安徽省农业气象灾害时间分布特征与灰色关联分析

为了探寻安徽省农业气象灾害的分布特点以及各种气象灾害对粮食生产的影响,本研究基于安徽省1992—2012年有关气象灾害数据,对4种主要气象灾害(旱灾、水灾、风雹灾、霜冻灾)的分布特征进行统计分析,并采用灰色关联分析研究其对安徽省粮食单产的影响。结果表明:1992—2012年,安徽省气象灾害具有发生频率高、波动大的特点,但整体上呈下降趋势。旱灾和水灾是发生面积较大的气象灾害,且常在时间上交织、空间上并存。灰色关联分析表明,4种气象灾害对粮食产量影响顺序:风雹灾水灾旱灾霜冻灾,说明风雹灾是影响粮食产量最主要的气象灾害,其次是水灾、旱灾,霜冻灾影响较小。本研究可为安徽省防灾减灾措施的制定提供决策依据。     

河西灌区田间固定道保护性耕作下作物轮作模式效益评价

在甘肃河西走廊,通过田间试验结合入户调研的方式,运用综合评价的方法,对基于固定道保护性农业的7种轮作模式进行了分析。结果表明：小麦-加工型甜椒-玉米经济效益最好,净收益、产投比和单方水产值分别为1.52×10⁴元·hm^-2、2.00和5.39元·m^-3;小麦-啤酒大麦-小麦劳动生产率最高,达240.2元·人^-1·a^-1,社会效益在所有轮作模式中也相对最好;小麦-油葵-啤酒大麦区域水资源安全保障度、水分能量生产效率、热量利用率分别为1.83、2.07×10⁴ kJ·m^-3和66.12%,生态效益最好;综合效益相对较好的4种轮作模式分别为小麦-加工型甜椒-玉米、小麦-马铃薯-小麦、小 麦-玉米-玉米和小麦-针叶豌豆-小麦。兼顾考虑固定道保护性农业系统的稳定性维护,小麦-加工型甜椒-玉米、小麦-玉米-玉米和小麦-针叶豌豆-小麦三种轮作模式更适宜在固定道保护性农业技术体系中进行应用和推广。     

普洱市七叶莲野生资源分布分析研究

在全面调查普洱市七叶莲野生资源地理分布基础上,采用主成分分析法研究七叶莲野生资源地理分布与气候、地形之间的关系,并对海拔与七叶莲枝叶总皂甙含量做相关性分析。调查结果表明：七叶莲野生资源在普洱全市均有分布,在喀斯特地貌区域分布尤为集中,其水平分布范围为99°20′11″E～101°55′04″E,22°18′20″N～24°17′58″N,垂直分布范围为海拔500～1900 m。经主成分分析表明,影响七叶莲地理分布的主要水热指标的排序为湿度因子>热量因子>降水因子;相关分析结果表明,七叶莲所分布的海拔与其林木枝叶总皂甙的含量具负相关关系,其相关系数为-0.948,最高海拔（1460 m）与最低海拔（1006 m）的七叶莲枝叶总皂甙含量比为1.0∶1.5。     

四川柑橘适宜分布及其对气候变化的响应研究

柑橘是四川省和我国主要水果产品之一。以气候为主的环境变化,对作物空间布局产生了显著影响。为合理优化柑橘生产空间,本研究基于最大熵模型（MaxEnt）构建柑橘适宜分布与环境变量的关系模型,运用受试者工作特征曲线（ROC曲线）检测模型精度,刀切法（Jackknife）筛选主导环境变量;采用ArcGIS技术对比1980年、2010年四川柑橘适宜区分布,揭示近30 a气候变化背景下四川省柑橘适宜区的分布与变化情况。结果显示：四川柑橘适宜性的主导环境变量主要体现为以光、热、水为特征的气候环境变量。近30 a四川省气候暖干化的变化趋势改变了区域生态系统的结构和功能,引起了柑橘种植适宜区的时空变化。1980—2010年柑橘种植适宜性空间格局呈现出2个变化特征,一是高适宜区呈整体向北迁移的趋势,主要分布在成都平原区与川东北地区过渡地区;中适宜区界线向东南方迁移。二是适宜性级别呈现出逐级调整,低、中适宜区的等级调整变化明显。2010年高适宜区面积约为4.22万km²,中适宜区4.19万km²,低适宜区4.4万km²,大部分地区为不适宜区。以高适宜区为参照,通过政策措施,政府部门可增加在川南地区、成都平原地区南部的柑橘生产布局。本研究客观地反映了气候变化下,四川省柑橘种植适宜性变化特征,合理确定了柑橘适宜性面积及分布,为柑橘空间优化提供了科学依据。最大熵模型在对物种分布进行准确模拟和预测时具有较强应用价值,对作物气候适宜性区划具有重要指导意义。但对于不同区域和作物应选取合适的环境变量、空间尺度和物种采样位置,减少系统累计误差,提高作物气候适宜区划定精度。     

Dynamics of arbuscular mycorrhizal fungi and glomalin in the rhizosphere of Artemisia ordosica Krasch. in Mu Us sandland, China

To understand the ecological significance of arbuscular mycorrhizal (AM) associations in semi-arid and arid lands, the temporal and spatial dynamics of AM fungi and glomalin were surveyed in Mu Us sandland, northwest China. Soil samples in the rhizosphere of Artemisia ordosica Krasch. were collected in May, July and October 2007, respectively. Arbuscular, hyphal and total root infection and spore density of AM fungi peaked in summer. The mean contents of total Bradford-reactive soil proteins (T-BRSPs, TG) and easily extractable Bradford-reactive soil proteins (EE-BRSPs, EEG) reached maximal values in spring. Spore density and two BRSPs fractions were the highest in the 0-10 cm soil layer, but the ratios of two BRSPs fractions to soil organic carbon (SOC) were the highest in the 30-50 cm soil layer. Hyphal infection was negatively correlated with soil enzymatic activity (soil urease and acid phosphatase) (P < 0.05). Arbuscular infection was negatively correlated with soil acid phosphatase (P < 0.01). Spore density was positively correlated with edaphic factors (soil available N, Olsen P, and SOC) and soil enzymatic activity (soil acid and alkaline phosphatase) (P < 0.01). Two BRSPs fractions were positively correlated with edaphic factors (soil available N and SOC) and soil enzymatic activity (soil urease, acid and alkaline phosphatase) (P < 0.01). TG was positively correlated with soil Olsen P (P < 0.05). We concluded that the dynamics of AM fungi and glomalin have highly temporal and depth patterns, and influenced by nutrient availability and enzymatic activity in Mu Us sandland, and suggest that glomalin are useful indicators for evaluating soil quality and function of desert ecosystem on the basis of its relationship to AM fungal community, soil nutrient dynamics and carbon cycle.     

皖西南春棉田主要害虫和天敌种群时序动态格局

为探索直播春棉田害虫与其天敌之间的相互作用和竞争共存机制,采用直接观察法,系统研究了棉田主要害虫和天敌种群的时间动态变化,及其生态位宽度和生态位重叠值。研究结果表明,在直播春棉的不同生育期,棉田害虫和天敌的优势种不同。主要害虫和天敌的发生高峰期多集中在6—7月,而棉蚜高峰期在5月下旬,棉叶蝉高峰期在9月下旬。不同种群的时间生态位不同,害虫中棉盲蝽的生态位宽度最大,其次是棉铃虫,棉叶蝉和棉叶螨的生态位宽度较小;天敌中蜘蛛类天敌的生态位宽度最大,其次是小花蝽,黑襟毛瓢虫的生态位宽度最小。而黑襟毛瓢虫和瓢虫类天敌与棉蚜、棉叶螨生态位重叠度较大。因此,皖西南棉区直播春棉田可利用瓢虫类天敌抑制棉蚜和棉叶螨的危害,保护并利用好蜘蛛类天敌,需重点防治棉盲蝽和棉铃虫。     

Genotypic differences of maize in grain yield response to deficit irrigation

This study was undertaken to investigate genotypic differences of five maize cultivars in grain yield response to two different modes of deficit irrigation, conventional deficit irrigation and partial root zone irrigation. Three irrigation treatments were implemented: (1) FULL irrigation, the control treatment where plant water requirement, 100% Class-A pan evaporation, was fully met and the furrows on both sides of the plant rows were irrigated; (2) partial root zone irrigation (PRI), 35% deficit irrigation, compared to FULL treatment, was applied in every other furrow thus irrigating only one side of the plant rows. The furrows irrigated were alternated every irrigation; (3) conventional deficit irrigation (CDI), the same amount of water as PRI was applied in furrows on both sides of the plant rows, similar to FULL irrigation treatment. Five maize cultivars (P.31.G.98, P.3394, Rx:9292, Tector and Tietar) showing extreme growth response to water stress were selected out of ten cultivars tested with earlier completed greenhouse-pot experiment. A split-plot experimental design, comprising three irrigation treatments and five maize cultivars with four replicates, was used during two years of work, in 2005 and 2006. Total of nine irrigations, with one-week irrigation interval, were annually applied using a drip-irrigation system. Soil water status was monitored using a neutron moisture gauge, in addition to measuring leaf water potential and above-ground biomass production throughout the growing season. Grain yield and other yield attributes were measured at harvest as well as assessing differences in plant root distributions. Decrease in grain yield and harvest index of the tested cultivars, compared to FULL treatment, was proportionally less under PRI than CDI. Whether or not a significant yield advantage can be obtained under PRI compared to CDI showed significant (P < 0.05) genotypic variability. Tector and Tietar among the tested cultivars of maize showed significantly higher grain yield (P < 0.05) under PRI than CDI. The yield advantage of the genotypes (P.3394 and Tector) under PRI compared to CDI seems related to their enhanced root biomass developed under PRI.     

黄土高原典型草原植被及土壤化学计量对降水变化的响应

研究植被和土壤生态化学计量及其耦合关系,是解析气候变化背景下草地植被养分动态平衡和能量流动的重要途径.本研究以宁夏固原云雾山典型草原为研究对象,采用控雨-滴灌装置模拟3个降水梯度(自然降水的50％,100％和 150％),分析了植物叶片、根系、凋落物及土壤的碳(Carbon,C)、氮(Nitrogen,N)、磷(Pho...     

薇甘菊的分布危害、生物防治及资源化利用研究现状与展望

薇甘菊作为唯一一种全国林业检疫有害植物,由于其较强的攀援、繁殖扩散能力,以及极强的化感作用,对入侵地区的林农业发展产生了极大的危害;作为一种菊科植物薇甘菊有极强的资源化利用价值,在生物农药,药物等方面都有着广泛的利用前景。此文对薇甘菊的生物学特性、分布、适生区及危害进行介绍,对国内外薇甘菊生物防治及资源化利用的研究现状进行综述。     

柴达木盆地荒漠地区生态位研究初报

采用定量分析的方法,对柴达木盆地南缘巴隆地区的11种主要植物进行生态位研究,通过测定各主要植物种的生态位宽度、生态位相似比例、生态位重叠,对各植物种生态位的生态学意义进行分析,目的是为此地区植被恢复工作提供理论参考.