| Jiuzhaigou County is China's main producing area of one of Codonopsis. pilosula Nannf. var. modesta(Nannf.)L. T. Shen. The Radix Codonopsis were cultivated in Dao Kouba were also named DaoDang, most of which were exported. Planting Dangshen has become the main local one of pillar industries to peasants. It created great benefit for the agricultural every year. The soil fertility status has important influence on the yield and quality of Radix Codonopsis. The study on the soil fertility of Radix Codonopsis planting soil from Jiuzhaigou County and its relationship with the quality of Radix Codonopsis, which can provide theory basis for the development of production and GAP production base. In our research, we has determined the fertility level of Radix Codonopsis planting soil to analysis the varied regulation of yield and exterior quality of Radix Codonopsis according to the soil fertility distribution. The main results as follow:1. Radix Codonopsis planting soil fertility conditions:The overall level of Radix Codonopsis planting soil fertility is well, Producing coarse soil texture is mainly silty loam, medium loam 60%, the rest is heavy loam.The soil fertility conditions analysis results of soil profile A (0～25 cm) and B (25～60 cm) as follow:Soil profile A:The content change range of organic matter was 7.5～118.7 g/kg, the average value was 60.7 g/kg, the 86% of samples which organic matter contents higher than 40.0 g/kg was in high level. The content change range of total nitrogen was 0.8～5.4 g/kg, the average value was 2.9 g/kg, the 86.5% of samples which total nitrogen contents higher than 2.0 g/kg was in high level. The content change range of alkaline hydrolysis nitrogen was 23.3～223.8 g/kg, the average value was 114.6 mg/kg,67.6% of samples higher than100.0mg/kg, secondary level. The content scope of total phosphorus was 0.5-1.35 g/kg, the average value was 0.8 g/kg,84% of samples higher than 0.6 g/kg, high level. Rapidly-available phosphorus were 2.0～13.5 mg/kg, the average value was 6.4 mg/kg, 0.8% of samples higher than 10.0mg/kg, lower level. Total potassium were 18.3～32.9 g/kg, the average value was 23.8 g/kg,30% of samples higher than 25.0 g/kg, high level. Rapidly-available potassium were 43.6～269.9 mg/kg, the average value was 122.6 mg/kg, 51.4% of samples higher than 100.0 mg/kg, secondary level. Rapidly-available phosphorus were 2.0～13.5 mg/kg, the average value was 6.4 mg/kg,0.8% of samples higher than 10.0mg/kg, lower level. The pH were6.0～8.3, the average value was 7.2,65.0% of samples lower than 7.5.Soil profile B:The content change range of organic matter was 8.5～53.0 g/kg, the average value was 26.6 g/kg, the 60% of samples which organic matter contents higher than 20.0 g/kg was in higher level. The content change range of total nitrogen was 0.6～3.3 g/kg, the average value of total nitrogen was 1.6 g/kg, the 51.4% of samples which organic matter contents higher than 1.5 g/kg was in higher level. The content change range of alkaline hydrolysis nitrogen was 18.1～137.6 g/kg, the average value was 57.8 mg/kg, there were 14.3% samples'alkaline hydrolysis nitrogen contents higher than 90.0 mg/kg, lower level. The total phosphorus was 0.3～1.0 g/kg, the average value was 0.5g/kg, 28.6% of samples higher than 0.6 g/kg, lower level. Rapidly-available phosphorus were 2.2～8.0 mg/kg, the average value was 4.5 mg/kg,66.0% of samples higher than5.0g/kg, lower level. Total potassium were 14.2～27.8 g/kg, the average value was 21.3 g/kg, 64.9% of samples higher than 20.0g/kg, high level. Rapidly-available potassium were 21.1～233.1 mg/kg, the average value was 69.3 mg/kg,14.3% of samples higher than 100.0g/kg, lower level. The pH were 5.9～8.2, the average value was 7.2,69.0% of samples lower than 7.5.Comprehensive analysis soil fertility characteristics between profile A and B, the results indicated that the profile A were rich in organic matter and nitrogen, phosphorus, potassium; the profile B were rich in organic matter and nitrogen, were poor in other indexes. The soil fertility of the profile A was significant higher than the profile B. The vertical distribute of soil fertility obviously. There are moderate ranges of soil pH from 5.9 to 8.3. The soil was osteoporosis, ventilation permeability well which has good protection and supplying fertility capacity.2. The relationship between soil fertility and yield and exterior quality of Radix Codonopsis. The research results indicated that there were significant positive correlation, and P value reached 0.01 or 0.05 between organic matter, total nitrogen, alkaline hydrolysis nitrogen, total phosphorus, rapidly-available phosphorus and fresh weight, dry weight, length. The contents of rapidly-available potassium were significant positive correlation with length. The weight, length and diameter are important indicators for yield and exterior quality evaluation of Radix Codonopsis. That organic matter, total nitrogen, total phosphorus, alkali-hydro nitrogen, total phosphorus and phosphorus content is higher, the yield is higher and the quality of Radix Codonopsis is well.3. Principal component analysis of soil fertility. The principal component analysis results indicated that the 3 extraction main components can reflex 85.1% of all information about soil fertility. So, it was effectively that use the principal component analysis on fertility characteristic of Radix Codonopsis planting soil from Jiuzhaigou County. Organic matters, total nitrogen, alkaline hydrolysis nitrogen, total phosphorus have most contribution which occupied 52.53%, soil pH, total potassium and rapidly-available phosphorus as follow,21.71%, rapidly-available potassium at last,10.91%.4. Comprehensive evaluation of soil fertility. Through the principal component analysis of soil fertility factors score and comprehensive score, and the system clustering analysis, the results showed that:The comprehensive scores range of soil fertility from-1.873 to 2.828, only 2 samples more than 2.0.'Therefore, the ranges of comprehensive score can identification between-1.873 and 1.429, the extreme was 3.30 which can be accepted. The soil fertility can be divided into four grades to representative of soil fertility of level. First grade was higher level, second grade was high level, third grade was secondary level and the last grade was lower level. The regional distribution of soil fertility as follow, the first and second soil main distribute in Shuanglong village, the soil fertility of Jiawu and Gouli village were main the third grade and less of the second and last grade, the Chenggou and Shangshuanghe village were main the last grade soil. The first and second grade soil was very suitable for the growth of Radix Codonopsis, the third grade was suitable and the last grade was not suitable, respectively. |
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