BIODIVERSITY IN AGROECOSYSTEMS - CHAPTER 14 pdf

... already using. Sperling et al. (1993) successfully involved farmers in Rwanda in breeding and selecting segregating populations of beans. Integration of formal and informal breeding efforts are increasing ... CHAPTER 14 Conserving and Using Crop Plant Biodiversity in Agroecosystems Wanda W. Collins and Geoffrey C. Hawtin CONTENTS Introduction Sources of Genetic Diversity in Cr...

Ngày tải lên: 11/08/2014, 17:20

... especially in the rain-fed mixed farming systems of the developing world that will provide an incentive for investment in long-term soil fertility improvements, such as the use of inorganic fertilizers ... that in well-balanced grazing systems, especially those using multispecies, plant biodiversity increases. An exten- sive review of grazing and production data of 236 sites worldwide...

Ngày tải lên: 11/08/2014, 17:20

... also increases in abundance following exces- sive livestock grazing in the spring (West and Young, 1998). Livestock grazing also reduces the chance of fires by removal of fine fuels in the interspaces ... ecosystems, including indige- nous human cultures living in sustainable ways. All these views are legitimate and have to be respected in democratic societies. Even though scientists...

Ngày tải lên: 11/08/2014, 17:20

... processes (Tilman, 1996), maintaining and increasing protozoan biodiversity will contribute to more sustainable agriculture. Ecofarming and organic fertilizer management enhance pro- tozoan activity. Protozoa ... through burrowing move- ments and passing ingested cysts through guts, providing new hot spots and releasing greater quantities of nutrients, which have led to increased plant yiel...

Ngày tải lên: 11/08/2014, 17:20

... Orchesella cincta. The lethal concentration (LC 50 ) for atrazine was estimated at 224 µg/g atrazine in food. Mortality and molting frequency increased with increasing concentrations of atrazine. The ... role in faunal-induced mineralization of microbial carbon and nitrogen (van Veen and Kuikman, 1990). Carbon and nitrogen mineralization is generally faster in coarse than in fine-textu...

Ngày tải lên: 11/08/2014, 17:20

... beneficials. Today, high-yielding, high-quality, insect-, disease-, and weed-free monocultures require high-energy inputs to produce and harvest. With production costs escalating, interest in enduring and efficient ... Insects and Their Value Biodiversity Crisis Biodiversity in Farmland Biodiversity Monitoring Key Beneficials in Agroecosystems Intraspecific Diversity of Beneficials...

Ngày tải lên: 11/08/2014, 17:20

... Nicholls CONTENTS Introduction The Nature and Function of Biodiversity in Agroecosystems Patterns of Insect Biodiversity in Agroecosystems Plant Biodiversity and Insect Stability in Agroecosystems Patterns ... FUNCTION OF BIODIVERSITY IN AGROECOSYSTEMS Biodiversity refers to all species of plants, animals, and microorganisms existing and interacting within an ecosyst...

Ngày tải lên: 11/08/2014, 17:20

... Medium-Term Plan 199 8-2 000, ICRAF, Nairobi, Kenya. Ingram, J., 1990. The role of trees in maintaining and improving soil productivity — a review of the literature, in Agroforestry for Sustainable ... since in addition to their biodiversity these multistrata damar agroforests in Sumatra are financially attractive. Damar resins are utilized by industries in Indonesia or exported...

Ngày tải lên: 11/08/2014, 17:20

... 1987). Breeding in western North America during the boreal summer, Swainson’s hawks migrate to the nonbreeding grounds in South America with the advancing austral summer, maintaining both climatic ... made illegal in Argentina. An ecotoxicology program was initiated, with field and labo- ratory training for government agents, students, and veterinarians living in the Figure 2 Swainson’...

Ngày tải lên: 11/08/2014, 17:20

... 1) in the climax stage of succession (Odum, 1969). An increase in physical (inorganic) materials in urban systems coincides with a decreasing P/R ratio (i.e., a significant increase in main- tenance ... diversity in terms of maintaining wild or native species populations. Increased biodiversity at the landscape level (in the form of increased habitat or agroecosystem diversity) wi...

Ngày tải lên: 11/08/2014, 17:20