闽江下游山地巨桉无性系施肥试验研究

对巨桉无性系施用不同肥料组合的试验研究结果表明:以火烧垃圾土做基肥再配施适量的尿素做追肥,组成了有机—无机复混肥体系,其施用效果明显优于纯化肥类肥料组合,不但能明显提高林分生产力、维持地力,而且经济效益较好,充分显示出有机无机混合肥的施用优势;采用火烧垃圾土2 kg.株-1(基肥)+尿素200 g.株-1(追肥)的施肥方案,2年生时林分平均树高、胸径、材积和蓄积分别可达9.41 m、9.51 cm、0.0335 m3和53.72 m3.hm-2,投入产出比高达1∶2.9,经济纯收入是纯化肥类肥料组合的2.0~2.8倍,符合桉树短工林集约经营和持续发展方向,值得推广应用。     

湖南湘潭矿业废弃地土壤特性研究

对湖南湘潭锰矿废弃地的土壤基质特殊性和少量自然定居植物营养元素和重金属元素含量进行研究.结果表明:尾矿废弃地土壤以砂粉土为主,通气透水性能差,渗透系数小,易造成地面积水;矿渣废弃地渗透系数大,蓄水量少而蒸发失水强,抗旱力弱.2类废弃地土壤营养元素含量低,重金属元素锰、铜的含量高,毒害大.在自然定居的少量植物中,商陆和荩草为超积累植物.采用植物生物原位修复法改善极端生境条件,既经济又高效.     

四川主要农用土壤中丛枝菌根真菌数量和种类的初步研究

用形态学分类法测土壤样品中丛枝菌根真菌的数量和种类分布特点,结果表明,丛枝菌根真菌广泛分布于四川农业土壤中,但其数量和种类较少,种群结构单一。共计分离鉴定出3个属18种丛枝菌根真菌,球囊霉属(Glomus)13种,无梗囊霉属(Acaulospora)2种,盾巨孢囊霉属(Scutellospora)3种,其中只有Gl.mosseae,Gl.cale-donium,Gl.constrictum的出现频率大于10%,是主要四川省农用土壤中的优势种。研究还发现,地域因素、土壤类型和土壤的理化性质以及人为因素对丛枝菌根真菌的数量和种类有显著影响(P<0.05)。     

Controlling factors of sheet erosion under degraded grasslands in the sloping lands of KwaZulu-Natal, South Africa

The current increase in the global demand for food and fresh water and the associated land use changes or misuses exacerbate water erosion which has become a major threat to the sustainability of the soil and water resources. Soil erosion by rainfall and runoff is a natural and geologic phenomenon, and one of the most important components of the global geochemical cycle.Despite numerous studies on crop lands, there is still a need to quantify soil sheet erosion (an erosion form that uniformly removes fertile upper soil horizons) under grasslands and to assess the factors of the environment that control its spatial variation. For that purpose, fifteen 1 m² micro-plots installed within a 23 ha catchment under pasture in the sloping lands of KwaZulu-Natal (South Africa) were monitored during the 2007-2008 rainy season to evaluate runoff (R) and sediment losses (SL). Soil losses computed from the 37 rainfall events with soil erosion averaged 6.45 ton ha⁻¹ year⁻¹with values from 3 to 13 ton ha⁻¹ year⁻¹. SL were significantly correlated with the proportion of soil surface coverage by the vegetation (P < 0.01) whereas the slope gradient, and soil characteristics such as bulk density or clay content were not correlated. R and SL increased as the proportion of soil surface coverage decreased and this trend was used to predict the spatial variations of sheet erosion over the 23 ha catchment. Greater sheet erosion occurred at the catchment plateau and at the vicinity of gully head cuts probably in relation to regressive erosion. Mitigating sheet erosion would require an appropriate management of the soil cover through appropriate management of cattle grazing, especially at places where “natural” erosion is likely to occur.     

A preliminary assessment of the potential for using Pbex measurement to estimate soil redistribution rates on cultivated slopes in the Sichuan Hilly Basin of China

In order to assess its potential for estimating soil redistribution rates, the naturally occurring fallout radionuclide ²¹⁰Pb_ex has been used in parallel with ¹³⁷Cs, derived from the atmospheric testing of nuclear weapon testing in the 1950s to 1970s, to estimate rates of soil redistribution on a sloping field with traditional erosion control measures located near Jiajia Village, Jianyang County, in the Sichuan Hilly Basin of China. The local ²¹⁰Pb_ex reference inventory of 12,860 Bq m^− 2 is higher than those reported for many other areas of the world and may reflect the influence of cloudy weather in preventing ²¹⁰Pb released to the atmosphere across the local region moving up into the upper troposphere, where is would be more widely dispersed. The mean ²¹⁰Pb_ex and ¹³⁷Cs inventories measured in cores collected from the upper part of the field with an average slope of 10° were 8028 Bq m^− 2 and 993 Bq m^− 2, respectively, and the equivalent values for the lower part of the field, where the slopes are steeper (20°) were 11,388 Bq m^− 2 and 1299 Bq m^− 2. The pattern of post-fallout ²¹⁰Pb_ex and ¹³⁷Cs redistribution on the sloping field reflects not only the effects of water erosion and redistribution by tillage, but also the local traditional practice of “Tiaoshamiantu”, whereby sediment trapped in the ditches is returned to the fields by the farmer. The estimates of annual rates of soil loss provided by the ²¹⁰Pb_ex measurement are closely comparable with those derived from the ¹³⁷Cs measurements and are consistent with existing knowledge for the study area. The results obtained from this study confirm the potential for using ²¹⁰Pb_ex measurement to estimate soil erosion rates over medium-term timescale of 50–100 years. By combining the estimates of erosion rates provided by the ²¹⁰Pb_ex and ¹³⁷Cs measurements, the weighted mean net soil loss was estimated to be 48.7 t ha^− 1 year^− 1 from the upper subfield and 16.9 t ha^− 1 year^− 1 from the lower subfield. These rates are considerably lower than the erosion rates obtained from runoff plot measurements in the local area. It is suggested that the traditional erosion control practices and the practice of “Tiaoshamiantu” have a significant effect in reducing soil loss and conserving valuable cultivated soil on sloping fields in the Sichuan Hilly Basin.     

塔里木河干流耕地动态变化及其景观格局

基于3S(RS、GIS、GPS)技术,并结合数理统计和景观格局数量分析方法,运用2000年CBERS、2005年CBERS和2010年TM遥感影像对塔里木河干流10年耕地面积的时空变化、景观格局及其生态影响进行了定量研究.结果表明:(1)在过去10年中,塔河干流耕地面积明显增加.具体地,2000年耕地面积为1.61×105 hm2,所占研究区总面积比例为3.89％,至2010年增加至3.27×l05 hm2,比例为7.88％,年增长率为1.66×104 hm2 a-1;(2)塔里木河干流耕地空间变化的区域差异明显.A、B、C、D断面耕地分布宽幅分别为2l～23 km、ll～16 km、6～17 km、4～9 km,塔河北岸C、D断面和南岸D、E断面耕地的增速最快;(3)2000-2010年耕地的斑块数不断增加,面积加权形状指数增大,形状趋于不规则.景观聚集度适中,景观内斑块大小分布均匀性降低,景观多样性下降,各个景观类型所占比例趋于不协调.     

New versus old scientific names in strawberries (Fragaria L.)

New Potentilla synonyms of the Fragaria species names are discussed and considered to be dispensable. Further unnecessary nomenclatural changes based on the argument to recognize monophyletic but not paraphyletic taxa should be avoided to maintain nomenclatural stability for global communication about plant genetic resources. The new combination Fragaria×rosea (Mabb.) K. Hammer et Pistrick is presented for the hybrid Potentilla palustris (L.) Scop. ×Fragaria×ananassa Duchesne ex Rozier.     

多尺度EGLSN的构建及耕地地力模拟研究

准确获得区域耕地地力是配方施肥的基础。本文依据景观生态学"过程、尺度与等级"原理,通过探索山西省耕地地力影响因素的等级与作用过程的控制范围,提出生态气候、地貌景观、利用措施、土壤条件、养分管理5个从大到小的不同尺度,构建了多尺度EGLSN(eco-climate,geomorphologic landscape,land usemeasure,soil condition,nutrient management)耕地地力模拟模型。根据山西省117个县(市、区)的土壤调查GPS采样点数据进行统计获得模型相关参数,应用多尺度EGLSN模型针对山西省北部的忻府区、中部的榆次区和南部的襄汾县3个典型区域,选择了积温、地形、地貌、平整措施等指标计算作物产量,进行耕地地力模拟。模拟结果误差检验表明,榆次区地貌景观尺度、利用措施尺度、土壤条件尺度、养分管理尺度模拟单产与土壤调查GPS点数据单产的标准根均方误差(NRMSE)依次为32%、27%、15%、4%,襄汾县4个尺度单产的NRMSE依次为35%、28%、13%、7%,忻府区4个尺度单产的NRMSE分别是31%、26%、14%、3%。忻府区、榆次区和襄汾县3个典型区域总产量相对生态气候尺度基准偏差的检验结果中,地貌景观尺度模拟精度分别为83%、80%和82%,利用措施尺度模拟精度为93%、90%和91%,土壤条件模拟精度分别是95%、95%和91%,养分管理尺度模拟精度依次达到96%、95%和93%。这一模拟方法适用于多尺度耕地地力模拟研究,可为大尺度耕地地力模拟及配方施肥提供借鉴。     

Changes in soil nitrogen availability due to stand development and management practices on semi‐arid sandy lands,in northern China

Soil nitrogen (N) availability is one of the limiting factors for plant growth on sandy lands. Little is known about impacts of afforestation on soil N availability and its components in southeastern Keerqin sandy lands, China. In this study, we measured N transformation under sandy Mongolian pine (Pinus sylvestris var. mongolica Litv.) plantations of different ages (grassland, young, middle‐aged, close‐to‐mature) and management practices (non‐grazing and free‐grazing) during the growing seasons using the ion exchange resin bag method. Results showed that, for all plots and growing season, soil NH‐N, NO‐N, mineral N, and relative nitrification index, varied from 0·18 to 1·54, 0·96 to 22·05, 1·23 to 23·58 µg d⁻¹ g⁻¹ dry resin, and 0·76 to 0·97, respectively, and NO‐N dominated the available N amount due to intense nitrification in these ecosystems. In general, the four indices significantly increased in the oldest plantation, with corresponding values in non‐grazing sites lower than those in free‐grazing sites (p < 0·05). Our studies indicated that it is a slow, extended process to achieve improvement in soil quality after afforestation of Mongolian pine in the study area. Copyright © 2009 John Wiley & Sons, Ltd.     

施肥对丹参产量及丹参根主要有效成份含量的影响

研究了苏北中药材种植基地常用有机肥及化肥对丹参产量和丹参根主要有效成份丹参酮ⅡA、丹参酮Ⅰ、隐丹参酮、丹酚酸B含量的影响。结果表明,施肥可以提高丹参根产量,影响三种丹参酮及丹酚酸B的含量。有机肥对丹参产量和丹参酮、丹酚酸B含量的影响优于化肥,三种有机肥常规施肥水平处理均优于相对应的两倍施用量处理;三种有机肥中猪粪较菜籽饼和鸡粪更有利于丹参酮和丹酚酸B的累积。根膨大期的丹参根中三种丹参酮、丹酚酸B的含量高于成熟期。为了提高丹参产量,稳定其有效成分含量,建议大田生产中合理施用有机肥,适度密植,适当提早采收期。