ALBERT

Description: Purpose   We attempted to determine the contribution of entrapped gas bubbles to the soil methane (CH 4 ) pool and their role in CH 4 emissions in rice paddies open to the atmosphere. Methods   We buried pots with soil and rice in four treatments comprising two atmospheric CO 2 concentrations (ambient and ambient +200 μmol mol −1 ) and two soil temperatures (ambient and ambient +2 °C). Pots were retrieved for destructive measurements of rice growth and the gaseous CH 4 pool in the soil at three stages of crop development: panicle formation, heading, and grain filling. Methane flux was measured before pot retrieval. Results   Bubbles that contained CH 4 accounted for a substantial fraction of the total CH 4 pool in the soil: 26–45 % at panicle formation and 60–68 % at the heading and grain filling stages. At panicle formation, a higher CH 4 mixing ratio in the bubbles was accompanied by a greater volume of bubbles, but at heading and grain filling, the volume of bubbles plateaued and contained ~35 % CH 4 . The bubble-borne CH 4 pool was closely related to the putative rice-mediated CH 4 emissions measured at each stage across the CO 2 concentration and temperature treatments. However, much unexplained variation remained between the different growth stages, presumably because the CH 4 transport capacity of rice plants also affected the emission rate. Conclusions   The gas phase needs to be considered for accurate quantification of the soil CH 4 pool. Not only ebullition but also plant-mediated emission depends on the gaseous-CH 4 pool and the transport capacity of the rice plants. Content Type Journal Article Category Regular Article Pages 1-13 DOI 10.1007/s11104-012-1356-7 Authors Takeshi Tokida, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan Weiguo Cheng, Faculty of Agriculture, Yamagata University, 1-23 Wakaba-cho, Tsuruoka, Yamagata 997-8555, Japan Minaco Adachi, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan Toshinori Matsunami, Akita Prefectural Agriculture, Forestry and Fisheries Research Center, 34-1 Yuwaaikawa-aza-genpachizawa, Akita, 010-1231 Japan Hirofumi Nakamura, Taiyo Keiki Co., Ltd, Tokyo, 114-0032, 1-12-3 Nakajujo, Kita-ku, Tokyo 114-0032, Japan Masumi Okada, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan Toshihiro Hasegawa, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description: Background and aims   Dryland soil organic carbon (C) pools account for a large portion of soil C globally, but their response to livestock grazing has been difficult to generalize. We hypothesized that some difficulty generalizing was due to spatial heterogeneity in dryland systems. We examined the importance of heterogeneity at vegetation and landform scales on the response of litter and soil C and nitrogen (N) to grazing. Methods   Litter and soil C and N pools were quantified in different vegetation microsites (tree, shrub, open) and landform elements (dune, swale) across a grazing disturbance gradient in an eastern Australia semi-arid woodland. Results   Vegetation, landform, and grazing disturbance affected litter and soil C and N pools singly and through interactions. Resource pools were distributed unevenly across vegetation and landforms, and were largest beneath trees in swales. Grazing reduced pools in vegetation-landform combinations where pools were greatest. Pool increases from high to moderate disturbance sites were minimal. Conclusions   Litter and soil C and N pools are strongly affected by livestock grazing, although responses to grazing relaxation may be non-linear. Accurately predicting C and N responses to grazing in drylands will require accounting for patch differences at multiple spatial scales. Content Type Journal Article Category Regular Article Pages 1-15 DOI 10.1007/s11104-012-1288-2 Authors Jane G. Smith, Biology Department, New Mexico State University, MSC 3AF, Las Cruces, NM 88003-0032, USA David J. Eldridge, Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia Heather L. Throop, Biology Department, New Mexico State University, MSC 3AF, Las Cruces, NM 88003-0032, USA Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    Successful revegetation of saline land is dependent on seedling recruitment to maintain vegetative cover for lowering of saline water tables and agricultural production. This paper examines seasonal effects of tree/shrub microsites and leaf-litter on soil conditions and seedling recruitment in a saline grazing system planted with Eucalyptus sargentii Maiden tree rows (15 years old) and saltbush ( Atriplex spp.) inter-rows (8 years old). Salt bush rows were also slightly mounded. As litter accumulation decreases with increased distance from tree rows, soil conditions and seedling recruitment were compared between paired bare and litter-covered zones within three microsites: tree row, saltbush row 1 (saltbush row closest, viz. 3–4 m, to tree row) and saltbush mid-row (middle row of saltbush between adjacent tree rows, viz. 7–9 m from trees). Microsite facilitation in winter was negligible due to moderate temperatures and high water availability. However, in warmer months, saltbush mid-row microsites were most favourable for recruitment. Tree microsites inhibited recruitment through increased salinity, water repellency and potential root competition. Despite negative interactions within the tree row, trees indirectly facilitated recruitment through litter provision in saltbush rows. Overall, litter increased seedling densities through amelioration of soil temperatures and salinity. Litter reduced salinity (top 2 cm) in warmer months, from ‘severe’ where only halophytes survive, to ‘moderate’ where growth of non-halophytic species is possible, but at reduced rates. Recruitment was influenced by microsite characteristics including, litter quantities, mounding and row position. Content Type Journal Article Pages 1-13 DOI 10.1007/s11104-011-0850-7 Authors Claire Farrell, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia Christopher Szota, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia Richard J. Hobbs, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia Timothy D. Colmer, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    Warming and elevated atmospheric CO 2 (eCO 2 ) can elicit contrasting responses on different SOM pools, thus to understand the effects of combined factors it is necessary to evaluate individual pools. Over two years, we assessed responses to eCO 2 and warming of SOM pools, their susceptibility to decomposition, and whether these responses were mediated by plant inputs in a semi-arid grassland at the PHACE ( P rairie H eating a nd C O 2 E nrichment) experiment. We used long-term soil incubations and assessed relationships between plant inputs and the responses of the labile and resistant pools. We found strong and contrasting effects of eCO 2 and warming on the labile C pool. In 2008 labile C was increased by eCO 2 and was positively related to plant biomass. In contrast, in 2007 eCO 2 and warming had interactive effects on the labile C, and the pool size was not related to plant biomass. Effects of warming and eCO 2 in this year were consistent withtreatment effects on soil moisture and temperature and their effects on labile C decomposition. The decomposition rate of the resistant C was positively related to indicators of plant C inputs. Our approach demonstrated that SOM pools in this grassland can have early and contrasting responses to climate change factors. The labile C pool in the mixed-grass prairie was highly responsive to eCO 2 and warming but the factors behind such responses were highly dynamic across years. Results suggest that in this grassland the resistant C pool could be negatively affected by increases in plant-production driven available soil C. Content Type Journal Article Pages 1-12 DOI 10.1007/s11104-011-0853-4 Authors Yolima Carrillo, Department of Botany, University of Wyoming, Laramie, WY 82071, USA Elise Pendall, Department of Botany, University of Wyoming, Laramie, WY 82071, USA Feike A. Dijkstra, Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Level 4, Biomedical Building—C81, Australian Technology Park, Eveleigh, NSW 2015, Australia Jack A. Morgan, Rangeland Resources Research Unit, USDA-ARS, Crops Research Laboratory, 1701 Center Ave, Fort Collins, CO 80526, USA Joanne M. Newcomb, Department of Botany, University of Wyoming, Laramie, WY 82071, USA Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    Recent studies suggest that phosphatase activity in soil under legumes is higher than under other plants, but whether this is due to plant activity, microbe activity, or a response to altered soil N or P is unclear. I addressed two main questions: (i) do legumes have a higher root phosphomonoesterase (PME) activity than non-legumes?, and (ii) does root PME activity of legumes and non-legumes respond differently to variation in P or N supply? In four greenhouse experiments, I compared PME activity of seven leguminous forbs and nine other herb species (mostly forbs), under various supplies of inorganic P or N. Under low P and high N supply, legumes had on average a 50% or 120% higher PME activity than other forbs (expressed per fresh or dry roots). Legumes were similar or more plastic in their response to gradients of P, but less plastic to gradients of N. Root PME activity did not seem to depend on the presence of nodules, nor on growing in species monocultures or mixtures. On average leguminous forbs do have a higher root PME activity than other forbs, particularly under low inorganic P and N supply. Under higher N supply, the difference between leguminous and non-leguminous forbs becomes smaller, and PME activity of grasses may even be higher than that of legumes. The results help explaining why legumes can become abundant in plant communities on P and N-poor soils. Content Type Journal Article Pages 1-10 DOI 10.1007/s11104-011-0834-7 Authors Harry Olde Venterink, Institute of Integrative Biology, ETH Zurich, Universitätsstrasse 16, 8092 Zurich, Switzerland Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    Forest plantations and agroforestry systems with Schizolobium parahyba var. amazonicum have greatly expanded in the Brazilian Amazon, generally as an alternative for reforesting degraded areas. To our knowledge there are no reports of above- and below-ground production in these forest systems. We quantified litter and fine root production in 6-yr old Schizolobium -based plantation forests (monospecific: MON, mixture: MIX, and agroforestry system: AFS) and in ~25-yr old regrowth forest (REG) over 8–12 months. We used litter traps and ingrowth cores to quantify litter and fine root production, respectively. Annual litter production was significantly lower in Schizolobium -based plantations (mean ± standard error, MON = 5.92 ± 0.15, MIX = 6.08 ± 0.13, AFS = 6.63 ± 0.13 Mg ha −1  year −1 ) than in regrowth forest (8.64 ± 0.08 Mg ha −1  year −1 ). Schizolobium -based plantations showed significantly higher litter stock (MON = 7.7 ± 1.0, MIX = 7.4 ± 0.1 Mg ha −1 ) than REG (5.9 ± 1.3 Mg ha −1 ). Total fine root production over an 8-month period was significantly higher in Schizolobium -based plantations (MON = 3.8 ± 0.2, MIX = 3.4 ± 0.2, AFS = 2.7 ± 0.1 Mg ha −1 ) than in REG (1.1 ± 0.03 Mg ha −1 ). Six-yr old Schizolobium -based plantations and ~25-yr old regrowth forests showed comparable rates of litter + fine root production, suggesting that young forest plantations may be an interesting alternative to restore degraded areas due to early reestablishment of organic matter cycling under the studied conditions. Content Type Journal Article Pages 1-10 DOI 10.1007/s11104-011-0857-0 Authors Antonio Kledson Leal Silva, Universidade Federal do Para, Programa de Pos-graduacao em Ciencias Ambientais, Belem, Para, Brazil Steel Silva Vasconcelos, Embrapa Amazonia Oriental, Laboratorio de Ecofisiologia Vegetal, Belem, Para, Brazil Claudio José Reis de Carvalho, Embrapa Amazonia Oriental, Laboratorio de Ecofisiologia Vegetal, Belem, Para, Brazil Iracema Maria Castro Coimbra Cordeiro, Tramontina Belem S.A., Belem, Para, Brazil Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    Several studies have shown that soil biotic communities from organically managed fields are more diverse and exhibit higher activity levels compared to conventionally managed fields. The impact of these different soil communities on plant productivity and the provision of soil ecosystem services are, however, still unclear. Here, we test the effects of soil inoculation from each of three organic and three conventional maize fields on maize productivity and nutrient loss during leaching events induced by simulated rain. In particular, we examine whether differences in productivity and nutrient loss are related to the abundance and species composition of arbuscular mycorrhizal (AM) fungi. We hypothesized that soil biota from organically managed fields would improve maize growth and reduce nutrient leaching significantly more than those from conventionally managed fields. In contrast to our hypothesis, we found that plant productivity was negatively affected by soil inoculation, and this effect was stronger with inoculum from organic fields. Plant productivity was inversely correlated with AMF abundance, suggesting that enhanced carbon allocation to AMF is at least in part responsible for plant growth reduction under our experimental conditions. However, soil inoculation did alter the ecological functioning of the system by reducing phosphorus leaching losses after simulated rain. Moreover, these leaching losses were lower with increased hyphal density and were related with abundance of particular AMF types, suggesting that abundance of AMF and their community composition may be useful indicators of phosphorus leaching losses. The results demonstrate that soil communities from different agricultural fields vary in their impact on plant productivity and nutrient leaching losses. The results further indicate that there is a potential tradeoff between positive effects of soil communities on sustainability and negative effects on crop productivity. Content Type Journal Article Pages 1-13 DOI 10.1007/s11104-011-0828-5 Authors Erik Verbruggen, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands E. Toby Kiers, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands Patrick N. C. Bakelaar, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands Wilfred F. M. Röling, Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands Marcel G. A. van der Heijden, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, the Netherlands Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    For establishing rational farming mechanism, it is essential to know the relative contribution of different geological background and anthropogenic activities to trace elements in agricultural soil. In this paper, 282 surface soil samples were collected based on the different geological background. Five harmful trace elements (As, Cd, Cr, Hg and Pb) were analyzed. The results indicated most of trace elements contents were far beyond the threshold of uncultivated soil background, which indicate anthropogenic input strongly influenced on trace elements in agricultural soil. In addition, correlation analysis showed trace element contents exhibited high relationships with soil pH, C/N and physical clay (〈0.01 mm) ( p  〈 0.05). The principal component analysis showed that the first component included Cd, Cr and Hg, while Pb and As formed the second component. Furthermore, in the agricultural topsoil derived from carbonate rock, the high background values of trace elements and alkaline condition made the enrichments of Cd, Cr and Hg were the most significant. In the agricultural topsoil derived from red residua, the Pb and As contents was the highest values among the soil categories, partly because the type of soil had amount of physical clay (〈0.01 mm). In the agricultural topsoil derived from shale, the pH or physical clay had significant relationship with Cd, Pb, Hg and As ( p  〈 0.01). In the agricultural topsoil derived from sand stone, the acid condition and loose texture might account for the lowest values of Cd, Cr, Pb and As content to some extent. Content Type Journal Article Pages 1-11 DOI 10.1007/s11104-011-0866-z Authors Chenglong Tu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 China Tengbing He, Agricultural college, Guizhou University, Guiyang, 550001 China Congqiang Liu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 China Xiaohui Lu, School of Geographic and Environmental Sciences, Guizhou Normal University, Guiyang, 550001 China Yunchao Lang, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002 China Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description: Genes do not form channels Content Type Journal Article Pages 1-3 DOI 10.1007/s11104-011-0872-1 Authors Dev T. Britto, Department of Biological Sciences, University of Toronto, Toronto, ON, Canada M1C 1A4 Herbert J. Kronzucker, Department of Biological Sciences, University of Toronto, Toronto, ON, Canada M1C 1A4 Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X

Description:    This study aims to quantify nitrogen (N) effect on occurrence of perfect rice kernel (PRK) and imperfect grains which includes white-belly rice kernel (WBRK), white-core rice kernel (WCRK), green rice kernel (GRK), opaque rice kernel (ORK), and other imperfect grains (OTHERS). Two-year field experiments involving six japonica rice cultivars and seven N treatments were performed. The structural differences between white-belly and white-core tissues were compared using scanning electron microscope. Averaged over cultivars, grain yield increased progressively with N rate. PRK increased with N rate in 2008, but decreased with increased N rate in 2009. WBRK and WCRK decreased as N rate increased for both years. High N input resulted in higher occurrence of GRK and OTHERS for both years. Most starch granules in white-belly tissues are intact and surrounded by globular protein bodies, with many air spaces between them; while in white-core tissues, starch granules are easily broken into many single granules and no protein bodies are visible. Our results suggest that N has suppressing influence on chalky grains but favorable effect on other imperfect grains, and indicate different mechanism between WBRK and WCRK. Content Type Journal Article Pages 1-12 DOI 10.1007/s11104-011-0861-4 Authors Jiangfang Qiao, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Zhenghui Liu, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Shanyu Deng, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Huifeng Ning, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Xiaoyu Yang, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Zhaomiao Lin, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Ganghua Li, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Qiangsheng Wang, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Shaohua Wang, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Yanfeng Ding, College of Agronomy, Nanjing Agricultural University, Nanjing, 210095 China Journal Plant and Soil Online ISSN 1573-5036 Print ISSN 0032-079X