论文标题:应用数学模型研究宁夏围栏内甘草的分布格局和土壤水分对甘草生长发育的影响
An Approach to the Distribution Pattern of Liquorice in Fence in Ningxia and Effects of Soil Water on the Growth of Liquorice Using Mathematical Models
论文作者
论文导师 王季槐,论文学位 硕士,论文专业 应用数学
论文单位 西北第二民族学院,点击次数 297,论文页数 73页File Size839K
2007-04-01论文网 http://www.lw23.com/lunwen_1148437/
Model;; Liquorice;; Regression analysis;; Kriging method;; Distribution pattern;; Logistic curve
甘草属多年生草本或灌木,主要分布于我国黑龙江、陕西、甘肃、宁夏、青海、新疆等省,是防风固沙的重要植物,它的分布区具有明显的区域性。本文通过研究宁夏野生甘草的分布格局以及人工种植甘草的高度、枝条数、叶片、地上生物量、地下根茎及侧根与土壤含水量之间的关系,得出如下结果: (1)利用球状模型作为半变异函数的理论模型,通过分析知:2005年野生甘草在研究区域内由随机因素引起的空间异质性占总空间异质性的51.82%,且主要体现在15m以下的小尺度上,而由空间自相关引起的空间异质性占总空间异质性的48.18% ,主要体现在15 m～49.5616m的中尺度范围内,说明在小尺度上甘草的生态学过程起主要作用;2006年野生甘草在研究区域内由随机因素引起的空间异质性占总空间异质性的38.09%,且主要体现在15m以下的小尺度上,而由空间自相关引起的空间异质性占总空间异质性的61.91% ,主要体现在15 m～36.8254m的中尺度范围内,说明,野生甘草在小尺度上的分布没有明显的规律,而在中尺度上具有团状分布的特点。 (2)在半变异函数的理论模型基础上,利用Kriging插值在二维平面上绘制甘草的空间分布图,从分布图中可以看到相对于2005年来说,2006年野生甘草聚集密度更高,面积更广,并在样方多处出现小的聚集斑块,主要是因为2006年的降雨量多,蒸发量少,自然环境适合甘草的生长,甘草的密度自然就会增大。 (3)通过逻辑斯蒂增长模型的分析得出,不同水分处理对甘草植株的高度、枝条数、单叶叶面积,叶片数量以及地上生物量都有很大的影响。随着土壤含水量的增大,甘草植株的高度随之增高,单叶叶面积,叶片数量以及地上生物量随之增大、增多;当土壤含水量增大到15%时,甘草的枝条数达到最大值,随着土壤水分的继续增加,甘草的枝条数开始下降,说明土壤含水量15%是甘草在生长方面的一个临界值。 (4)在盆栽试验中,由于意外,7月下旬5%处理进水,受干旱胁迫的甘草植株获得水分后,植株高度,枝条数,单叶叶面积,叶片数量以及生物量都有增加,并超过9%处理,且和12%处理的之间没有显著差异。说明,在甘草的生长过程中,先使甘草受到一定的干旱胁迫,然后再给其加入少量的水,甘草获得水资源后,就迅速生长,植株高度、枝条数、单叶叶面积,叶片总数以及生物量均有显著的提高,这可能是一种节水的好办法。 (5)从试验的耗水量得到,18%处理的水分耗散量最多,但其甘草植株的高度,叶面积,叶片数量,生物量与15%之间的差异并不是很显著,而且植株的枝条数比15%处理的还要少,因此,我们认为在宁夏这种条件下,种植甘草采用土壤含水量为15%处理最为合理。 (6)由于盆栽试验只做了一年,甘草地下部分的主根没有变化,水分对其影响无从下结论,但水分对甘草的侧根数量影响十分明显,随着土壤水分含量的增加,甘草的侧根数增多;水分对甘草的根茎也有一定的影响,从试验结果看,5%,9%,12%,15%各个处理之间甘草根茎的生物量和长度没有显著的变化,但18%处理与其他处理之间存在显著的差异,这也可能是甘草本身的生物学特性造成的。 (7)本文在借鉴地统计学空间分布插值以及生长发育模拟模型原理和方法的基础上,建立了野生甘草的半变异函数的理论模型以及甘草生长发育的模拟模型,半变异函数理论模型配合克里格插值,能很好的估算出野生甘草的空间分布;生长发育模型能较好地预测甘草植株的高度、枝条数量、单叶叶面积、叶片数量、地上生物量以及地下侧根数量的变化。
The liquorice is perennial herbaceous or brush plant, it distributs mainly over Heilongjiang, Shanxi, Gansu, Ningxia, Qinghai and Xinjiang provinces in China. It is an important plant to protect sand from wind. Its distribution area is obviously regional. This article studied the distribution pattern of the wild liquorice within the enclosure in Ningxia and the relation between the heights, stem numbers, leaf, above-ground biomass, underground rhizome, lateral root of liquorice and soil moisture. The results are as follows: (1)This article makes use of spherical model as the theoretical model of semivariograms. We have found, from the analysis of the model, that in 2005 the wild liquorice’s spatial heterogeneity caused by random factors accounted for 51.82% of total spatial heterogeneity in the research area, which is mainly embodied in small scale under 15 meters; while the spatial heterogeneity caused by spatial dependence accounts for 48.18% of total spatial heterogeneity. It displays in the middle scale between 15 meters to 49.5616 meters. The result shows that the ecology process of liquorice in small scale plays an important part; while in 2006, the wild liquorice’s spatial heterogeneity caused by random factor and spatial dependence respectively accounted for 38.09% and 61.91% of total spatial heterogeneity. The former displays in the middle scale between 15 meters to 36.8254 meters.The result indicates that wild liquorice has no obvious regulation in the distribution of small scales, but it has the characteristic of mass distribution in middle scales. (2)On the base of the theoretical model of semivariograms, we used the Kriging interpolation to draw the plot of liquorice’s spatial pattern in 2D plane. From the chart, we can see that in 2006 the wild liquorice’s aggregation density is higher, the aggregation area wider than 2005. The reason is that there were more rainfall and smaller evaporation, and the environment was suit able for the growth of liquorice in 2006, so the density of liquorice is higher. (3)Based on the analysis of Logistics growing model, we can find that different water supply has great influence on the height, stem numbers, single leaf area, leaf numbers and aboveground biomass. With the increase of soil moisture, the height of liquorice would be higher, the single leaf area larger, as well as the leaf numbers and the biomass above ground more. When soil water content reaches to 15%, the stem numbers reaches to max numbers, but the stem numbers of liquorice decrease with increase of soil moisture. 15% of soil moisture may be regarded as a critical point. (4)In pot incubation test, the treatment of 5% was added superfluity water in the July due to an accident. Therefore the height of liquorice in the treatment was higher, stem numbers, single leaf area, amount of leaf and biomass of liquorice in the treatment more than 9%, but these indexes were something like that of 12%. It shows that liquorice endangered by drought grows better and more quickly when gaining more water, which suggests that it may be a possible way to save water. (5)From the consumption water account of the experiment, we have the following conclusion: the account of consumption of the 18% treatment is the most one, but the indexes (height, leaf area, leaf numbers and aboveground biomass of the liquorice) are not obviously different from 15%, the stem numbers are also less than 15%. Therefore, we understand that using the soil contents 15% water in Ningxia province is the most reasonable. (6)The change of main roots of liquorice in the pot incubation test has not discovered because the experiment was conducted noly one year. Alghough we can’t conclude that water affects the main roots, it is obvious that water has a clear influence on the quantity of lateral root of liquorice. The number of lateral root grows with the incease of water in the soil. Water also has an influence on the stem and roots of liquorice. According to the experiment, there is no great change among the biomass and length of the roots and stems of the liquorice planted on the soil moisture of 5%, 9%, 12%, 15%, but that of the 18% water is quite different. This may result from the biological character of liquorice itself. (7) In this thesis, theorical model of semivariograms of wild liquorice and simulation model of the liquorice growth and development. The theoretical model of semivariograms with the Kriging interpolation may be used to evaluate wild liquorice’s spatial pattern distribution well, and the growth and development model to predicate the change of the height, stem numbers, single leaf area ,leaf numbers, aboveground biomass and the amount of under ground lateral root of liquorice.
|
