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1.
Four important parasitic nematodes were found associated with roots of 26 crops sampled from four locations in E Nigeria. Commercial agriculture will result in further establishment of nematodes as major pathogens in agricultural fields to the detriment of farmers and consumers. It is suggested that certain features in native farming system worked into commercial agriculture could reduce damage to crops and losses to the Nigerian farmer.  相似文献   

2.
Geoinformational analysis shows that the fraction of lands that are optimal for farming of the main crops in Russia is about 10% of the available land at best (for summer wheat, buckwheat). For the majority of other crop cultures, this value is a few percent at most. The available resources are used very incompletely. The index of completeness of land resource potential use is no more than 10% for the majority of crops. Only in the case of soy are the available resources almost completely involved, whereas available land resources of winter wheat, grain maize, and sunflowers are used at 20–30%.  相似文献   

3.
Rie Makita 《Geoforum》2012,43(6):1232-1241
This paper explores a confluence of Fair Trade and organic initiatives under the prevalence of Bt cotton in India, using as an interpretative framework Guthman’s conventionalization thesis for organic farming in the Northern context. In a case study conducted in Andhra Pradesh, the confluence of the two initiatives, contrary to their ethical standards, contributed to the spread of genetically modified (GM) seed. The Fair Trade initiative, lacking a scheme for compensating for the decrease in income that producers have to endure during the conversion period, tends to take a more relaxed attitude toward GM crops in order to assist small farmers. Fair Trade’s dilemma between helping poor farmers and promoting organic farming may have indirectly allowed Fair Trade producers to tend towards conventional farming with Bt seeds. As a result, the confluence of the two initiatives has not intensified the organic concept as “an alternative accumulation strategy for agrarian capitalism,” but neither has it released disadvantaged Southern farmers from agrarian capitalism. Rather, it has led farmers into another form of agrarian capitalism.  相似文献   

4.
西北地区特色作物对气候变化响应及应对技术的研究进展   总被引:3,自引:1,他引:2  
总结了白兰瓜、 大樱桃、 酿酒葡萄、 苹果、 桃、 当归、 党参、 黄芪、 甘草、 枸杞等10种特色作物的生长发育、 种植区域、 气象灾害、 生物量、 产量与品质等对现代气候暖干化的响应特征. 结果表明: 气候暖干化使多年生特色作物萌芽或返青提早, 生长发育速度提前加快; 瓜果类作物全生育期缩短, 根类作物全生育期延长; 使种植区的高度提高150 m左右, 向更高纬度扩展, 种植面积迅速扩大. 对旱作农业区的特色作物气候产量下降, 对灌溉农业区的影响较少, 有利于喜温凉特色作物气候产量增加, 对较耐旱的影响较轻, 对不够耐旱受到较大的影响.有利于提高瓜果类作物的品质, 尤其含糖量提高. 提出了建立特色作物种植基地或示范区, 实现农工商产业系列服务, 创建现代农业发展模式和管理新模式适应气候变化; 制定精细化综合农业自然资源区划, 合理调整种植结构; 根据未来气候预测和不同气候年型调整作物种植比例; 加强气象灾害监测、 评估、 预警与防御工作等4个方面的措施应对气候暖干化.  相似文献   

5.
The integration of farmers and nomads in northwestern China during the Han Dynasty(206 BCE ~ 220 CE) provides a crucial opportunity to reconstruct the material exchanges, formation and development of the Silk Road in antiquity. The subsistence strategy is arguably an effective proxy for the integration of various groups of people(e.g. farmers and nomads). In this paper, we have reported new stable isotope data from the Huangwan tombs dated to the Han dynasty in middle Gansu, which was the key juncture between the Han and Xiongnu empire, in order to fill the gap and further understand the substance strategies employed by the local people. According to the results of plant remains and stable isotopic data, millet farming, the typical agricultural activities for the Han Chinese in the Central Plains, was also the primary lifestyle for the Huangwan people in the mid Gansu. More importantly, this shows fundamentally remarkable difference from the agricultural practices in the Bronze Age Gansu Corridor, which were based on a variety of crops, including wheat, barley and millet. This major shift in the subsistence production at Huangwan can be correlated to a wider historical background in which the Han empire showed increasing political and military presence in the Gansu Corridor, indicating that local indigenous nomads followed the lifestyle of Han Chinese(e.g., millet farming), and/or the Han immigrates maintained millet farming.  相似文献   

6.
Southern Africa rainfall station network is suffering from an unfortunate serious decline while climate-related food insecurity is worsening. In the current work, we demonstrate the possibility of exploiting the complementary roles that remote sensing, modeling, and geospatial data analysis can play in forecasting maize yield using data for the growing seasons from 1996/1997 to 2003/2004. Satellite-derived point-specific rainfall estimates were input into a crop water balance model to calculate the Water Requirement Satisfaction Index (WRSI). When these WRSI values were regressed with historical yield data, the results showed that relatively high skill yield forecasts can be made even when the crops are at their early stages of growth and in areas with sparse or without any ground rainfall measurements. Inferences about the yield at national level and small-scale commercial farming sector (SSCF) sector can be made at confidence levels above 99% from the second dekad of February. However, the most unstable models are those for the communal farming sectors whose inferences for yield forecast can only be made above the 95% confidence level from the end of February, after having recovered from a state of complete breakdown two dekads earlier. The large-scale commercial farming (LSCF) sector has generally the weakest fitting, but it is usable from the first dekad of February to the end of the rainy season. Validation of the national yield models using independent data set shows that an early estimation of maize yield is quite feasible by the use of the WRSI.  相似文献   

7.
Farmers in the Zuni area of the semiarid American Southwest have successfully cultivated maize and other crops for over three millennia without using artificial fertilizers. Zuni agricultural fields are among the oldest, more or less continuously cultivated areas in the United States. Traditional Zuni agriculture is based on runoff farming, a system whereby runoff and organic‐rich sediment generated in small watersheds are captured and directed onto fields for crop use. We conducted a study to compare soil properties associated with paired and unpaired cultivated, abandoned, and uncultivated fields to evaluate the long‐term effects of cultivation on soil quality. Sampling and analytical methods of this research are especially applicable to geoarchaeological studies of anthropogenic effects on soil fertility and agricultural sustainability in ancient and traditional historical farming systems. Results of the Zuni soil study indicate that cultivation has altered some soil properties, including bulk density, organic carbon, total nitrogen, and C:N ratios in paired fields, but there is no indication that agricultural soils are degraded. This assessment supports the perception of Zuni farmers that long‐term cultivation has not caused a decline in agricultural productivity. © 2005 Wiley Periodicals, Inc.  相似文献   

8.
Environmental pollution induced by heavy metal(loid)s from pig farming   总被引:1,自引:0,他引:1  
The development of intensive and large-scale livestock farming, such as pig husbandry, is significantly increasing the amount of manure globally. Mineral additives are commonly used in animal feed, and heavy metal(loid)s (HMs) are introduced to the feed via incomplete purification processes of those mineral additives, which leads to inevitable environmental pollution by HMs in conjunction with manure production. When these toxic-metal-containing manures are used as fertilizer, the HMs accumulate in soils and crops, which further causes potential risks to human health and the ecological environment. In this review, the focus is on seven HMs that are related to human activities or frequently contained in animal feed, including copper, zinc, cadmium, chromium, lead, mercury, and arsenic. The toxicities of these HMs and the elimination methods to reduce the HM toxicity of pig manure when it is added to soil, i.e., liquid–solid separation, adsorption, bioleaching, and composting, are summarized. The ultimate aim of this review is to outline the systematic pollution management strategies for HMs from pig farming.  相似文献   

9.
Research on soil fertility is presented in the context of runoff agriculture, a venerable farming system that has been used for millennia in arid to semiarid regions, where water is a major limiting resource for crop production. The agroecology of runoff farming was studied with the Zuni to evaluate nutrient and hydrologic processes, management, maize productivity, and soil quality in some of the oldest recognized fields in the United States. This ancient Southwest agriculture has functioned without conventional irrigation or fertilization by tapping into biogeochemical processes in natural watersheds connected to fields. Carefully placed fields are managed on alluvial fans and other valley margin landforms to intercept runoff and associated sediment and organic debris transported from adjoining forested uplands. We report on research to evaluate and link nitrogen and phosphorus, two key nutrients for crop production, in watershed, soil, and crop components of this agroecosystem. Nutrient data have been collected by observational and experimental methods for each component and the transport of nutrients from watershed to field to maize. The condition of Zuni agricultural soils suggests that their knowledge and management of soils contributed to effective conservation. This study and others indicate the need for further long‐term monitoring and experimental research on watersheds, runoff processes, field soils, and crops across a range of arid to semiarid ecosystems. © 2007 Wiley Periodicals, Inc.  相似文献   

10.
The application of agrochemicals in crops can cause pollution of aquifers, especially those with a shallow water table and covered by thin soils; such is the case of Yucatan, Mexico. Information about the requirements and application of fertilizers to major irrigation and rainfed crops as well as the volume of water consumed in growing were used to determine the potential amount of nitrate delivered to groundwater. The research reported in this paper was conducted in the metropolitan area of the city of Merida, in Yucatán, Mexico, where groundwater plays an important role since it is the main source of supply, due to the lack of surface water in the region. In addition, the vulnerability of this aquifer is threatened by the various activities taking place in the municipalities, which emphasize agriculture, located within the groundwater basin. This activity is analyzed as a source of contamination given the concentration of NO3 ? present in groundwater intended for human consumption. The results show that the contribution of farming that enriches the presence of nitrates in the aquifer is different for each municipality in the study area. For the ZMM, the average nutrient leaching is 44 % of the original mass applied; it could be diluted approximately 12 times, in the groundwater.  相似文献   

11.
虚拟水战略已经被认为是一种提高全球水资源利用效率和缺水地区获得水安全的有效工具. 虚拟水战略新论指出, 应充分利用各种社会资源, 打通优化配置水资源(实体水和虚拟水)的渠道. 虚拟水战略能否有效实施的首要任务, 是地区产业结构内部配置的优化. 本文在估算民勤县主要农作物虚拟水量的基础上, 利用部门水效益分析了虚拟水由农业(种植业)部门向第二、三产业转移的三种情景下产生的净效益和创造的社会就业机会, 刻画了实施虚拟水战略的重要理论意义, 佐证了虚拟水战略全新定义的现实意义.  相似文献   

12.
Farming among urban dwellers in Sub-Saharan Africa is a common phenomenon. The present study, carried out in a medium-sized town in Kenya, not only confirmed this but also showed that farming by urban dwellers in the rural areas was even more important for these households’ livelihoods than farming in town. However, those who could benefit most from farming, i.e. the urban poor, appeared to be underrepresented among urban farming households and those urban poor who did farm, either in urban or in rural areas, performed worse than the farming non-poor. The importance of farming as a livelihood source is illustrated by the fact that in years with very little or no harvest due to drought, many of the poor farming households faced food shortages.  相似文献   

13.
Godwin Masuka 《Geoforum》2012,43(3):573-584
The paper examines the relations between farmers and The Cotton Company of Zimbabwe (COTTCO) in Rushinga district of Zimbabwe. Based on interviews with farmers and secondary data, it examines the practice of side marketing of contracted seed cotton. While a large body of literature has discussed the social and economic effects of contract farming on farmers, there are less critical studies on side marketing of crops by farmers in unstable economic and political environment such as Zimbabwe. The paper demonstrates that farmers taking advantage of the macroeconomic environment in Zimbabwe violated contracts by selling seed cotton to other buyers. In the process, farmers renegotiated the meaning of the contract and appealed to market rationality embedded in the neo-liberal ideology. For these farmers, side marketing was part of a survival strategy, albeit in imperfect markets and a difficult economic environment. Nonetheless, side marketing of seed cotton strained relations between farmers and COTTCO. The paper shows the tensions in contracts that require regulation by the state and the neo-liberal ideology that promote free markets and argue against strong regulation.  相似文献   

14.
R. Kada 《GeoJournal》1982,6(4):367-371
Part-time farming is a wide-spread phenomenon in contemporary rural Japan. Characterized by an extremely small-scale rice farming and by a unimodal equitable rural development, most Japanese farm households have combined farming with off-farm employment. In this article, after an examination of the definition of part-time farming (farm household as the unit), the trend of and factors for part-time farming are described and analyzed. Growth and expansion of off-farm employment opportunities, continued small-sized farming, rapid increase in farmland prices and development and diffusion of labor-saving technology are among the major forces which encouraged part-time farming in Japan. Although the overall performance of part-time farms appears less efficient in the use of non-labor resources (e.g., land and machinery), part-time farms still occupy a significant share in the aggregate agricultural production and in the total farmland cropped. Various on-farm and off-farm adjustments are pointed out which have enabled dual employment patterns to be adopted by these people. In essence, due to the limited opportunities for farm-size expansion, part-time farming is considered a necessity, rather than a choise, for most Japanese farm families. But this has also caused some serious agricultural problems, especially with respect to its impact on farmsize structure and inefficient land use. At least for the purpose of maintaining a high income level and for equitable access to opportunities, part-time farming has seemingly contributed beneficially to the farming population of Japan.  相似文献   

15.
Mage  J. A. 《GeoJournal》1982,6(4):301-311
This paper presents a macro level geographic vista and a theoretical vista as research avenues for an approach to the study of part-time farming. In Canada about one-third of all farm operators have reported off-farm work in addition to farming in each census period since 1941. The utility of the Canadian Census is illustrated and the temporal and spatial variations in the degree and intensity of part-time farming in Canada are examined. Variations in the degree of part-time farming appear to represent an aggregate response to the needs, opportunities and traditions associated with specific regions while variations in the intensity of off-farm work appear to represent some component of the form or nature of part-time farming.The theoretical vista is a call for agricultural geographers to incorporate part-time farming as one of the elements in the systems approach to the study of agriculture and as a key index in agricultural typologies. It is also suggested that specific typologies of part-time farming be developed. In the Canadian context a theoretical spatial order consisting of 1) areas of symbiotic relationship; 2) areas of low economic opportunity; 3) rural-urban fringe areas and; 4) areas of high agricultural potential, can be utilized to synthesize the degree, intensity and form of part-time farming.  相似文献   

16.
In southeastern Nigeria where population pressure is a problem of accelerating importance the agricultural land is in short supply thereby necessitating off-farm jobs to supplement farm income. There is therefore, a high incidence of part-time farming in the region. Analysis of the operational characteristics of thirty-six villages confirms that the intensity of part-time farming varies spatially according to the severity of environmental degradation resulting from population pressure. In addition, villages around urban/industrial centres participate actively in part-time farming since opportunities for off-farm employment are relatively higher. The situation in southeastern Nigeria is used to illustrate the prospects and problems of part-time farming in a developing economy. The implications of part-time farming on the agricultural economy and on rural development generally are examined. Policy measures are suggested that will direct the co-existence of part-time farming with work in the off-farm sector in order to achieve a beneficial and integrated rural development.  相似文献   

17.
The results of detailed pollen‐analytical investigations of a core from Lough Dargan, Co. Sligo, Ireland are presented. The pollen diagram spans much of the postglacial and documents changes in woodland composition and cover, and farming activity. Special attention is paid to prehistoric farming and to the significance of cereal‐type pollen. The first sign of arable farming coincides with the Elm Decline at c. 3760 BC. This early Neolithic farming phase extended over c. 750 years, the main Landnam phase having a duration of 700 years. After a break of about three centuries, Neolithic farming resumed. Late Neolithic farming was at first predominantly pastoral, but later (c. 2360–2130 BC) it had a distinct arable component. In the early Bronze Age, beginning c. 2130 BC, farming increased and woodland was substantially reduced for the first time. From then until the beginning of the late Iron Age (c. 80 BC), there was a sustained and strong human impact. In the late Iron Age, a distinct lull in pastoral farming lasted for about four centuries (c. 80 BC–AD 350). This facilitated woodland regeneration that included yew. Substantial woodland clearance, and farming that included a considerable arable component, characterized the Medieval and later periods. The changes recorded at L. Dargan and other sites in the region are discussed in the light of evidence for climate change provided by regional and super‐regional climate proxies. It is argued that climate may not have been a decisive factor in determining human impact and farming activity.  相似文献   

18.
Zhang, J., Lu, H., Wu, N., Li, F., Yang, X., Wang, W., Ma, M. & Zhang, X. 2010: Phytolith evidence for rice cultivation and spread in Mid‐Late Neolithic archaeological sites in central North China. Boreas, Vol. 39, pp. 592–602. 10.1111/j.1502‐3885.2010.00145.x. ISSN 0300‐9483. The history of rice (Oryza sativa) cultivation in North China is ambiguous owing to a lack of evidence from rice remains with precise ages in archaeological sites. In this paper, we present rice phytolith evidence from six archaeological sites in the Guanzhong Basin, central North China, dating from c. 5500 to 2100 cal. a BP (calibrated/calendar ages) based on 19 AMS‐dates. The phytoliths found in the three archaeological sites located on the second river terrace (Quanhu, Yangguanzhai and Anban) include three types of phytoliths from rice, namely bulliform, parallel‐bilobe and double‐peaked. These findings suggest that the earliest cultivated rice in central North China occurred not later than c. 5690 cal. a BP. After c. 5500 cal. a BP, the farming pattern in the Guanzhong Basin was characterized by dominant dry crops (e.g. millets) and locally cultivated rice. A likely spread route of rice from the lower reaches of the Huanghe (Yellow) River towards the Guanzhong Basin in central North China is speculated to have happened at c. 5690 cal. a BP. The findings of this study help us to understand the farming pattern in the area and how rice spread across the semi‐arid regions of East Asia.  相似文献   

19.
张掖市农耕期热量资源变化特征及对农业生产的影响   总被引:1,自引:0,他引:1  
殷雪莲  王涓力 《冰川冻土》2015,37(5):1406-1411
利用张掖市6个气象观测站1961-2010年实测气温资料,运用5 d滑动平均、气候倾向率、Mann-Kendall检验等方法,对农耕期初日、终日、持续日数及≥0℃积温的分布特征、年际和年代际演变规律及突变特点进行分析,结果表明:张掖市农耕期初日随海拔高度的升高推迟,终日则相反,农耕期日数自西北部向东南缩短,积温南北差异显著;近50 a初日提早,终日推迟,持续日数延长,积温增加趋势明显;20世纪70-80年代前期各地表现出农耕期初日推迟,终日提前,持续日数较短,≥0℃积温偏少的特点;20世纪90年代以来,终日延迟程度大于初日提前程度,积温增加显著,尤其2001-2010年增幅为50 a最大;山前绿洲及荒漠绿洲农耕期终日、持续日数及积温分别在1995/1997年、1982/1990年、1996/1999年发生了突变;农耕期热量资源增加,对作物种植结构的调整、生育进程的加快及产量均产生一定影响.  相似文献   

20.
以彭州川芎种植区的菜园土、稻田翻耕土、稻田免耕土和旱地(未种过川芎和蔬菜)四种土壤为研究对象,探讨了不同耕作方式下川芎对土壤中Cd、Pb的富集特征。结果表明:在四种耕作方式下,菜园土中Cd、Pb含量显著高于其他三种土壤,分别为1.10mg·kg-1和29.78mg·kg-1;土壤Cd综合污染指数和Hacanson系数分别为3.76和133.07,处于重污染和强生态危害状态。稻田翻耕土、稻田免耕土和旱地三种类型土壤在Cd含量上差异显著,依次为稻田免耕土(0.86mg·kg-1)稻田翻耕土(0.59mg·kg-1)旱地(0.37mg·kg--1),在Pb含量上三者差异不显著。川芎植株对Cd的富集在菜园土中显著高于其他土壤,表现为菜园土稻田免耕土旱地稻田翻耕土;川芎植株对Pb的富集以在稻田免耕土中最大,依次为稻田免耕土旱地稻田翻耕土菜园土。在四种土壤中,川芎叶片对Cd、Pb的富集能力均大于根茎,其中川芎叶片对Cd的富集能力是根茎的1.37倍,对Pb的富集能力是根茎的1.42倍,二者对Cd的富集能力在菜园土中差异最大(叶/根为1.56),对Pb的富集能力在稻田免耕土中差异最大(叶/根为1.98)。川芎对Cd、Pb的富集主要受轮作作物种类和耕作措施的影响。  相似文献   

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