小麦秸秆全量还田下腐熟剂对下茬水稻产量及土壤的影响     

周德平 《中国农学通报》2018,34(19):102-107

旨在为稻麦轮作模式中秸秆全量还田提供有效配套措施,采用田间大区试验,开展了小麦秸秆全量还田配套腐熟剂研究。试验设3处理,分别为不施腐熟剂CK、施腐熟剂A和施腐熟剂B处理。结果显示腐熟剂A处理水稻比CK减产2.37%,B增产1.74%;A处理土壤速效NPK分别比CK增加了2.34mg/kg、1.00mg/kg和4.00mg/kg,铜、锌含量下降,砷含量上升3.03mg/kg;B处理速效NP分别比CK降低5.33mg/kg和6.47mg/kg,有机质减少3.66g/kg,铜、锌、砷含量均低于CK。腐熟剂A、B均可促进土壤微生物增殖,提升整体代谢活性,增加物种多样性指数;其中A处理细菌与真菌增加明显,而B对放线菌的促进更为明显。综合腐熟剂对水稻产量、土壤理化及微生物种群和代谢特征的影响,配套腐熟剂B更利于水稻产量和土壤健康。  相似文献   

晚稻全生育期Cd的迁移转化规律及预测模型研究     

杨国航  李琼  和利钊  顾静  牛婧  张海欧  郑子健  赵振 《中国农学通报》2021,37(25):1-10

为探讨晚稻全生育期Cd的迁移转化规律及预测模型,采用长沙市望城区大田试验土壤-水稻Cd点对点数据,对水稻4个典型生育期（苗期、分蘖期、灌浆期和成熟期）及不同部位（根、茎叶及籽粒）Cd的吸收、累积和分配差异进行研究。结果表明,同一生育期各部位Cd含量和富集能力均为根>茎叶>籽粒,且根部明显高于其他部位,不同生育期差异显著,具体为成熟期>灌浆期>分蘖期>苗期;Cd转运能力为土-根>根-茎叶>茎叶-籽粒>根-籽粒,籽粒Cd大部分来自于茎叶的转移,且分蘖期转运能力显著高于其余生育期;Cd积累量和分配差异为茎叶>根>籽粒,且分蘖期和成熟期远大于苗期和灌浆期;土壤pH和有效态镉(ACd)含量是影响水稻Cd吸收的主控因子,pH为负效应,有效态镉为正效应,分蘖期茎叶Cd含量受其影响最大,是控制Cd进入籽粒的关键时期。可利用分蘖期土壤pH和有效态镉含量预测成熟期籽粒Cd含量,最优预测模型为lgCd_{成熟期籽粒}=0.158-0.099pH_分蘖期+0.261lgACd_分蘖期。研究结果可为中国长株潭地区稻田土壤Cd污染风险评估和管控提供理论依据和数据支撑。  相似文献   

黄土丘陵区不同退耕模式对土壤物理性状影响研究—以甘肃定西市为例   总被引：3，自引：1，他引：3  

赵岩  杨越  孙保平  郭建英  周文渊 《中国农学通报》2009,25(16):99-105

甘肃定西全面实施退耕还林近10年来,取得了显著的成效。本文以退耕还林重点地区定西市安定区为例,通过采集、实地调查取样和实验室分析,对比研究了不同退耕植被类型地与对照地（农田和天然草地）的土壤物理性状的变化情况。包括土壤的含水量、容重、土壤孔隙度、土壤水稳性团聚体结构。研究结果表明：天然草地和柽柳的含水量最高,分别为13.44%和13.52%。农田和山杏的含水量最低为8.01%和8.2%。0～60cm不同土层中柠条的容重最小且变化不大,农田的上下变化最大。在20～60cm退耕还林地的孔隙度均高于天然草地和农田,天然草地和农田非毛管孔隙度小且上下变化大,不利于土壤入渗。刺槐、柠条、柽柳的水稳性团聚体的含量最多,分别是农田的3.4、2.8和2.4倍。退耕还林以后,林地的土壤物理性状得到明显的改善,与农田和天然草地相比,刺槐,柠条的改良效果最好。因此对退耕还林地区进行植被恢复过程中,要深入了解当地的土壤环境特征,做到因地制宜,适地适树。  相似文献   

河套灌区畦田内不同位置土壤入渗特性及影响因素分析   总被引：1，自引：0，他引：1  

孙娜  李瑞平  苗庆丰  范雷雷  周利颖  李聪聪 《节水灌溉》2022,(2):1-6

为明确河套灌区畦田田块不同位置土壤的入渗特性,通过野外试验和室内检测对试验区田块不同位置土壤理化性质和入渗过程进行分析,并基于土壤入渗模型对试验区田块不同位置的土壤入渗过程进行拟合,同时探讨影响土壤入渗过程的影响因素.研究结果表明:试验区田块内不同位置土壤理化性质及入渗特性具有一定差异性且不同位置土壤入渗特性与土壤理化...  相似文献   

植物诱导抗病技术的发展现状     

路阳 《农机化研究》2009,31(6)

对植物诱导抗病技术进行了综述;针对生物诱导因子、物理诱导因子和化学诱导因子,分析了各种诱导因子的特征和应用;指出了植物诱导抗病性研究的现状和问题;并对诱导抗病性的应用和发展方向做作了概括.  相似文献   

Repeated physical disturbances and the stability of sub‐tropical coral communities in Hong Kong,China     

Tze‐Wai Tam  Put O. Ang Jr 《水产资源保护:海洋与淡水生态系统》2008,18(6):1005-1024

• 1. This paper reports on the dynamics of the coral community structure at A Ma Wan (AMW) and A Ye Wan (AYW) in Tung Ping Chau, Hong Kong, focusing on data collected before and after the summer typhoon seasons in 1997 to 1999. This period (1999) experienced the highest frequency of severe tropical cyclones to hit Hong Kong with one cyclone being the strongest to hit in the last 23 years (1984 to 2006).
• 2. This is part of a long‐term monitoring programme of subtropical coral communities that has been set up in AMW since May 1997 and AYW since May 1998 with nine fixed position 40 m long transects and 0.5 m × 0.5 m permanent quadrats laid at 5 m intervals along each transect. A total of 45 scleractinian coral species from 21 genera (12 families) was recorded, with 40 species in AMW and 32 species in AYW recorded at the beginning of the study.
• 3. Multidimensional scaling ordinations showed distinct spatial variations in the coral communities within and between sites. These variations were probably a result of the differential effects of the repeated cyclone impacts on the communities. Cyphastrea serailia, Goniopora lobata, Montipora peltiformis and Pavona decussata were the dominant species most strongly affected by cyclone impacts at AMW, experiencing a 6.2–16.2% loss of mean area cover during the study period. Some dominant species (e.g. P. decussata) in AYW also experienced a 6.5–14.3% loss of mean area cover within the same period.
• 4. Overall, these coral community structures appeared relatively stable and resistant to repeated physical disturbances. However, they may have low resilience towards more severe disturbances in the future. Preserving the resilience of coral communities/species in Tung Ping Chau should be one of the main goals of coral conservation strategies for the island.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

大果沙棘籽和油的理化成分研究     

忻耀年  张红梅  刘新  李红卫 《国际沙棘研究与开发》2009,7(1):1-3

本文对采于新疆青河的大果沙棘籽进行了理化指标的分析研究。结果表明：大果沙棘籽在粗脂肪、粗蛋白含量上优于中国沙棘,在脂肪酸组成、维生素E含量上与中国沙棘无明显区别。该结果为大果沙棘籽的进一步开发利用奠定了基础。  相似文献   

Effects of wind turbines and other physical elements on field utilization by pink-footed geese (Anser brachyrhynchus): A landscape perspective     

Larsen  Jesper Kyed  Madsen  Jesper 《Landscape Ecology》2000,15(8):755-764

The effects of wind turbines and other physical landscape elements on field utilization by wintering pink-footed geese (Anser brachyrhynchus) were studied in a Danish farmland landscape. Within the study area geese were feeding on pastures, which together with cereals were the main crop types. Apart from wind turbines a variety of potentially disturbing landscape elements was present, e.g., high-power lines, windbreaks, roads and settlements. Patterns of field use were assessed by measuring goose dropping densities along transects perpendicular to wind farms (with turbines in clusters and in lines) and other landscape elements. Local effects were expressed in terms of `avoidance distance', i.e., the distance from a given landscape element to the point at which 50% of maximal dropping density was reached. The spatial distribution of landscape elements within an eight km radius from the goose roost was determined from aerial photographs. The area occupied by various elements, together with the adjacent zones which were not available to geese due to their associated avoidance distances, were quantified using Geographic Information System (GIS).The avoidance distance of wind farms with turbines in lines and in clusters were ca 100 m and ca 200 m, respectively. Geese did not enter the area between turbines within the cluster. At the landscape level, the combined effect of physical elements other than wind turbines caused an effective loss of 68% of the total field area (40 km²). Wind turbines caused an additional loss of 4% of the field area. However, of the remaining area available to geese (13 km²), wind turbines caused a loss of 13% of the total area. The habitat loss per turbine was higher for the wind farm with turbines arranged in a large cluster than for wind farms with turbines in small clusters or lines. This difference was mainly due to the fact that wind farms in small clusters or with a linear layout were generally placed close to roads or other elements with existing associated avoidance zones, whereas the large cluster was placed in the open farmland area. The avoidance zones associated with physical elements in the landscape do not take into account possible synergistic effects and, hence, actual field areas affected are likely to be minimum estimates. Implications of these findings for planning of wind farms in areas of conservation interest to geese are discussed.  相似文献   

木薯叶片厚度、蜡质含量和气孔密度与抗朱砂叶螨的关系     

肖建辉  周颖  叶剑秋  覃新导 《热带作物学报》2017,(3):541-544

为明确不同木薯品种的叶片组织结构与抗朱砂叶螨的关系,通过对木薯田间螨害情况的调查,计算出感、抗性稳定的感螨品种华南101、华南124和抗螨品种华南7号、华南13号的螨害指数,同时对叶片的相关物理性状进行测定,分析了叶片厚度、蜡质含量和气孔密度与木薯抗朱砂叶螨的关系。结果表明:4份木薯种质华南101、华南124、华南7号和华南13号的螨害指数依次为89.2%、65.8%、38.3%和0.8%;木薯叶片厚度与螨害指数呈显著负相关;气孔密度与螨害指数呈显著正相关;蜡质含量与螨害指数无显著相关性。上述结果为深入探究木薯抗螨机制提供了初步的理论基础。  相似文献   

微波杀青对茶在制品物理特性影响的初探     

滑金杰  袁海波  王近近  江用文  董春旺  邓余良 《茶叶科学》2017,37(5)

以一芽一叶的福鼎大白茶鲜叶为原料,设定6个微波杀青的时间梯度(0、30、60、90、120、150 s),按时间点取样,测定在制品的含水率、容重、色差Lab值、长度、宽度等,研究微波杀青时间对茶在制品物理特性的影响。结果表明,随着微波杀青的进行,在制品的含水率在前90 s匀速缓慢下降,而后急速下降,容重在微波30 s后显著下降;茶在制品的平均相对长度差、相对宽度差和面积差呈现先降后升的趋势,在微波60~90 s时相对最小;在制品色差L值、|a|值、b值随着微波杀青的进行,呈先升后降的趋势,微波前90 s均较鲜叶有显著提升,而后显著下降。相关性分析表明,微波杀青时间和含水率均对L值、|a|值、b值、相对长度差等呈显著影响,总体上看以微波杀青60~90 s最有利于获得较优的外形属性。  相似文献