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

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.