海南胡椒种植基地土壤重金属评价及来源分析

在对海南省主要胡椒种植区-文昌、琼海两市种植地土壤重金属含量调查的基础上,采用单项污染指数法和综合污染指数法,结合绿色食品产地环境技术条件及土壤环境质量二级标准,对其重金属含量现状进行了评价;然后结合深层土壤、母质岩石样品及海南岛1:25万多目标区域地球化学调查成果,对其土壤重金属来源进行了综合分析。结果表明,相对所选标准,沉积砂岩区(F11~F13)、第四系松散沉积物区(F7、F14)和花岗岩区一种植地(F9)均符合绿色食品产地要求。玄武岩区(F1~F6)土壤Cu、Cr、Ni超标,花岗岩区另一种植地(F8)和变质岩区(F10)土壤Pb、As超标。综合分析结果显示,胡椒基地土壤环境质量整体良好,成土母质是土壤中重金属元素的主要控制因素,但部分种植地浅层土壤中Cd、Pb、As等重金属元素已受到人类活动的影响。     

Response of Rice Seedlings to Copper Toxicity and Acidity

Metal toxicity and soil acidity affect plant growth. A hydroponic experiment was conducted to simulate effects of pH and copper concentration [Cu] on early growth and biomass production of high-yielding rice seedlings (Oryza sativa L. cv. ‘NIAB 6’). The rice seedlings were allowed to grow in Yoshida nutrient solution with 1 (control), 8, 16, and 32 μM Cu at buffered pH levels of 4.5, 5.0, and 5.5, respectively. Shoot and root growth, leaf chlorophyll content, and root lipid peroxidation and K⁺ leakage of 15-day-old rice seedlings were determined. Results show that [Cu] had significant adverse effects on rice seedlings. Shoot height and root length were reduced by 18%–60% and 7%–69%, respectively, compared with the control, and shoot and root weight decreased by 26%–56%, and 25%, respectively, in response to progressive increases in [Cu]. Similarly, leaf chlorophyll content decreased by 150%–245% compared with the control treatment. Rice seedling roots suffered from significant increases in lipid peroxidation followed by K⁺ leakage (> 8–23 times) in response to increasing [Cu]. Averaged across [Cu], seedling growth and biomass were greater at pH 5.5 than at other pH treatments. In some instances, increasing pH minimized the adverse effects of Cu at low concentrations on rice seedlings.     

育肥猪舍用混凝土微缝地板的截面优化

为解决现有混凝土微缝地板因截面设计不尽合理产生的承载力富余过大,导致实际生产中板体自重大、生产和运输成本高等问题。该文通过计算假定、截面和荷载转化的方法,对混凝土微缝地板的结构进行了理论剖析,对其制造材料、板体尺寸、配筋等进行了优化和力学性能计算。在截面面积减少3600mm2、纵向钢筋面积减少213mm2、混凝土的标号由C30调至C25的情况下,单块地板的正截面抗弯值为3.14kN.m,斜截面抗剪值为3.56kN,裂缝宽度值为0.167mm,跨中截面挠度值为3.70mm,均可满足育肥猪安全使用要求。优化后,单块地板混凝土使用量可节省0.01m3,每平米地面铺设成本降低18%。     

工程车辆翻车事故中司机头部伤害与保护仿真

为了研究司机的头部在碰撞中的机械响应特性,该文采用有限元三维实体建模技术,建立了成人头部碰撞模型。通过虚拟试验方法使用成人头部模型对驾驶室内饰进行冲击分析,比较不同厚度和密度的聚氨酯泡沫对人体头部损伤评价指标的影响。结果表明：头部损伤值（HIC(d)）随着泡沫厚度的增加而减小,随着密度的增大,呈现先减后增的二次抛物线趋势。在驾驶室内壁覆盖18 mm厚的聚氨酯泡沫材料可以降低翻车事故中二次碰撞对司机头部的损伤。     

肉大鸡颗粒饲料的吸湿解吸平衡模型

为了研究成品饲料的吸湿解吸平衡规律,用GAB模型及其含温度变量的改良模型（mGAB, modified GAB）拟合静态法获得的肉大鸡颗粒料在15、25、35和45℃环境下,在11%至97%平衡相对湿度（即水活度0.11～0.97）范围内的吸湿平衡以及11%～75%（即水活度0.11～0.75）范围内的解吸平衡,得到优异的拟合精度。结果表明：随温度上升,饲料的平衡含水率下降,吸湿和解吸之间存在明显的滞后现象。用BET解吸模型计算的15～45℃范围内单层含水率为6.34%～5.39%（干基）,并且随温度升高线性下降。以水活度0.65为安全贮存的临界点,对应于吸湿和解吸过程, 用改良GAB模型估计4个温度点的安全水分（干基）分别为13.09%和14.71%、12.92%和14.33%、12.74%和14.00%、12.56%和13.66%。研究结果为饲料的贮存和冷却过程规律研究提供了参考。     

梅江盆地叶塘组紫色岩上发育土壤的物理性质研究

采用野外调查、取样和室内实验分析相结合的方法,研究了梅江盆地白垩系上统叶塘组（Kyt^2）紫色岩上土壤物理性质特征扣差异,结果表明：叶塘组紫色岩母质发育的土壤粘粒含量低而砂粒含量高,具有容重较大,比重相对偏小,孔隙度不高,自然含水量偏低的特点。从丘顶、丘腰到丘脚,土层逐渐增厚,土壤粘粒含量逐渐增加,砂粒含量逐渐减少,容重递增而比重减小。孔隙度表现出丘顶〉丘腰〉丘脚的趋势,含水量则表现出丘顶〈丘腰〈丘脚的趋势。针对情况,提出相应建议以维护紫色土利用的可持续发展。     

Composts Vary in Their Effect on Soil P Pools and P Uptake by Wheat

With diminishing world reserves of phosphorus (P) deposits and rising fertilizer prices, it is important to find alternate sources of P for crops. The aim of this research was to evaluate the effect of four different composts C1 (animal manure and straw), C2 (garden waste), C3 (wood chips and bark), and C4 (kitchen waste) on soil P pools and P uptake by wheat on 14, 28, and 72 days after compost application. The composts were applied as a 2.5 cm thick layer on the soil surface. During sampling, only the soil underlying compost was sampled. Soil pH and total organic carbon were not affected by the amendments. Soil respiration was significantly higher in compost-amended soils compared with the unamended soil except with C4 on day 72. Addition of composts increased plant growth, and P uptake being highest on day 72 with C1 and C4. With little effect on available P concentration on day 14, there was a conversion of organic P into inorganic P in the compost treatments suggesting net mineralization of organic P on day 28. On day 72, the concentrations of the less labile P forms were higher in the compost treatments compared with the unamended suggesting precipitation and fixation as well as synthesis of organic P. This study showed that mulching with composts having high available and total P concentrations can provide plants with P and also increase soil P concentrations which could reduce the fertilizer requirement for the following crop.     

不同有机物料对连作大豆土壤养分及团聚体组成的影响

为探究不同有机物料对连作大豆土壤养分和团聚体组成的影响,采用大田试验方法,研究了在连作7年条件下,腐熟鸡粪(JF)、玉米秸秆(JG)和木耳菌渣(JZ)三种不同类型有机物料对连作大豆土壤养分、产量、团聚体组成和稳定性的影响。结果表明:与CK相比有机物料能有效提高连作大豆土壤养分含量,显著影响土壤团聚体组成,0.25~2 mm粒级团聚体含量明显增加。畜禽粪便类的鸡粪(JF)对碱解氮的提高作用最明显,较CK提高13.85%;天然类的秸秆(JG)对速效磷含量提高作用显著,较CK提高4.13%;JF对提高速效钾含量效果最好,较CK提高8.97%;JG对提高有机质含量效果最好,较CK提高7.28%。半腐解类的菌渣(JZ)较CK相比土壤养分含量也有明显的提高,但不如JF和JG效果明显。有机物料能提高连作大豆产量,JF效果显著。所有有机物料对改善土壤团聚体组成,增加0.25 mm水稳性团聚体含量效果均比较显著,对土壤水稳性团聚体平均重量直径以及土壤团聚体的稳定性指数有显著提高作用。     

基于Ecotect的不同墙体材料猪舍光热环境和热性能分析

北方地区冬季寒冷漫长,为探究北方冬季养猪的采光及保温问题,该文基于Ecotect软件,以吉林省内某大型猪场的典型猪舍为对象,等比例建模仿真,研究猪舍的光热环境及猪场生产区光环境,探究猪舍内不同高度的采光系数及猪场生产区采光情况,分析4种形式不同墙体材料猪舍的保温性能。结果表明,试验猪舍各研究高度采光系数均高于2%,满足绿色建筑标准;猪场生产区采光良好,在大寒日的太阳辐射量可达5.38 MJ/(m2·d),日照充足无遮挡;通过对比4种形式不同墙体材料猪舍的逐月能耗值,计算出4种形式猪舍中黏土多孔砖猪舍、泡沫混凝土猪舍、酚醛夹芯板彩钢猪舍和低密度聚乙烯薄膜温室大棚猪舍的保温性能最好,考虑成本后更推荐炉渣砖砌体猪舍、粉煤灰加气砌块猪舍、聚苯夹芯板彩钢猪舍和低密度聚乙烯薄膜温室大棚猪舍;通过将试验实测值与软件模拟值进行数据对比,计算得出相对误差范围为0.74%～8.62%,验证了模型的可靠性。该文可以为探究北方猪舍的光热环境提供理论依据,为建筑设计师在方案实施前提供更多优化设计方案的思路。     

光子陆地棉种质资源主要性状的遗传评价

以102份光子陆地棉材料为母本,分别与遗传标准系TM-1杂交,获得102个F₁群体。采用随机区组设计,设置3个重复,对光子陆地棉材料主要性状进行遗传评价。结果表明,调查的11个性状表型差异均较大,材料间产量性状(株高、果枝数、铃数、铃重、衣分和子指)差异大于纤维品质性状(纤维长度、纤维强度、马克隆值、整齐度和伸长率),特别是衣分、铃数等性状差异更明显; 除果枝数、马克隆值、伸长率以外,光子亲本群体其他性状的平均值都小于F₁群体。而亲本群体所有性状的变异系数均大于F₁,不同光子材料的杂种优势有很大差别,中亲优势和超亲优势也有很大的差别,有些种质某些性状的中亲、超亲优势为负值,其后代性状表现劣势; 纤维品质性状的中亲、超亲优势与毛子程度均呈负相关,而产量性状的中亲、超亲优势与毛子程度均呈正相关,说明可利用光子材料杂种优势改良纤维品质,而其后代产量性状的杂种优势利用受到限制; SSR分子标记遗传相似系数与各个性状的中亲、超亲优势的相关都不显著,说明在光子材料的育种中,杂种优势是不能通过亲本之间的遗传背景相似程度来预测的。