L. Bergström – författare

Agriculture in the industrial world has gone A common interest of the contributors is increas­ through dramatic changes over the past decades. ing the understanding of the turnover of carbon Mechanization in combination with high inputs of and inorganic nutrients in terestrial ecosystems. fertilizers and pesticides has turned deficits of agri­ The authors approach this topic from different cultural products into surplus. Over the same directions depending on their interests and ex­ period we have experienced increased environment­ pertise. Difficulties are identified in the quantifica­ al problems in both the atmosphere and our water tion of below-ground production where death and resources, which have been associated with the re-growth, if incorporated into the calculations, changes in management practices. can change production figures considerably as Concern about the potential pollution by compared to values derived from "peak" estimates. nitrogen fertilizers as well as the low utilization The role of root-derived carbon is investigated in efficiency of applied nitrogen by plants has created relation to nutrient competition between roots and a need for a better understanding of nitrogen microorganisms, the cost of N2 fixation and the cycling in the plant-soil-water system. To achieve decomposition of organic nitrogen. Mycorrhizae this, it is neccessary to study process interactions use root-derived carbon and their roles in phos­ and process regulation in an ecosystem context. phorus conservation and in supplying nutrients to During the last decade many ecosystem studies the host are exemplified.

It is generally felt in the cosmology and particle astrophysics community that we have just entered an era which later can only be looked back upon as a golden age. Thanks to the rapid technical development, with powerful new telescopes and other detectors taken into operation at an impressive rate, and the accompanying advancement of theoretical ideas, the picture of the past, present and future Universe is getting ever clearer. Some of the most exciting new findings and expected future developments are discussed in this invaluable volume.The topics covered include the physics of the early Universe and ultra-high energy processes. Emphasis is also put on neutrino physics and astrophysics, with the evidence for non-zero neutrino masses emerging from both solar neutrinos and atmospheric neutrinos covered in great depth. Another field with interesting new results concerns the basic cosmological parameters, where both traditional methods and the potential of new ones, like deep supernova surveys and acoustic peak detections in the cosmic microwave background, are thoroughly discussed. Various aspects of the dark matter problem, such as gravitational lensing estimates of galaxy masses, cluster evolution and hot cluster electron distortions of the thermal microwave background spectrum, are also discussed, as are particle physics candidates of dark matter and methods to detect them. Cosmic rays of matter and antimatter are included as a topic, and so is the problem of the enigmatic dark energy of the vacuum.