Comparison of Nitrification in Poplar and Metasequoia

Plantations

By: Antionette FowlkesMentors: Dr. Elica Moss, Dr. Shengzuo Fang and Prof. Ye Tian

Outline

I. ResearchII. Cultural Experience

Introduction 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.

IntroductionWhat is Nitrification? Nitrification is the process by which ammonium is

oxidized to nitrite NO2 and nitrate NO3 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 hydroxylamineo Step two of nitrification is nitrite oxidizing bacteria into

nitrite to nitrate Soil nitrification processes include:

Autotrophic nitrificationHeterotrophic nitrification

Soil Quality 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 biomasso Soil microbial biomass is an early indicator of changes

that may occur in the long term with regards to soil fertility

Importance of Soil pHo Soil pH measures the acidic and alkaline soils and has a

fundamental effect on plant growth and nutrient availability

Overview of Nitrification

Goal & Objective

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.

Experimental Site Research Sites

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

Materials and MethodsField 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

Materials and MethodsSoil Preparation Soil samples were

prepared by grinding through a 2 mm-sieve

Samples were then bagged stored at 4 °C until analyses

Materials and Method

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

Materials and MethodsGravimetric Water Content (Soil Moisture)

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

Materials and MethodsMicrobial Biomass N

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

Materials and MethodsIncubation Period

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

Data & Results

P1 P2 P3 S1 S2 S37.7

7.757.8

7.857.9

7.958

8.058.1

Soil pH of Poplar and Metasequoia Plantations

Rep 1Rep 2Rep 3

Treatment Areas

pH V

alue

P1 P2 P3 S1 S2 S305

1015202530354045

Soil Moisture Content of Poplar and Metasequoia Plantations

REP 1REP 2REP 3

Treatment Areas

% G

ravi

mett

ric W

ater

Con

tent

Data & Results

P1 P2 P3 S1 S2 S30

1

2

3

4

5

6

Microbial Biomass N (Fumigation Method)

Rep 1Rep 2Rep 3

Treatment Areas

(mg*

kg-1

)

P1R1P1R3

P2R2P3R1

P3R3 P1 P2 P2 P3 P1 P1 P2 P3 P3 P1 P2 P2 P3-5

0

5

10

15

20

25

30

35 Net Nitrification Rates Using Different Substartes in the Poplar Plantation

actidonenitrapyringlycine

Poplar Plantation Soil Samples

Net

Nitr

ifica

tion

Rate

s and

(µg/

g)

P1R1P1R3

P2R2P3R1

P3R3

P1R2A2

P2R1A2

P2R3A2

P3R2A2

P1R2A3

P1R3A3

P2R2A3

P3R1A3

P3R3A3

P1R2A4

P2R1A4

P2R3A4

P3R2A4-505

10152025303540

Net Nitrification of Different Substartes in the Metasequoia Plantation

ActidioneNitrapyrineGlycineAmmonum Chloride

Metasequoia Plantation Soil Samples

Net

Nitr

ficati

on R

ates

and

(µg/

g)

Discussion & Conclusion

Previous studies indicate that soil nitrification is regulated by several factorso Temperature o Moistureo Microbial biomasso 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

Discussion & Conclusion

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 too the optimal rate of nitrification requires some what

alkaline conditions

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

My Cultural Experience

People

Places

Food

A Special Thank You 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