Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferon...

Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient composition o...

Sugar cane is one of the most successful tropical crops, with many agronomic factors in its favour such as high yield, tolerance of a wide range of soils, resistance-to pests, a perennial growth habit, and a sophisticated supportive technology providing improved varieties and cultural practices. It is still grown almost exclusively for sugar production; however, a number of alternative uses hav...

Astrid Oberson, Else K. Bünemann, Dennis K. Friesen, I.M. Rao, Paul C. Smithson, Benjamin L. Turner, and Emmanuel Frossard, Institute of Plant Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland School of Earth and Environmental Sciences, University of Adelaide, Adelaide, Australia International Center for the Improvement of Maize and Wheat (CIMMYT) and International Q1 Fertili...

1. The Andes are predicted to warm by 3-5 °C this century with the potential to alter the processes regulating carbon (C) cycling in these tropical forest soils. This rapid warming is expected to stimulate soil microbial respiration and change plant species distributions, thereby affecting the quantity and quality of C inputs to the soil and influencing the quantity of soil-derived CO2 released...

Introduction Conclusions References

An appreciation of the dynamism of the links between soil resources and society provides a platform for examining food security over the next 50 years. Interventions to reverse declining trends in food security must recognize the variable resilience and sensitivity of major tropical soil types. In most agro-ecosystems, declining crop yield is exponentially related to loss of soil quality. For t...