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1.
The impact of increasing farm size and mechanization on rural income and rice production in Zhejiang province,China 总被引：1，自引：0，他引：1
M. Marrit Van den Berg Huib Hengsdijk Joost Wolf Martin K. Van Ittersum Wang Guanghuo Reimund P. Roetter 《Agricultural Systems》2007
Economic growth in China’s agricultural sector lags behind growth in industry and services, creating an ever widening rural–urban income gap. Development of the non-agricultural sectors offers new opportunities for farmers in China’s more advanced provinces such as Zhejiang. Increased income in the urban sector creates markets for new products, and migrating farmers rent their land to those staying. Until now, the prevailing rice-based systems have been managed mainly using manual labour and animal traction, but the larger farms resulting from migration may facilitate, or even require mechanization. In this study, we use a simulation model of the farm household to analyse the effects of increasing farm size and the transition from rice to vegetable production, while also studying the effects of mechanization. 相似文献
2.
Agriculture faces an array of interrelated problems that call for development of new and revision of existing cropping systems towards the multiple needs of the 21st century. Agro-ecological engineering approaches aimed at design and exploration of alternative land use systems at various scales may support the identification of appropriate land use options. Engineering approaches are based on mathematical representations of well-founded agro-ecological principles while taking into account available resources and prevailing land-related objectives. The goal of this paper is to contribute to the development of a formalized approach to engineer cropping systems at the land unit level that can be used as building blocks for systematic explorations of land use options at farm or regional scale. The approach for engineering cropping systems at the land unit level consists of three steps: (i) goal-driven design of cropping systems, (ii) quantification of biophysical production targets and (iii) definition of the optimal mix of inputs required to realize production targets. This paper describes the approach and illustrates it with examples from the Sudano-Sahelian zone of Mali. Explicit attention is paid to the required numerical tools and their application to analyze consequences of uncertainty in the performance of engineered cropping systems. Using numerical tools, uncertainty is made explicit with the aim to better manage or reduce it. Identification of uncertainty at the designer's desk allows taking uncertainty into account before applying engineered land use systems in regional model studies or testing such systems in practice. Problems related to the application of numerical tools are discussed, including the future role of agro-ecological engineering as independent discipline within agricultural science. 相似文献
3.
普通野生稻稻瘟病广谱抗性基因Pi-gx（t）的遗传分析和定位 总被引：1，自引：1，他引：0
【目的】探明来源于广西普通野生稻的稻瘟病抗源RB221与部分已知抗病基因水稻品种抗谱的异同,其抗性基因的遗传模式及在染色体上所处的位点,确定其抗病基因是否为新的抗病基因。【方法】采用从广西不同稻作区收集的8个稻瘟病菌系对抗源RB221和11个已知抗病基因的水稻品种进行抗谱测定,并对RB221抗病基因进行等位性分析、经典遗传分析及分子标记定位。【结果】抗源RB221的抗谱与11个已知抗病基因的水稻品种有差异,其对8个菌系均表现出抗病反应,在所有参试品种中抗谱最广。等位性测定结果表明,抗源RB221所携抗病基因与已知抗病基因品种所携带的Pi-3、Pi-7（t）、Pi-ta、Pi-K、Pi-b是不等位。经典遗传分析结果显示,抗源RB221对03-35E菌系的抗性受1对显性基因控制。SSR标记定位结果表明,RB221抗病基因定位于第2染色体的SSR标记RM240与RM1092之间,与RM240的遗传距离为1.3 cM,与RM1092的遗传距离为2.2 cM。【结论】抗源RB221的抗性基因Pi-gx（t）为新发现的抗病基因,位于第2染色体上,与第2染色体上已定位的抗性基因处于不同基因位点上。 相似文献
4.
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
5.
Ex situ household rainwater harvesting (RWH) systems have been introduced at a large scale in Ethiopia to increase the water availability for smallholders through supplementary irrigation. The first objective of this paper is to review the performance of these systems in Ethiopia based on various assessment studies. The second objective is to provide quantitative biophysical and socio-economic analyses of ex situ household RWH systems contributing to the better understanding of their performance and the identification of options to improve their performance. Uptake of RWH systems by smallholders in Ethiopia is limited and the available information suggests that this is associated among others with poor planning and implementation, poorly functioning input and output markets and the lack of farmers’ skills to use these systems effectively. Our quantitative meta-analyses illustrate that water availability of three studied RWH systems is low in relation to crop water needs, particularly for maize. The variation in area that can be irrigated across years exposes users of RWH systems to considerable risks as the availability of irrigation water depends on prevailing rainfall conditions. The area that can be irrigated varies greatly depending on amount and distribution of rainfall, type of RWH system and crop type. The economics of onion (cash crop) are promising only for plastic lined RWH systems, but those for maize are unfavourable independent of the studied RWH systems. Associated labour requirements especially for water lifting and application are high and possibly constraining the sustainable use of RWH systems. The potential of ex situ household RWH systems to increase agricultural production and income is site-specific depending on biophysical, institutional and socio-economic conditions, and depends on household-specific conditions. 相似文献
6.
Huib Ghijsen 《Euphytica》2009,170(1-2):229-234
Today the free access to germplasm for breeding purposes is becoming more and more limited by two different developments: the patenting of traits and varieties on the one hand and the evolution with regard to access and benefit sharing in the convention on biological diversity (CBD) and the international treaty for plant genetic resources of food and agriculture (IT-PGRFA) on the other hand. Patents are generally more restrictive regarding research and breeding than plant breeder’s rights in which the important notion of the breeder’s exemption in the laws based on the international union for the protection of new varieties of plants. Conventions provides free access to commercialized, protected plant varieties for further commercial breeding. This breeder’s exemption is limited by the notion of essential derivation: closely bred “essentially derived varieties” (EDV’s) need for the purpose of commercialization the permission of the owner of the protected initial variety where the EDV has been derived from. New traits, from natural or artificial sources, can be protected by patents. The plants containing a patented trait do fall under its patent protection. In the USA conventional varieties can also be patented, which is not possible in most other countries in the world. This patent system allows claims on the progenies resulting from crossing patented plants with other plants. As each new variety consists of a unique combination of existing characteristics and crossing this variety with plants of other varieties yield new combinations, the ownership of a particular variety should not extend to the progenies of the crossing parents. The CBD and IT-PGRFA treaties subject the access to germplasm to particular rules for benefit sharing, whereby the terms for access under the CBD are still to be established and the outcome of the present negotiations is very uncertain. On top of these developments private companies use increasingly Material Transfer Agreements and restrictions printed on seed bags to limit the access to commercial varieties for breeding purposes. The question arises whether this tightening straitjacket will benefit or harm the breeding of new varieties in the long run and how the breeders in the field (will) cope with these developments. 相似文献
7.
Thomas C. Ponsioen Huib Hengsdijk Joost Wolf Martin K. van Ittersum Reimund P. Rötter Tran Thuc Son Alice G. Laborte 《Agricultural Systems》2006
Agricultural research in East and Southeast Asia is increasingly challenged by the search for land-use options that best match multiple development objectives of rural societies (e.g., increased income, food security, and reduced environmental pollution). In order to support the identification of sustainable land-use options and to support decision making with respect to land use, a tool was developed for quantifying inputs and outputs of cropping systems at the field level. TechnoGIN, the tool described in this paper, integrates systems analytical and expert knowledge and different types of agronomic data enabling the assessment of inputs and outputs of a broad range of cropping systems and the evaluation of their resource use efficiencies. By using methods of spatial aggregation in combination with linear programming, results can also be used to explore trade-offs in resource-use efficiencies at higher levels such as the farm household, municipality and province. New features in TechnoGIN compared with similar tools include the annual rotation of up to three crops, the distinction between aerobic and anaerobic growing conditions of crops, and the procedure for estimating crop nutrient uptake. TechnoGIN is illustrated with results from the Tam Duong district in North Vietnam. The design of TechnoGIN enables easy access to its data, parameters and assumptions, and rapid generation and evaluation of input–output relationships of cropping systems in order to add new information and to improve data. TechnoGIN raises awareness about the assumptions incorporated and thus supports data collection and setting of the research agenda with respect to agro-ecological processes for which knowledge is incomplete, and is relevant for showing trade-offs between production, economic and environmental impacts of different land-use systems. 相似文献
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9.
The effects of ions on bulk properties of liquid water, such as viscosity, have suggested that ions alter water's hydrogen-bonding network. We measured the orientational correlation time of water molecules in Mg(ClO4)2, NaClO4, and Na2SO4 solutions by means of femtosecond pump-probe spectroscopy. The addition of ions had no influence on the rotational dynamics of water molecules outside the first solvation shells of the ions. This result shows that the presence of ions does not lead to an enhancement or a breakdown of the hydrogen-bond network in liquid water. 相似文献
10.
Kamel Louhichi Argyris Kanellopoulos Sander Janssen Guillermo Flichman Huib Hengsdijk Paul Berentsen Martin Van Ittersum 《Agricultural Systems》2010,103(8):585-597
The disciplinary nature of most existing farm models as well as the issue specific orientation of most of the studies in agricultural systems research are main reasons for the limited use and re-use of bio-economic modelling for the ex-ante integrated assessment of policy decisions. The objective of this article is to present a bio-economic farm model that is generic and re-usable for different bio-physical and socio-economic contexts, facilitating the linking of micro and macro analysis or to provide detailed analysis of farming systems in a specific region. Model use is illustrated in this paper with an analysis of the impacts of the CAP reform of 2003 for arable and livestock farms in a context of market liberalization. Results from the application of the model to representative farms in Flevoland (the Netherlands) and Midi-Pyrenees (France) shows that CAP reform 2003 under market liberalization will cause substantial substitution of root crops and durum wheat by vegetables and oilseed crops. Much of the set-aside area will be put into production intensifying the existing farming systems. Abolishment of the milk quota system will cause an increase of the average herd size. The average total gross margin of farm types in Flevoland decreases while the average total gross margin of farms in Midi-Pyrenees increases. The results show that the model can simulate arable and livestock farm types of two regions different from a bio-physical and socio-economic point of view and it can deal with a variety of policy instruments. The examples show that the model can be (re-)used as a basis for future research and as a comprehensive tool for future policy analysis. 相似文献