【作者】 陈亚；

【导师】 袁玲； 习向银；

【作者基本信息】 西南大学 ， 植物营养学， 2009， 硕士

【摘要】 本文通过盆栽试验,采用完全随机试验设计,以烤烟K326为试验材料,研究了水氮耦合对植烟土壤理化生物特性及烤烟生长的影响;并通过建模与优化提出了适宜的水氮耦合模式,为优质烟叶生产中合理灌水和氮肥施用提供科学依据。主要研究结果如下:1.不同处理中植烟土壤全氮、碱解氮、有效磷和有机质含量均随生育期的推进而降低,土壤pH值前期增加后期降低;收获后,土壤放线菌最多,细菌次之,真菌最少,微生物碳含量高于微生物氮含量。2.土壤全氮和碱解氮含量随施氮量增加而增加,适宜灌水有利于全氮和碱解氮积累;适宜增加施氮量可促进土壤有效磷含量的提高,氮肥不足且高灌水则降低其含量;土壤有机质含量在适宜施氮范围内随施氮量增加而增加,随灌水量增加而降低;过量施氮可降低土壤pH值,高灌水可则提高土壤pH值。3.收获后,植烟土壤细菌、放线菌和真菌均随施氮量增加有不同程度的增加,在适宜施氮范围内,灌水有利于提高微生物碳氮含量,氮肥不足且高灌水则抑制三种菌活动。4.施氮为3-7克/株且灌水为60-80升/株,可使烤烟株高增加,茎围增粗并促进烟叶伸展,且各部位烟叶干重较高。成熟期烟叶叶绿素含量和硝酸还原酶活性随叶位升高而增加;叶绿素含量随施氮量和灌水量增加而增加;烟叶硝酸还原酶活性随施氮量增加而增加,高灌水则抑制硝酸还原酶活性。5.烟叶总氮含量为上部叶＞中部叶＞下部叶;全磷含量为下部叶＞中部叶＞上部叶;全钾含量则下部叶显著高于中部和上部叶。各部位烟叶含氮量,随施氮量增加而增加,随灌水量增加而降低;适量施氮在一定程度上可以促进烤烟对钾素和磷素的吸收,低施氮时灌水有利于烤烟对钾素的吸收,高灌水降低烟叶钾和磷素含量;烤烟缺氮会增大对钾素和磷素吸收的比例。施氮为3-7克/株且灌水为60-80升/株时,以上各指标含量较适宜。6.烟碱、蛋白质及氯离子含量随叶位升高而增加;还原糖含量为中部叶＞下部叶＞上部叶。烟叶烟碱和蛋白质含量随施氮量增加而增加,随灌水量增加而降低;还原糖含量,在低施氮范围随施氮量增加而增加,过高施氮则降低其含量;低施氮高灌水可使还原糖含量降低;适量施氮可降低烟叶氯离子含量,增加灌水则提高其含量。7.各部位烟叶氮碱比变化幅度不大;糖碱比在下部叶和中部叶明显高于上部叶;钾氯比在下部叶明显高于中部和上部叶。增加施氮量可以增加中部和上部叶氮碱比,高施氮高灌水可降低下部叶氮碱比;适宜灌水高施氮可降低糖碱比,适量灌水可增加糖碱比;增加施氮量有助于提高钾氯,高灌水降低钾氯比。8.在本试验条件下,紫色植烟土壤每株烤烟适宜的施氮量为3-7克,灌水量为60-80升。水氮耦合对烟叶干重的影响为:施氮效应＞灌水效应＞水氮耦合效应,水氮具有正交互趋势。施氮为5.62克/株,灌水为78.19升/株时,烟叶干重可达最高(94.91克/株)。更多还原

【Abstract】 A pot experiment was carried out with flue-cured tobacco K326 by completely randomized trial design to study the effects of water and nitrogen coupling on the growth of tobacco and physicochemical and biological properties of soil.An appropriate model of water and nitrogen coupling was proposed through modeling and optimization for rational supplies of water and nitrogen resources in tobacco cultivation.Following are the main results obtained:1.The contents of organic matter,total N,and available N and P in tobacco-grown soil were reduced as the growing period prolonged in experimental treatments,Soil pH,however,was increased early and decreased lately.Large number of actinomycete was foumd,followed by bacteria, and fungus was lowest at tobacco harvest,and the content of microbial carbon was detected higher than microbial nitrogen at the same time.2.Total and available N in soil were increased with nitronge application increased.Appropriate irrigation application benefited the accumulation of total and available N in soil.They were decreased in case of insufficient nitrogen fertilizer.Organic matter was accumulated with appropriate nitronge fertilized into soil and behaved otherwise as more water was irrigated.In regard of pH in soil,it was reduced by over supply of nitrogen fertilizer but increased by irrigation.3.The numbers of soil microorganisms,such as bacteria,actinomycetes and fungi,were increased in some extent with nitronge fertilizer increased at tobacco harvest.The contents of microbial carbon and nitrogen were increased by irrigation with appropriate nitronge fertilized; however,activities of the three microorganisms in soil were inhibited by over irrigation with less nitrogen supplied.4.When 3-7 g N·plant^-1 was fertilized together with 60-80 L water·plant^-1 was irrigated,the height,stem diameter,leaf expansion and weight of tobacco leaves at variable locations were increased.The higher leaves located on stems,the higher the chlorophyl content and the activity of nitrate reductase（NR） were detected at mature period.In addition,the content of chlorophyl was increased as more nitronge and water supplied.The activity of NR was stimulated by nitronge fertilization and inhibited by excessive irrigation.5.The content of total N was observed highest in upper leaves of tobacco,followed by middle leaves,and lowest in lower leaves.The content of total P chaged the the sequence:lower leaves＞ middle leaves＞upper leaves.The content of total K in lower leaves was significantly higher than the middle and the upper leaves.N in tobacco leaves of various loactions was increased with the increment of nitrogen fertilized but reduced with more water irrigated.More P and K were accumulated in tobacco plants with appropriate N supplied.Irrigation benefited the absorption of K in less nitrogen fertilized but excessive irrigation decreased the contents of P and K in tobacco leaves. The shortage of nitrogen could increase the proportion of P and K in the leaves.3-7 g·plant^-1 fertilized together with with 60-80 L water·plant^-1 irrigated could result in the appropriate content and absorption of nutrient.6.The contents of nicotine,protein and chloride ion were increased from lower leaves to the upper ones in general.The content of reduced sugar was highest in middle leaves,followed by lower leaves,and lowest in upper leaves.Nicotine and protein increased with the increment of nitrogen fertilized and decreased with more water irrigated.Reduced sugar increased with the increment of less nitrogen fertilized but reduced at over supplies of nitrogen.Reduced sugar also decreased at less nitrogen with excessive irrigation.Similarly,the concentration of chloride was reduced at appropriate nitrogen fertilized but increased as more water irrigated.7.The ratio of nitrogen to nicotine in various leaves changed little,if any.The ratio of sugar to nicotine varied in lower and middle leaves was found higher than upper leaves.The ratio of potassium to chloride in lower leaves was found higher than middle and upper leaves.The ratio of nitrogen to nicotine in middle and upper leves was increased by the increment of nitrogen fertilization but decreased by irrigation.Appropriate irrigation could increase the ratio of sugar to nicotine but reduced by high amount of nitrogen fertilized in the taobacco leaves.The ratio of potassium to chloride,however,increased as nitrogen increased and behaved otherwise in as more water supplied.8.3-7 g N·plant^-1 and 60-80 L water·plant^-1 supplied is appropriate in tobacco cultivation in our present experiment.The effects of nitrogen and water on dry weight of leaves was obtained highest for nitrogen fertilization,then irrigation,and lowest for water-nitrogen coupling.There was a positive interaction trend of water and nitrogen.The best amount of fertilization and irrigation was 5.62 g·plant^-1 for nitrogen and 78.19 L·plant^-1 for water,and the highest dry weight of tobacco leaves(94.91 g.plant^-1) could be obtained in this case.更多还原