叶面喷施硒肥对水稻含硒量及产量的影响

黑龙江省处于缺硒地区。盆栽和田间叶面喷硒试验表明,根外追肥是补充水稻含硒量的有效措施,叶面喷施硒肥(Na2SeO3)的最佳用量为11 25g/hm2。同时对水稻具有一定增产作用。     

落叶松针叶的质量对落叶松毛虫影响的研究

本文研究了落叶松针叶质量对落叶松毛虫生殖，生存及发育速度的影响，结论是；落叶松毛虫成虫有选择产卵环境的趋向，发育状况优良，产卵能力强的雌虫更倾向于在落叶松针叶质量优良的未受害或受害轻微的林分中产卵，而发育状况差，产卵能力弱的雌虫则倾向于在原危害区产卵；饲喂不同林龄针叶的落叶松毛虫产卵量差异显著，取食林龄小于４０ａ针叶的落叶松毛虫的产卵量比取食林龄大于４０ａ的高，饲喂不同危害区落叶松针叶的落叶松毛虫     

Performance of Dimethomorph + Mancozeb Applied to Seed Potatoes in Early Management of Late Blight (<Emphasis Type="Italic">Phytophthora infestans</Emphasis>)

Treating seed potatoes with contact fungicides prevents infection of Phytophthora infestans from tuber to tuber during handling but does not prevent field infections in the young plant. Dimethomorph (DMM) 9% + mancozeb 60% (Acrobat MZ, BASF) can cover both aspects due to the contact and systemic action of mancozeb and DMM, respectively. Experiments were performed under greenhouse and field conditions (three seasons and two locations) with cvs Kennebec, Shepody, Spunta, Russet Burbank, and Ranger Russet. Immediately after cutting, seed pieces were treated with Acrobat MZ at doses equivalent to 2, 3, and 4 kg ha⁻¹. At any dose, Acrobat MZ protected healthy seed tubers against P. infestans infections. Acrobat MZ (4 kg ha⁻¹) also protected the foliage of all cultivars against artificial inoculation of P. infestans, assessed by the detached-leaf method. These effects were observed up to 30 days after emergence in greenhouse experiments and up to 28 days after crop emergence under field conditions in two growing seasons. In cv Spunta, significant foliage protection was observed up to 35 days after field emergence whereas in seed tubers of cv Kennebec planted in sandy soils, significant foliage protection persisted longer. Additional evidence for acropetal translocation of Acrobat MZ in field crops was also found. With this strategy, there is no need to apply contact or systemic fungicides early in the season, and spraying costs and environmental risks are also reduced.     

光谱技术在农业领域的应用与展望

光谱技术以其简便、快速、精度高和无损测定等优越性。成为获取农田生物环境信息的重要手段．在精确农业发展中发挥着重要作用。从土壤光谱特性、植物光谱特性和冠层光谱特性角度,综合分析了光谱技术在土壤性质测定、作物水分监测、营养诊断、产量估测、籽粒品质检测以及病虫害和农药残留监测等方面的应用现状．探讨了应用中存在的光谱分辨率不高、模型不完善、应用体系不完整、应用尺度不统一等问题,并对其应用前景进行了展望。     

Performance of eight tree species in the highland Vertisols of central Ethiopia: growth, foliage nutrient concentration and effect on soil chemical properties

The coverage of trees in the highland Vertisol areas of Ethiopia is very scarce. A tree screening trial was conducted from 1997 to 2002 in Ginchi (central Ethiopia) to select fast growing and high biomass producing tree species; evaluate foliage macronutrient concentration of different tree species; and assess effects of trees on soil chemical properties beneath their canopies. Acacia decurrens Willd, A. mearnsii De Wild and Eucalyptus globulus Labill attained the highest height growth at 64 months as compared to other indigenous and exotic species. E. globulus provided better height increment from 24 to 36 and 36 to 64 months than other tree and shrub species. Acacia mearnssi and A. saligna Labill Wendl produced high biomass at 40 and 64 months. Differences between the highest and lowest dry biomass at 12, 40 and 64 months were 1.13, 29.19 and 38.89 kg tree⁻¹, respectively. None of the tree species resulted in a foliage to stem biomass ratio of >0.98 at 40 and 64 months. Sesbania sesban (L.) Merr had high N and P concentrations in its foliages and stems at 12 and 40 months. Total N under Acacia abyssinica Hochst. Ex Benth, A.␣saligna and S. sesban was slightly greater at 40 months than 12 months.     

南方红豆杉扦插繁殖技术研究——Ⅲ.叶面肥与透光度对扦插苗生长的影响

试验研究叶面肥和透光度对南方红豆杉扦插苗生长的影响结果表明,喷施叶面肥对扦插苗生长和叶绿素含量的影响呈正效应,而透光度的影响则呈负效应,且前者效应大于后者。喷施叶面肥和未喷施叶面肥处理间扦插苗新梢长、苗鲜物质量和根鲜物质量及叶绿素含量间差异均达显著水平;且喷施叶面肥处理40%与80%透光度间以上指标差异达显著水平,40%与60%透光度间或60%与80%透光度间差异仅部分指标差异显著;而未喷施叶面肥处理透光度对扦插苗叶绿素含量的影响仅部分处理间有明显差异,但不足以导致扦插苗生长量的显著差异。     

根外施用钙肥对苹果树生育期及产量的影响

作物产品中的钙含量是人类钙营养元素的重要来源,施钙能够提高植物性食品中的含钙量,从而有利于人类健康。若植物新根生长受阻或蒸腾作用减小,作物中钙的含量急剧降低,这样将影响作物的正常生长发育。通过对作物进行根外喷施钙肥,能够快速有效的补充植物对钙元素的需要。本试验通过在苹果的开花期、结果期以及膨大期连续三次叶面喷施不同含量的钙肥,测出喷施含钙量为160g/L钙肥的苹果树的每公顷产量较对照清水的增产5666.6kg,增产率达14.4%,并且方差分析达极显著水平;在喷施含钙量为120g/L的钙肥的苹果树的每公顷产量较对照清水的增产4888.8kg,增产率达12.4%,并且方差分析达显著水平。     

根外施钾对日光温室番茄光合速率的影响

试验研究了番茄生育期根外施钾对其光合速率的影响,结果表明,根外施钾可促进光合速率,一定程度缓和“午休”现象。番茄生育期11月~次年3月份4次根外施钾对促进番茄光合速率和营养积累有显著作用,其效应优于根外2次施钾和3次施钾处理,每次施钾作用持续时间达25 d左右。     

土壤、蔬菜的铅污染相关性分析及土壤铅污染阈限值研究

为探求土壤重金属污染和蔬菜污染的相关性,为绿色蔬菜生产提供技术支持,以郑州市常见的5种叶菜类蔬菜[油麦菜（Lactuca sativa var．Asparagina）、荆芥（Schizonepeta tenuifolia Briq）、蕹菜（Lpomoea aquelica）、生菜（Lactuca sativa）、苋菜（Amaranthus hypochondriacus）]为试验材料,采用温室盆栽土培的方法研究了土壤Pb浓度与蔬菜污染的相关性,并对绿色蔬菜生产要求的土壤Pb污染阈限值进行了预测。研究结果表明：低浓度Pb污染的土壤对蔬菜生长、产量无明显影响;随着施Pb浓度的增加,5种蔬菜中的Pb含量均呈增加趋势,且与土壤中的Pb含量相关性显著;模拟得出的Pb阈限值油麦菜为39．9092&#177;2．4469mg&#183;kg^-1,荆芥43．8986&#177;3．5855mg&#183;kg^-1,蕹菜35．2934&#177;1．7872mg&#183;kg^-1,生菜33．6964&#177;2．1512mg&#183;kg^-1,苋菜34．5396&#177;2．4254mg&#183;kg^-1;对Pb富集能力由大到小排序为生菜〉苋菜〉蕹菜〉油麦菜〉荆芥。