1.  By: Antionette Fowlkes Mentors: Dr. Elica Moss, Dr. Shengzuo Fang and Prof. Ye Tian

2.  I. Research II. Cultural Experience

3.  Poplar and Metasequoia plantations are usually established at riparian land for timber production and for maintaining healthy aquatic ecosystems as buffer zones  Poplars are broad-leaved deciduous trees with rounded contours. There are various species of poplar growing in a range of soil types under different situations.  Metasequoia is a fast-growing, deciduous tree. It is one of three species of conifers known as redwoods.

4. What is Nitrification?  Nitrification is the process by which ammonium is oxidized to nitrite NO 2 and nitrate NO 3 by ammonia-oxidizing bacteria  Nitrification occurs in a two step process: o Step one of nitrification is a ammonium oxidizing bacteria that oxidize ammonia to nitrite via hydroxylamine o Step two of nitrification is nitrite oxidizing bacteria into nitrite to nitrate  Soil nitrification processes include: Autotrophic nitrification Heterotrophic nitrification

5.  Importance of Soil Moisture o Soil moisture is key in controlling the exchange of water and heat energy between the land surface and atmosphere through evaporation through and plant transpiration  Importance of Microbial biomass o Soil microbial biomass is an early indicator of changes that may occur in the long term with regards to soil fertility  Importance of Soil pH o Soil pH measures the acidic and alkaline soils and has a fundamental effect on plant growth and nutrient availability

7.  To compare the characteristics of soil N nitrification and Ammonium Nitrate between Poplar and Metasequoia plantations in riparian zone. It includes: o to evaluate the relative importance of autotrophic and heterotrophic nitrification in Poplar and Metasequoia plantations.

8.  Research Sites o National Wetland Park (119°15′ E ， 33°22′ N) in Baoying, Yangzhou City, Jiangsu Province

9. Field Work  Fresh soil samples (0-10 cm and 10-20 cm) were taken from 3 random soil profiles in each plantation on June 13, 2013  Samples were collected and taken to the laboratory and stored at 4 °C until analyses

10. Soil Preparation  Soil samples were prepared by grinding through a 2 mm-sieve  Samples were then bagged stored at 4 °C until analyses

11.  Ten grams of soil were measured in triplicates  50 mL of water was then added and stirred  After 30 minutes pH was measured Soil pH

12.  Initially the weight of a small mason jars were recorded  Approximately 18.5 g of fresh, sieved soil was measured in triplicate and added to each jar  Soil samples were then oven dried at 65°C for 48 hours

13.  Five grams of soil were measured in triplicates  Two milliliters of KCl (potassium chloride) was added to each soil sample  Samples were covered and secured with Styrofoam and placed on shaker and allowed to mix for 30minutes

14.  Ten grams of fresh soil was weighed, placed in small mason jars and triplicated in four groups based on substrates  1mL of Ammonium Chloride was added to Group A1  1mL of Glycine was added to Group A2  1mL of Nitrapyrin was added to Group A3  1mL of Actidione was added to Group A4  Sample were incubated for one week on the ammonium nitrate analyzer

18.  Previous studies indicate that soil nitrification is regulated by several factors o Temperature o Moisture o Microbial biomass o pH  Both sites have an annual mean temperature of 14.4 ℃ and are similar in pH and moisture content  However, the Poplar plantation is slightly higher in microbial biomass N and net Nitrification than that of the Metasequoia plantation, indicating more microbial activity

19.  Studies show there is a high net nitrification rate when glycine and ammonium chloride substrates are added to soil samples  Studies also show there is a higher net nitrification rate in the Poplar vs. the Metasequoia plantations  Studies show that acidic soils that have glycine is nitrified more readily than ammonium chloride  Alkaline soil rates are about the same this is due to o the optimal rate of nitrification requires some what alkaline conditions

20.  Actidione is an antibiotic that is known to be and inhibitor to microbial growth  In conclusion, a possible reason for the higher MBN and net N nitrification in the Poplar plantation may be because the trees are rapid-growing, but relatively short-lived, which suggest that leaves frequently fall, causing high organic matter, leading a higher MBN and thus a higher net N nirtification

26.  Alabama Agricultural and Mechanical University  Nanjing Forestry University  National Science Foundation  Dr.Elica Moss  Dr. Shengzuo Fang  Professor Ye Tian  Graduate Students of Dr. Fang  Jonjala Jackson Questions & Answers