长期施用家畜废弃物堆肥对土壤剖面15N自然丰度的影响

通过对两个长期田间试验的研究,分析了日本火山灰土(Andisols)及其溶液中15N自然丰度(δ 15N)在土壤剖面的分布,其目的是为了评价δ15N值能否作为预测家畜废弃物氮在迁移转化过程中形成的NO3-N污染的指标.在日本中央农业综合研究中心(NARC)进行了6年的试验处理包括猪场废弃物堆肥(猪粪堆肥),缓释尿素(缓释肥),普通铵态氮肥(普通化肥),及不施肥(对照);而在日本农业研究所(NARI)进行了12年的试验则包括三个施用量的牛场废弃物堆肥(牛粪堆肥),以该地长期不施肥的森林土壤(森林)作为对照.研究结果表明在NARC长期施用猪粪堆肥显著改变了δ15N值在土壤剖面的分布模式,猪粪堆肥小区0～20cm的δ15N值最高,然后按对照≥普通化肥＞缓释肥排列,原因主要为猪粪堆肥本身的δ15N值较高及其随后在土壤中的转化等反应;缓释肥处理后的土壤δ15N值最低,表明缓释肥施入土壤后的循环速率较慢或相对于施肥量其损失较低.在NARI,土壤δ15N值随着施肥量的增加而升高.同样不施肥条件下,NARI的森林土壤剖面的δ15N值比相对应的NARC的对照土壤剖面值高1～2个δ单位.NARC土壤剖面100 cm收集的土壤溶液的δ15N值的大小排列为猪粪堆肥＞普通化肥≥对照＞缓释肥;并且普通化肥小区土壤溶液δ15N最低值出现在剖面深度200～250 cm左右.以上结果显示土壤表层或土壤溶液中的δ15N值将有助于我们在火山灰土地区定性地预测污染物来源.     

Responses of waterbirds to flooding in an arid region of Australia and implications for conservation

Floods are a frequent but irregular feature of Australia's dryland river catchments. We investigated changes in abundances of waterbirds in north western New South Wales with changes in wetland distribution at local, catchment and broad scales. The abundance of most functional groups of waterbirds changed in response to broad scale changes in wetland distribution, while local abundance remained highly variable. Patterns of abundance varied among functional groups of waterbirds, with some immediately responding to changes in wetland distribution and area flooded, and others apparently responding to sequences of wetting and drying. In Australia, the main conservation issue for waterbirds is water and its use across the landscape and not the spatial arrangement of any fixed array of reserves established to protect them.     

Nitrogen Fixation and N-Balance Studies on Bambara Groundnut (Vigna subterranea L. Verdc) Landraces Grown on Tropical Acidic Soils of Malaysia

Bambara groundnut has great potential as an alternative crop for improving food security in its production regions and beyond. A field experiment was conducted at the Field Research Centre of the Crops for the Future to obtain information on the nitrogen (N) fixation and N balance of Bambara groundnut landraces on tropical acidic soils of Malaysia. Treatments consisted of three Bambara groundnut landraces (Ex-Sokoto, Kaaro, and NN-1) laid out in a randomized complete block design replicated three times. Results obtained revealed that Ex-Sokoto landrace was greater in yield and N fixation, whereas N balance (-haulm) was greater in NN-1 landrace. The results revealed grain yield of 703–2256 kg ha^?1 and N fixation from 32–81 kg ha^?1 and suggest that Bambara groundnut could be integrated into a cereal-based cropping system. Ex-Sokoto landrace appeared to be the most promising for yield and N fixation under Malaysian acidic soil conditions.     

Using natural 13C abundances to differentiate between three CO2 sources during incubation of a grassland soil amended with slurry and sugar

This study describes a novel approach to separate three soil carbon (C) sources by one tracer method (here ¹³C natural abundance). The approach uses the temporal dynamics of the CO₂ efflux from a C₃ grassland soil amended with added C₃ or C₄ slurry and/or C₃ or C₄ sugar to estimate contributions of three separate C sources (native soil, slurry, and sugar) to CO₂ efflux. Soil with slurry and/or sugar was incubated under controlled conditions, and concentration and δ¹³C values of evolved CO₂ were measured over a 2‐week period. The main assumption needed for separation of three C sources in CO₂ efflux, i.e., identical decomposition of applied C₃ and C₄ sugars in soil, was investigated and proven. The relative contribution to the CO₂ efflux was higher, but shorter with an increased (microbial) availability of the C source, i.e., sugar > slurry > SOM. The shortcomings and limitations as well as possible future applications of the suggested method are discussed.     

Habitat requirements of passerines and reedbed management in southern France

Reedbeds have high conservation value in Europe. In southern France, they are the major breeding habitat of five passerine species. Yet, habitat management is done primarily by water control to serve socio-economic rather than conservation interests, because we lack information on the species' ecological requirements. Determinants of passerine abundance were assessed through a comparative analysis of water regime, plant structure, and arthropod (food) distribution at 12 sites consisting of at least 10 ha of marsh densely covered with common reed (Phragmites australis). Overall bird abundance estimated through standardised mist netting was positively correlated with food availability (sweep-netted arthropods weighted by their occurrence in birds' diet), which was in turn negatively correlated with duration of ground dryness between June and December. Abundance of four of the five bird species was associated with specific vegetation parameters (reed diameter, dry reed density, growing reed height, etc.), which could be associated with particular management practices, especially with regard to water levels and salinity. Potential impact of socio-economic activities through their water management is addressed, as well as possible ways to minimise these impacts.     

土壤多样性: 中国山东省基于1:100万比例尺的SOTER的实例研究

The diversity of soils derived from different parent materials and developed on different terrains inShandong Province, China, was analyzed with the theory of pedodiversity using a 1:1000000 scale soilsand terrain digital database (SOTER) of Shandong Province in a geographical information system (GIS)environment. Diversity index of soils derived from different parent materials followed the sequence of igneousrock ＞ sedimentary rock ＞ metamorphic rock ＞ unconsolidated material. Diversity index of soils developedon different terrains followed the sequence of plain ＞ medium-gradient mountain ＞ medium-gradient hill＞ valley floor ＞ medium-gradient escarpment zone ＞ depression ＞ high-gradient mountain. Abundancedistributions of these soil groups matched the logarithmic normal distributions.     

苜蓿土壤氮磷钾丰缺指标初步研究

选取综合肥力差异较大的5种农田土壤,安排全肥(适量N,P,K肥)、缺氮、缺磷、缺钾盆栽试验,依据第一年干草产量用养分丰缺法确定了种植新牧1号紫花苜蓿土壤的氮、磷、钾丰缺指标。盆栽试验结果表明:种植新牧1号紫花苜蓿,土壤碱解氮含量10～21mg·kg-1为缺、21～29mg·kg-1为中、29～40mg·kg-1为丰,大于40mg·kg-1为极丰;土壤速效磷含量3.3～7.7mg·kg-1为缺、7.7～11.3mg·kg-1为中、11.3～17.8mg·kg-1为丰,大于17.8mg·kg-1为极丰;土壤速效钾含量49～123mg·kg-1为缺、123～191mg·kg-1为中、191～338mg·kg-1为丰,大于338mg·kg-1为极丰。     

稻油轮作田杂草种子库组成及其垂直分布特征

杂草种子库是潜在的杂草群落，对杂草可持续治理具有重要意义。在稻油轮作田杂草种子库中共检测到28种杂草，主要隶属于禾本科、玄参科和菊科，种子库密度达224 550 seed/m2，其中约64％为冬季油菜田杂草种子。从杂草种子库中种子的垂直分布来看，土壤表层的种子密度较高，占整个种子库数量的63.88%，而中层和下层的种子密度较小，其垂直分布主要有3种类型。种子库中优势恶性杂草有菵草Beckmannia syzigachne、异型莎草Cyperus difformis、看麦娘Alopecurus aequalis、稻槎菜Lapsana apogonoides和日本看麦娘Alopecurus japonicus等，随着土层深度的增加，各土层的优势种组成也有差异。通过采取措施调控杂草种子库的规模，有望实现稻油轮作田杂草的可持续治理。     

白纹伊蚊生活习性及年数量消长

结果表明:伊蚊白天产卵量大于晚上,而且喜在黑色、粗糙的容器中(靠近水面处)产卵;盛水容器离地面距离越高,白纹伊蚊产卵量越少.在福州,幼虫出现在3月中旬,成虫始见于3月下旬,7至9月为发生高峰期;10月底至翌年3月上旬不见成虫活动.