Compared effects of long-term pig slurry applications and mineral fertilization on soil denitrification and its end products (N2O, N2)

The long-term (9 years) effect of pig slurry applications vs mineral fertilization on denitrifying activity, N₂O production and soil organic carbon (C) (extractable C, microbial biomass C and total organic C) was compared at three soil depths of adjacent plots. The denitrifying activities were measured on undisturbed soil cores and on sieved soil samples with acetylene method to estimate denitrification rates under field or potential conditions. Pig slurry applications had a moderate impact on the C pools. Total organic C was increased by +6.5% and microbial biomass C by ≥25%. The potential denitrifying activity on soil suspension was stimulated (×1.8, P<0.05) 12 days after the last slurry application. This stimulation was still apparent, but not significant, 10 months later and, according to both methods of denitrifying activity measurement (r ²=0.916, P<0.01 on sieved soil; r ²=0.845, P<0.001 on soil cores), was associated with an increase in microbial biomass C above a threshold of about 105 mg kg⁻¹. The effect of pig slurry on denitrification and N₂O reduction rates was detected on the surface layer (0–20 cm) only. However, no pig slurry effect could be detected on soil cores at field conditions or after NO₃ ⁻ enrichments at 20°C. Although the potential denitrifying activity in sieved soil samples was stimulated, the N₂O production was lower (P<0.03) in the plot fertilized with pig slurry, indicating a lower N₂O/(N₂O + N₂) ratio of the released gases. The pig-slurry-fertilized plot also showed a higher N₂O reduction activity, which is coherent with the lower N₂O production in anaerobiosis.     

两种灌木根系对异质生长空间的适应分布特征

为探究灌木根系对异质空间的适应策略,以紫穗槐和胡枝子两种灌木为研究对象,采用盆栽控制生长空间的研究方法,以放置不同形状的木板在盆内模拟不同喀斯特异质空间条件(孔隙型、圆形裂缝型、条形裂缝型和孔隙+岩石阻挡型),研究了异质空间条件下两种灌木根系分布特征。结果表明:(1)异质空间条件下紫穗槐和胡枝子根系各项指标均高于均质空间,异质空间条件对根系生长有促进作用。不同植物受异质空间的影响程度不同,胡枝子在异质空间下的根系生物量显著高于均质空间。不同异质空间对根系生长的影响不同,紫穗槐和胡枝子根系均在孔隙型和圆形裂缝型两种空间条件下最为发达。(2)紫穗槐和胡枝子根生物量分布特征受异质空间影响。在异质空间下两种树种根生物量的垂直分布均集中分布在土层深度5—10 cm和15—20 cm范围内,水平分布均集中分布在距植株中心0—3 cm内。紫穗槐根系生物量的水平分布受异质空间具体形状影响较大,孔隙型空间和圆形裂缝型空间对其水平分布影响较为显著。(3)两种灌木对异质空间的适应策略不同,紫穗槐根系对异质空间的适应策略为寻找更多空间,而胡枝子根系对异质空间的适应策略为占据有限空间。综上,紫穗槐和胡枝子根系生...     

外源四环素对菜田土壤微生物活性及数量的影响

通过向土壤中添加四环素溶液的方法研究了油菜种植条件下,不同浓度(0.3,0.6,0.9mg/kg)的外源四环素对土壤微生物活性及数量的影响,以评价其环境生态效应。结果表明,土壤中加入四环素后,不同浓度的四环素药物对微生物量碳的影响表现为抑制作用,在27d达到最低,为空白的6.25%～11.97%;而对土壤代谢商qCO2却表现出明显的激活作用,7d达到最高,为空白的550%～622%,且微生物活性的受抑制—激活程度及持续时间与处理浓度成负相关,50d后施药土壤和对照组土壤的代谢商qCO2基本趋于一致。土壤中加入四环素后,各浓度处理对土壤微生物数量有强烈的抑制作用。     

思茅松中幼龄人工林的生物量碳密度及其动态变化

 通过样地实测生物量和采用重铬酸钾法测定植物碳索含量,研究了思茅松中幼龄人工林生物量碳密度的分配特征及随林龄的动态变化规律。结果表明：1)林龄为3-5、6-10、11 -20和21 -30 a思茅松人工林的生物量碳密度分别为（20.15 ±3.09)、(27. 24 ±2.25)、（94. 89 ±9. 90)和147. 58 t/hm2。随林齡增长,乔木层、枯落物层和林分的碳密度显著增加,灌木层和草本层的碳密度有所减少。林分、乔木层和枯落物层的生物量碳密度随林龄的变化用逻辑斯蒂模型可实现良好拟合,而灌木层和草本层拟合效果差。2)林龄为3-5、6-10、11 -20和263思茅松人工林的年均固碳量分别为（4. 92 ±0.63)、（3. 52 ±0.25〉、（6. 44 ±0.30)和5. 68 t/(hm2·a)0乔木层的年均固碳量与林龄存在显著正相关,灌木层和草本层的年均固碳请与林龄存在显著负相关,林分年均固碳量与林龄呈较弱的正相关。乔木层和草本层的年均固碳量与林龄的关系以逻辑斯蒂模型拟合效果较好,灌木层年均固碳量和林龄关系以Gauss模型拟合效果较好,林分的年均固碳量与林龄的拟合效果差。     

Molecular characterisation of Berberis thunbergii cultivars using microsatellite markers

Due to a growing concern for black stem rust (BSR) disease in wheat-producing regions of the USA and Canada, the sale and movement of barberry plants to ‘quarantined’ regions is restricted to just a few cultivars approved as being BSR-resistant. Currently, verification of a given barberry plant as being ‘true-to-type’ of the approved cultivar relies on comparing its morphological features with those of its reference cultivar. Frequently, this approach leads to mis-identification of cultivars due to the similarity of morphological features among young plants. The approach is complicated, or not at all useful, when the plants are dormant, which is the stage at which plants are sold. A reliable technique that could be used at any stage of plant growth to identify and verify cultivars is needed. In this study, the genetic diversity of 51 barberry cultivars was assessed using microsatellite markers, and their genotypic profiles were developed based on the allele composition of different microsatellite loci. A total of 43 alleles were generated at seven microsatellite loci, and all were polymorphic. An unweighted pair group method with arithmetic averaging (UPGMA) cluster analysis of the Jaccard’s coefficient of similarity matrix showed that 84.3% of the 51 cultivars tested were distinct from each other. Ten of the 11 cultivars approved for import into Canada were distinguishable based on their genotypic profiles. The results indicated that microsatellite-based genotyping could be used by regulatory agencies to identify and offer ‘true-to-type’ guarantees to cultivars destined for BSR ‘quarantined’ regions, and to verify the uniqueness of new cultivars when issuing Plant Patents.     

我国玉米茎腐病研究进展

玉米茎腐病是一种世界性土传真菌病害,该病害在我国玉米产区均有发生。近年来,受耕作制度（如保护性耕作、秸秆还田等）的改变和气候变化的影响,生产中使用的高抗茎腐病的玉米品种不多等因素,致使田间病原菌数量增加,我国玉米茎腐病有逐渐加重的趋势。针对玉米茎腐病危害逐年加重的现状,本文系统综述了玉米茎腐病致病菌、发病症状表现、病情分级标准、病害侵染规律、抗性鉴定评价方法等方面的研究进展情况,并提出了玉米茎腐病的防治策略。     

北京市生物质能源化利用效益评价方法的研究

北京市能源消耗量大,提高生物质能利用率可缓解能源供应压力。为推动北京市生物质能源化利用产业的发展,需增进对其经济效益、社会效益和环境效益的综合认识。通过建立综合效益评价体系,运用层次分析法确定各评价指标权重,提出了北京市生物质能源化利用综合效益的评价方法,再以怀柔区发展生物质成型颗粒燃料为例,对其经济效益、社会效益和环境效益进行模糊评价,最后以怀柔杨宋成型颗粒燃料项目的数据为依据,进行分析验证,结果显示模糊综合评价的结论较为准确。     

放牧强度、植被结构与草地生态环境的关系

本文综述了放牧对草地植物组成及植物生物量的影响、不同放牧方式和强度对家畜和草地的影响、高寒草甸地区人工草地建植和利用的研究进展。为了保护草地植物多样性及获得较高草地生产量,应使草地承受适当的放牧压力。     

不同水分管理旱直播水稻生长生理与节水效应

为了探讨东北黑土区水稻高效节水种植模式,于2017年在黑龙江省庆安县采用测坑微区试验,研究了旱直播对水稻光合特性、各器官生物产量、干物质累积速率、根冠比、伤流强度、产量水分利用效率(WUEy)、叶片水分利用效率(WUEl)和产量因子等的影响。试验设置了3个处理:滴灌旱直播(DH)、漫灌旱直播(MH)和常规插秧淹灌(CK),并以CK处理作为对照。结果表明:DH与MH处理的净光合速率Pn(分蘖末期除外)、蒸腾速率Tr、气孔导度Gs、以及叶、鞘、茎、穗等冠部干物质累积量、冠部干物质累积速率(分蘖中期至末期除外)、冠部最大累积速率在整个生育期均低于CK,但WUEl、根部干物质累积量(分蘖前期和中期除外)、根部干物质累积速率、根系活力(分蘖中期与拔节孕穗期除外)均高于CK。3个处理的胞间CO2浓度Ci整个生育期波动幅度不大。根部和总干物质最大累积速率及各生育期根冠比以DH最大,CK最小。DH与MH处理的千粒质量和结实率较CK下降不显著(P0.05),穗长和穗粒数下降显著(P0.05),有效穗数上升显著(P0.05)。DH较CK、MH分别节省灌溉用水63.88%和39.52%,WUEy分别提高2.66倍和1.64倍。滴灌旱直播种植不仅大幅度减少了灌溉用水量,显著提高了水稻的WUEy,而且具有较为可观的经济效益和显著的社会效益。研究结果可为东北黑土区水稻种植模式的选取提供技术支撑,对保障黑土区农业水土资源可持续利用具有重要意义。     

葡萄组织培养中愈伤组织的诱导

采用三因素(萘乙酸NAA,吲哚丁酸IBA,6-苄氨基嘌呤6-BA)四水平的正交试验设计,对"鄞红"葡萄近梢处的嫩茎段和幼果进行愈伤组织诱导试验。结果表明,6-BA对愈伤组织诱导影响最大。以嫩茎段为外植体的最佳培养基配方是MS+1.00 mg/L 6-BA+0.10 mg/L NAA+0.20 mg/L IBA,其诱导率为70.00%。以幼果为外植体的最佳培养基配方是MS+0.80 mg/L 6-BA+0.10 mg/L NAA+0.20 mg/L IBA,诱导率为61.85%。嫩茎段是"鄞红"葡萄愈伤组织诱导最理想的外植体。