Responses of soil nematode community structure to soil carbon changes due to different tillage and cover crop management practices over a nine-year period in Kanto,Japan     

《Applied soil ecology》2015

The response of the soil food web structure to soil quality changes during long-term anthropogenic disturbance due to farming practices has not been well studied. We evaluated the effects of three tillage systems: moldboard plow/rotary harrow (MP), rotary cultivator (RC), and no-tillage (NT), three winter cover-crop types (fallow, FL; rye, RY; and hairy vetch, HV), and two nitrogen fertilization rates (0 and 100 kg N ha⁻¹ for upland rice, and 0 and 20 kg N ha⁻¹ for soybean production) on changes in nematode community structure. Sixty-nine taxa were counted, total nematode abundance (ALL), bacterial feeders (BAC), predators (PRD), omnivores (OMN), and obligatory root feeders (ORF) were more abundant in NT than in MP and RC, but fungal feeders and facultative root feeders (FFR) were more abundant in RC than in NT and MP. Cover crop also influenced nematode community structure; rye and hairy vetch were always higher in ALL, BAC, FFR, ORF, and OMN than fallow. Seasonal changes in nematode community structure were also significant; in particular, as soil carbon increased, nematode abundance also increased. The relationship between nematode indices and soil carbon was significant only in NT, but not in MP and RC. In NT, with increasing soil carbon, enrichment index and structure index (SI) were positive and significant and channel index was negative. Bulk density was significantly negatively correlated with FFR and ORF. Seasonal difference in nematode community between summer and autumn was larger in an upland rice rotation than in a soybean rotation. Over the nine-year experiment, SI increased not only in NT but also in MP and RC, suggesting that repeated similar tillage inversions in agroecosystems may develop nematode community structures adapted to specific soil environmental conditions. Because NT showed the highest values of both SI and soil carbon, the increase of soil carbon in NT is expected to have a great impact on developing a more diverse nematode community structure.  相似文献   

Sugar beet rotation effects on soil organic matter and calculated humus balance in Central Germany     

《European Journal of Agronomy》2016

In order to quantify the influence of land use systems on the level of soil organic matter (SOM) to develop recommendations, long-term field studies are essential. Based on a crop rotation experiment which commenced in 1970, this paper investigated the impact of crop rotations involving increased proportions of sugar beet on SOM content. To this end, soil samples were taken in 2010 and 2012 from the following crop rotation sequences: sugar beet–sugar beet–winter wheat–winter wheat (SB–SB–WW–WW = 50%), sugar beet–sugar beet–sugar beet–winter wheat (SB–SB–SB–WW = 75%), sugar beet–grain maize (SB–GM = 50%) and sugar beet-monoculture (SB = 100%); these were analysed in terms of total organic carbon (TOC) and microbial biomass carbon (MBC) content, MBC/TOC ratio and the TOC stocks per hectare. In addition, humus balances were created (using the software REPRO, reference period 12 years) in order to calculate how well the soil was supplied with organic matter. In the field experiment, harvest by-products (WW and GM straw as well as SB leaves) were removed. After 41 years, no statistically significant differences were measured between the crop rotations for the parameters TOC, MBC, MBC/TOC ratio and the TOC stock per hectare. However, the calculated humus balance was significantly affected by the crop rotation. The calculated humus balance became increasingly negative in the order SB–SB–WW–WW, SB–SB–SB–WW, SB monoculture and SB–GM, and correlated with the soil parameters. The calculated humus balances for the reference period did not reflect the actual demand for organic matter by the crop rotations, but instead overestimated it.  相似文献   

依靠科学推进黄平县林业生态建设     

荀世芬 《北京农业》2011,(18):132-133

贵州省黄平县是少数民族聚居的国家重点扶贫山区农业县。依据县情,依靠科学谋划林业生态建设。从黄平县的实际情况出发,对今后发展黄平县林业生态建设提出了一些建议。  相似文献   

藏北高原退化高寒草甸土壤团聚体有机碳变化特征   总被引：1，自引：0，他引：1  

于宝政  彭岳林  蔡晓布 《草地学报》2017,(6):1212-1220

采用湿筛法对藏北高原退化高寒草甸表层(0~10cm)、亚表层(10~20cm)土壤团聚体有机碳及其变化进行了研究。结果表明,高原冷湿环境中退化草地表层、亚表层SAOC的下降幅度随草地退化加剧均趋于显著提高,轻度、严重退化草地表层各粒级SAOC降幅均明显高于亚表层;草地退化缩小了不同土层间SAOC含量的差异,草地退化程度越高则表层、亚表层间SAOC含量的差异越小,退化草地大团聚体(0.25mm)SOC、微团聚体(0.25mm)SOC含量的土层分布亦呈相同趋势。轻度退化草地不同土层大团聚体SOC降幅均较高,严重退化草地不同土层微团聚体SOC降幅则较高;正常草地、轻度退化草地、严重退化草地表层大团聚体SOC/微团聚体SOC比值分别为0.95,0.87,1.55,亚表层分别为0.96,0.72,2.33,表明轻度、严重退化草地中大团聚体SOC含量随土层加深分别更趋下降、更趋提高。退化草地表层、亚表层SAOC贡献率在总体上亦均按2~0.25 mm,2 mm,0.25~0.053mm,0.053mm的顺序依次大幅降低,表明不同土层大团聚体SOC贡献率均较高。土壤团聚体与SAOC、SOC与SAOC间的关系受草地退化程度的影响。  相似文献   

大通县长宁镇退耕还林(草)后续产业探讨     

郑淑惠 《青海草业》2010,19(3):40-42,51

分析了退耕还林(草)现状,结果表明,退耕还林草的后续产业发展不足,提出发展退耕还林草的后续产业对策。  相似文献   

生态林业建设的现状与策略分析     

兰火长 《北京农业》2012,(18):117-119

分析生态林业建设的现状和存在的问题,就如何以提高生态林业建设水平为抓手,促进生态林业建设的完善提出建议。  相似文献   

基于生态文明价值观的家庭林场发展研究     

张驰  杨帆  曾维忠 《中南林业科技大学学报(自然科学版)》2015,(2):130-134

家庭林场经营模式的优点,除了创新经营管理体制,解放农村生产力,调动广大林农的生产经营积极性,促进林农脱贫致富外,还在于该模式内涵丰富的生态文明价值理念,能够将生态文明价值观在代际间传递延续,指导生产实践,保护生态环境,实现永续发展,这对促进生态文明建设、构建美丽中国具有重大的现实作用和深远的影响意义。本研究在阐明家庭林场内涵丰富的生态文明价值理念的基础上,阐释了发展家庭林场的经济、社会和生态效益,并针对目前家庭林场发展存在的问题提出对策建议。  相似文献   

激光雷达技术在林业科学研究中的进展分析   总被引：1，自引：1，他引：0  

黄华国 《北京林业大学学报》2013,35(4):134-143

基于Web of science 数据库检索平台,应用科学引文分析方法对检索到的1 355 篇2000 年以来激光雷达技术 在林学上的应用的文章进行了全面分析,主要涉及发表年份、国家分布、作者排行、期刊分布、作者单位分布、提取 参数等,对该领域所涉及到的主要国际国内会议进行了总结。分析了激光雷达的主要传感器类型和2 种数据结构 (波形和点云),系统总结了主要森林参数的提取方法,包括波形分析、点云分析、参数预测和数据融合。分析认为: 激光雷达技术的林学应用研究的深度和广度均呈现快速上升趋势,研究方法渐成体系,有系统化的国际会议;但研 究水平的地域差异较大,参数提取的机理性、实用性不足,尚未达到成熟,还有很大的提升空间。最后,从理论、应 用及组织3 个方面提出了建议。   相似文献   

农林类高校女研究生就业困境及对策     

杨洪一  李丽丽 《安徽农业科学》2017,45(29)

以农林类高校女研究生就业困境问题为切入点,对当前农林类高校女研究生就业的现状进行了分析,并探讨了就业困境的原因,同时结合农林类高校女研究生就业的实际情况,并借鉴欧美促进女性就业的策略,提出了相关建议和措施。  相似文献   

An experimental study of charcoal degradation in a boreal forest     

《Soil biology & biochemistry》2013

Degradation rates of pyrogenic carbon (PyC) under natural environmental conditions are largely unknown. Here we present results from a field experiment monitoring the change in mass, C- and N concentrations of a variety of charcoal types in a Norwegian boreal forest over a period of 20 months. The charcoal types represent different feedstock tree species, production temperature regimes, and placements in the forest, i.e. above ground, in the humus layer or in contact with the mineral subsoil. The types of charcoal had different initial C concentrations mainly depending on their production temperature. Nevertheless, all types of charcoal at all placements in the forest showed an initial drop in their C concentrations, which subsequently rose back to reach near initial values in part of the charcoal types. In part of the charcoal types, N concentrations decreased throughout the experiment, exhibiting considerable variation among feedstock species, production temperature regime, and placements in the forest. C/N ratios rose especially in charcoal made from wood of Scots pine (Pinus sylvestris L.), and charcoal that had been stored in contact with the mineral subsoil showed the most rapid mass gain. Our results confirm the important influence of production temperature and feedstock type on the degradation of charcoal, but they also show that microbial activity and environmental conditions play significant roles in charcoal degradation and thus for the fate of pyrogenic carbon under natural conditions.  相似文献