crops in agriculture? What are the ecological implications of their introduction? Are there effective measures to control the spread of transgenes to wild relatives? This paper addresses these questions, with special emphasis on oilseed rape production in the UK, but includes examples from other crops and countries where appropriate.  相似文献   

6.
随着测序技术的发展,主要麻类作物(黄麻、红麻、苎麻、亚麻和工业大麻)参考基因组从2011年至2020年陆续完成测序,这标志着麻类作物科学已经进入基因组时代。文章首先详细概述主要麻类作物基因组测序。其次,评述了基于基因组学的麻类作物重要应用价值基因挖掘。基于参考基因组和转录组测序,大量关于纤维发育、响应非生物胁迫的候选基因被挖掘,以促进麻类作物纤维的物种特性和“不与粮食争好地”的逆境农业。同时不同麻类作物特异性状候选基因陆续被报道,如红麻雄性不育、亚麻种子含油量和大麻大麻素相关候选基因等。再次,麻类作物基因组测序完成为基于组学的麻类作物遗传改良提供可能:有助于麻类作物种质资源形成和演化机制研究,系统解析纤维产量、纤维品质、抗病耐逆等农艺性状形成的分子基础;有助于建立高通量基因型-表型数据库,挖掘优异基因资源与创制新种质;有助于创新并集成分子标记辅助选择、基因组选择、转基因等技术,建立高效的快速育种技术体系。宜选育高产高效、抗逆抗病、适宜轻简化机械化、优质专用的多用途麻类作物新品种,以满足麻类作物相关产业的市场需求,适应麻类作物生产方式。尽管已经获得重要基因以及位点的信息,但如何高效率利用已有基因资源对麻类作物进行遗传改良仍需面临一系列挑战,如成熟稳定的遗传转化体系、麻类作物基因编辑体系构建及基因组选择育种等。  相似文献   

7.
J. Sneep 《Euphytica》1977,26(1):27-30
Summary If a breeder is to apply selection to a cross-population of a self-fertilizing crop and wishes to maximize his chances of finding a productive genotype, he will have to introduce yield tests in the F3 lines. Should he not do so because of his intention to work on many populations simultaneously, his tests would be considerably less accurate and the finding of a favourable combination more or less a matter of mere chance.Bulk breeding will result in genetic drift or numbers of plants too large to manage, or in a combination of both.Application of the Single Seed Descent for quantitative characteristics causes such a genetic drift, that the method is not to be recommended.Multiple crosses (double-crosses) to improve quantitative characteristics require populations of a size, that cannot be realized and/or selected. This type of crosses is more suited for cases in which qualitative characteristics form the breeding goals and when it is impossible to obtain the favourable combination using only two varieties.Genic recessive male sterility may be a means to raise large progenies. In the F3 it confuses the issue of yield of fruits or seeds, which is highly vulnerable in any case. In the F2 its significance for finding the proper recombinant is very low.  相似文献   

8.
农业的持续发展必须建立在土地肥力持续发展的基础上。长期单施偏施化肥和有机肥投入的减少,是造成土壤肥力下降、环境污染和农产品品质降低的重要原因。有机肥的产业化利用是解决环境污染问题,促进有机肥增施、提高农产品品质的新路子,也是农业持续发展的需要。本文提出了实施有机肥产业化的建议,以促进我国农业的持续发展。  相似文献   

9.
In this paper, 5 high-rise hotels in Xi'an were selected for research, their energy consumption data from 2015 to 2016 were collected and analyzed, their comprehensive energy consumption per unit area was compared by using the standard coal coefficient, and their energy use characteristics and influencing factors were obtained. The test analyzed various parameters of the indoor environment and evaluated the indoor environmental quality according to the specifications and standards. Starting from the perspective of energy use systems, this paper found energy consumption priorities and problems of these hotels, and proposed feasible energy conservation measures, in a view to providing a reference for energy conservation design of high-rise hotels in Xi'an.  相似文献   

10.
Summary A mathematical model was constructed to determine the theoretical effectiveness of selection under various protocols in initial trials of clonally propagated crops. Effectiveness was quantified as the proportion of top phenotypes selected that can also be expected to be the best genotypes in trial. In the absence of replication there is a non-linear increase in this proportion with increase in broad-sense heritability. The proportion of best genotypes included is reduced as the intensity of selection increases. Replication effectively raises broad-sense heritability. The resulting increases in selection effectiveness are quantified for three levels of single-plant heritability (0.1, 0.5 and 0.9) and three selection intensities (0.1, 0.01 and 0.001) using a model based on the Normal Distribution and in which it is assumed that the trial area increases in size in direct relation to the degree of replication.When the trial area is of fixed size, replication reduces the number of genotypes that can be tested and the effectiveness of selection is, therefore, calculated with regard to the initial population of genotypes which could have been tested in the absence of replication. This showed that replication has a marginal benefit only where very high selection intensities are applied to characters with very low heritabilities. In other cases, replication is not beneficial since increases in selection effectiveness fail to compensate for good genotypes left in the seed packet. This conclusion proved to be equally valid when genetic variation was non-Normally distributed. Any increase in trial area for initial selection is best employed by increasing the total number of genotypes and growing just one representative plant of each. These conclusions could be relevant in other circumstances such as the evaluation stage of the single-seed descent breeding method for sexually propagated crops.  相似文献   

11.
利用受环境因子胁迫不利于生产粮食的农田种植能源作物,不仅能保证农业的可持续发展,还可为生产生物质能源提供原料,缓解能源危机.由于能源作物中的糖分是生产生物质燃料乙醇的基础,所以本文综述了水分、盐碱、温度、NPK(氮、磷、钾)养分、种植密度、植物激素和重金属等因子对能源作物糖分积累的影响,发现干旱、盐碱、适宜低温等非生物...  相似文献   

12.
A. A. Rosielle 《Euphytica》1984,33(1):153-159
Summary Computer simulation techniques were used to compare the efficiency of bulk-yield testing with direct-line yield testing. Bulk testing was almost always more efficient than direct-line testing for a wide range of values for population parameters. The differences between the two methods were smaller when the among-bulk heritability was low, the within-bulk genetic variance was high relative to the among-bulk variance, the variance of the within-bulk genetic variance was high, and the correlation between bulk means and within-bulk genetic variances was highly negative.With the direct-line testing method, discarding lines with low means after the first year of testing was always more efficient than retaining all lines for 2 years. Selection of 25% of the lines was slightly more efficient than selection of 50%. In general, it was better to evaluate more crosses and less lines per cross with the direct-line testing procedure.  相似文献   

13.
K. Yonezawa  H. Yamagata 《Euphytica》1978,27(1):113-116
Summary The number and size of crosses in a breeding programme were discussed to the conclusion that the number of crosses rather than the size of a cross should be increased with a given total population size. The advantage due to this manipulation, however, is relatively small when such genotypes as improved for many (twenty-five or more) loci are to be obtained, or when a high proportion (around 0.1 or more) of available combinations have the potentiality of releasing the objective genotypes. In such a case, the ease with which crossing and cultivation can be carried out becomes the decisive factor.  相似文献   

14.
Experimental results showing cooperation–competition interactions in dual-component crops for mixtures created from Pisum sativum L. (pea), Vicia sativa L. (spring vetch) and Linum usitatisimum L. (linseed) are studied by means of a mathematical model describing the plant interactions. The model introduces parameters enabling to distinguish competition and cooperation between the species in the crop. The model parameters are established on the basis of the entire vegetation period of plants, so they provide exhaustive characteristics of the plant interactions in the mixtures. The model factors allow the estimation of the mixtures with respect to the final biomass yield as well. The experimental data verify possible economic benefits from the proposed plant mixtures and allow to critically check the beliefs that legumes improve the field productivity. Additionally, for comparison with the biomass yield, the seed yield is analyzed in the respective crops. Especially, it is indicated that the increased biomass yield for linseed in the mixture with a leguminous plant is accompanied with a decrease of the seed yield for this species. As concerns pea in the mixture with linseed, a decrease in the pea biomass was registered when compared to the sole crop but at the same time an increase in the seed yield was achieved in the mixture. No influence on the biomass of the spring vetch was noticed when it was cultivated with linseed but its seed yield appeared to be diminished with respect to the sole crop.  相似文献   

15.
The flow of people changes very greatly in the public areas of public buildings, so the energy demand should also change with the flow of people. However, under the traditional model, the pedestrian flow is rarely considered when accounting energy output, which causes some of the energy invalid. How to assess the energy efficiency to reduce energy waste is an emergent problem to be solved for building energy conservation. The concept of energy utilization efficiency is put forward to judge the degree of utilization of energy, and the formula for calculating energy utilization efficiency is also provided. In a hospital public waiting area, a lot of experiments have been carried out. By comparing the energy consumption before and after the experiments, it is found that energy utilization efficiency can assess the effectiveness of energy. And to improve the energy efficiency of buildings greatly in public areas can be realized by promoting the energy utilization efficiency.  相似文献   

16.
分子标记技术在农作物品种鉴定上的研究进展及未来展望   总被引:1,自引:1,他引:0  
概述了以AFLP、ISSR、SRAP以及SSR 等4 种主要的分子标记技术在农作物品种鉴定上的研究进展,提出了SSR将是未来利用分子标记技术鉴定品种纯度以及品种DUS测试的首选分子标记技术。同时介绍了在快速鉴定品种纯度上的研究进展,并预测未来利用互联网技术将分子标记指纹图谱和农作物品种形态学特征相结合实现品种快速检索、不同品种之间数字指纹比对以及比对信息快速输出以实现品种的快速鉴定,实现在农作物任何生长期均可达到快速鉴定品种纯度和真实性的目的,促进农作物品种权的保护以及中国种业的健康发展。  相似文献   

17.
Hong Kong continues to struggle over which environmental governance approach is in its best interest while fulfilling its environmental obligations. With regard to climate change, Hong Kong's approach is characterised by a passive form of governance that is highly dependent on China's national policy directions. This is reflected, for example, in Hong Kong having not set its own mitigation targets. Market mechanisms have received little attention in developing a city‐wide climate change strategy. A transformative impulse, China's national emissions trading scheme, may provide momentum to a market‐based approach. However, the necessary conditions for such a market mechanism to be successfully implemented in China remain relatively undeveloped. This raises question about early participation by Hong Kong. Direct benefits are likely to be limited, due to Hong Kong's economic structure and weak demand for emissions reduction. Besides, there are regulatory barriers to enforcing emissions targets and/or recognising emissions allowances and credits from China. We therefore argue that nationwide emissions trading may, at this time, present more challenges than opportunities for Hong Kong to leverage its efforts on climate change mitigation. An alternative is to promote voluntary emissions trading that will require active involvement and leadership by businesses.  相似文献   

18.
张慧坚 《中国农学通报》2009,25(16):309-315
概述了我国热带能源作物发展现状、存在问题,并依据国外热带能源作物发展过程中的经验,提出中国热带能源作物发展建议。  相似文献   

19.
In field experiments conducted for 2 consecutive years at Shimla (31°06'N, 77°10'E at 2202 m above mean sea level with potato ( Solarium tuberosum L.), weekly means of rainfall (P), potential evapotranspiration (PET), pan evaporation (PAN) and photosynthetically active radiation (PAR) were estimated during the crop season. It was evident that from April to end of June, the evaporative demand was more than the precipitation and that the crop suffered from water deficit from emergence to tuber initiation. Four different energy summation indices accumulated over important phenological stages of growth and energy-use efficiency in terms of biomass production at these stages were estimated for two seasons. Weekly cumulative biomass production showed a significant correlation with accumulated PET, PAN and PAR in the four genotypes tested in year 2.  相似文献   

20.
本文对云南省几种农村能源作物的分布状况进行了概述,并分析了云南省发展农村能源作物的优势和不足,同时对云南省未来如何发展农村能源作物提出了建议和措施。  相似文献   

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