Natural 15N and 13C abundance in Andisols influenced by long-term fertilization management in Japan

Two field experiments were conducted on Andisols in Japan to evaluate the changes in the natural ¹⁵N and ¹³C abundance in the soil profile and to determine whether the values of δ¹⁵N could be used as an indicator of fertilizer sources or fertilizer fate. The 6-year experiment conducted at the National Agricultural Research Center (NARC) consisted of the following treatments: application of swine compost (COMPOST), slow-release nitrogen fertilizer (SRNF), readily available nitrogen fertilizer (RANF), and absence of fertilization (CONTROL). Experimental plots located at the Nippon Agricultural Research Institute (NARI) received cattle compost at different rates for 12 years; a forest soil at this site was sampled for comparison. Swine compost application led to a considerable change in the δ¹⁵N distribution pattern in the soil profile, with the highest δ¹⁵N values recorded in the top 20 cm layers of the COMPOST plot, decreasing in the sequence of CONTROL >- RANF > SRNF, mainly due to the relatively high δ¹⁵N value of swine compost and its subsequent decomposition. In contrast, SRNF application resulted in the lowest δ¹⁵N values in soil, indicating the presence of negligible nitrogen losses relative to input and low nitrogen cycling rates. Values of δ¹⁵N increased with compost application rates at NARI. In the leachate collected at 1-m depth, the δ¹⁵N values decreased in the sequence of COMPOST > RANF ≥ CONTROL > SRNF. The δ¹³C values in soil peaked in the 40–60 cm layers for all the fertilizers. The δ¹³C value was lowest in forest soil due to the presence of plant residues in soil organic matter. These results indicated that the δ¹⁵N values in the upper soil layers or leachate may enable to detect pollution sources of organic or inorganic nitrogen qualitatively in Andisols.     

Enrichment of natural 15N abundance in frankia-infected nodules

Abstract

The enrichment of ¹⁵N in the nodules of some N₂-fixing leguminous plants is an interesting finding (Shearer et al. 1982). The extent of ¹⁵N enrichment differed depending on the plant species (Shearer et al. 1982; Yoneyama 1987) and bacterial strains (Steele et al. 1983), and in soybeans it was apparently related to the nitrogen fixation efficiency (Shearer et al. 1984)     

Habitat use and demography of Mus musculus in a rural landscape of Argentina

The main goal of the paper was to determine the habitat distribution of the house mouse (Mus musculus) within a rural landscape of Buenos Aires province, Argentina. We also studied the seasonal variation in abundance and reproductive activity. The habitats studied were poultry farms, human houses in a small village, cropfields, pastures, cropfield and pasture edges, riparian habitats (streams), railway embankments and woodlots. We captured 817 M. musculus and 690 individuals of 5 native rodent species. M. musculus was captured in poultry farms, houses, riparian habitats, cropfield and borders, but it showed a significantly higher abundance in poultry farms compared to the other habitats. Its presence outside poultry farms was significantly related to the distance to streams and poultry farms. The mean trapping success index of M. musculus did not show significant variations between periods, but the proportion of active males was significantly higher in the spring–summer period than in the autumn–winter period. All captures of M. musculus in cropfields, borders and riparian habitats occurred in the spring–summer period. The capture of M. musculus in many types of habitats suggests that it can disperse outside poultry farms, and streams may be used as corridors.     

Patterns of Liana Abundance,Reproductive Traits and Liana-Tree Relationships in Relation to Forest Management in a Tropical Forest in Ghana

The study determined the impacts of three forest management regimes—logging treated (LT), tropical shelterwood system (TSS) treated, and untreated forest (UF)—on liana abundance, reproduction and climbing guilds, and liana-tree relationship patterns in the Asenanyo Forest Reserve, Ghana. The first two regimes involved liana cutting over 20 and 53 yr ago, respectively. Lianas and their hosts were sampled in 10 randomly demarcated plots (40 × 40 m²) in each regime. Liana abundance and infestation were significantly lower in the LT forest than the UF, whereas these attributes were comparable in the TSS treated and the UF. Overall, the patterns of liana reproduction and climbing guilds were similar in the treated and untreated forests. Tree diameter was positively and significantly correlated to liana load, basal area, and degree of colonization in the treated and untreated forests. Mean liana load was the same on different tree bark types in the forest management regimes. These findings suggest that the impact of liana cutting on liana abundance was still apparent in the LT forest but not in the TSS treated forest. Again, the impacts of liana cutting on patterns of liana reproduction and climbing guilds and liana-tree relationships were not noticeable in the treated forests.     

陕北南部塬区苹果施肥指标体系研究

[目的]为高产、高效、土壤培肥和农环保护提供理论指导。[方法]采用"3414"完全实施设计方案,探究延安南部塬区土壤养分指标和施肥指标体系。[结果]研究不同处理下苹果的收获产量,制定、修正苹果地土壤养分丰缺指标,评价土壤养分状况,制定推荐施肥。[结论]开展测土配方施肥工作,必须建立或重新校验土壤养分丰缺指标,建立相应的推荐施肥指标。     

基于Landsat TM遥感影像的扬州市生态环境质量动态分析

利用扬州市近5年的遥感影像,对扬州市生态环境质量进行了动态分析。通过对遥感影像进行几何校正,对遥感数据进行解译,提取土地利用/覆盖信息,计算了扬州市生态环境质量指数,研究了扬州市近5年生态环境状况动态变化趋势。研究表明：扬州市近5年林地面积大幅度提高,植被覆盖指数、生物丰度指数逐年增加,生态环境状况逐年好转。     

Seasonal dynamics of biting midges (Diptera: Ceratopogonidae: Culicoides), the potential vectors of bluetongue virus, in Sweden

The outbreak of bluetongue (BT) in northern Europe 2006 initiated the monitoring of vectors, biting midges of the genus Culicoides in Sweden. In order to determine the diversity, distribution and seasonal dynamics of Culicoides, weekly collections were made during 2008 and during March-December 2009 using the Ondestepoort Veterinary Institute black light trap. Twenty sampling sites were selected in 12 provinces. In total of 30,704 Culicoides were collected in 2008 and 32,252 in 2009. The most abundant species were the potential vectors of BTV Culicoides obsoletus/C. scoticus that comprised of 77% of the total catches. Other biting midges collected were Culicoides impunctatus (9%), Culicoides grisescens (3%), Culicoides punctatus (2%), Culicoides chiopterus (2%) and Culicoides pulicaris (2%). Culicoides obsoletus/C. scoticus were most abundant during May-June and August-September. The majority of the species were active from March to November in 2008 and April to October in 2009. Species considered as potential vectors of bluetongue virus (BTV) occurred as far north as latitude 65°N (Kalix).     

三峡库区重庆段表层水体中微塑料组成及分布特征

为了解三峡库区水体中微塑料污染现状,于2019年12月对三峡库区重庆段4个城市人口密集区域江段进行表层水体采样,共采集12个水体样品,进行微塑料定性定量分析.结果显示:三峡库区重庆段各水域12个水体样本中微塑料的检出率为50％,主要形状包括颗粒、碎片、薄膜和纤维4类,其中以纤维和碎片为主,丰度范围为20.83～83.3...     

Interactions between past land use, life-history traits and understory spatial heterogeneity

Past land use has contributed to variability in the distribution of herbaceous species by reducing plant abundance and altering species’ chances of recolonizing suitable habitat. Land use may also influence plant heterogeneity by changing environmental conditions within stands. We compared the variability of understory herb abundance in southern Appalachian forests with different land-use histories to examine how past land use influenced plant heterogeneity. The cover of eleven focal species or genera was estimated and mineral soil concentrations were determined during 2001 and 2002 in eight stands that were farmed, logged, or had no disturbance history (reference) in western North Carolina. Analysis of the coefficients of variation revealed that the abundance of understory plants was more heterogeneous in disturbed stands compared with reference stands. However, when nutrient availability differences were accounted for by detrending the plant cover data, understory variability within stands declined, and no differences between disturbed and reference stands could be distinguished. This finding suggests that nutrient availability has important effects on plant heterogeneity, which depend on past land use. Species dispersal, seed size, and phenology also explained variability in the spatial heterogeneity of plants, but generally only before soil nutrient differences were statistically controlled. In addition to demonstrating that past land use has long-term effects on plant heterogeneity, these results indicate that soil nutrients may play different roles in determining vegetation patterns in historically altered and unaltered forests.