[...]... cover Crops on tree-land Forest gardens – 2.1.2 Cropping phase of shifting cultivation – 2.1.2 Trees on pasture/rangeland – 2 Plantation tree crops Trees and pasture silvopastoral Pasture on tree-land Plantation forest /trees Forest/plantation grazing – 2.1.1 / 2.2.3 Natural forest/tree cover Fodder banks – 2.2.5 Trees as fodder Trees and animals (not pasture) Trees and poultry Trees and pigs Trees and. .. understanding of the biological bases of soil fertility (Woomer and Swift, 1994) Trees with their numerous beneficial effects on soil fertility play an important role in this strategy The fundamental assumption in agroforestry, that the integration of trees into farming systems and landscapes can increase soil fertility, productivity and sustainability, was initially based mainly on the observation that soil. .. agroforestry studies in the future 10 G Schroth and F.L Sinclair This is not a methods book in the conventional sense, as it does not provide detailed field and laboratory descriptions of research methods It has been produced to augment rather than to replace established methods texts, such as Tropical Soil Biology and Fertility: a Handbook of Methods (Anderson and Ingram, 1993), by furnishing a broader... economic, chemical, physical and biological aspects of soil fertility Because of the integrated presentation of theoretical concepts and research methodologies, the book is particularly suitable for people who intend to do practical research on the interaction between trees and soils It will be most useful to those who already have some basic knowledge of both agroforestry and soil science, although there... worthwhile topics for their research, and for students to see individual research results within the context of the larger body of knowledge and hypotheses relating to tropical soil fertility and agroforestry The methods sections not only include those methods that are currently used in agroforestry, but also methods whose utility has been demonstrated in other fields and that could and should be applied... the tropics, the general biophysical processes are similar, and so most of the information presented here is also relevant to temperate conditions Moreover, trees and soils in agroforestry are not fundamentally different from trees and soils in forests and especially in savannas, and we expect that students and researchers in forestry, agronomy and ecology will also find much useful information in the... (Chapter 15) and soil fauna (Chapter 16) Soil erosion is the topic of the last chapter (Chapter 17) Throughout the text Impacts of Trees on Fertility 11 some effort has been made to demonstrate that the chemical, physical and biological components of soil fertility strongly interact Topics related to soil fertility and agroforestry that have not been included in this book include salinization and waterlogging,... abandoned and revert to secondary forest or savanna vegetation, unless woody regrowth is prevented by recurrent fires, as in the Imperata grasslands of South-east Asia (Garrity et al., 1997) © CAB International 2003 Trees, Crops and Soil Fertility (eds G Schroth and F.L Sinclair) 1 2 G Schroth and F.L Sinclair Although the rise in human populations has caused pronounced reductions in tree cover, trees. .. components of soil fertility Trees can improve the 8 G Schroth and F.L Sinclair nutrient balance of a site both by reducing unproductive nutrient losses from erosion and leaching and by increasing nutrient inputs through nitrogen fixation; they can improve soil structure, water-holding capacity and crop rooting volume; and they can increase the biological activity in the soil by providing biomass and a suitable... with valuable trees (Gouyon et al., 1993) Farmers in West African savannas maintain valuable trees, which also resist periodical fires, in and around their fields, giving rise to a distinct, park-like landscape (Boffa, 1999) Planters of tree crops such as cocoa, coffee and tea maintain or establish shade trees to reduce pest and disease pressures and nutrient requirements of their crops and protect them . x0 y0 w0 h0" alt="" TREES, CROPS AND SOIL FERTILITY CONCEPTS AND RESEARCH METHODS