| It is important to clarify the restrictive effect on the soil environment on crop quality in karst rocky desertification area.And it provides the reference to promote the overall development of ecological construction and regional economy and adjusts the industrial structure in order to form the ecological derivative industry with featured cash crops as main characteristics.This study integrates the geography,agronomy,plant ecology,soil chemistry and multiple disciplines as guiding ideology.The ecological restoration theory,sustainable development theory and soil environmental control theory are also applied in this study.The Salaxi county in Bijie city,a potential-light rocky desertification integrated Control demonstration area in Guizhou Plateau mountainous area,which represents the overall structure of karst ecological environment in South China was chosen to be a research area.The literature review analysis,comprehensive analysis,comparative analysis,quantitative and qualitative analysis of research methods are Comprehensively used in this study.On the basis of the background survey in the year of 2015 and 2016,the representative Rosa roxburghii,Juglans regia were chosen as the featured cash crops and the samples were collected in April and October,2017.The 198 samples from soils and fruits in total are obtained,which are originated from Karst depressions,eroded terraces,courtyard plantations and four types of terrain areas on mountain slopes.The 21 analysis indicators from the samples were tested twice.And from the experiment,3924 data was obtained,the data was analyzed by mathematical Statistics and the result showed the soil environment represented by soil physical and chemical properties impacts to the fruit quality of Rosa roxburghii and Juglans regia.Through evaluating the plantations of Rosa roxburghii and Juglans regia,the soil environment in different region has restricted the quality of the fruit of Rosa roxburghii and Juglans regia in karst rocky desertification area.Regulatory recommendations are proposed to optimization the soil environment.1.The characteristics of physical and soil nutrients in the soil environment of Rosa roxbunghii and Juglans regia planted in different terrains were studied by descriptive statistics.The result showed that different topographic areas has different soil environment,which is caused by the difference between the rocky desertification control pattern and the terrain composition.The karst depression has not been interved by the human activities and the soils washed by rainfall has accumulated a certain amount of nutrients and deposited there.The intercropping of Rosa roxbunghii and Juglans regia on the erosion platform resulted in competition between them in terms of root niche composition and nutrients.Juglans regia was planted on the mountain slope with biological ladder,while Rosa roxbunghii was planted on the slope in a single form,which constituted the difference of soil physical and chemical properties between them.In addition,the Juglans regia planted in the courtyard were subject to human management factors that constituted different physical and chemical properties in the soil environment which is totally different from other terrain areas.2.The characteristics of fruit quality of Rosa roxbunghii and Juglans regia planted in different terrain in rocky desertification control area were studied.Affected by different terrain areas,the differences were obvious:(1)The fruit quality and fruit shape index of Rosa roxbunghii were as follows: eroded platform<mountain slope<karst depression;(2)The soluble solids of Rosa roxburghii showed karst depression>erosion platform>mountain slope;(3)Vitamin C and SOD of Rosa roxbunghii showed eroded platform>karst depression>mountain slope;(4)the quality of Juglans regia's single fruit,the shell thickness of Juglans regia,and the amino acid of Juglans regia all represented eroded platform>mountain slope>courtyard planting;(5)The Juglans regia fruit shape index showed mountain slope>eroded platform>courtyard planting;(6)The protein in Juglans regia showed eroded platform> courtyard planting> mountain slope.3.The relationship between the quality of Rosa Roxburghii and Juglans regia was preliminarily revealed by the correlation analysis of experimental data.The height of porosity in the soil capillary in the Rosa roxburghhii planting place in the karst dissolution depression,the content of capillary water and the content of available phosphorus in soil(P<0.05)are the main factors affecting soluble solids of Rosa roxburghii.The soil bulk density and total soil porosity affect the soluble solids of Rosa roxburghii in the eroded platform(P<0.05),The accumulation and synthesis of vitamin C in Rosa roxburghii,which is affected by soil capillary porosity,capillary water holding capacity,soil organic matter(P<0.05).Soil moisture content and capillary water holding capacity and soil organic matter content(P<0.05)are the factors affecting soluble solids of Rosa roxburghii in mountain slopes.The Soil moisture content and capillary water holding capacity and soil organic matter content(P<0.05)are the factors which affect the soluble solids of Rosa roxburghii in the mountain slope.4.The total soil porosity of Juglans regia planted in the courtyard has a significant positive correlation with the quality of Juglans regia fruit(P<0.05).The porosity of soil non-capillary tube has a significant positive correlation(P<0.001)in the average thickness of Juglans regia shell.The total nitrogen in soil has a significant positive correlation with the of index of walnut fruit shape(P<0.05).The total potassium in soil has a significant positively correlation to the protein composition of Juglans regia(P<0.05).The soil bulk weight and total phosphorus which planted Juglans regia on the mountain slope have significant positive correlations with the average thickness of Juglans regia shell(P<0.001).The total phosphorus in soil has negative correlations with the amino acid composition(P<0.05),which indicate the on centration of total phosphorus in the soil affects the accumulation and synthesis of Juglans regia amino acids.5.Through the assessment of soil environmental quality in the planting areas of Rosa roxbunghii and Juglans regia in rocky desertification,the adjustment proposals for soil improvement in the planting areas of Rosa roxbunghii and Juglans regia were provided.The scores of different rocky desertification control modes and different topographical areas are as follows: karst depressions 0.790>erosion platform 0.635>mountain slope0.412 in Rosa roxbunghii planting land,for Juglans regia planting land,mountain slopes0.775>courtyard planting0.608>erosion platform0.544.After evaluation and comparison,the soil nutrient comprehensive evaluation score(0.642)of Juglans regia planting land is greater than that of the Rosa roxbunghii planting land(0.612),The ecological regulation of soil improvement and field management is taken to form the proposed measures of grass planting,soil sand viscosity regulation,soil deep turn and ripening,and intercropping spacing,which fully consider the planting characteristics of different terrain areas and optimize the soil improvement suggestions to maximize the utilization of land space resources and to maximize the utilization of land resources. |
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