Refinar búsqueda
Resultados 1-10 de 2,868
Agricultural Research in an Era of Adjustment: Policies, Institutions and Progress
1995
Tabor, Steven R.
Agricultural research in an era of adjustment
1995
Tabor, Steven R.
Agricultural research in an era of adjusment. policies, institutions, an progress.
1995
Tabor, S. R.
Hydrochemical study of an aquifer system in an agricultural area in South West Spain
1995
Villalba, M. | Barragan de la Rosa, F.J. | Ternero Rodriguez, M. | Jimenez Sanchez, J.C. (Department and Analytical Chemistry, University of Seville, Avda Reina Mercedes s/n, E-41012 Seville (Spain))
Domestic Geese: Biological Weed Control in an Agricultural Setting Texto completo
1995
Wurtz, Tricia L.
Vertebrate herbivores can be effective agents of biological weed control in certain applications. I compared the use of domestic geese for weed control in an agricultural field with the herbicide hexazinone and with hand control. Newly planted spruce seedlings acted as a prototype crop that would be unpalatable to the geese. Trampling by geese led to as much as 47% tree seedling mortality during the 1st yr; this was reduced significantly by either limiting the amount of time the geese spent in the plots or surrounding seedlings with small wire fences. When compared with plots with no weed control, weed control by geese improved the diameter growth of the surviving seedlings by over 100% during the 1st yr of the study, but had no effect in the 2nd yr. The geese controlled a variety of weed species, but were most effective against quackgrass (Agropyron repens). However, grazing effectively selected for unpalatable weed species (including pineapple weed, Matricaria matricarioides, prostrate knotweed, Polygonum aviculare, and wild chamomile, Tripleurospermum phaeocephalum) so that by the end of the 2nd yr plots weeded only by geese had 25 times as much cover of unpalatable species as plots with no weed control. In contrast, the herbicide was ineffective against grass and effective against the unpalatable weed species. A successful integrated weed management strategy would thus require combining geese with another method of weed control, and would include measures to prevent crop trampling.
Mostrar más [+] Menos [-]Managing equity and gender in an agricultural programme in Malawi
1995
Hirschmann, D. (International Development Program, School of International Service, the American University, 4400 Massachusetts Avenue, Washington DC, 20016 (USA))
Mammalian wildlife conservation efforts in Malaysia: an agricultural perspective
1995
Hafidzi Mohd Noor (Pertanian Malaysia Univ., Serdang, Selangor (Malaysia))
Wildlife is an integral part of agricultural systems. Plantations, paddy fileds and other agricultural holdings are a natural or adopted habitat of myriad forms of wildlife. With a substantial percentage of present land use falling under the agricultural or cultivated category, the need to draw up an agricultural policy which accomodates conservation efforts is essential. A review of the present status of agricultural development should be undertaken so that further degradation of natural habitats to fullfill agricultural objectives is justifiable and genuine. Buffer zones and demarcation boundaries between agricultural land and forest reserve should be reviewed because of the shrinking habitats available to support viable populations of wildlife due to logging and deforestation programmes. Conversion of less productive agricultural land to forest 'reverts' is a possible move to absorb the pressure exerted on the viability of habitats which have been stretched beyond their limits. The reversal in agricultural policy calls for greater cooperation and coordination between government, state authorities and agricultural agencies together with forest and wildlife departments for planning and implementation. A review of policy in the long run should benefit wildlife through the creation of new ranging grounds and agriculture from reduced losses in productivity due to less frequent wildlife intrusions. With increasing interest in wildlife conservation agricultural land provides an opportunity for examining the various ecological components of wildlife such as predator-prey dynamics, spatial and temporal distribution of species, behaviourial adaptaions in new environments, responses to habitat modification and other processes. The concept of agricultural ecology should be redefined as its full appreciation will substantially contribute to our present understanding, conservation and management of the Malaysian natural habitat
Mostrar más [+] Menos [-]Nonpoint source pollution potential in an agricultural watershed in northwestern Pennsylvania
1995
Brenner, F.J. | Mondok, J.J.
A 155,947 ha portion of the Shenango River watershed in western Pennsylvania was evaluated as to the potential impact of agriculture drainage on water quality. Approximately a third of the area is being used as either cropland or pasture with approximately an equal percentage in forest lands. Eleven subwatersheds were evaluated as to their potential for nonpoint source pollution according to the criteria established by the Pennsylvania Department of Environmental Resources for the Chesapeake Bay Pollution Abatement Program. The individual components and overall rating for each subwatershed were then evaluated as to their correlation with four water quality variables based on 104 samples collected at 26 sampling stations throughout the watershed. There was a significant correlation between the overall rating factor for each subwatershed and each of the four water quality variables. In general, the watershed delivery factor, animal nutrient factor, and management factors were correlated with fecal coliform and phosphorus in the receiving streams, whereas the ground water delivery factor appeared to be more important in determining nitrate concentrations in these streams. These results indicate that manure and nutrient management, along with the exclusion of livestock from streams and the enhancement and/or replacement of riparian wetlands, are important approaches in reducing agricultural impacts in fresh water ecosystems.
Mostrar más [+] Menos [-]An economic study on the fragmented agricultural holdings in Japan
1995
Matsuoka, A. (Ehime Univ., Matsuyama (Japan). Coll. of Agriculture)
An ecoregional approach to enhancing agricultural research in tropical America
1995
International Center for Tropical Agriculture
