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1.
J. Sauerborn 《Journal of Agronomy and Crop Science》2002,188(6):363-367
If we call a significant yield increase in single crops a ‘green revolution’, then the first green revolution took place about 10 000–12 000 years ago, when humans started to cultivate land. This was also the beginning of civilization. Since then, humans have increasingly transformed the land and natural vegetation and have risen to be the main creators of the biogeosphere. Today, there is hardly any ecosystem around the globe that has not been influenced by humans. It was only in 1930 that the world population reached 2 billion, and since then it has increased to 6 billion in the year 2000. Because of this rapid increase, the demand for food, feed and industrial crops has grown enormously. Half of the 1.5 billion ha of arable land – 18 % of the biologically productive land area of the earth – was first cultivated only in the 20th Century, and mostly forest was sacrificed to meet this requirement. The second green revolution started only in the late 1960s when high‐yielding varieties of wheat and rice were designed to overcome the predicted hunger crisis. Great achievements were made, especially in relation to irrigated agriculture, while rain‐fed farming was hardly affected by this revolution. World agriculture today faces two major constraints to which not enough attention is paid by scientists and decision makers. First, we increasingly restrict our food basis to a limited number of plant species. Today, 65 % of the world's arable land is reserved for only 21 annual crops. Even more worrying is the fact that 60 % of our food energy and protein comes from only three cereals – wheat, rice and corn. Designing ‘functional’ food using gene technology to improve food quality, for example in rice, will speed up this process of constriction since diversified ingestion is no longer necessary to meet the daily required balance of food types. Secondly, arable land resources are under‐utilized because of poor management. Yields of rice, for example, are below the world average of 3.8 t ha?1 (1998) in 70 countries. If those countries achieved only the average level for their continent, for example 2.2 t ha?1 in Africa, world rice production could be increased by 17 %. There is a need to invest in better management of arable land to prevent further loss in productivity and simultaneously to investigate under‐explored plants to broaden our future food basis. 相似文献
2.
Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques. 相似文献
3.
The article shows results of an international and interdisciplinary project with the title ‘Rainfall and its Erosivity in
Ethiopia’. Rainfall variability affects the water resource management of Ethiopia. The influence of rainfall variability on
flow regimes was investigated using five gauging stations with data availability from 1982–1997. It was confirmed that the
variability in rainfall has a direct implication for surface runoff. Surface runoff declined at most of the gauging stations
investigated. Therefore, effective water resource management is recommended for the study area. Future research should focus
on watershed management which includes land-use and land cover. The question posed here is whether the variability in rainfall
significantly affected surface flow in the study area. 相似文献
4.
Parasitic weed species of the genus Orobanche are a serious threat for the production of several crops in Europe, Africa and Asia. In contrast to other broomrape species of agronomic importance, O. ramosa (branched broomrape) has a broad host range and in Europe particularly affects hemp, tobacco, tomato and, in recent times, oilseed rape. Two separate sets of experiments investigated the effect of two populations of O. ramosa on nine tobacco cultivars grown in Europe and belonging to the three major tobacco types: Virgin (flue-cured), Burley (light air-cured) and dark air-cured under standardized glasshouse conditions. The two broomrape populations were discriminated by means of polymorphic DNA fragments obtained by PCR of the intersimple sequence repeat regions (ISSRs). The Orobanche populations exhibited different levels of pathogenicity but all various tobacco cultivars were susceptible. Dark air-cured tobacco cultivars were the least susceptible to both broomrape populations. Virgin and Burley tobacco cultivars were more susceptible to one population of O. ramosa . 相似文献
5.
The effects of diet supplemented with Lactobacillus rhamnosus on tissue parameters of rainbow trout,Oncorhynchus mykiss (Walbaum) 
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下载免费PDF全文 Natalija Topic Popovic Ivancica Strunjak‐Perovic Roberta Sauerborn‐Klobucar Josip Barisic Margita Jadan Snjezana Kazazic Inga Kesner‐Koren Andreja Prevendar Crnic Jelena Suran Blanka Beer Ljubic Vesna Matijatko Rozelindra Coz‐Rakovac 《Aquaculture Research》2017,48(5):2388-2401
This study was carried out to establish the effects of a 6 week treatment with the diet supplemented with L. rhamnosus in concentrations of 107 CFU g?1 (G1 group) and 108 CFU g?1 (G2 group) on the condition expressed by condition factors (Fulton's, Clark's and B), intestinal microbiology, haematological, histological and selected antioxidative parameters of rainbow trout. A significantly higher condition factors were found in G1 group indicating that higher concentration of probiotic (108 CFU g?1) did not result in the better condition. Cholesterol and urea levels were significantly higher in both G1 and G2 groups, albumin in G1 and creatinine in G2 group with respect to control. A significantly higher liver TBARS level was observed in G2 group. The feeding with supplemented probiont apparently changed the resident microbiota. Three weeks after withdrawal of the supplemented feed, the microflora mostly reverted to the control composition, although L. rhamnosus in faecal matter of fish remained inherent. The epithelial structure of the proximal and distal intestine revealed the increased absorptive area in both treated groups, as well as the increase in the mucin‐secreting goblet cells. The L. rhamnosus‐treated groups demonstrated the capacity for the augmentation of the innate host defence. 相似文献
6.
Gerhard Langenberger Vanessa Prigge Konrad Martin Beatriz Belonias Joachim Sauerborn 《Agroforestry Systems》2009,76(1):173-194
Complex agroforestry systems that mimic local forest structure, so-called ‘analogs’, are assumed to be of specific value to
rural people as well as the environment. The objective of this study was to document and evaluate the utilization of plant
resources by Philippine lowland farmers to identify native species suitable for integration in such a system. The interviewed
farmers maintain a comprehensive ethnobotanical knowledge. They reported using 122 plant species for 77 purposes. Eighty species
have medicinal value, 35 provide food, and 32 serve other uses. About 64% of the identified species are Philippine natives.
The life form composition of these species is dominated by trees but also includes herbs, lianas, and graminoids, thus providing
the structural elements required in analog systems. Nevertheless, only a few of the species seem to be promising for cultivation.
Many of them are ubiquitous in the vicinity of villages. Some species are also not much appreciated but act as staple food
only during food shortage. Even though several of the species have proven market value, such as rattan (e.g. Calamus
merrillii), or are reputed medicines, such as ‘Philippine ginseng’ (Sarcandra glabra), no cultivation could be observed. This shows that usefulness in itself cannot be the only criterion to promote species
but that it requires a careful analysis of the marketability of the respective species. In this context we suggest the following
three species that are of proven medicinal value for in-depth study: the liana Tinospora crispa (Menispermaceae), the tree Picrasma javanica (Simaroubaceae), and the herb Sarcandra glabra (Chloranthaceae). They represent three different life form strategies and would thus fit well in vertically structured agroforestry
systems. 相似文献
7.
A three years' trial was conducted in a farmers' field in northern Ghana to evaluate the effect of sole crops (cotton, cowpea, groundnut, soybean, and sunflower) planted once or twice on yield of the staple foods of the region, maize and sorghum. Sole cropping for only one year already resulted in significant yield increases for maize and partly for sorghum compared to the conventional cropping of mixed stands of maize–sorghum or maize–groundnut and natural fallow. Lowest yield of maize and sorghum was obtained where these cereals followed maize–sorghum (monoculture). Intercropping of maize with groundnut led to subsequent maize and sorghum yields which were similar to those obtained after maize–sorghum. After growing legumes and sunflower for one year the grain and straw yield of maize and sorghum was significantly higher in the two consecutive years than after cereal (maize–sorghum) monoculture. In this trial maize and sorghum were found to be not as tolerant to the disadvantages of monoculture or preceding cereals–legumes mixture. The results suggest that continuous intercropping with cereals under the given conditions has negative effects on soil fertility and can lead to an increase in soil-borne pests and troublesome weeds like Striga comparable to monocropped cereals. 相似文献
8.
世界有机农业发展的历史回顾与发展动态 总被引：20，自引：0，他引：20
简要回顾了世界有机农业的发展历程。将世界有机农业的发展历程分为产生、扩展和增长3个阶段，介绍了各阶段的代表人物和思想。从有机农业的面积、占耕地比例和有机产品的市场状况，综述了世界有机农业的发展动态，并讨论了世界有机农业进一步发展存在的主要问题。简述了中国有机农业的发展动态、问题和对策。 相似文献
9.
Dorette?Müller-St?verEmail author Holger?Buschmann Joachim?Sauerborn 《European journal of plant pathology / European Foundation for Plant Pathology》2005,111(3):193-202
Fusarium oxysporum Schlecht. f.sp. orthoceras (Appel & Wollenw.) Bilai is a potential biocontrol agent against the root-parasitic weed Orobanche cumana. In pot experiments with different sunflower cultivars, the application of F. oxysporum was combined with a treatment of BTH (Benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester), a product known to induce resistance against O. cumana in sunflower. The combined treatments resulted in highly reliable control and sometimes in increased control level compared to the Fusarium treatment alone. In laboratory experiments, no enhancing effect of BTH on virulence and growth of the fungus was observed. Future experiments should further investigate the basic mechanisms of the effect achieved by combining the two control strategies as well as the transfer of this innovative control approach into field experiments. 相似文献
10.
MA Shi-ming Joachim Sauerborn 《中国农业科学(英文版)》2006,5(3):169-178
The history of the organic farming worldwide was reviewed in this paper. The development of the organic farming worldwide had gone through three stages, emergence, expansion, and growth. The contributors and their thoughts during the different development stages of the organic farming were briefly introduced. And the development status of the organic farming worldwide was reviewed from the aspects of land area under organic management, land area under organic management in percentage of total agricultural area, and world markets for organic products. Besides, the main existing problems for the further development of the world＇s organic farming, as well as the development status, problems and strategies of the Chinese organic farming were discussed. 相似文献