Study on Vegetation Characteristics & Soil Properties of Secondary Grassland in Farmland Areas Abandoned for Different Years in Minqin Oasis

[Objectives]This study was conducted to investigate the vegetation community characteristics and soil properties of secondary grassland in abandoned farmland areas of different years in Minqin Oasis. [Methods] By the method of space-for-time substitution, the changes of vegetation community characteristics(species composition, structural characteristics and important values) and soil microbial and enzyme activity were determined, and the correlation between various soil factors was analyzed. [Results](1) There were 39 species belonging to 32 genera of 15 families in the research area, including 8 shrub plants, 15 perennial herbs and 16 annual herbs.(2) Soil microbial biomass carbon, nitrogen and phosphorus contents were higher in the upper layer than in the lower layer, and the phenomenon of “surface aggregation” was obvious. The differences were different with the change of abandoned years.(3) Soil catalase content was the highest among different plots, and soil phosphatase, sucrase and urease all showed a trend of fluctuating decline with the increase in abandoned years. Soil enzyme changes were different in different soil layers. [Conclusions] This study can provide a theoretical basis for the restoration, reconstruction and rational protection and utilization of secondary grassland in abandoned farmland.

Comparison on Morphology and Micromorphology of Paris polyphylla Sm. var. polyphylla with Different Year Numbers

[Objectives] The research aimed to identify Paris polyphylla with different growth year numbers and evaluate its resource quality.[Methods]Comparative research on P. polyphylla with different growth year numbers was conducted by using morphological identification and microscopic identification method. [Results] By contrasting original plant morphology,transverse sections of rhizome and fibrous root,powder,it displayed that microstructure of P. polyphylla had regularity difference in cell shape and size,duct quantity,trait and size,size and distribution of calcium oxalate cluster crystal. [Conclusions] The microstructure change of P. polyphylla was related to the number of its growth year,which could provide the reference for identifying the growth year number of P. polyphylla and evaluating its resource quality.

Chemical Composition and Ruminal Digestibility of Ceratoides, a Salt-tolerant Perennial Plant,at Different Years

It has been proposed that salt-tolerant plant could be used as a feed resource for ruminants whereby salt would be removed from salinized land (Asian -Aust. J. Anim. Sci. (2002) 15:998 -1001). Ceratoides arborescens (Losinsk.) Tsien et C. G. Ma is known as a drought-and salt-tolerant plant,a kind of shrubs, growing in semi-arid land of Inner Mongolia. Because the covering effect of the perennial plant as a mulch over the soil might be expected, the optimum covering effect would be obtained after the growth period.The perennial plant produces seeds around summer and end its growth thereafter. Nutrient value of the perennial salt-tolerant plant, however,had not been reported in flowering period at different year. It is necessary to know the ruminal degradability of the plants of each growing year in order to determine the regimen to diet for ruminants. The present experiment,therefore,was undertaken to analyze the digestibility and chemical composition of Ceratoides arborescens as feed for ruminants.

Effects of Different Gravel Mulched Years on Soil Microbial Flora and Physical and Chemical Properties in Gravelsand Mulched Fields

Soil microbial flora and influencing factors of soil microbes in soil and gravel-sand mixed layer（ SGSML）,roots denseness layer（ RDL）,eluviate layer（ EL） and calcium accumulation layer（ CAL） in gravel-sand mulched fields（ GSMFs） with different gravel mulched years（ 1,6,12,19 and 25 years） were studied. The results showed that in the composition of soil microbes in the GSMFs,the quantity of bacteria was the largest,followed by actinomycetes,while the number of fungi was the smallest. The total quantity of soil microorganisms in the GSMFs dropped rapidly with the increase of soil depth,which was related to the sudden decrease in the quantity of bacteria. The number of microbes in the RDL was larger than that in the SGSML with few roots due to the effects of root distribution. The number of bacteria and actinomycete in the growing season was larger than that in the non-growing season,while the quantity of fungi in the growing season was smaller than that in the non-growing season. The quantity of bacteria and fungi was the largest in the GSMFs which had been mulched with gravel for 6-12 years. With the increase of mulching time,the GSMFs aged gradually,so their quantity reduced gradually. The quantity of actinomycetes was the smallest in the GSMFs which had been mulched with gravel for 6-12 years and increased with the increase of mulching time. The number of soil microbes in the GSMFs had a good correlation with soil moisture content,p H and mulching time. Soil total carbon content was an important factor restricting the quantity of soil microbes in the GSMFs.

Study on the chemical composition of Nauclea officinalis in different months of the same year and different growth years

Objective:Based on the quality analysis of Nauclea officinalis in different growth years and different months in the same year,the most suitable harvest year and the specific month in the same year were determined according to the evaluation of the active components in the stem of medicinal parts of Nauclea officinalis.Methods:LC-MS/MS method was used to investigate the quality of Nauclea officinalis from different growth years and different months in the same year,mainly including the content determination of the active ingredients in the medicine.Results:With the prolongation of production life,the content of active ingredients in stem of Nauclea officinalis increased continuously.After reaching a certain number of years,the content of active ingredients increased little;In the middle of the same year,from mid-October to mid-June of the next year,the content of iso-vincin lactam was relatively high,especially between the end of March and the end of May.The content was high and stable,and the highest point was the stem sample collected in May.Conclusion:The content of each component in the stem of Nauclea officinalis with a growth life of more than 5 years has reached a relatively high and stable level.Nauclea officinalis with a growth life of more than 5 years should be collected as raw materials for medicinal materials.The month with high and stable content of isocyanoside lactam,namely May of each year,was taken as the best harvest time of gallbladder in one year.The best harvest time was from mid-October to mid-June of the next year,or from March to May of each year.