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1.
Recent literature describing the process and pathways of the agrarian transition in Southeast Asia suggests that the rise of agricultural intensification and the growth of commodity markets will lead to the demise of swidden agriculture. This paper offers a longitudinal overview of the conditions that drive the agrarian transition amongst indigenous swidden cultivators and migrant paddy farmers in central Palawan Island, the Philippines. In line with regional agrarian change, we describe how a history of conservation policies has criminalized and pressured swidden farmers to adopt more intensive “modern” agricultural practices. We examine how indigenous swidden cultivators adjust their practice in response to recent changes in policies, security of harvests, and socio-cultural values vis-à-vis intensification. Rather than suggest that this transition will lead to the demise of swidden, results reveal that farmers instead negotiate a shifting ground in which they lean on and value swidden as a means of negotiating agrarian change.  相似文献   

2.
The trajectory of the public discourse on agriculture in the twentieth century presents an interesting pattern:shortly after World War II, the manner in which farming and farmers were discussed underwent a profound shift. This rhetorical change is revealed by comparing the current debate on farmland preservation with a tradition of agricultural discourse that came before, known as agrarianism. While agrarian writers conceived of farming as a rewarding life, a public good, and a source of moral virtue, current writers on farmland preservation speak of farming almost entirely in utilitarian terms describing its productive capacity and its economic returns. Proponents of farmland preservation use essentially the same underlying framework as critics of preservation:n economic utilitarian paradigm that purports to eschew normative values and evaluate land use decisions based on economic criteria only. I argue that, despite their good intentions, farmland preservationists are doomed to piecemeal victories at best, because their arguments, which rely on a utilitarian justification and disregard the agrarian ethic, are inadequate. Without expanding its focus beyond farmland to encompass farming and farmers, the movement risks losing both integrity and effectiveness.Matthew J. Mariola recently received his Masters degree in the Land Resources program at the Gaylord Nelson Institute for Environmental Studies, University of Wisconsin-Madison. His research focuses on agrarian philosophy and farmer identity among conventional and organic farmers.The errors of politicians ignorant of agriculture can only rob it of its pleasures, and consign it to contempt and misery.– John Taylor, 1813  相似文献   

3.
基于梯度图像的玉米种胚褶皱识别   总被引:1,自引:1,他引:0  
针对玉米品种自动识别中玉米种胚特征的提取问题,提出一种根据玉米种胚图像梯度图,采用基于密度的K-均值聚类算法识别分析玉米种胚褶皱的方法。根据阈值识别出胚部区域,计算其长轴方向的梯度;利用Sobel算子与膨胀算子,去除梯度图像边缘噪声,利用中值滤波去除孤立点噪声;以像素点的R、G、B梯度为特征,组成特征向量空间;采用基于密度的初始中心点优化算法,启发式的找到初始聚类中心;K-均值聚类分析,得到褶皱区域,标记区域并统计褶皱个数。对300颗玉米籽粒进行胚部褶皱识别分析,结果表明:无论是深褶皱、还是浅褶皱的,该方法均能有效识别,与人工观测值的平均吻合率达82.7%。通过本方法获取的褶皱信息体现了玉米种胚纹理特性,为玉米籽粒品种自动识别中特征参数的选取提供了新的思路和方法。  相似文献   

4.
Roman agriculture suffered traumatic changes during the 2nd century B.C. The traditional farmers who tilled their few acres and served family, gods and community were being squeezed out by large estate owners using slaves for investment farming. Politicians, scholars and poets tried to revive the ancestoral rustic life. In 133 B.C. the Gracchi legislated land reform to relieve the distress of the farmer soldiers who had won the empire. Although their efforts led to political confrontation that deteriorated into civil war, programs for the traditional farm became a permanent part of government policy from the late Republic until the end of the empire in 476 A.D. Scholars and poets made a contribution to the revival of agriculture with knowledge for improving the farm and by encouraging an agrarian mentality. The agricultural manuals (e.g. Cato (c. 150 B.C.), Varro (c. 50 B.C), and Columella (c.65 A.D.), defined the nature of the desirable farm and gave practical advice. Profit was the goal, but good farming practices made for pleasure and virtue as well. The image of the ancestoral farmer was perpetuated as was the notion that farming was the only honorable and respectable occupation for a Roman gentleman. In the Augustan Age (34 B.C.—14 A.D.) poets were encouraged by the government to adopted a rustic theme in hopes it would stimulate a return to the land and aid in the rebirth of Rome and Romans. In the GeorgicsVirgil begins with the practical details of farming, but uses myth and philosophy to explore the nature and meaning of life. He admits that Jove made life perilous. But Jove also gave man the art of agriculture and with hard work man could know the pleasure of a simple, virtuous, productive life. Horace directed his poetry against the allure of city life and in praise of rustic living. Epicureanism and Stoicism, in the guise of life on the farm, could show that although fate was unpredictable, the world was orderly and, if one recognized and accepted its limits, one could make a garden of the world and live a simple but happy life. By 300 A.D. Rome missed the peasant-farmer-soldier and by the 470's life had returned to an agrarian condition. Bishop Sidonius, trying to furnish meaning and perspective for the emerging new age, resorted to the Roman agricultural traditions still cherished as that world disappeared.  相似文献   

5.
C-type lectins (CTLs) are a superfamily of Ca2+-dependent carbohydrate-recognition proteins, and an important pattern recognition receptor (PRR) in insect innate immunity which can mediate humoral and cellular immunity in insects. In this study, we report a novel dual carbohydrate-recognition domain (CRD) CTL from Plutella xylostella which we designate PxIML. PxIML is a protein with a 969 bp open reading frame (ORF) encoding 322 amino acids, containing a signal peptide and a dual-CRD with EPN (Glu124-Pro125-Asn126) and QPD (Gln274-Pro275-Asp276) motifs. The expression of PxIML mRNA in the fat body was significantly higher than in hemocytes and midgut. The relative expression levels of PxIML in the whole insect and the fat body were significantly inhibited after infection with Bacillus thuringiensis 8010 (Bt8010) at 18 h, while they were significantly upregulated after infection with Serratia marcescens IAE6 or Pichia pastoris. The recombinant PxIML (rPxIML) protein could bind to the tested pathogen-associated molecular patterns (PAMPs), and the bacteria of Enterobacter sp. IAE5, S. marcescens IAE6, Staphylococcus aureus, Escherichia coli BL21, and Bt8010 in a Ca2+-dependent manner, however, it showed limited binding to the fungus, P. pastoris. The rPxIML exhibited strong activity in the presence of Ca2+ to agglutinate Bt8010, Enterobacter sp. IAE5 and S. aureus, but it only weakly agglutinated with E. coli BL21, and could not agglutinate with S. marcescens IAE6 or P. pastoris. Furthermore, the rPxIML could bind to hemocytes, promote the adsorption of hemocytes to beads, and enhance the phenoloxidase (PO) activity and melanization of P. xylostella. Our results suggest that PxIML plays an important role in pathogen recognition and in mediating subsequent humoral and cellular immunity of P. xylostella.  相似文献   

6.
Mass media images offer audiences models for how to perform the social roles they depict. Opinions and other attributes of credible media models may likewise be embraced by audience members seeking to identify with those models. Thus farm magazine narratives about “successful” farmers may encourage readers to model or aspire to featured farmers' production and management techniques and ascribe legitimacy to models' responses to current agricultural issues. However, production of agrarian images in the mass media — including images of farms, farmers, and farmers' values — are inevitably biased such that media representations of successful farmers selectively present objective characteristics in terms of the media's own ideological frameworks, which in turn reflect the dominant ideology of the social relations in which the media are engaged. As a first step in identifying farm magazines' role in creating social models for farmers, this study analyzes articles featuring “successful,” “leading,” or “innovative” farmers in leading agricultural magazines. The featured farmers are categorized according to enterprise characteristics and characterizations of them and their management philosophies. Findings show that farmers in farm magazines have larger than average operations and are portrayed in a way that blends a “farming as business” orientation with more conventional agrarian values but that generally omits non-business aspects of farm life.  相似文献   

7.
With a view to closing the nutrient loop between sanitation and fish culture, advanced fry of different species of fish (rohu, bata, mrigal, common carp, tilapia, punti) and larvae of freshwater prawn were reared in twelve experimental tanks in a mixed culture system for 120 days using three treatments (fresh urine, stored urine and mix of fresh and stored human urine) and control in triplicate. The total weight for all the species of fish and prawn in the stored urine (420.0 g) was 18 and 27% higher compared to fresh (356.0 g) and mixed urine (332.0 g) treatments, respectively. Likewise, primary productivity of phytoplankton and heterotrophic bacterial load related to phosphate level of water were also highest and lowest in the stored urine (GPP—508 ± 39.87 mg C m–2 h–1; heterotrophic bacteria—38.38 cfu × 103 mL–1) and control system (GPP—214 ± 38.09 mg C m–2 h–1; heterotrophic bacteria—13.53 cfu × 103 mL–1), respectively. The mean count of E. coli, on the other hand, did not differ between urine fed treatment and control. As a possible mechanism, it is suggested that stored urine upon transfer to aquaculture pond underwent degradation and mineralization that induced the autotrophic and heterotrophic food webs conducive to fish growth.  相似文献   

8.
Detecting oestrus by monitoring sows’ visits to a boar   总被引:1,自引:0,他引:1  
This paper suggests a method for automatic detection of sows returning to oestrus in the gestation department. The detection is based on monitoring of sows’ visits to a boar, where the duration and frequency of visits are modelled separately and subsequently combined. The hypothesis is that it is possible to reduce the response time and the number of false alarms compared to previously published attempts. The duration of visits to a boar is defined as seconds per hour the sow is near the boar - logarithmically transformed. The duration is modelled with a multiprocess dynamic linear model with first order Markov probabilities. The indicator of oestrus is the probability of the model describing oestrus, P(MOE), and it is monitored with a threshold value. The frequency of visits to a boar is defined as number of visits per 6 h. A dynamic generalised linear model with two built-in diurnal periods is applied. The indicator of oestrus is the relative deviation from the forecasted frequency, which is monitored with a threshold value. The probability, P(MOE), and the relative deviation from the forecasted frequency are combined by means of Bayes Theorem. The combined probability of oestrus is monitored with a threshold value as well. Results indicate that the specificity is superior compared to previously published attempts. The model describing duration alone yields the most satisfactory specificity - 99.4% per sow day, which is considerably greater than previously published studies. Furthermore, this model detects 87.4% of the sows entering oestrus, which is slightly lower than previous attempts. The response time of the models is 1 h for the duration model and the combined model and 6 h for the frequency model. This is better than previous attempts. Even though the specificity is greater, the proportion of false alarms on a day-to-day basis is still too high (91.0%), which is due to the very large proportion of the sow days defined as non-oestrus. In order to improve the specificity of the detection method, it is suggested to combine the detection method in the present study with other information sources about oestrus.  相似文献   

9.
The Forestry Pilot Plan set intomotion collectively-owned and managed forestry in overforty communities in Quintana Roo, Mexico and hasshown the promise of a forestry development model thatpromotes conservation by giving local people a genuinestake in sustainable resource management. Today, thelegacy of the PPF is under great pressure. Externally,neoliberal policy reform restructures agrarianproduction in ways that favor individual overcollective management of natural resources.Internally, organizational problems createinefficiencies within both forestry ejidos(cooperative agrarian communities) and theirintermediate level forestry civil societies. Peasants'capacity to defend their interests and dealeffectively with their production problems throughstrong representative organizations is beingundermined by new rules for economic associationwithin the ejidos and by the turning over of technicalservice financing to the market. Though organizationalinnovations within the ejidos hold positive potential,existing civil societies merit continued assistance askey actors promoting sustainable forestry. Studyingcommon property management regimes across multiplelevels and dimensions reveals that in Mexico, policyreform overlooks the crucial social resourcesrepresented by peasant organization, undermining thepossibility of sustainable forest management whileassigning the peasant most of the cost ofconservation. If conservation is indeed encouraged bythe genuine participation of those with a stake insustainable use of natural resources, national andinternational communities that value Mexico's tropicalforests should also invest in both social and economiccosts of conservation.  相似文献   

10.
Dependence of net photosynthesis rate in Nerium oleander L. on environmental factors, leaf temperature, transpiration, and also on the changes of these factors during vegetation has been studied under conditions of the Southern Coast of Crimea. The mapping of a photosynthesis response function onto environmental factors in a three-dimensional coordinate system represents a convex surface with the maximum at the top point. This fact makes it possible to obtain numerical coefficients for nonlinear regression equations (simulators) describing interrelations between the net photosynthesis and the main environmental factors, leaf temperature, and transpiration. The data obtained provide a possibility to interpret a photosynthesis rate as a potential ecophysiological characteristic of this species that makes it possible to compare different plant species growing under similar conditions using parameters measured by the same method. Nerium oleander L. has a high photosynthetic potential for acclimatization to high temperatures. If air temperature exceeds the optimum value, photosynthetic intensity sharply decreases. The threshold temperature for leaves is 36.5°С. After the termination of the active growth phase, the maximum net photosynthesis rate decreased during August–October by 51.73%, while transpiration intensity and leaf temperature decreased by 78 and 28.58%, respectively. Compared to August, the optimums of the air temperature, air humidity deficit, and PAR illumination in October shifted to lower values by 17, 89.14, and 31.58%, respectively.  相似文献   

11.
Adaptations made by agrarian households in the face of global change risks are largely dependent on their livelihood goals. I argue that adaptation-limit research is crucial to many agrarian development programs because a focus on adaptation limits may allow researchers and practitioners to better understand and support successful adaptation and allow smallholders to pursue their goals. In this study of smallholder farming in Northwest Costa Rica, I found that security and the unique parcelero identity of rice farmers in this region define livelihood goals. I show that an understanding of the multidimensionality and fluidity of farmer livelihood goals may enrich our current understanding of actor-centered adaptation limits as insurmountable thresholds. In response to worsening global change risks, farmers in this study traded off certain goals to pursue others. In this way, farmers do not perceive adaptation limits as insurmountable. Alternative indicators of adaptation limits did exist; irreversibility in adaptation and the great hardship associated with tradeoffs among livelihood goals may mark adaptation limits.  相似文献   

12.
The whitefly, Bemisia tabaci, is a major pest of cassava, particularly in Africa where it is responsible both for the transmission of plant viruses and, increasingly, for direct damage due to feeding by high populations. To date, there have been no practical solutions to combat this emerging problem, due to the inability of the subsistence farmers that grow cassava to afford expensive inputs such as insecticides. A programme of research was carried out linking institutes in Africa, the UK and South America, to identify possible resistance sources in cassava to the whitefly, Bemisia tabaci. The South American genotype MEcu 72 and several Ugandan cassava landraces including Ofumba Chai, Nabwire 1 and Mercury showed good levels of resistance to B. tabaci. Field and screen-house experiments showed that all of the improved, high-yielding cassava mosaic disease (CMD) resistant cassava genotypes assessed were highly susceptible to B. tabaci and supported high populations of all life stages. These data support the hypothesis that the continuing high populations of cassava B. tabaci in Uganda are due, in part, to the widespread adoption of CMD-resistant cassava varieties during the CMD pandemic. They also show that the whitefly, Aleurotrachelus socialis, resistance present in the South American cassava genotypes could have broader applicability in the Old World.  相似文献   

13.
14.
This paper emerges from and aims to contribute to conversations on agricultural biodiversity loss, value, and renewal. Standard international responses to the crisis of agrobiodiversity erosion focus mostly on ex situ preservation of germplasm, with little financial and strategic support for in situ cultivation. Yet, one agrarian collective in the Peruvian Andes—the Parque de la Papa (Parque)—has repatriated a thousand native potatoes from the gene bank in Lima so as to catalyze in situ regeneration of lost agricultural biodiversity in the region. Drawing on participant action research and observation, this paper engages with the projects underway at the Parque—as well as “indigenous biocultural heritage” (IBCH), the original action-framework guiding the Parque’s work. IBCH grounds the ecology of successful crop diversity within the Andean cosmovisión, or worldview—which is included, but marginalized, in mainstream agrobiodiversity conservation policies. The IBCH concept counters apolitical renderings of agrobiodiversity erosion, arguing that this disregard of biocultural heritage perpetuates colonialist devaluations of efficacious “traditional ecological knowledge” and epistemologies. Accordingly, this paper discerns here an on-site, or in situ, political ecology of agricultural biodiversity conservation.  相似文献   

15.
By means of DNA markers of potato golden nematode resistance genes H1 and Gro1, 109 Russian- and foreign-bred potato varieties are assessed. A sufficiently high level of coincidence of the presence of marker alleles with phenotypic resistance of potato varieties is revealed. However, not all resistant forms have specific amplification products. The use of DNA markers of only two genes H1 and Gro1 will not make it possible to completely replace mass laboratory testing, but it will make it possible to select potato forms resistant to this parasite by a simple and reliable method in a shorter time and thereby to considerably reduce the number of genotypes in the sample for further breeding.  相似文献   

16.
Hungry Brazil     
The essay, based on four years of living and teaching philosophy in Brazil, is a series of aphorisms about food and hunger as concerns that have left their mark on the Brazilian mind. Alimentary jokes and homilies are retold, gustatory episodes are recalled, larders and cuisines remarked, markets and mealtimes remembered—with constant reference to the idiom of Brazilian Portuguese. The style of thinking is “postphilosophical” in the sense developed in Part II of the author's Negative Dialectics and the End of Philosophy[Longwood, 1990]: it does not so much argue theses as it displays the character of the topic.  相似文献   

17.
One of the main problems in greenhouse crop production is the presence of pests. In order to address this problem, the implementation of a Integrated Pest Management (IPM) system involving the detection and classification of insects (pests) is essential for intensive production systems. Traditionally, this has been done by placing hunting traps in fields or greenhouses and later manually counting and identifying the insects found. This is a very time-consuming and expensive process. To facilitate this process, it is possible to use machine vision techniques. This work describes an application of the machine vision system LOSS V2 algorithm, an expanded version of the LOSS algorithm discussed in a previous work by the same authors. This expanded version demonstrated improved potential and was used to detect and identify the following pest species: Diabrotica (Coleoptera: Chrysomelidae), Lacewings (Lacewings spp.), Aphids (Aphis gossypii Genn.), Glassy (Empoasca spp.), Thrips (Thrips tabaci L.), and Whitefly (Bemisia tabaci Genn.). The algorithm identifies pest presence in the crop and makes it possible for the greenhouse manager to take the appropriate preventive or corrective measures. The LOSS V2 involves the application of the LOSS algorithm for initial pest identification, followed by the application of the image processing technique known as scale invariant feature transform (SIFT). This allows for more accurate pest detection because it is possible to discriminate and identify different types of insects. Therefore, when compared to manual pest counting, the newly developed LOSS V2 algorithm showed more precision in identifying different pest varieties, and also, a much higher determination coefficient, R2 = 0.99.  相似文献   

18.
耕地征用价格构成的理论分析   总被引:1,自引:0,他引:1  
以耕地功能价值为依据,运用社会成本和私人成本理论,揭示现行耕地征用补偿偏低及其引发的问题,在此基础上提出以耕地功能价值为确定征用价格的理论依据,并给出耕地总价值的量化标准.  相似文献   

19.
1982年的农户土地承包以“均田制”和“分田制”为主。十几年来,特别是近年来,90%左右的农户进行了调田,自发转包和转让趋于活跃,农村土地使用权转让的主要形式有:“两田制”、“调换”、“股份”、“开发”、“租赁”、“反包”等经营方式。土地流转中尚存在抛荒、半抛荒,转包、转让手续不全,制度不规范,违背政策等现象。当前要稳定土地承包关系,实行“增人不增地,减人不减地”政策,建立健全以转让、转包、局部性调整、租赁、拍卖为主要内容的土地流转机制。  相似文献   

20.
In recent years, an increasing number of different types of japonica rice cultivars have been released in the southern rice region of China. The grain yield and quality of these new cultivars showed significant differences in large scale planting. However, the causes of the differences remain little known. Therefore, three typical types of japonica rice cultivars were used in this study to investigate their grain yield and quality. A scanning calorimeter(DSC), X-ray powder diffractometer(XRD), rapid viscosity analyzer(RVA) and taste analyzer were used to evaluate the cooking and eating properties. The results showed that the yield of non-soft hybrid japonica rice cultivars was significantly higher than that of non-soft inbred japonica rice cultivars and soft inbred japonica rice cultivars. Soft inbred japonica rice cultivars had a low amylose content and moderate protein content, which are the main reasons for the superior cooking and eating quality. In addition, the relative crystallinity of soft inbred japonica rice cultivars was significantly higher than that of non-soft inbred and non-soft hybrid japonica rice cultivars, which is considered the major factor resulting in higher transition temperature and gelatinization enthalpy(ΔHgel). Non-soft hybrid japonica rice cultivars had a higher number of large starch granules than soft inbred and non-soft inbred japonica rice cultivars. The setback value(SB) and breakdown value(BD), indirectly reflecting the cooking and eating quality of the three types of japonica rice cultivars, also confirmed that soft inbred japonica rice cultivars with a low SB value and a high BD value had better palatability than the other two types. This study provides guidance for future plantation of different types of japonica rice cultivars in large rice-producing areas.  相似文献   

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