有机体之间化学相互作用的研究及其应用

有机体之间化学相互作用的研究及其应用宋启示（中国科学院昆明生态研究所,６５０２２３）ＣｈｅｍｉｃａｌＩｎｔｅｒａｃｔｉｏｎＡｍｏｎｇＯｒｇａｎｉｓｍｓａｎｄＴｈｅｉｒＡｐｐｌｉｃａｔｉｏｎ￥ＳｏｎｇＱｉｓｈｉ（ＫｕｎｍｉｎｇＩｎｓｔｉｔｕｔｅｏｆＥｃｏｌｏ－ｇｙ,ＡｃａｄｅｍｉａＳｉｎｉｃａ６５０２２３）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（１）：４５－４８。Ｔｈｉｓｐａｐｅｒｒｅｖｉｅｗｓｔｈｅｍｏｓｔａｃｔｉｖｅｒｅｓｅａｒｃｈｆｉｅｌｄｓｏｎｃｈｅｍｉｃａｌｉｎｔｅｒａｃｔｉｏｎａｍｏｎｇｏｒｇａｎｉｓｍｓ：（１）ａｌｌｅｌｏｐａ－ｔｈｙａｍｏｎｇｐｌａｎｔｓ,ｗｈｉｃｈｉｓｗｉｄｅｌｙａｐｐｌｉｅｄｉｎａｇｒｉｃｕｌｔｕｒｅａｎｄｈｏｒｔｉｃｕｌｔｕｒｅ,（２）ｂｉｏｃｈｅｍｉｃａｌｉｎｔｅｒａｃｔｉｏｎｂｅ－ｔｗｅｅｎｐｌａｎｔｓａｎｄｉｎｓｅｃｔｓ,（３）ｂｉｏｃｈｅｍｉｃａｌｉｎｔｅｒａｃｔｉｏｎａｍｏｎｇｉｎｓｅｃｔｓａｎｄ（４）ｂｉｏｃｈｅｍｉｃａｌｉｎｔｅｒａｃｔｉｏｎａｍｏｎｇｍａｍｍａｌｓａｎｄｂｅｔｗｅｅｎｍａｍｍａｌｓａｎｄｐｌａｎｔｓ．Ｉｎａｄｄｉｔ     

架棚中酚类化合物的研究

从架棚（ＣｅｒａｔｏｓｔｉｇｍａｍｉｎｕｓＳｔａｐｆｅｘＰｒａｉｎ）的乙酸乙酯部分分离得到１４个酚类化合物。经波谱技术,特别是２ＤＮＭＲ技术鉴定,其中化合物ｐｌｕｍｂｏｃａｔｅｃｈｉｎｓＡ（１）和Ｂ（２）为新化合物。其他１２个化合物被分别鉴定为ｐｌｕｍｂｏｌａｃｔｏｎｅＡ（３）、ｐｌｕｍｂａｂｉｃａｃｉｄ（４）、ｉｓｏｓｈｉｎａｎｏｌｏｎｅ（５）、ｅｐｉｓｏｓｈｉｎａｎｏｌｏｎｅ（６）、Ｎｔｒａｎｓｃａｆｅｏｙｌｔｙｒａｍｉｎｅ、Ｎｔｒａｎｓｆｅｒｕｌｏｙｌｔｙｒａｍｉｎｅ、ａｐｏｃｙｎｉｎ、ｖａｎｉｌｉｃａｃｉｄ、ｓｙｒｉｎｇｉｃａｃｉｄ、ｇａｌｏｃａｔｅｃｈｉｎ、（＋）ｃａｔｅｃｈｉｎ和１,２,６ｔｒｉＯｇａｌｏｙｌｇｌｕｃｏｓｅ。     

荒漠沙蜥的年龄划分

荒漠沙蜥的年龄划分徐海根（国家环保局南京环境科学研究所,２１００４２）杨凤翔,宋志明（兰州大学,７３００００）（四川大学,成都６１００６４）ＡｇｅＤｉｆｆｅｒｅｎｔｉａｔｉｏｎｏｆＰｈｒｙｎｏｃｅｐｈａｌｕｓｐｒｚｅｗａｌｓｋｉｉｏｎＤｅｓｃｒｔｓ￥．ＸｕＨａｉｇｅｎ（ＮａｎｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＥｎｕｉｒｏｎ－ｍｅｎｔａｌＳｃｉｅｎｃｅｓ,２１００４２）,ＹａｎｇＦｅｎｇｘｉａｎｇ（ＬａｎｚｈｏｕＵｎｉｕｅｒｓｉｔｙ,７３００００）,ＳｏｎｇＺｈｉｍｉｎｇ（ＳｉｃｈｕａｎＵｎｉｕｅｒ－ｓｉｔｙ,Ｃｈｅｎｇｄｕ６１００６４）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（４）：３０－３２．Ｕｓｉｎｇｍａｒｋ－ｒｅｃａｐｔｕｒｅｍｅｔｈｏｄａｎｄａｃｃｏｒｄｉｎｇｔｏｔｈｅｓｎｏｕｔ－ｖｅｎｔｌｅｎｇｔｈｇｒｏｗｔｈｐａｔｔｅｒｎ,ｆｉｖｅａｇｅｇｒｏｕｐｓｏｆＰｈｒｙ,ｉｏｃｅｐｈａｌｕｓｐｒｚｅｗａｌｓｋｉｉｏｎｄｅｓｅｒｔｓａｒｅｄｉｆｆｅｒｅｎｔｉａｔｅｃｄ．Ａｎｄｂａｓｅｄｏｎｔｈｅｄａｔａｏｆｌｉｚａｒｄｓｍｏｒｐｈｏｌｏ－ｇｙ,ｔｈｅｃｏｍｍｕｎｉｔｙｏｆＰｈｒｙｎｏｃ     

洞庭湖滩血吸虫易感地带保水生态灭螺的试验研究

洞庭湖滩血吸虫易感地带保水生态灭螺的试验研究张元培,朱南屏（湖南省水产科学研究所沅江４１３１００）（湖南省华容县血防站４１４２００）ＥｃｏｌｏｇｉｃａｌＥＩｉｍｉｎａｔｉｏｎｏｆＳｎａｉｌ（Ｏｎｃｏｍｅｌａｎｉａ）ｂｙＲｃｔａｉｎｉｎｇＷａｔｅｒｉｎＢｌｏｏｄＦｌｕｋｅ（Ｓｃｈｉｓｔｏｓｏｍａ）Ｓｕｓｃｅｐｔｉ－ｂｌｅＲｅｇｉｏｎｓＡｒｏｕｎｄＤｏｎｇｔｉｎｇＬａｋｅ￥．ＺｈａｎｇＹｕａｎｐｅｉ（ＩｎｓｔｉｔｕｔｅｏｆＦｉｓｈｅｒｉｅｓＲｅｓｅａｒｃｈｏｆＨｕｎａｎＰｒｏｖｉｎｃｅ,Ｙｕａｎｊｉａｎｇ４１３１００）,ＺｈｕＮａｎｂｉｎｇ（ＳｔａｔｉｏｎｏｆＳｎａｉｌＦｅｖｅｒＣｏｎｔｒｏｌｏｆＨｕａｒｏｎｇＣｏｕｎｔｙ,ＨｕｎａｎＰｒｏｖｉｎｃｅ,４１４２００）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（３）：２３－２５．Ｉｎｂｌｏｏｄｆｌｕｋｅ（Ｓｃｈｉｓｔｏｓｏｍａ）ｓｕｓｃｅｐｔｉｂｌｅｒｅｇｉｏｎｓｏｆｔｈｅｌａｋｅｂｅａｃｈ,ｅｘｐｅｒｉｍｅｎｔｓｏｆｗａｔｅｒｉｎｕｎｄａｔｅｄｅｌｉｍｉ－ｎａｔｉｎｇｓｎａｉｌ（Ｏｎｃｏｍｅｌａｎｉａ）ａｒｅｃａｒｒｉｅｄｏｕｔｂｙｂｕｉｌ     

海洋微藻基因工程的选择标记

６种海洋微藻新月菱形藻（Ｎｉｔｚｓｃｈｉａ ｃｌｏｓｔｅｒｉｕｍ Ｅｈｒ．）、牟勒氏角刺藻（Ｃｈａｅｔｏｃｄｒｏｓ ｍｕｅｌｌｅｒｉ Ｌｅｍｍ．）、三角褐指灌（Ｐｈａｅｏｄａｃｔｙｌｕｍ ｔｒｉｃｏｒｎｕｔｕｍ Ｂｏｈｌ．）绿光等鞭金藻８７０１（Ｉｓｏｃｈｒｙｓｉｓ ｇａｌｂａｎａ Ｐａｒｋｅ ８７０１）、亚心形扁藻（Ｐｌａｔｙｍｏｎａｓ ｓｕｂｃｏｒｄｉ－ｆｏｒｍｉｓ（Ｗｉｌｌｅ）Ｈａｚｅｎ）和     

云衫针层孔菌化学成分的研究

从云衫针层孔菌Ｐｈｅｌｌｉｎｕｓ ｙａｍａｎｏｉ（Ｔａｍｚ．）ｓｈａｗ分离得到１２个化合物,借助光谱分析鉴定为：８,１１,１３－ａｂｉｅｔａｄｉｅｎ－１８－ｏｉｃ ａｃｉｄ（１）,１,２－ｂｅｎｚｅｎｅｄｉ－ｃａｒｂｏｘｙｌｉｃ ａｃｉｄｂｉｓ（２－ｅｔｈｙｌ－ｈｅｘｙｌ）ｅｓｔｅｒ（２）,ｅｒｇｏｓｔｅｒｏｌ ｐｅｒｏｘｉｄｅ（３）,ｅｒｇｏｓｔａ ７,２２（Ｅ）－ｉｄｅｎ－３－ｏｌ（４）,ｅｒｇｏｓｔａ ７,２２（Ｚ）－ｄｉｅｎ－３－ｏｌ（５）,ｏｃｔａｄｅｃａｎｏｉｃ ａｃｉｄ－１,３－ｐｒｏｐａｎｅｄｉｙｌ ｅｓｔｅｒ（６）,ｏｃｔａｄｅｃａｎｏｉｃ ａｃｉｄ（７）,８（１９）,１４－ｌａｂｄａｄｉｅｎ－１３－ｏｌ（８）,ｅｒｇｏｓｔａ－４,６,８（１４）,２２－ｔｅｔｒａｅｎ－３－ｏｎｅ（９）,化合     

山海螺的化学成分研究

从药用植物册海螺（Ｃｏｄｏｎｏｐｓｉｓ Ｉａｎｃｅｏｌａｔａ）中分离得到４个化合物,分别鉴定为：莽草酸（ｓｈｉｋｉｍｉｃ ａｃｉｄ）⑴、顺丁烯二酸（ｓｕｃｃｉｎｉｃ ａｃｉｄ）⑵、丁香脂素（ｓｙｒｉｎｇａｒｓ８ｉｎｏｌ）⑶、鸢尾甙（ｔｅｃｔｏｒｉｄｉｎ）⑷、化合物１－４均为首次从该植物分得。     

宽阔水自然保护区的虫草及其相关真菌I.

本文报道采用贵州省宽阔水自然保护区的９种虫草,它们是多壳虫草新咱（ＣｏｒｄｙｃｅｐｓｐｏｌｙｃａｒｐｉｃａＬｉａｎｇ＆Ｌｉｕｓｐ．ｎｏｖ）,鼠尾虫草新种（ＣｏｒｄｙｃｅｐｓｍｕｓｉｃａｕｄａｔａＬｉａｎｇｅｔＬｉｕｓｐ．ｎｏｖ）针孢虫草（ＣｏｒｄｙｃｅｐｓａｃｉｃｕｌａｒｉｓＲｅｖ．ｅｘＢｅｒｋ．）罗伯茨虫草（Ｃｏｒｄｙｃｅｐｓｒｏｂｅｒｔｓｉｉ（Ｈｏｏｋ）,Ｇｒａｙ）下垂虫草（Ｃｏｒｄｙｃｅｐｓ     

持续农业是生态农业的继续与发展

持续农业是生态农业的继续与发展袁从,赵强基（江苏省农业科学院,南京２１００１４）ＳｕｓｔａｉｎａｂｌｅＡｇｒｉｃｕｌｔｕｒｅ—ＴｈｅＣｏｎｔｉｎｕａｔｉｏｎａｎｄＤｅｖｅｌｏｐｍｅｎｔｏｆＥｃｏｌｏｇｉｃａｌＡｇｒｉｃｕｌｔｕｒｅ．￥ＹｕａｎＣｏｎｇｙｉ;ＺｈａｏＱｉａｎｇｊｉ（ＪｉａｎｇｓｕＡｃａｄｅｎｚｙｏｆＡｇｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｅｓ,Ｎａｎｊｉｎｇ２１００１４）．ＣｈｉｎｅｓｅＪｏｕｍａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：１３－１５．Ｉｎｌｉｇｈｔｏｆｔｈｅｃｏｎｄｉｔｉｏｎｏｆｏｕｒｃｏｕｎｔｒｙ,ｔｈｉｓｐａｐｅｒｉｎｔｒｏｄｕｃｅｓｔｈｅｃｏｎｃｅｐｔｓａｎｄｃｏｎｔｅｎｔｓｏｆｓｕｓｔａｉｎａｂｌｅａ－ｇｒｉｃｕｌｔｕｒｅａｎｄｉｔｓｑｕａｎｔｉｔａｔｉｖｅｅｖａｌｕａｔｉｏｎｉｎｄｉｃｅｓ──ｓｕｓｔａｉｎａｂｉｌｉｔｙ,ｓｔａｂｉｌｉｔｙ,ｅｑｕａｌｉｔｙａｎｄｈａｒｍｏｎｉｔｙ（ｄｉ－ｖｅｒｓｉｔｙ）．Ｓｉｍｐｌｉｆｉｅｄｓｙｓｔｅｍｉｎｐｕｔ—ｏｕｔｐｕｔｅｑｕｉｌｉｂｒｉｕｍｉｓｕｓｅｄｔｏｅｓｔｉｍａｔｅｔｈｅｄｙｎａｍｉｃｓｏｆｓｏｉｌｆｅｒｔｉｌｉｔｙ．Ｐ     

兴安盟山杏灌木草原的排序

兴安盟山杏灌木草原的排序王晓江,章中,刘永军,章海波（内蒙古林业科学研究院,呼和浩特０１００１０）ＯｒｄｉｎａｔｉｏｎｏｆＰｒｕｎｕｓｓｉｂｉｒｉｃａＳｈｒｕｂ－ＳｔｅｐｐｅｓｉｎＸｉｎｇａｎＬｅａｇｕｅ,ＩｎｎｅｒＭｏｎｇｏｌｉａ￥ＷａｎｇＸｉａｏｊｉａｎｇ;ＺｈａｎｇＺｏｎｇ;ＬｉｕＹｏｎｇｊｕｎ;ＺｈａｎｇＨａｉｂｏ（ＩｎｎｅｒＭｏｎｇｏｌｉａＡｃａｄｅｍｙｏｆＦｏｒｅｓｔｒｙＳｃｉｅｎｃｅｓ,Ｈｕｈｈｏｔ０１００１０）．Ｃｈｉ－ｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（１）：２９－３２。ＴｈｅＰｒｕｎｕｓｓｉｂｉｒｉｃａｓｈｒｕｂ－ｓｔｅｐｐｅｓｉｎＸｉｎｇａｎＬｅａｇｕｅｏｆＩｎｎｅｒＭｏｎｇｏｌｉａａｒｅｓｔｕｄｉｅｄｕｓｉｎｇａｎｕｍｂｅｒｏｆｏｒ－ｄｉｎａｔｉｏｎｍｅｔｈｏｄｓ,ｉｎｃｌｕｄｉｎｇｐｏｌａｒｏｒｄｉｎａｔｉｏｎ（ＰＯ）,ｐｒｉｎｃｉｐａｌｃｏｍｐｏｎｅｎｔａｎａｌｙｓｉｓ（ＰＣＡ）ｏｒｄｉｎａｔｉｏｎａｎｄｃｏｒｒｅｓｐｏｎｄｅｎｃｅａｎａｌｙｓｉｓ（ＣＯＡ）ｏｒｄｉｎａｔｉｏｎ,２２ｐｏｌｔｓｏｆＰｒｕｎｕｓｓｉｂｉｒｉｃａｓｈｒｕｂ－ｓｔｅｐｐｅｓａｒｅｃ     

Histosol as an ecologically active constituent of peatland: a case study from Estonia

This study clarifies the area distribution of Estonian peat soils by three factors: main peat soil groups, peat thickness and peat decomposition degree. A digital soil map (1:10,000) and supplementary database were used for summarizing the distribution of peat soils. From the combined database with 859,701 polygons the soil mapping unit code, formula of soil texture (including peat) and formula of epipedon fabric were compiled using the MapInfo software. Peat soils form altogether 10,038 km² or 23.5% of the total Estonian soil cover. From the peat soils the fen soils form 59.0%, bog soils 21.7% and transitional bog soils 14.7%. 45% of peat soils are well, 26% moderately and 29% slightly decomposed, by the peat thickness 13% are very shallow, 21% shallow and 66% thick. The general ecological characterization of peat soils and their mutual relationship with plant cover are given for the main peat soil taxa. The dominant natural ecosystems formed on peatlands are: (1) mixed birch, alder, spruce and pine forests on thin (<100 cm) well decomposed eutrophic fen soils, and (2) a sparse pine forests and hummock-ridge-hollow raised bogs wooded sparsely by pine on thick (>100 cm) slightly decomposed oligotrophic bog soils. The accumulation of organic carbon in peatlands soil cover (0–50 cm) totals 269.4±12.7 Tg and in epipedon layer (as superficial part of soil cover; 0–30 cm) 129.9±5.8 Tg. The former is sequestrated into 543.7 Tg of peat, which forms 22.9% of the total Estonian peat resources (2.37 Pg).     

Distribution of total mercury in peat soil profiles in West Siberia

Total mercury content in peat soils of different botanical composition has been determined. Mercury content in peat depends on principal properties of peat soil such as botanical composition, ash content, degree of peat decomposition, as well as nitrogen, carbon, and humic acid content in peat. A model based on the mercury/biomass concept is proposed to determine the distribution of total mercury in peat soil profiles in West Siberia from the content of the main biogenic elements C and N.     

施用泥炭对风沙土改良及蔬菜生长的影响

通过盆栽试验比较了施用不同剂量的泥炭(0％、2％、5％、8％及10％)对风沙土改良的效果和对白菜生长及产量的影响。结果表明,泥炭能增强风沙土的持水能力,降低土壤的pH值,增加土壤中有机质、全氮、速效氮和速效磷等的含量;白菜根系长度、生物量、高生长和地上部分的生物量均有增加,其中8％泥炭处理为最佳,其根系长度、根鲜重、干重、高生长、地上部分鲜重、干重依次比对照增加71％、402％、464％、107％、847％和1001％;同时施用泥炭还有利于提高白菜干物质的积累及其品质。     

Trichoderma harzianum—interaction with plants and effect on growth response

The fungus Trichoderma harzianum which was applied to pathogen-free soil, induced an increase in emergence of seedlings, plant height, leaf area and dry weight. The fungus was applied to the soil by three different methods: conidial suspension, wheat-bran/peat preparation and seed coating. The most prominent effect was observed in the wheat-bran/peat preparation. Responses occurred in different plant growth substrates such as sandy loam soil, autoclaved soil, vermiculite, peat and a mixture of vermiculite and peat (1:1, v/v). T. harzianum was also found in roots of plants growing in soil treated with the fungus.     

宁夏典型天然草地土壤团聚体稳定性及其有机碳分布特征

土壤团聚体作为土壤结构的基本单元和土壤有机碳存在的重要场所,对维系土壤质量和生态环境可持续发展具有重要作用。为探究宁夏天然草地土壤团聚体稳定性及其有机碳分布特征,以宁夏4种典型的天然草地（草甸草原、温性草原、草原化荒漠和荒漠草原）为研究对象,系统开展研究。结果表明：草甸草原、温性草原和草原化荒漠各粒级机械团聚体和水稳性团聚体含量均呈现随粒径减小而先减小后增大趋势,荒漠草原机械团聚体含量呈现随粒径减小而先减小后增大的趋势,水稳性团聚体含量呈现随粒径减小逐渐增大的趋势;且草甸草原和温性草原机械稳定性和水稳性团聚体在0-10 cm、10-20 cm和20-40 cm 3个土层均以>0.25 mm大团聚体为主,草原化荒漠和荒漠草原水稳性团聚体均以<0.25 mm的微团聚体为主。4种草地类型机械团聚体和水稳性团聚体MWD和GMD,以及各粒级土壤团聚体有机碳含量均表现为草甸草原和温性草原显著高于草原化荒漠和荒漠草原。草甸草原和温性草原在3个土层深度均以>0.25 mm的大团聚体对有机碳的贡献率最高,分别达到43.86%、59.26%、58.89%和58.02%、54.03%、57.15%;草原化荒漠和荒漠草原在3个土层深度,均以<0.25 mm的微团聚体贡献率高,分别达到了60.37%、55.86%、54.33%和75.61%、78.34%、78.74%。结果表明：草甸草原和温性草原较草原化荒漠和荒漠草原土壤团聚体稳定性更高,更有利于土壤有机碳累积。     

Vertical structure of bacterial communities in peats of the Yakhroma river floodplain

The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole.     

Recovery of Methanogenesis Following Summer Drought in Soils from Two Cool Temperate Peatlands,New York State,USA

Following a summer drought, intact cores of peat soil from two cool temperate peatlands (a rain-fed bog and a groundwater-fed swamp) were exposed experimentally to three different water table levels. The goal was to examine recovery of anaerobic methanogenesis and to evaluate peat soil decomposition to methane (CH₄), carbon dioxide (CO₂), and dissolved organic carbon (DOC) upon rewetting. Methane emission from soils to the atmosphere was greatest (mean = 80 μmol m^?2 s^?1) when the entire peat core was rewetted quickly; emission was negligible at low water level and when peat cores were rewetted gradually. Rates of CO₂ emission (mean = 1.0 μmol m^?2 s^?1) were relatively insensitive to water level. Concentrations of CH₄ in soil air spaces suggest that onset of methanogenesis induces, but later represses, aerobic oxidation of CH₄ above the water table. Concentrations of CO₂ suggest production at the soil surface of swamp peat versus at greater depths in bog peat. Portions of peat soil incubated in vitro without oxygen (O₂) exhibited a lag before the onset of methanogenesis, and the lag time was less in peat from the cores rewetted quickly. The inhibition of methanogenesis by the selective inhibitor 2-bromoethanesulfonic acid (BES) decreased CO₂ production by 20 to 30% but resulted in an increase in concentrations of DOC by 2 to 5 times. The results show that methanogens in peat soils tolerate moderate drought, and recovery varies among different peat types. In peat soils, the inhibition of methanogenesis might enhance DOC availability.     

Ion flux from precipitation to peat soil in spruce forest–<Emphasis Type="Italic">Sphagnum</Emphasis> bog communities in the Ochiishi district,eastern Hokkaido,Japan

To evaluate the contribution of proton flux from precipitation on peat acidification in mire ecosystems, we estimated ion fluxes to peat soils from bulk deposition in Sphagnum-dominated bogs and from throughfall plus stem flow in spruce forests in three cool-temperate ombrogenous mires in the Ochiishi district, northeastern Japan. We tested the hypothesis that proton fluxes from the atmosphere to peat soils are affected by vegetation types, leading to the consequent difference in soil acidity. The proton flux in bulk deposition was higher than that in throughfall plus stem flow, but the concentration of H⁺ in the peat surface water in Sphagnum bogs was lower than that in spruce forests. The inverse relationship between proton flux and soil water acidity means that the soil water acidity could not be explained quantitatively by proton flux from the atmosphere to the peat surface. The ion fluxes of sea-salt components were dependent on the distance from the coast to the mires. This means that the sea-salt accumulation in the peat surface soil can be directly attributed to the high flux of sea-salt from precipitation. The flux of sea-salts deposited on the mires positively correlated with the H⁺ concentration of the peat surface water in each community, implying that the acidity of peat surface water depends on the cation fluxes from precipitation.     

An Ecological Study of Marked Rhizobium trifolii Strains on the Host Plant Trifolium repens var. Huai in an Acidic Peat and a Neutral Mineral Soil

An ecological study of the nodulation of Trifolium repens var. grassland Huai by genetically marked Rhizobium trifolii was carried out in two Irish soils, a neutral mineral and an acidic peat. An indigenous population of 2 x 10⁴ R. trifolii /g was found in the mineral soil. In the peat soil, 4 x 10¹ R. trifolii /g was found in the uninoculated peat. This number increased to 4.5 x 10⁵ R. trifolii /g, however, eight weeks after the peat soil was neutralized, supplemented with nutrients and sown with uninoculated clover seed. Indigenous R. trifolii strains from the mineral soil were effective whereas strains from the peat soil were ineffective on the host plant T. repens under plant room conditions. The introduced strains were inoculated on to clover seed at the rate of 1 x 10⁵ R. trifolii /seed. In the mineral soil, the introduced inoculum failed to establish at any period during the growing season. In the peat soil, the percentage establishment of the introduced inoculum varied from 40-50% of nodules selected eight weeks after sowing to 70-90% of nodules selected at the end of the growing season.     

Mycotrophy of crops in rotation and soil amendment with peat influence the abundance and effectiveness of indigenous arbuscular mycorrhizal fungi in field soil

Mycotrophy of previous crops has been shown to have an impact on arbuscular mycorrhizal fungi (AMF), and the growth and productivity of succeeding crops. We studied the impact of 3 years of cultivation of eight crops with different degrees of mycotrophy, including mycorrhizal (strawberry, rye, timothy, onion, caraway) and non-mycorrhizal (turnip rape, buckwheat, fiddleneck) hosts, as well as the impact of peat amendment, on the effectiveness, amount and diversity of indigenous AMF. A field experiment having a split-plot design with peat amendment as the main plot, crop cultivation as a sub-plot and three replications, was carried out on silt clay mineral soil in 1999–2001. A well-humified dark peat was applied immediately before establishment of the field experiment. Each year, the relative mycorrhizal effectiveness of soil collected in September, in terms of shoot dry weight (RME_DW), was determined in a bioassay. In the 3rd year of the experiment, AMF spores were also extracted and identified from the field soil. Expressed as the mean of 3 years of cropping in unamended soil, the mycorrhizal crops strawberry and caraway maintained RME_DW most effectively, while the values were lower in the non-host crops buckwheat, turnip rape and fiddleneck. In addition, the numbers of AM spores detected in soil were considerably greater during 3 years of strawberry cultivation. In soil under caraway, there were high numbers of AM spores compared to the other crops. In soil amended with peat, the situation was in some cases opposite of that of unamended soil; RME_DW was highest in rye and onion and lowest in strawberry and caraway. The reasons behind the negative impact of peat on mycorrhizal effectiveness in strawberry soil may be due to the microbiological properties of peat. The importance of including mycotrophic species in crop rotations for maintaining high soil quality and for increasing yields of subsequent crops is discussed.