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1.
Papua New Guinea has astonishing biological and cultural diversity which, coupled with a strong community reliance on the land and its biota for subsistence, add complexity to monitoring and conservation and in particular, the demonstration of declines in wildlife populations. Many species of concern are long-lived which provides additional challenges for conservation. We provide, for the first time, concrete evidence of a substantive decline in populations of the pig-nosed turtle (Carettochelys insculpta); an important source of protein for local communities. Our study combined matched village and market surveys separated by 30 years, trends in nesting female size, and assessment of levels and efficacy of harvest, each of which was an essential ingredient to making a definitive assessment of population trends. Opportunities for an effective response by local communities to these declines needs to consider both conservation and fisheries perspectives because local communities consider the turtle a food resource, whereas the broader global community views it as a high priority for conservation. Our study in the Kikori region is representative of harvest regimes in most rivers within the range of the species in Papua New Guinea, and provides lessons for conservation of many other wildlife species subject to harvest.  相似文献   
2.
Field experiments conducted under different levels of irrigation and fertilizers reveal that water and fertilizers increased each others' efficiency in several field crops. However, the over dose of fertilizers in the absence of adequate watering or nutrients deficiency under frequent watering had adverse effects on crop productivity. These effects were mediated through plant water status and related physiological processes. Thus, a proper combination of irrigation water and fertilizers is required for attaining high water and fertilizers use efficiency in field crops.  相似文献   
3.
以不同穗型水稻品种为试材,研究不同氮素水平下水稻产量性状的结果表明:直立穗品种的 生物产量高于弯曲型品种,经济系数低于弯曲型品种。在低氮条件下,两品种的经济系数均提高,且 弯穗型品种的经济产量略高于直穗型品种,在高氮条件下则相反。在相同肥力下,抽穗前两品种的物 质生产差异不大,但抽穗后直穗型品种的物质生产明显高于弯穗型品种。同时发现在低氮条件下,两 品种的穗数明显减少,但穗粒数增多,结实率提高,一、二次枝梗的千粒重均高于高氮处理。  相似文献   
4.
 对硬粒小麦(T.durum)-簇毛麦(H.villosa)杂种幼胚和F#-1幼穗诱导的愈伤组织进行秋水仙素处理获得硬-簇双二倍体TH1,TH1W,TH2W,TH3,TH3W。平均加倍率为78.8%,最高为94.1%。通过与普通小麦(T.aestivum)回交,幼胚和花药培养,得到了6D/6V异代换系94G22-1,94G25-1,94G32-1,94G33-1。谷草转氨酶(GOT)和酯酶(EST)同工酶可作为这些材料的生化标记。RAPD分析中,引物OPAN3可作为其分子标记引物。  相似文献   
5.
不同氮水平下固氮菌肥对油菜施用效果研究   总被引:1,自引:0,他引:1  
为了确定固氮菌的最佳氮素范围,本文通过油菜盆栽生物模拟试验,在石灰性土壤上研究了固氮菌与不同氮水平配施对土壤养分、油菜生长发育的影响,结果表明:①与M1(不施菌肥)相比,M2(固氮菌)使土壤全氮、碱解氮、速效磷、速效钾平均提高了19.2%、20.7%、12.0%、11.5%;使油菜鲜重、干重、株高平均增加33.5%、26.5%、15.8%;使油菜氮、磷、钾含量增加了22.5%、12.0%、13.6%,且在N3水平增幅最大;使油菜Vc含量、叶绿素、还原糖增加了8.8%、13.8%、30.4%,硝酸盐含量降低了34.4%,且中高氮水平时对提高油菜品质较为明显;②经隶属函数法对施用固氮菌肥后油菜综合施用效果分析,隶属函数值均呈N3N4N2N1趋势,表明固氮菌在N3(0.15 g.kg-1)水平对油菜的综合施用效果最好。  相似文献   
6.
铅对烤烟K326和红花大金元生长和品质的影响   总被引:1,自引:0,他引:1  
选用烤烟K326和红花大金元,在不同铅含量(0、300、500 mg/kg)土壤进行栽培试验,测定烟株铅含量,比较烤烟农艺性状、生理指标、品质的差异,探讨铅对烤烟生长和品质的影响.结果表明:K326在铅含量较低时农艺性状各指标、硝酸还原酶活力和根活力保持较高水平,铅吸收较少,在铅含量较高时农艺指标及品质指标明显减小;红...  相似文献   
7.
栽培措施对玉米根系生长状况影响   总被引:8,自引:2,他引:6  
本文通过用ABT生根粉4#、肥宝对玉米种子的不同处理及不同施肥水平试验观察结果为:ABT生根粉及肥宝对玉米有明显的促进生根作用,其根长、根重、根体积均比对照在同一生育期有显著增加,尤以生根粉+肥宝处理的效果最佳,表现明显互作正效应;不同施肥水平比较观察,在N、P2O5及K2O为2∶1∶1情况下施用中肥处理即:N∶P2O5:K2O为250kg∶125kg∶125kg/hm2为最佳,表现出根系强壮的特点.根重对维持叶绿素含量水平有一定作用.表现为根重大者,其叶绿素含量相对为高.  相似文献   
8.
This 4-year study examined the susceptibility of nine cultivars of apple, Malus domestica Borkhausen to attack by woolly apple aphid (WAA), Eriosoma lanigerum in Jordan. The cultivars under investigation were: Prima Rouge, Delberd Steval, Early Gold, Starking Delicious, Harmony, Golden Smoothee, Fuji, Melrose, and Golden Delicious. Estimation of susceptibility was based upon a numeric scale of 0–4 for both root and shoot, but each with different specifications. A tree infestation rating was obtained by calculating the average rating of both edaphic and arboreal ratings of each tree. Fuji was significantly the most infested cultivar during the period of study and it ranked as a highly susceptible cultivar. Prima Rouge, Early Gold, Starking Delicious, Golden Smoothee, and Golden Delicious showed lower susceptibility. Harmony was an immune cultivar as it sustained neither edaphic (root inhabiting) nor arboreal colonies of woolly apple aphid. We propose the development of rootstocks from Harmony cultivar. The latter offers a new gene for resistance to WAA that will open the door for plant breeders to produce different resistant rootstocks.  相似文献   
9.
A field trial was conducted during the kharif (rainy) seasons of 2002 and 2003 at the Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India. The trial was carried out to study the effect of planting methods, sources and levels of nitrogen on soil properties, yield and NPK uptake by rice (Oryza sativa L.) under direct seeded condition. Planting methods significantly influenced the physical, chemical and biological properties of soil. Bulk density (1.385 g cm−3), organic carbon (0.43%) and soil moisture content (15.46%) were higher in zero till seeding plots than rotavator and conventional seeding. However, infiltration rate, soil temperature, pH and electrical conductivity showed a declining trend under this treatment and were found maximum (11.54 mm h−1, 36.21 °C at 55 DAS, 30.65 °C at harvest, 7.59 and 0.47 ds m−1) with conventional seeding. The maximum population of bacteria (25.60 × 105), fungi (14.26 × 104) and azotobactor (10.19 × 103) were found in the plot with zero till seeding while in case of actinomycetes the highest population (25.61 × 105) was found in conventional seeding. Nitrogen sources as well as levels failed to bring about any significant change in the soil properties. The highest grain (3825 kg ha−1) and straw yields (5446 kg ha−1) and N, P, K uptake were recorded in conventional seeding and were found significantly superior to zero till seeding (3144 kg ha−1) but it remained at par with rotavator seeding (3585 kg ha−1). Among the nitrogen sources, neem (Azadirachta indica) coated urea produced significantly higher grain (3761 kg ha−1) and straw yields (5396 kg ha−1) with greater NPK uptake than prilled urea and prilled urea + spent mentha. (The distillation waste of mint (Mentha arvensis) herbage is known as spent mentha.) Application of 150 kg N ha−1 produced maximum grain (3828 kg ha−1) and straw yields (5460 kg ha−1) although it remained at par with 100 kg N ha−1 (3738 and 5393 kg ha−1).  相似文献   
10.
吴敏  何鹏  韦家少  吴炳孙 《安徽农业科学》2011,39(31):19191-19193,19197
[目的]研究不同钾水平对巴西橡胶树(Hevea brasiliensis)幼苗各器官磷组分和酸性磷酸酶活性的影响。[方法]采用水培试验。试验材料为巴西橡胶树RRIM600种子实生幼苗,K2O浓度分别为0、1、10、50、250 mg/L。[结果]缺钾降低了橡胶幼苗各器官中可溶性磷含量及其比例,但提高了橡胶幼苗各器官中不可溶性磷含量及其比例。橡胶幼苗各器官中可溶性磷含量差异显著,且大小顺序为根〉皮〉叶,而不可溶性磷含量在根中极显著大于叶和茎部的皮,但根和茎部的皮中不可溶性磷含量差异不显著。酸性磷酸酶活性在各器官之间差异极显著,但同一器官中,不同钾营养浓度下,酸性磷酸酶活性则差异不显著。[结论]该揭示了不同钾水平下天然橡胶幼苗不同器官磷组分特性和酸性磷酸酶活性的变化特点,可以为天然橡胶生长中的磷钾营养合理配施奠定理论依据。  相似文献   
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