Studies on arbuscular mycorrhiza (AM) in the Alentejo (Portugal) using pea mutants resistant to AM fungi as a control tool for field conditions

The utilization and management of arbuscular mycorrhiza (AM) symbiosis may improve production and sustainability of the cropping system. For this purpose, native AM fungi (AMF) were sought and tested for their efficiency to increase plant growth by enhanced P uptake and by alleviation of drought stress. Pot experiments with safflower (Carthamus tinctorius) and pea (Pisum sativum) in five soils (mostly sandy loamy Luvisols) and field experiments with peas were carried out during three years at four different sites. Host plants were grown in heated soils inoculated with AMF or the respective heat sterilized inoculum. In the case of peas, mutants resistant to AMF colonization were used as non-mycorrhizal controls. The mycorrhizal impact on yields and its components, transpiration, and P and N uptake was studied in several experiments, partly under varying P and N levels and water supply. Screening of native AMF by most probable number bioassays was not very meaningful. Soil monoliths were placed in the open to simulate field conditions. Inoculation with a native AMF mix improved grain yield, shoot and leaf growth variables as compared to control. Exposed to drought, higher soil water depletion of mycorrhizal plants resulted in a haying-off effect. The growth response to this inoculum could not be significantly reproduced in a subsequent open air pot experiment at two levels of irrigation and P fertilization, however, safflower grew better at higher P and water supply by multiples. The water use efficiency concerning biomass was improved by the AMF inoculum in the two experiments. Transpiration rates were not significantly affected by AM but as a tendency were higher in non-mycorrhizal safflower. A fundamental methodological problem in mycorrhiza field research is providing an appropriate (negative) control for the experimental factor arbuscular mycorrhiza. Soil sterilization or fungicide treatment have undesirable side effects in field and greenhouse settings. Furthermore, artificial rooting, temperature and light conditions in pot experiments may interfere with the interpretation of mycorrhiza effects. Therefore, the myc- pea mutant P2 was tested as a non-mycorrhizal control in a bioassay to evaluate AMF under field conditions in comparison to the symbiotic isogenetic wild type of var. FRISSON as a new integrative approach. However, mutant P2 is also of nod- phenotype and therefore unable to fix N2. A 3-factorial experiment was carried out in a climate chamber at high NPK fertilization to examine the two isolines under non-symbiotic and symbiotic conditions. P2 achieved the same (or higher) biomass as wild type both under good and poor water supply. However, inoculation with the AMF Glomus manihot did not improve plant growth. Differences of grain and straw yields in field trials were large (up to 80 per cent) between those isogenetic pea lines mainly due to higher P uptake under P and water limited conditions. The lacking N2 fixation in mutants was compensated for by high mineral N supply as indicated by the high N status of the pea mutant plants. This finding was corroborated by the results of a major field experiment at three sites with two levels of N fertilization. The higher N rate did not affect grain or straw yields of the non-fixing mutants. Very efficient AMF were detected in a Ferric Luvisol on pasture land as revealed by yield levels of the evaluation crop and by functional vital staining of highly colonized roots. Generally, levels of grain yield were low, at between 40 and 980 kg ha-1. An additional pot trial was carried out to elucidate the strong mycorrhizal effect in the Ferric Luvisol. A triplication of the plant equivalent field P fertilization was necessary to compensate for the mycorrhizal benefit which was with five times higher grain yield very similar to that found in the field experiment. However, the yield differences between the two isolines were not always plausible as the evaluation variable because they were also found in (small) field test trials with apparently sufficient P and N supply and in a soil of almost no AMF potential. This similarly occurred for pea lines of var. SPARKLE and its non-fixing mycorrhizal (E135) and non-symbiotic (R25) isomutants, which were tested in order to exclude experimentally undesirable benefits by N2 fixation. In contrast to var. FRISSON, SPARKLE was not a suitable variety for Mediterranean field conditions. This raises suspicion putative genetic defects other than symbiotic ones may be effective under field conditions, which would conflict with the concept of an appropriate control. It was concluded that AMF resistant plants may help to overcome fundamental problems of present research on arbuscular mycorrhiza, but may create new ones.

A Modeling Analysis of Changing Global Land Use as affected by Changing Demands for Wood Products

The 21st century has brought new challenges for forest management at a time when globalization in world trade is increasing and global climate change is becoming increasingly apparent. In addition to various goods and services like food, feed, timber or biofuels being provided to humans, forest ecosystems are a large store of terrestrial carbon and account for a major part of the carbon exchange between the atmosphere and the land surface. Depending on the stage of the ecosystems and/or management regimes, forests can be either sinks, or sources of carbon. At the global scale, rapid economic development and a growing world population have raised much concern over the use of natural resources, especially forest resources. The challenging question is how can the global demands for forest commodities be satisfied in an increasingly globalised economy, and where could they potentially be produced? For this purpose, wood demand estimates need to be integrated in a framework, which is able to adequately handle the competition for land between major land-use options such as residential land or agricultural land. This thesis is organised in accordance with the requirements to integrate the simulation of forest changes based on wood extraction in an existing framework for global land-use modelling called LandSHIFT. Accordingly, the following neuralgic points for research have been identified: (1) a review of existing global-scale economic forest sector models (2) simulation of global wood production under selected scenarios (3) simulation of global vegetation carbon yields and (4) the implementation of a land-use allocation procedure to simulate the impact of wood extraction on forest land-cover. Modelling the spatial dynamics of forests on the global scale requires two important inputs: (1) simulated long-term wood demand data to determine future roundwood harvests in each country and (2) the changes in the spatial distribution of woody biomass stocks to determine how much of the resource is available to satisfy the simulated wood demands. First, three global timber market models are reviewed and compared in order to select a suitable economic model to generate wood demand scenario data for the forest sector in LandSHIFT. The comparison indicates that the ‘Global Forest Products Model’ (GFPM) is most suitable for obtaining projections on future roundwood harvests for further study with the LandSHIFT forest sector. Accordingly, the GFPM is adapted and applied to simulate wood demands for the global forestry sector conditional on selected scenarios from the Millennium Ecosystem Assessment and the Global Environmental Outlook until 2050. Secondly, the Lund-Potsdam-Jena (LPJ) dynamic global vegetation model is utilized to simulate the change in potential vegetation carbon stocks for the forested locations in LandSHIFT. The LPJ data is used in collaboration with spatially explicit forest inventory data on aboveground biomass to allocate the demands for raw forest products and identify locations of deforestation. Using the previous results as an input, a methodology to simulate the spatial dynamics of forests based on wood extraction is developed within the LandSHIFT framework. The land-use allocation procedure specified in the module translates the country level demands for forest products into woody biomass requirements for forest areas, and allocates these on a five arc minute grid. In a first version, the model assumes only actual conditions through the entire study period and does not explicitly address forest age structure. Although the module is in a very preliminary stage of development, it already captures the effects of important drivers of land-use change like cropland and urban expansion. As a first plausibility test, the module performance is tested under three forest management scenarios. The module succeeds in responding to changing inputs in an expected and consistent manner. The entire methodology is applied in an exemplary scenario analysis for India. A couple of future research priorities need to be addressed, particularly the incorporation of plantation establishments; issue of age structure dynamics; as well as the implementation of a new technology change factor in the GFPM which can allow the specification of substituting raw wood products (especially fuelwood) by other non-wood products.

The Corticiaceae (Basidiomycetes) in Taiwan

Geographically, Taiwan is an Island and situated in the northeast of Asia, on the western side of the Pacific Basin, at the southeast of main China, south of Japan, and north of the Philippines. The main topographic character is the longitudinally oriented mountainous area. More than 200 peaks rise above 3000 m. They departed Taiwan into two lowland areas, an eastern and western plain. Taiwan is departed into subtropical (north area) and tropical zone (south area), which have a warm and humid climate, due to the Tropic of Cancer passing through. The average annual temperature in the lowland amounts to 28°C (7~38°C). The temperate climate also presents in the mountainous areas. The tropical typhoons usually come in summer and bring heavy rain, while the monsoon seasons have an important effect on the regional rainfall distribution. The mean annual rainfall of Taiwan is about 2600 mm (1000~6700 mm); the mountainous areas receive more rain than the lowlands. In Taiwan, according to different temperature and vegetation, the ecological environments were given rise to vertical biotic zonations, and form five major types: highland snowfield, highland meadow, coniferous forest, deciduous forest, and tropical forest. Six National Parks in Taiwan are located in the mountainous areas, in the north, the south, and on Jinmen Island. The National Parks represent about 8.4% of the country area. In this study, the collection sites are situated in Yangmingshan, Shei-Pa, Yushan, and Kenting National Park. Due to the island isolation, the proportions of endemic species are great in Taiwan, which also presents a high biodiversity. There are 4255 species of vascular plants including 1133 endemic. 5936 species in 1276 genera of fungi are hitherto reported in Taiwan. Among them, 233 Corticiaceae species were recorded, over one third (79 species) of them are known only from Taiwan. The first fungal report in Taiwan is about Phytophthora cyperi, published by the Japanese researcher T. Kawakami in 1904. Therefore, the history of research about fungi in Taiwan is more than one hundred years old. An eminent Japanese mycologist K. Sawada made an intensive survey from 1919 to 1959, and reported 2464 fungi species in his eleven volumes of “Descriptive Catalogue of Formosan Fungi”. However, only a few species (21 species in 9 genera) of Corticiaceae were recorded. From 1973, Chen and Lin resumed the study on Corticiaceae, and also some other foreign mycologists contributed for this field after 1980. The German research group lead by Franz Oberwinkler from Tübingen University collected in Taiwan several times. They published a number of new species and new records. Since 1989, S. H. Wu, a Taiwanese mycologist, has published a great amount of reports on corticioid fungi from Taiwan. Corticioid fungi were made up by the large and heterogeneous unnatural family Corticiaceae and other resupinate fungi belonging to other natural families in the Agaricomycetes. Molecular studies have shown that corticioid genera are distributed across all major clades of Agaricomycetes indicating that the corticioid fungi represent a polyphyletic group. They have resupinate fruitbodies and similar habitats. Species are characterized by simple fruitbody, more or less effused, and present smooth, porioid, grandinioid to odontioid hymenial surface. The fruitbodies are differently colored and usually soft to tough. Most of the Corticiaceae species are wood-saprobic organisms and gain the energy from the decomposing of wood-substrate such as cellulose or lignin. Materials for this study were collected by the author and other mycologists in Taiwan during surveys in April and May 1996, and March 2007, using the spring season with its high humidity and warm climate which are optimal conditions for the development of fungi. For assembling, the convenience sampling method was used in this study. This approach was chosen because it enables to detect a high biodiversity in a short time, and also to find species with rare or patchy distribution. The collecting sites from the North to the South include four National Parks and some preserved forests. They cover many different habitats such as low lands and high mountains. Fresh specimens were dried and analysed with a light microscope. 265 specimens belonging to Corticiaceae were studied in this research. Among them, 50 species in 21 genera including 11 new records and 10 new species were described with text and drawing. Four new species are belonging to Hyphodontia (H. sp. nov. 1, H. sp. nov. 2, H. sp. nov. 3, and H. sp. nov. 4), four to Schizopora (Sch. sp. nov. 1, Sch. sp. nov. 2, Sch. sp. nov. 3, and Sch. sp. nov. 4), one in Trechispora (T. sp. nov. 1), and one in Tubulicrinis (T. sp. nov. 1). Species recorded as new are Aleurodiscus amorphus, Botryohypochnus isabellinus, Hyphodontia cineracea, Hyphodontia palmae, Hypochnicium vellereum, Merulius tremellosus, Metulodontia nivea, Paullicorticium ansatum, Phlebia radiata, Phlebiella ardosiaca, and Xylobolus frustulatus. Besides, Botryohypochnus, Merulius, Metulodontia, Paullicorticium, and Xylobolus are also newly recorded genera in Taiwan. The genus Hyphodontia presents the highest diversity with 20 out of 50 species recorded. The second important genus is Hyphoderma, however with only 5 species. This indicates that Hyphodontia and Hyphoderma have a higher ability to develop in variable environments and approximately shows the predominance of these two genera in Taiwanese Corticiaceae. There are 11 new records out of the 50 species recorded, representing 22%. Some species, e.g. Hypochnicium vellereum and Paullicorticium ansatum were in the past recorded only in Europe and North America with cold and temperate climate. The samples of them are for the first time found in the subtropical belt, and display some difference from those of temperate regions. These collections should be molecularly investigated to clarify if they represent the same species of temperate areas. Patchily distributed species, for example Phlebiella ardosiaca, previously known only in Europe, and Hyphodontia palmae collected only in Brazil, were first recorded in different continents. Two possibilities are indicated by these new records: they are worldwide species but very rare to be found, or the Taiwanese specimens are taxonomically different. More survey from other continents and molecular study for these collections should be done in the future to solve this question. The distribution of Corticiaceae in Taiwan presents the variations in the north, central, and south areas and shows the diversity in lowlands and high mountains. The results of this study provide the evidence that the temperate Corticiaceae species displays a wider distribution. Subtropical and tropical taxa probably have also high dispersal capacities, and could possibly be found in the future in neighboring areas such as China, Japan, Korea or South Asia, but this needs further researches. In the total of 50 species, 10 new taxa were described in this study, giving about 20%. Some new species (e.g. Hyphodontia sp. 1, Hyphodontia sp. 2, and Hyphodontia sp. 3) are very similar to known species (Hyphodontia sambuci and Hyphodontia formosana), and the distinctive characters of Schizopora sp. nov. 1 are intermediate between those of Schizopora paradoxa and Hyphodontia flavipora. Thus, these small differences between the new and known species, suggest that the speciation occurred when the fungi migrated into Taiwan, due to the high diversity of environment, and amounts of the endemic plants. Taiwan is an intermediate place for the south (tropical) fungal species to migrate and adapt to north (temperate) regions. The middle and high altitude environments in Taiwan offer good conditions for the fungal speciation and possibly the occurrence of physiological changes to adapt to the temperate climate. Thus Taiwan has an important position for the biogeography of Asia mycobiota. 5936 known species in Taiwan represent about only 20% of the estimated number (24000) of Taiwanese fungal taxa. In this study, the findings (22% new records and 20% new species) indicate that amounts of unknown fungi species are expected in Taiwan. The lack of knowledge indicates that many new species are awaiting description, and fungal survey in Taiwan remains in a Pioneer phase. The last three wide surveys of Corticiaceae researches took place 20 years before this study (Chen & Lin 1977, Lin & Chen 1989, Wu 1990). After previous important contributions, the present taxonomic study comprising 21 genera is the most extensive on Corticiaceae of Taiwan.

Short-term effects of human urine fertiliser and wood ash on soil pH and electrical conductivity

The fertiliser value of human urine has been examined on several crops, yet little is known about its effects on key soil properties of agronomic significance. This study investigated temporal soil salinization potential of human urine fertiliser (HUF). It further looked at combined effects of human urine and wood ash (WA) on soil pH, urine-NH_3 volatilisation, soil electrical conductivity (EC), and basic cation contents of two Acrisols (Adenta and Toje series) from the coastal savannah zone of Ghana. The experiment was a factorial design conducted in the laboratory for 12 weeks. The results indicated an increase in soil pH by 1.2 units for Adenta series and 1 unit for Toje series after one week of HUF application followed by a decline by about 2 pH units for both soil types after twelve weeks. This was attributed to nitrification of ammonium to nitrate leading to acidification. The EC otherwise increased with HUF application creating slightly saline conditions in Toje series and non-saline conditions in Adenta series. When WA was applied with HUF, both soil pH and EC increased. In contrast, the HUF alone slightly salinized Toje series, but both soils remained non-saline whenWA and HUF were applied together. The application ofWA resulted in two-fold increase in Ca, Mg, K, and Na content compared to HUF alone. Hence, WA is a promising amendment of acid soils and could reduce the effect of soluble salts in human urine fertilizer, which is likely to cause soil salinity.