Study On The Spatial Heterogeneity And Marginal Effect Of Jerusalem Artichoke Morphological Traits

Geostatistics has been developed for use in mineral exploration in the 1950s. So far, it has been widely used in quantitative description of natural variables of spatial or spatiotemporal domain, including spatial variability and structural analysis, spatial prediction, space simulation and so on. Geostatistical simulation is a helpful tool allowing reproduction of spatial variability of data and providing measures of spatial uncertainty through multiple equally probable realizations. Jerusalem artichoke, which originated in the north-central U.S., is a perennial grown as an annual. Distributed throughout the world, Jerusalem artichoke has showed a wide ecological adaptability. Unlike most crops that store carbon as starch (a polymer of glucose), in the Jerusalem artichoke carbon is stored as inulin (a fructose polymer). Both above-and belowground parts of Jerusalem artichoke are utilizable for various applications, for instance, the tops for biomass and animal feed and the tubers as a feedstock for food and nonfood chemical industry. Geostatistical methods create mathematical models of spatial correlation structures with a variogram as the quantitative measure of spatial correlation. But there is no research of the spatial correlation about Jerusalem artichoke by using geostatistics. This study was aimed at evaluating the spatial differences in growth of Jerusalem artichoke by using geostatistics. An understanding of the range and spatial variability of Jerusalem artichoke morphological characters is a prerequisite for characterizing the plant-saline soil interactions before effective utilization of saline soils in growing Jerusalem artichoke for various biorefinery applications.The spatial heterogeneity and marginal effect of Jerusalem artichoke were studied in Dafeng and Taian experimental bases. Spatial heterogeneity was studied based on statistics of meshing of morphological data of 78 sampling points and 0-5 cm,5-10 cm, 10-20 cm depth soil salinity data of Dafeng in 2012 and 41 morphological data of sampling sites of Taian in 2013, respectively. Marginal effect of the 5 m bandwidth in Dafeng and the marginal effect of the size and scope were studied in Taian. The data of morphological traits of Jerusalem artichoke were measured by descriptive statistical analysis, test of normal distribution and the calculation of Pearson correlation coefficient using MATLAB. The spatial heterogeneity distribution of related parameters was also gained by the GS+and ArcMap software. The marginal effect of Jerusalem artichoke was calculated:Marginal effect using formula (E)=(edge line value-expert)/adept value×100%. The main results were as follows:(1) The fresh weight of root and tuber number in the north-south direction were lower than the south north of value in Dafeng experimental base. Both in the north-south direction and east-west stout, the changes of stem diameter were small, but still slightly larger than the south north of Jerusalem artichoke. There were no significantly difference of fresh tuber weight both in the north-south direction and east-west. Plant height in the north was significantly higher than the south. Fresh tuber weight and number of tubers of space distribution were relatively similar, but no relation with the fresh weight of tuber. The space of different soil salinity distribution shown that soil salt content increased with increasing soil depth and the salinity of north soil was larger. But there was significantly difference of salinity content in the west and east direction.(2) The spatial heterogeneity of morphological was high in Taian experimental base. The tuber number and weight was higher in the middle of the north and south direction. Branch number, stem diameter and plant height on the spatial distribution of the western hemisphere was higher in the eastern hemisphere. Aboveground fresh weight in the south was higher than northern. Root fresh weight space heterogeneity was very bigger(3) The Pearson correlation coefficient in Dafeng and Taian experimental bases was relatively similar. The Pearson correlation coefficient of the number of tubers and fresh weight showed strong correlation,0.763 in Taian,0.696 in Dafeng, which shown that the fresh weight of tuber increased by the increase of the number of tubers.(4) The marginal effect of Jerusalem artichoke in Taian experimental base showed the order of tubers fresh weight>aboveground fresh weight>stem diameter >number of tuber>branch>plant height>root fresh weight. Jerusalem artichoke tubers fresh weight in the edge was higher 50.46% than in middle of the field. While the marginal effect of Jerusalem artichoke in Dafeng experimental base showed the order of number of tuber> tubers fresh weight>plant height>stem diameter>root fresh weight and the tubers fresh weight in the edge was higher 18.82% than in middle of the field.This study combined geostatistics and advanced statistical analysis to determine the spatial distribution characteristics and the relative importance of factors controlling the spatial variation of Jerusalem artichoke’s morphological characteristics. The results shown that inherent spatial variability in soil and environmental parameters and would strongly influence morphological characteristics of Jerusalem artichoke.