| An intimate relationship exists between Geology and agriculture. Geochemical investigation on specific geological backgrounds for the agricultural products not only can help develop characteristic agricultural products suitable for the local conditions, but also camprovide scientific references for industrial design of characteristic agriculture, enlarge the planting areas of high quality characteristic agricultural products, and facilitate the development of standardized green agriculture; thus we can improve the economic output of agriculture, increase peasant’s income, and finally achieve an efficient, sustainable development of modern characteristic agriculture.Yantai area in Shandong province has a good climate, and four seasons are distinct. This area is one of the main apple producing areas in China. This study targeted the growing areas with different geological backgrounds, and related samples such as rocks, soils (the root system soils, profile soils), waters, the apple tree roots, stems, leaves and fruits were systematically collected. Based on the geochemical survey results of soils in study areas, we studied the geological background and geochemical characteristics of apple planting areas as well as the distribution of elements and their migration transformation in the rock-soil-plant system. Through analytic hierarchy processing, this study established an evaluation model for the soil fertility and environmental quality of the studying areas; furthermore, the study proposed an apple quality evaluation method which combined cluster analysis and analytic hierarchy processing with consideration of the organic nutrition components in apples as the main index. An evaluation model for apple planting adaptability was proposed based on the relevancy between characteristic elements in apples and soil-plant system. The main results were summarized as below:1. The chemical compositions of parent rocks in different geological units are significantly of difference. The quality of apples in different growing areas with different soils also is different. Because of the soil weathering and formation processes, the element concentration in soils tend to be homogenized, and the extents of difference in element concentrations in soils are smaller than those in their parent rocks. Overall, relative to the soils in China Eastern plain, the soils in study areas are rich in Na, Se, Au, Sr etc., and strongly lack in B, Mg, Ca etc. The most important nutritional components, K, N. P and organic matter are low in contents in the bottom soils but much higher in the surface soils(especially for the organic matter) in study areas.2. Investigation on active forms of elements suggests that the total contents of P, Ca, Cu, and Mn etc. in soils are important control factor for activity these elements. The pH of the soil has notable effect on the active forms of B, K. Fe and Ca. The high content of organic matter benefits the activation of B, K and Fe, accordingly in turn increasing the effective quantity. The redox potential has a positive correlation with the quantities of available B and Fe. Investigation on different parent soil profiles shows that the element migration in soils was controlled by lithology in the specific geological units, and the element compositions in deep soil and surface soil of different parent materials are different.3. By using single factor pollution index and Nemero index, this study evaluated the water chemistry and water quality in study areas. The results shows that the water quality in the areas is good, and the degree of heavy metal pollution is low.4. Investigation on the elemental migration in the rock-soil-plant system showed that the migration abilities of the major elements of Fe2O3and MgO to the soils are strong, and the migration behavior of CaO is associated with different geological background unit. The migration of heavy metals and other important elements, such as B and Se, to the soil is very obvious, and the highest concentration is in the surface layer (layer A). B, Ca, Mn, Cu, As and Pb were significantly enriched in the leaves with increasing tendency from the root to stem, to the leaf and the lowest content in the fruit. Na.Co,Mo and rare earth elements were significantly enriched in roots. Plant roots took arsenic from the soil, and in the roots As (V)→As (111) reduction occurred because of the desulfurization reaction of glutathione reducing thiols in the plants. In the migration of arsenic upward in plants, the proportion of As (Ⅲ) decreased due to plants’ self-protection function, which tends to avoid the higher toxicity of As (Ⅲ) to the plant cells and tissues. However, there was existing monomethyl arsenic (MMA) in the plant leaves. This was due to the methylation during the upward transport process of arsenic. When dead leaves drop into the root soils the cycle and migration of arsenic in the soil-plant system are completed.5. By using analytic hierarchy processing, this study proposes an evaluation model for soil fertility and environmental quality. The assessment results show that the area ratio of soil fertility quality in rich level (assessment score value is above0.7) is19.2%. The area ratio of the quality of soil fertility in the moderate level (ranges from0.3to0.7) is61.3%. The proportion of soil fertility quality in poor level (<0.3) is19.6%. For soil environmental quality assessment, area ratios at first, second and third level are38.1%,26.1%. and35.9%, respectively. Combining the assessments of soil fertility quality and soil environmental quality, the geochemical study indicates that the soil areas in high, excellent, good, moderate and poor qualities are7.3%,45.0%,11.9%,28,2%and7.7%, respectively.6. Based on the organic nutrients in apple, by using cluster analysis and analytic hierarchy process and calculating the membership function, this study propose the hierarchy of apple quality analysis and evaluation. The results suggest that the apple quality for Taocun, Cunliji, and Shewopo villages (score value is above0.7) is the best; that for Wuning, Guandao, Zangjiazhuang villages (score value is between0.5and0.7) is good; for Chaoshui, Mouping, Zangjiazhuangbeidaqiao villages (score value is below0.5) is general. Research results are well consistent with field inspection results.7. By studying geochemical characteristics which affect apple quality, this study explored the correlation of characteristic elements in apple and the soil-plant system, and proposed an evaluation model based on the combination of characteristic elements, and the model was then used for evaluating the planting suitability of the study areas for apples. The results indicated that the42.6%,49.4%and8.0%areas are most suitable, suitable, generally suitable, respectively, for growing apples in study areas.Areas where the parent materials were sandstone, gneiss and granite are the most suitable for apple planting, while areas where the parent materials were limestone and mica schist are only generally suitable for apple planting. In general, the most appropriate planting soils for apple production are those from sand and Ma sand brown, and especially those with thick sandy loam, loose soil texture, and good property for holding water and fertilizer. Soils which are too sticky or contain massive coarse gravels are not suitable for apple production. |
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