3 results
Harnessing carbon markets for tropical forest conservation: towards a more realistic assessment
- J. SMITH, K. MULONGOY, R. PERSSON, J. SAYER
-
- Journal:
- Environmental Conservation / Volume 27 / Issue 3 / September 2000
- Published online by Cambridge University Press:
- 10 May 2002, pp. 300-311
-
- Article
- Export citation
-
The proposed Clean Development Mechanism (CDM) of the Kyoto Protocol paves the way for financial and technological transfers to support forestry projects that sequester carbon or protect carbon stocks. From its inception, the concept has been highly controversial. It has been enthusiastically supported by those who believe that conservation of tropical forests will be difficult unless forest owners and managers are compensated for the environmental services of their forests. Others believe that financial transfers supporting ‘carbon farming’ would ignore social concerns and the full range of goods and services of forests. This paper examines the implications of CDM for forest conservation and sustainable use, by drawing on recent literature and the results of a policy dialogue with CDM stakeholders. We conclude that initial estimates of the contribution tropical forestry could make to both climate change mitigation and to forest conservation need to be scaled down. CDM payments for tropical forestry are likely to be received in a far more limited area than initially expected. The cost-effectiveness of forestry projects relative to projects in the energy sector may have been overestimated. In particular few estimates have adequately accounted for the likelihood that the duration of CDM forestry projects is unlikely to be as long as the residency time of carbon in the atmosphere. Also political realities and investor priorities may not have been sufficiently understood. CDM funding for forestry may also decline in future as economically viable clean technologies are increasingly developed in the energy sector. Tropical forests are likely to be an intermediate climate change mitigation strategy for buying time, until more permanent options become available. The most important justification for including forests in CDM may lie in the contribution CDM could potentially make to forest conservation and sustainable use. An analysis of the implications of CDM for forests reveals the importance of involving forest stakeholders more closely in the CDM debate. To prevent perverse outcomes and reduce the risk of ‘leakage’ of emission reduction to areas outside project boundaries, CDM projects may need to be limited to niches which meet certain political and institutional preconditions and where sufficient understanding of local decision-making and the broader context is available. CDM may be more effective if used to remove non-economic impediments to forestry activities that are economically viable and meet local needs. Lessons from the forestry sector in relation to plantations, natural forest management, forest conser- vation and non-timber forest products are discussed to illustrate the dangers of misusing CDM and also to give examples of how CDM could be harnessed for better use of forests. CDM should be seen as one more tool for enhancing the effectiveness of more conventional ways of promoting forest conservation and sustainable use.
Contribution of arbuscular mycorrhizal (AM) fungi and hedgerow trees to the yield and nutrient uptake of cassava in an alley-cropping system
- O. FAGBOLA, O. OSONUBI, K. MULONGOY
-
- Journal:
- The Journal of Agricultural Science / Volume 131 / Issue 1 / August 1998
- Published online by Cambridge University Press:
- 01 August 1998, pp. 79-85
-
- Article
- Export citation
-
A field trial on alley-cropping was conducted at the University of Ibadan research farm in the 1990/91 cropping season to assess the contributions of arbuscular mycorrhizal (AM) fungi and hedgerow woody legumes to the yield and nutrient uptake of cassava (Manihot esculenta Crantz) as an intercrop in an infertile soil. The trial also investigated the influence of AM fungi on the interplanting of a non-nodulating woody legume Senna siamea (syn. Cassia siamea) with a nodulating woody legume (Leucaena leucocephala).
AM contributions to cassava were greater than the hedgerow contributions, which demonstrated that AM associations are an essential component in the nutrition of cassava. In contrast to cassava, AM inoculation only influenced the leaf dry weight and uptake of nutrients of non-interplanted woody legumes but not the above-ground biomass and P uptake of interplanted woody legumes. However, non-inoculated interplanted Leucaena benefited more from indigenous AM fungi than the competing Senna. The negative contributions to the nutrient uptake (K, Ca and Mg) of cassava by hedgerows and the lack of response to AM inoculation in interplanted hedgerow woody legumes could be attributed to root competition among the different plant species growing in close proximity to each other. The present results show that cassava benefits more from AM association than Leucaena which in turn benefits more than Senna in an alley-cropping system.
3 - Biofertilizers: agronomic and environmental impacts and economics
- Edited by E. J. DaSilva, C. Ratledge, University of Hull, A. Sasson
-
- Book:
- Biotechnology: Economic and Social Aspects
- Published online:
- 04 August 2010
- Print publication:
- 30 April 1992, pp 55-69
-
- Chapter
- Export citation
-
Summary
Introduction
During the last decades increased fertilizer and pesticide use contributed to a spectacular increase in crop production, especially in Asia and South America. However, the price of fossil-fuel-based inorganic fertilizers relative to the prices of most stable crops has increased and chemical pesticides are both costly and harmful when they persist in the soil and enter the food chain. This explains the emphasis on current attempts to control soil- and plant-associated microorganisms, to lower fertilizer production costs, reduce environmental pollution whilst ensuring fair or even high yields, and to expand the adaptability of plants to reputedly unfavourable situations. The approach adopted is to introduce into soil or rhizosphere soil symbiotic or non-symbiotic microorganisms, a practice known as inoculation. The inoculants are also known as biofertilizers. Inoculation of plants by beneficial bacteria or fungi is routinely used in the legume-rhizobia symbiosis, fairly often in the ectomycorrhizal and to some extent in the endomycorrhizal symbiosis. Recently inoculation of actinorhizal plants has been developed and successfully adopted both in temperate and tropical countries. With some exceptions, inoculation with plant-growth-promoting rhizobacteria (PGPR) is still in its experimental stage. Soil inoculation with free-living blue-green algae has been and is still practised in Southeast Asia but the results are irregular.
In this chapter the discussion is restricted (1) to the presentation of the main types of biofertilizers (exclusive of Azolla and other green manures) and their modes of action, (2) to their agronomic and environmental benefits, (3) to biofertilizer technology, and (4) to the economics of the application of biofertilizers. The use of chemicals of microbial origin such as antibiotics or toxins (e.g. toxins produced by Bacillus thuringiensis) is not dealt with.