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Eurasian Soil Science - Soil formation on the human time scale is immensely time consuming, although it can be significantly accelerated through the effects of vegetation. The content of... 相似文献
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Liina Talgre Enn Lauringson Hugo Roostalu Alar Astover Viacheslav Eremeev Are Selge 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(1):70-76
Abstract A field experiment was conducted in 2004–2006 to investigate the effect of green manure treatments on the yield of oats and spring barley. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, and organic matter driven into soil and their effect on cereal yield. The spring barley field had a total of 41.7–62.4 kg N ha?1 and 1.75–2.81 Mg C ha?1 added to the soil with straw, weed, and roots, depending on the level of fertilisation; with red clover, and both common and hybrid lucerne undersowing, with barley straw and roots, the values were 3.45–3.96 Mg C ha?1 and 139.9–184.9 kg N ha?1. Pure sowings of these three leguminous green manure crops had total applications of 3.37–4.14 Mg C ha?1 and 219.7–236.8 kg N ha?1. The mixed and pure sowing of bird's-foot trefoil provided considerably less nitrogen and carbon to the soil with the biomass than with the other leguminous crops. Application of biomass with a high C/N ratio reduced the yield of the succeeding spring cereals. Of the green manures, the most effective were red clover and both common and hybrid lucerne, either as undersowing or as pure sowing. Undersowings with barley significantly increased the N supply for the succeeding crop without yield loss of the main crop compared with the unfertilised variant. Compared with ploughing-in of green manure in autumn, spring ploughing gave a 0.2–0.57 Mg ha?1 larger grain yield. 相似文献
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The potential of invasive non-native species to modify ecosystems is well established. Yet, the resulting visibility of the field of invasion biology and its growing influence on policy decisions has led to the development of persistent critique. In addition, public opposition to the removal of non-native species has repeatedly delayed interventions, sometimes to the point where eradication has become impossible. Understanding the views of the lay-public is thus of crucial importance. Our study investigated views on invasive non-native species as held by both the general public and ecologists. We chose an in-depth qualitative social scientific approach to identify species attributes that people draw on to evaluate biological invasions and potential management options. Interviews and focus group discussions (n = 79 participants) were conducted in the North-east of Scotland, and included members of the public from a wide range of backgrounds, as well as research ecologists and professionals dealing with invasive non-native species. Two key arguments, namely (i) harmfulness of a species and (ii) human responsibility for its spread, shaped both ecologists’ and lay-people’s discussions. Non-nativeness was understood by our participants in various ways and did not necessarily raise concerns about a species. Our results indicate that for information campaigns on species management to be effective, values inherent to the debate about invasive non-native species need addressing in a more explicit and transparent manner. Arguments such as human responsibility that are currently neglected in the scientific discourse, but that were important criteria for a wide range of participants, should be made explicit. 相似文献
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