Study On Soil Fertility Condition In Panax Notoginseng Habitat And Nu Trient Distribution In The Plant Of Panax Notoginseng

Panax notoginseng is one of the specific and precious herbal medicines in China; its production is of great significance in the Chinese herbal medicine industry. E.g.in2012, the gross value of Panax notoginseng industry had exceeded one hundred million in Wenshan, Yunnan Province. In this paper,46representative P. notoginseng planting fields were chosen as the sampling zones in two years. The geographic information of each planting field, soil-plant nutrient content, plant external agronomic traits, biomass and plant internal quality indexes were systematacially investiCated, detected and analyzed by associating the methods of field investiCation and laboratory analysis. Furthermore, in order to provide basic data and scientific basis for the advisable P.notoginseng production regionalization and fertilization, and realize superior quality and high yield, the distribution of geography and elevation, soil-plant nutrient condition and the effects on P. notoginseng biomass and saponin content in different planting fields were compared. The main conclusions are as follows:(1) It was determined that the P.notoginseng planting fields have been moving in a trend towards northwest localities of high altitude, Banqiao town of Qujing (E104°03’、N25°58’,2021m) which is the one in the worst condition. This phenomenon reveals that the environment adaptability of P.notoginseng is improved.(2) There are significant differences in soil nutrient content between old and new areas,and between different planting fields of P. notoginseng.The situation is not uniform, different fertilization and nutrient management should be performed according to the specific needs. Except for the total K and available Fe, Mn, Cu, Zn, the average content of other indicators are all higher in the new fields than in the old ones.The content of NO3--N was much higher than NH4+-N in soil. The investigation found that the nutrient enrichment condition in different planting soils were sufficient, and acid and strong acid soils were clarified to be the major soil types in P.notoginseng planting fields. Compared the soil of root layer with that of background, pH and exchangeableCa and Mn were similar, but NO3--N, total K and available Fe were declined, other indexs were significantly increase, which together revealed that the planting soil nutrient enrichment condition mainly derived from fertilizer. The data of different years showed little change in nutrient status of P.notoginseng planting areas within two years. But the phase II investigation found that soil NO3--N increased by37.78%, while the NH4+-N dropped by34.71%, it might result from the fertilizer type shifting. There was a certain correlation between nutrients, the highest correlation degree was between the capacity index and intensity index, for example, total nitrogen and available nitrogen had significantly positive correlation. Organic matters tended to be positively related with most nutrients index, which had certain guiding significance for fertilization. However, not all nutrient indexes had strong relations, which demonstrated the complexity of the soil. Exchangeable Ca and the content of NH4+-N had a significant relationship with soil pH, liming would increase the pH value, and increasing NH4+would acidize the soil. This was confirmed in planting soil of P.notoginseng. The heavy metals content between different planting fields were significantly different, in some fields, Ni exceed the standard, while other indicators were not. Heavy metal residues were controllable in the production of P.notoginseng. Heavy metals were closely related; they might have similar accumulating source, and were positively related to TK and TP with the highest degree in soil, which might be caused by the fertilizer residues of heavy metals.(3) Significant difference of agronomic traits was found in different P.notoginseng planting fields. The lengths of Bub and tuberous root in the new planting fields were obviously longer than those in the original ones. To some degree, the agronomic trait of the leaves could reflect the sizes of tuberous root. All agronomic indexes could be divided into3factors, in which the overground factor was of the maximum weight. Moreover, according to the comprehensive assessment of agronomic trait, the new planting fields were superior to the traditional ones.(4) K, N and Ca were found to be the most abundant elements in each part of P.notoginseng. In the leaves and roots, the nutrients with the highest content were the most abundant species. The higher element content meant the greater variation. And the greatest difference existed in the roots’ nutrient contents. Except for N and B, all of the other nutrients presented significant difference in some parts of P.notoginseng, among which the nutrient contents of the plants from the new planting fields were much higher than those from the original ones. For copper content, situation was different in the roots, in which part the copper accumulation was the lowest with few phenomenon of exceeding standard. The nutrient contents of P.notoginseng in different years were similar, variance only existed in several parts of the plants. Nutrient contents of the soil were relevant to those of the plants, and most of them were of positive correlations. Moreover, the correlation trends and degrees of each indicator were different in different parts. Most indicators of soil nitrogen were of neCative or inapparent correlations, while that of NO3--N was of positive correlation, showing that the nitrogen fertilizer utilization in the P.notoginseng industry was not high and NO3--N was favorable for P.notoginseng. Different nutrient elements in different parts were related to each other closely, in which positive correlation was common. The elements of the notches presented the closest relations to the corresponding ones in the other parts. Among the elements, P and Mn had the closest relations in each part. Further, the correlations among different nutrient contents in P.notoginseng plants were not high, among which those of root sections had the most abundant amounts of significant correlations. This phenomenon could be ascribed to the fact that the root section owned the function of absorbing nutrient. Besides, K held the closest relations to other mineral elements.(5) There was significant difference in biomass of individual P.notoginseng plant and total saponin content,but was no apparent difference among the planting fields. The distribution of the5kinds of different saponin was in the order of bub> taproot> root section, the contents in each parts were as followed:Rg1＞Rb1＞Rd＞R1＞Re. Over60%of the tuberous root reached the superior grade level. Connections existed between biomass and saponin content, as for notches and tuberous root, if biomass increased, the total saponin content decreased, among which the trends of Rg1and Rb1were the most significant. The Effects of altitude on the P.notoginseng biomass is obvious, expect for the notches, the average biomass of the other parts increased significantly when the altitude improved. The variation rule of saponin content changing with altitude performed consistently in various medicinal parts. Saponin R1content increased significantly with altitude, while Re changed in the contrary trend. Impact of soil nutrient levels on the biomass was far weaker than the effect of saponin content. As for the effects on biomass, available K was the most obvious. After classification, it was found that NH4+-N was significantly neCatively correlated to individual plant biomass, and NO3--N was significantly positively correlated with the aboveground biomass, which indicated that the NH4+-N was harmful for the growth of P.notoginseng. The effects of each nutrient in soil on the total saponin content of each part of the underground plants were revealed in a consistent trend. With the pH increased, the saponin contents drceased. For the notches and root sections, this tendency was the most obvious. The orCanic matter affected the notches apparently. Except that NH4+-N, the effective Mn were of significantly neCative effect, the rest nutrients would be stimulative for the total saponin content of P.notoginseng. Total phosphorus, exchangeable Ca and available Zn were the nutrient indicators which showed significantly positive effects on the total saponin of the tuberous root. for the total saponin content of the tuberous root, it would climb a lot if the Fe content inceased.