Analysis On Qualities And Site Conditions Of The Yam Cultivating In Huilou, Yucheng County

The quality and site conditions of the yam in Huilou, Yucheng county were preliminary studied in this dissertation, through the fileld surey and sampling, indoor laboratory analysis.There are six main parts of this dissertation:Part I: The current situation and problems of the yam at home and aboard were introduced, as well as the content and the significance of this study.Part II : The research methods of this study were introduced.Part III: The content of nutritional ingredients about Huilou yam and the control samples were analyzed, as well as the high quality of the yam in Huilou was studied.Part IV: The effect on yam growth and quality is discussed, through analyzing the soil physical and chemical properties, nutrient status, the content of microelements and macroelements in huilou high-quality yam cultivating areas.Part V: The effect on yam growth and quality is discussed, through studying the groundwater physical and chemical properties, the content of the microelements and macroelements in Huilou high-quality yam cultivating areas.Part VI: In this part, the main conclusions were drawn. Depending on all above studies and experiments, the main conclusions were drawn as follows:(1) Huilou yam is easy to peel, rich in nutriention, has fine texture, tasting good and sweet, so it is a high quality variety. The content of reducing sugar, starch, polysaccharide, protein in Huilou yam is significantly higher than the control sample (Jiaozuo Dioscorea opposita in Henan province and Shanxian yam in Shandong province), the compositions of amino acids are comparatively complete. Among the seventeen amino acids, the content of histidine, lysine, threonine, methionine, alanine, glycine, serine, tyrosine and the total quantity of amino acid are higher than Jiaozuo Dioscorea opposita, the content of proline, isoleucine, valine, cystine is as much as Dioscorea opposita, the content of dry matter is higher than Jiaozuo Dioscorea opposite. However, the content of the water and the tare is lower. The features of the fine texture and high quality are most possibly related to these. It contains many microelements and macroelements. In the determination of 13 kinds of elements, Cu, Zn, Ni, Pb, Ba, Sr, Li, Mn, Fe and Ca in Huilou yam were higher than those of Jiaozuo Dioscorea opposita.(2) The soil site conditions of Huilou yam cultivating areas is rather superior, most elements and nutrient content are high, physical and chemical properties are suitable for the growth of yam, soil structure and aeration of Huilou yam cultivating areas are good. pH of the surface soil displays alkaline,which is slightly lower than the control areas. Groundwater quality is well, belonging to class III standard. pH increases slightly along with the section depth, it's probably due to the yam absorbing a lot of the base cations. Soil texture is mainly composed of sandy loam and sandy loam-based powder, the same as the surrounding control areas, having quite obvious layered texture, but physical sand (>0.05mm) is slightly higher than the control areas. Soil density is higher than the control areas, while the total porosity is lower than the control areas. The content of available K, available P in surface soil is slightly higher than the control areas; However, the soil texture in Huilou yam cultivating areas is lighter, the content of CEC is lower than the control areas, leading to the weak fertilizer retaining, fertilizer application and buffer capacity; The content of effective silicon is lower than the threshold of soil available silicon in North China Plain.The total content of Mn, Ca, Zn, Cu in soil surface samples (including the mixed samples and profile surface samples) are significantly higher than the surrounding control soils, and the total content of Cr, Fe, Pb, Co are equal to the control soils, however ,the total content of Ni, Ba, Sr, Mg, Li are significantly lower than the control soils. This may be related to the parent rocks and groundwater composition in yam cultivating areas.(3) The groundwater chemical composition of Huilou yam cultivating areas is sodium bicarbonate - calcium carbonate (NaHCO₃-CaCO₃) type, Salinity classification is belong to salt water and brackish water, and it is higher than the surrounding groundwater of the control areas, the average content of Cu, Pb, Zn, Ni, Ba, Co, Mn, Fe, Mg in the groundwater is higher than the surrounding groundwater of the control areas, which is related to the Sub-humid climate, relatively low-lying terrain, poor drainage in the yam-growing areas, and so on. (4) Currently, the cultivating area of high-quality yam in Huilou is small. The key factors affecting the yield are low-lying, frequent waterlogging, and the disease is rather serious. In the furture, drainage facilities should be establised and improved in the yam cultivating areas,and the research and prevention of yam diseases and insect pests should be enhanced. It can be introducted and promoted where the climate, the soils, groundwater, site conditions is similar to huilou yam, so as to make more farmers benefit from this famous native product.