黑钙土中真菌的时空分布及其在贫营养条件下菌落特征研究

[目的]对黑钙土中真菌的时空分布及其在贫营养条件下菌落特征进行研究。[方法]采用稀释平板法对真菌进行分离,用单孢子分离法进行纯化,用不同稀释浓度的察贝克培养基进行培养计数。[结果]从供试黑钙土中分离出9种真菌菌属,并且确定了4种优势菌属,同时发现黑钙土中真菌数量分布呈现出明显的季节性,并且随采样深度增加其数量呈现减少的趋势,在贫营养条件下真菌种类和数量均明显减少。[结论]该研究可为黑钙土中微生物的相关研究提供理论依据。     

黑龙江省东宁县烤烟主要含氮化合物的含量变化研究

[目的]研究不同土壤类型烟叶叶片中氮、烟碱及蛋白质含量的变化,确定适合的植烟土壤,生产出卷烟工业企业需要的原材料。[方法]对调制后的烟叶样品经烘干并粉碎过40目筛,采用自动分析仪法测定总氮和烟碱含量,间接分析法测定蛋白质。[结果]对不同土壤类型烤后烟叶氮含量的多重比较分析结果表明,氮含量平均值变化范围为1.1%~1.2%。暗棕壤烤后烟叶的氮含量最高,河淤土的氮含量次之,黑钙土的氮含量位居第三。不同部位烟叶间烟碱含量表现为上部叶中部叶下部叶,变化范围为1.5%~2.1%;烟叶蛋白质含量在不同部位、不同土壤类型间的差异不显著。[结论]根据东宁县烟区实际的自然条件及气候特点,建议在烤烟种植土壤上进行调整和转移,选择黑钙土及河淤土地块,尽量避免在暗棕壤上种植,从而减少烤烟叶片内主要含氮化合物的含量,同时还要依据卷烟企业的需求标准采取合理的栽培模式。     

不同耕作措施对土壤质构和玉米产量的影响

通过4年定位试验,研究不同耕作措施对黑钙土区耕地土壤结构和质量以及玉米产量的影响。结果表明,播种前,和常规旋耕(CK)相比,深松旋耕(DP)、秸秆覆盖还田+深松(DSM)和秸秆深翻还田(PS)使土壤容重降低5.22%～11.19%,孔隙度增加5.09%～11.45%;DP、DSM处理土壤含水率分别提高14.99%和18.58%;DSM处理下>5 mm的团粒量与CK差异不显著,DP和PS处理使>5 mm的团粒比例降低,2～1 mm、1～0.5 mm和0.5～0.25 mm团粒比例升高。收获期,DSM、PS和DP处理的有机质含量较CK分别增加3.92、3.03和2.47 g/kg,DSM、PS和DP处理均能提高各时期土壤全量和速效养分含量,最终使玉米增产3.2%、6.8%和1.3%。从综合效应来看,秸秆覆盖还田+深松是黑钙土区更为适宜的耕作措施。     

Yield development of winter wheat over 50 years of FYM,N, P and K fertilizer application on black earth soil in the Czech Republic

The black earths of Central Europe are an important soils for crop production but sustainability of crop production on such soils has not been examined. In the present paper, yield of winter wheat over 50 years of FYM, N, P and K fertilizer application (12 treatments altogether) was analyzed in the Ivanovice Crop Rotation Experiment (ICRE), established in 1955 on a degraded black earth soil (chernozem).     

Grassland soil organic carbon and the effects of irrigated cropping in Alberta,Canada

High heterogeneity in the spatial distribution of soil organic carbon (SOC) in grasslands causes uncertainty in estimating its content and storage. In this study, we investigated the spatial distribution of SOC content and storage in the prairies of southern Alberta, Canada, and how it is affected by land use such as irrigated cropping and other environmental conditions such as cattle grazing, slope landscape position and dominant plant species. The mean SOC content was determined to be 11.5 g kg^–1 (range: 8.9 to 22.4 g kg^–1) in the 0–10 cm layer and 6.8 g kg^–1 (range: 4.0 to 13.3 g kg^–1) in the 10–30 cm layer; mean SOC storage was 1.59 kg C m^–2 (range: 1.23 to 2.78 kg C m^–2) in the 0–10 cm layer and 2.07 kg C m^–2 (range: 1.21 to 3.62 kg C m^–2) in the 10–30 cm layer. The SOC content was significantly affected by slope position in both the 0–10 and 10–30 cm layers, in the following order: bottom >middle > top position. Moreover, SOC storage was higher in sites dominated by shrubs than graminoid/forb communities. Thus, SOC content and storage had distinctly clustered spatial patterns throughout the study area and were significant differences between the 0–10 and 10–30 cm soil layers. Prior land-use change from arid grassland to irrigated cropland increased SOC content and storage in bulk soils.     

秸秆还田方式下黑钙土土壤碳氮磷钾化学计量特征研究

以吉林省西部黑钙土为研究对象，探究土壤C、N、P、K及其化学计量特征对秸秆还田方式的不同响应，为科学进行土壤养分管理及筛选适宜耕作培肥技术提供理论依据。设置秸秆深翻还田(SF)、秸秆富集还田(FJ)、秸秆覆盖还田(FG)、秸秆离田(CK)4种方式，采用常规测定方法测定0～20 cm、20～40 cm土壤C、N、P、K含量。结果表明，黑钙土分解有机质速度较快、磷素转化效率较高，相较于土壤中充足的P含量，植物生长易受N元素的限制，且不同养分之间的比值不仅受直接相关养分的制约，还受其他养分的影响。秸秆还田能减缓有机质的分解速度(FG、FJ)及植物生长可能受到的N素威胁(SF、FJ)，建议降少化肥施用量(P、K)以增加黑钙土有机质固持能力。