【作者】 许静；

【导师】 和文祥；

【作者基本信息】 西北农林科技大学 ， 微生物学， 2010， 硕士

【摘要】 烟草是我国重要的经济作物,在国民生产和经济发展中发挥重要作用。近年来由于烟田连作以及滥用化肥,致使烟田土壤肥力下降、烟叶品质降低等问题日益严重,因此通过研究不同培肥措施对烟田土壤生化活性和烟草品质的影响,进而筛选出最佳培肥模式,同时了解施肥—土壤性质（化学和生物学）—烟草品质的关系,将会对烤烟生产等具有重要意义。国内外目前关于烟田培肥的研究有大量报道,但由于烟草具有明显的地域性特点,加之从土壤生物和生化活性角度研究烟田培肥鲜见报道,特别是关于培肥对烟田土壤酶动力学特征影响的研究未见到文献。因此十分有必要开展这方面的探讨。本研究在陕西省宝鸡市的陇县采用田间试验模式,较为系统地研究了不同培肥措施（对照、化肥、烟草专用肥、有机肥、有机肥+化肥）对烟田土壤质量和烟叶品质的影响,筛选获得本地区烟田的最佳培肥模式,最终为陕西渭北旱塬地区烤烟生产提供理论依据和技术支撑。研究获得的主要结果如下:1.培肥可提高烟田土壤的肥力水平,其中有机肥+化肥处理与其它培肥处理相比,显著增加了土壤中有机质、碱解氮、速效磷和速效钾的含量,揭示出有机肥和化肥混合施用对土壤养分状况的改善作用最明显。2培肥对烟株农艺性状和烟叶品质均有提高作用。相关分析表明土壤有机质、碱解氮、速效磷含量与烟草农艺性状的各项指标（如株高、叶数、茎围、节距、最大叶长和最大叶宽）均呈显著或极显著正相关,土壤中速效钾含量与烤烟烟碱、氮、钾含量呈显著或极显著正相关,说明施入肥料后改善了土壤的理化性质,促进了烟株的生长发育,合理调控了烟株营养,增强了烟叶内在化学成分的协调性,最终提高了烟叶的品质。其中有机肥+化肥处理的效果最好,说明从烟草性状角度来看,其为最优的培肥模式。3.培肥可使烟田土壤酶活性增加,其中尤以有机肥+化肥模式效果最明显,显著提高了土壤脲酶,蔗糖酶,碱性磷酸酶,脱氢酶和过氧化氢酶活性;其次为有机肥处理。相关分析表明,土壤脲酶、蔗糖酶、碱性磷酸酶和过氧化氢酶活性与有机质、碱解氮、速效磷等大部分指标达显著或极显著正相关,揭示出四种酶活性可在一定程度上表征土壤肥力水平的高低。4.采用我们构建的土壤总体酶活性参数,计算后发现总体酶活性可更好、更准确地反映了不同培肥措施下土壤整体生化活性的大小和土壤肥力水平的高低,再次从土壤酶角度佐证了有机肥+化肥是种较优的培肥措施。5.培肥对土壤微生物区系影响不同。总体上看来显著增加了土壤细菌数量,而土壤放线菌数量变化不显著,土壤真菌的差异则较大;其中烟草专用肥处理的土壤真菌数量显著高于对照,而其它施肥处理显著低于对照。有机肥和有机肥+化肥处理不仅有效增加了微生物数量,而且两者的McIntosh指数最高,从微生物区系方面说明配施有机肥的有机肥和有机肥+化肥处理为较好的培肥措施。6.培肥后土壤酶动力学特征显示土壤脲酶、蔗糖酶、碱性磷酸酶的K_m值均处于同一数量级,但培肥处理的脲酶和碱性磷酸酶的K_m值与对照相比有减小的趋势;培肥后土壤酶V_max、V_max/K_m及k均表现为增加的规律性变化,且以有机肥+化肥处理的增幅最大。说明施肥后不仅提高了土壤酶的含量,而且加快了酶与底物结合和酶与产物分离的速度,提高了酶促反应速率。7.相关分析表明酶动力学参数V_max、V_max/K_m和k与土壤有机质、碱解氮和速效磷间大多呈显著或极显著正相关,因此此三个参数也可作为评价培肥效果的指标之一。更多还原

【Abstract】 Tobacco is a kind of staple cash crop, it plays an important role in national production and economic development.Recently, continuous cropping and abusing chemical fertilizer leads to the decrease in tobacco quality and soil fertility. So it is important for tobacco production to have study on the effect of fertilization on soil biochemical activity and quality of tobacco. So that we can select the optimum fertilization model and have knowledge of relationships between fertilizer, soil characteristic （chemical and biology） and quality of tobacco.There has been many reports about fertilizing in tobacco field. However, tobacco has obvious regional characteristic and there are few reports about the study of fertilizing of tobacco field from the view of soil biology and biochemical activity, especially there is no report about the effect of fertilizer on soil enzymatic kinetics. So it is necessary to discuss this issue.We studied the effect of different fertilizations（ck,chemical fertilizer, tobacco- specific fertilizer, organic manure, organic manure and chemical fertilizer） on quality of soil and tobacco in longxian baoji city Shaanxi province. We also selected the optimum fertilization model in order to provide evidences to flue-cured tobacco production in Weibei dryland of Shaanxi province. The results were as follows:1.Fertilizers improved soil fertility. Compared with other treatments, in organic manure and chemical fertilizer treatment, Alkali N, Available P, Available K in soil increased significantly. This indicated that organic matter combined with chemical fertilizer can increase the soil nutrient.2.Agronomical character of tobacco and tobacco quality were improved by appling fertilizers.There were significant or remarkably significant positive correlations between organic, Alkali N, Available P of soils and agronomical characters of tobaccos（e.g. plant height, leaf numbers, stem girth, knot length,maximum leaf length and width）.And there were the same relations between the Available K in soil and Nicotine, Nitrogen and Potassi in tobacco. This indicated that fertilizer improved quality of soil, encouraged growth of tobacco and harmonized chemical composition of tobacco, improved tobacco quality finally. The model of organic matter combined with chemical fertilizer had the best effect, it can be the best one among fertilizers.3.Fertilizers improved soil enzyme activity, especially organic matter combined with chemical fertilizer. It remarkly increased activities of urease, invertase, alkaline-phosphatase, dehydrogenase, catalase. Organic matter model was following. The positive or apparent positive correlation was found between the activities of urease, invertase, alkaline- phosphatase, catalase and organic, Alkali N, Available P. So we concluded that the four enzymes could evaluate the soil fertility.4.Total enzymatic activity constructed by ourselves could more accurately reflect the levels of soil biochemical activity and fertility of different fertilizations. From the view of soil enzyme, it was also concluded that organic matter combined with chemical fertilizer was a better one.5.The effect of fertilizers on soil micro-organism was different. In general, bacteria increased significantly by appling fertilizers, there was no regular changes in the actinomyces but big varies in fungi. Only tobacco-specific fertilizer had more significant effect than ck. The two models of organic manure, organic manure and chemical fertilizer increased microbe number. And the McIntosh index was the highest in this two models .From the view of micro-organism, organic matter and organic matter combined with chemical fertilizer were better fertilizers.6.Accoring to urease,invertase and alkaline-phosphatase enzymatic kinetics, we concluded that K_m changed in the same rank quantitatively, but K_m of urease and alkaline-phosphatase of fertilizers were lower than ck. V_max, V_max/K_m and k increased after appling fertilizers increased significantly, especially in organic matter combined with chemical fertilizer treatment. It indicated that fertilizers not only increased content of enzyme, but also speeded the combination of enzyme and substrate and separation of production and enzyme and increased the speed of reaction.7.There were significant or remarkably significant positive correlations between V_max,V_max/K_m, k and Organic matter, Alkali N, Available P. So the three enzymatic kinetics could be indexes to evaluate fertilizer effect.更多还原