Effects of Fertilization Types and Cultivation Years on Dissolved Organic Carbon(DOC) in Paddy Soil under Water-logging Condition

In this study, the spatial and temporal distribution characteristics of dis- solved organic carbon （DOC） in water-logged paddy soil in Yanbian were investigat- ed under conditions of different fertilization types （single application of chemical fer- tilizer, mixed application and chemical and organic fertilizers and single application of organic fertilizer） and cultivation years （80 years and 120 years）. The results showed that the spatial and temporal distribution of DOC in water-logged paddy soil changed significantly with time going by. The single application of chemical fertilizer or mixed application of chemical and organic fertilizers contributed to the release of DOC in top paddy soil under water-logging condition; the single application of organ- ic fertilizer promoted the accumulation of DOC in bottom paddy soil, resulting in great heterogeneity of DOC in the vertical space, but the single application of chem- ical fertilizer weakened the vertical spatial heterogeneity of soil DOC; the DOC con- tent in the 80-year-old water-logged paddy soil was higher and more stable than that in the 120-year-old soil.

Effects of Different Propagation Materials and Cultivation Years on the Yield of Polygonatum odoratum under the Forest

This paper mainly studies the effects of different propagation materials and cultivation years on the yield of Polygonatum odoratum under the forest.In this study,the cultivation experiment of P.odoratum was carried out by using the stem tip,stem body and seeds of P.odoratum as propagation materials.The yield of P.odoratum in different cultivation years with propagation by rhizome was also investigated.That is,the continuous growth of P.odoratum and the yield of P.odoratum each year after cultivation was statistically analyzed.The results showed that the germination rate under stem tip cultivation was fast,and the emergence time was also fast,which was more than 2 weeks earlier than that under stem body cultivation,and the seedling emergence rate reached 100%.The stem body was a new plant formed by sprouting from the buds of internodes,and the emergence rate was more than 95%.P.odoratum propagated by rhizome was harvested in the third or fourth year after cultivation,and the third year was the best harvest time.

Changes in Soil Nutrients of Farmland with Different Cultivation Years of Panax ginseng

Through analyzing the soil organic matters(N,P,K) of farmland cultivated with different years of Panax ginseng,this paper studied the changes in soil nutrients of farmland with different vertical depths and cultivation years of P.ginseng.Results indicated that the vertical structure was obvious in soil nutrients of farmland with different cultivation years of P.ginseng;in most cases,the soil nutrient content gradually declined with the fibrous roots of P.ginseng spreading downward;the soil electrical conductivity(EC),total nitrogen(TN),total phosphorus(TP),total potassium(TK),available nitrogen,available phosphorus were manifested as surface layer > root layer > bottom layer,while the available potassium was manifested as surface soil and bottom layer > root layer;the soil pH changed in the range of 5.69-6.22,suitable for growth of P.ginseng.It is expected to provide theoretical basis for improvement of soil nutrients of farmland with cultivation of P.ginseng.

Cultivate Talent and Seek for Innovation in the past 20 Years——Exclusive Interview with Professor Li Chunling Dean of the School of Economics and Management, Yanshan University

Yanshan University was formerly known as Northeast Heavy Machinery Institute,and was one of the key universities in China at that time.As of1985,the institute moved to Qinhuangdao Island,and as it was located at the foot of Yanshan,it was called as Yanshan University.The School of Economics and Management was established in1979and the Management Engineering Department was established in1984,which was renamed as the School of Economics and Management in1998.This year is the20th anniversary for the establishment of the School.