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Rice (Oryza sativa L.) has been grown in the Ord River Irrigation Area (ORIA) in northern Western Australia since 1960. In 2011, a sheath rot of rice was observed in the ORIA. Symptoms were variable, appearing as either (i) oblong pale to dark brown lesions up to 3 cm length, (ii) lesions with pale grey/brown centers and with dark brown margins, or (iii) diffuse dark or reddish brown streaks along the sheath. Lesions enlarged and coalesced, often covering the majority of the leaf sheath, disrupting panicle emergence. Isolations from small pieces of infested tissues from plants showing sheath rot symptoms were made onto water agar, subcultured onto potato dextrose agar, cultures maintained at 20°C, and a representative culture lodged both in the Western Australian Culture Collection maintained at the Department of Agriculture and Food Western Australia (as WAC 13481) and in the culture collection located at the DAFF Plant Pathology Herbarium (as BRIP 54763). Amplification of the internal transcribed spacer (ITS)1 and (ITS)2 regions flanking the 5.8S rRNA gene were carried out with universal primers ITS1 and ITS4 according to the published protocol (4). The DNA PCR products from a single isolate were sequenced and BLAST analyses used to compare sequences with those in GenBank. The sequence had 99% nucleotide identity with the corresponding sequence in GenBank for Sarocladium oryzae (Sawada) W. Gams & D. Hawksworth. Isolates showed morphological (e.g., conidiophore and conidia characteristics) (2) and molecular (1) similarities with S. oryzae as described in other reports. The relevant sequence information for a representative isolate was lodged in GenBank (GenBank Accession No. JQ965668). Spores of S. oryzae were produced on rice agar under “black light” at 22°C to induce sporulation over 4 weeks. Under conditions of 30/28°C (day/night), 14/12 h (light/dark), rice cv. Quest, grown for 11 weeks until plants reached the tillering stage, was inoculated by spraying a susp

Forest soils in central Europe have received high atmospheric inputs of protons, sulphate and nitrogen (Chap. 15) since the beginning of industrialisation. As a result, chemical and biological processes in many German forest soils have changed (Godbold and Hüttermann 1994) and soil characteristics like pH, base saturation and C/N ratios have altered (Chap. 21). The mechanisms of the fate and the retention of this high atmospheric input of nitrogen still remain unclear. There are reports indicating that, despite high N-deposition since the beginning of the nineteenth century, most forests continue to retain nitrogen (Ulrich 1994; Johnson et al. 1997; Dise et al. 1998; Borken and Matzner 2004) even when the low C/N ratios in the surface organic layer have become low (Brumme and Khanna 2008). This raises the question of the retention mechanisms of nitrogen in forest soils. The use of labelled nitrogen makes it easy to follow internal nitrogen cycle of N-inputs in forest ecosystems (Nadelhoffer et al. 2004; Tietema et al. 1998; Feng et al. 2008) and soils (Mochoge and Beese 1983a, b). Often, labelled nitrogen is applied in a single dose which provides information on the nitrogen transformation rates under the current environmental conditions of addition. We applied constant rates of 15N labelled ammonium and nitrate as an artificial crown drip for long periods on undisturbed soil columns (Brumme and Aden 1995) under field and laboratory conditions in order to simulate continuous N-depositions so as to follow N-transformations under close to field conditions.

Micro-organisms (bacteria, fungi) contribute to more than 90% of the carbon dioxide evolved during decomposition of forest litter (Schaefer 1991), indicating their role in the element cycling in forest ecosystems. Nitrogen is mostly cycled between primary producers and decomposer biota. The activity and growth of micro-organisms depend on carbon and nutrient supply and the physico-chemical environment because of their high surface area/volume ratio of microbial bodies (Hattori and Hattori 1976; Paul and Clark 1996). Soil acidity has often been shown to reduce microbial biomass (Cmic) and to increase metabolic respiration (qCO2, ratio between microbial-respiration-C and microbial-biomass-C) in the surface mineral soil which was interpreted as an increased stress on micro-organisms living in acid soils (Anderson and Domsch 1993; Anderson, Chap. 20, this volume). In addition to the chemical stress, soil acidity may change the litter quality, litter amount and their distribution in the soil profile by acid sensitive earthworms. Quality and amount of litter determine the amount of micro-organisms that would live on the organic matter, and is indicated by the fraction of Cmic in organic carbon (Corg) (Anderson and Domsch 1986). Another effect of soil acidity relates to an increase in bacterial respiration with increasing pH. Less is known of microbial biomass and the mentioned relationships in the surface organic layer and deeper soil horizons. Here, we provide depthwise distribution of microbial carbon (Cmic), microbial nitrogen (Nmic), metabolic quotient (qCO2), the fraction of Cmic in Corg (Cmic-to-Corg ratio) and the fraction of fungal respiration of soil respiration in three beech forest soils, the Göttinger Wald, Zierenberg, and the Solling sites (for site description see Part A). The following questions will be addressed. (1) Does soil acidity reduce the microbial biomass and the qCO2 value in the acid soil profile at Solling site compared to the less acid soils at

Carbon and nitrogen are squantitatively important elements in forest ecosystems. Most of the carbon and nitrogen are stored in the soil and have a long turnover time. Only a small fraction of the N-pool is cycled every year through growth and litter fall and mineralisation of litter. Industrialisation has caused high acid and nitrogen inputs to ecosystems which have affected carbon and nitrogen stocks and mineralisation processes in forest ecosystems. In addition, global change of temperature and precipitation will also have a direct influence on carbon and nitrogen cycles in the short-term and on their stocks in the long-term. In order to detect measurable changes in the carbon and nitrogen stocks of forest soils, several decades and sometimes centuries may be needed because they have by nature high spatial variability and occur in large stocks. Therefore, it is very difficult to obtain information on fluxes of these elements by measuring changes in the bulk stocks. Direct measurements of input and output fluxes may provide useful information to assess any changes of the bulk stocks, and on understanding of human-induced changes in the mineralisation processes, as long as the values of input and output fluxes can be accurately measured.