# Presentation: 228059

## LEAF LITTER STUDY AND EFFECTS OF ERTILIZATION ON TREE GROWTH

- Dave  A. Mays
- Alabama A&M University
- Normal, AL 35762

## Question?

**How much leaf litter has accumulated under six year old sweetgum trees and what is its composition?**

## PROCEDURE!

**Total litter collection from one-square meter area at two places in each plot**
**Dry matter yield and chemical composition of litter determined by standard means**

## Effects of nitrogen on leaf litter accumulation and
composition

Parameters		Trees + N		Trees - N
Yield, mT ha-1		    12.5		    8.7
Organic C %		    22.4		  22.1
Nitrogen %		      1.07		    1.04
Phosphorus %		      0.054		    0.045
Potassium %		      0.11		    0.11
Calcium %			      2.9		    2.8
Magnesium %		      0.23		    0.25

_**composition**_
_**Parameters**__**	**__**	**__**Trees + N**__**	**__**	**__**Trees - N**_
- Yield, mT ha-1		    12.5		    8.7
- Organic C %		    22.4		  22.1
- Nitrogen %		      1.07		    1.04
- Phosphorus %		      0.054		    0.045
- Potassium %		      0.11		    0.11
- Calcium %			      2.9		    2.8
- Magnesium %		      0.23		    0.25

## Effects of nitrogen on yield of sweetgum leaf litter
constituents, kg ha-1
Constituents		Trees + N		Trees - N

Organic C			2828.0		1916.0
Nitrogen			  133.1		    89.8
Phosphorus		      7.0		      4.2
Potassium			    13.3		      9.5
Calcium 			  366.0		  252.0
Magnesium		    29.8		     21.5

_**constituents, kg ha**_**-1**
_**Constituents**__**	**__**	**__**Trees + N**__**	**__**	**__**Trees - N**_
- Organic C			2828.0		1916.0
- Nitrogen			  133.1		    89.8
- Phosphorus		      7.0		      4.2
- Potassium			    13.3		      9.5
- Calcium 			  366.0		  252.0
- Magnesium		    29.8		     21.5

## Effects of cover crop species on sweetgum leaf
litter yield and composition
__________________________________________
Parameter		   No 		 Tall	 	 Crimson 
				 Cover 	Fescue	   Clover
__________________________________________
Yield (mT ha-1)	    12.3	11.1		    11.2
Organic C %	    22.9	24.7		    27.6
Nitrogen %	    0.82	0.83		    1.02
__________________________________________

_**litter yield and composition**_
- __________________________________________
- Parameter		   No 		 Tall	 	 Crimson
- 				 Cover 	Fescue	   Clover
- __________________________________________
- Yield (mT ha-1)	    12.3	11.1		    11.2
- Organic C %	    22.9	24.7		    27.6
- Nitrogen %	    0.82	0.83		    1.02
- __________________________________________

## Effects of cover crop species on yield of leaf
litter constituents
__________________________________________
Constituents	   No 		 Tall	 	 Crimson 
				 Cover 	Fescue	   Clover
__________________________________________
Organic C		   2879	   2757	    3012

Nitrogen		   105.1	    92.1	    114.1
__________________________________________

_**litter constituents**_
- __________________________________________
- Constituents	   No 		 Tall	 	 Crimson
- 				 Cover 	Fescue	   Clover
- __________________________________________
- Organic C		   2879	   2757	    3012
- Nitrogen		   105.1	    92.1	    114.1
- __________________________________________

## Effects of Cover crop and prior fertilization on
tree size in 2000.
__________________________________________
Treatment	 Height(m)	  DBH(cm)	VI(cc)	
T + C + N		6.6		   7.5		     37712	
T + C - N		5.6		   6.9		     26247	
T - C + N		6.5		   8.1		     42022	
T - C - N		5.4		   6.7		     23908	
__________________________________________
T = Trees	    C = Cover	N = Nitrogen

_**tree size in 2000.**_
- __________________________________________
- _Treatment__	_ _Height(m)_	  _DBH(cm)__	__VI(cc)__	_
- T + C + N		6.6		   7.5		     37712
- T + C - N		5.6		   6.9		     26247
- T - C + N		6.5		   8.1		     42022
- T - C - N		5.4		   6.7		     23908
- __________________________________________
- T = Trees	    C = Cover	N = Nitrogen

## Effects of Fertilizer on Tree Height

## Effects of Fertilizer on Tree Diameter

- Ground-line was used as Diameter from 1995 - 1997
- DBH was used as Diameter from 1998 - 2000

## Effects of Fertilizer on Volume Index

- Ground-line was used as Diameter from 1995 - 1997
- DBH was used as Diameter from 1998 - 2000

## Effects of Cover crop and N fertilization on N
Concentration in sweetgum leaves,  July
2000.
_______________________________________
Treatment			N Concentration %
Trees + Cover + N			1.55
Trees + Cover - N			1.09
Trees - Cover + N			1.54
Trees - Cover - N			1.22
_______________________________________

_**Concentration in sweetgum leaves,  July**_
_**2000.**_
- _______________________________________
_**Treatment**__**	**__**	**__**	**__**N Concentration %**_
- Trees + Cover + N			1.55
- Trees + Cover - N			1.09
- Trees - Cover + N			1.54
- Trees - Cover - N			1.22
- _______________________________________

## YIELD OF SWITCHGRASS  kg ha-1
______________________________________
Year			Cut 1		Cut 2		Total	
____________________________________________
1995			4446		 ----		  4446
1996			4430		4000		  8430
1997			8637		3926		12563
1998			7692		2453		10145
1999			5306		2998		  8304
2000			4437		 ----		  4437
2001			8270		5444		13714
___________________________________________
N: 1995 - 2000 @ 120 kg ha-1;  2001 @ 200 kg ha-1

**______________________________________**
**Year****	****	****	****Cut 1****	****	****Cut 2****	****	****Total****	**
**____________________________________________**
**1995****	****	****	****4446****	****	**** ----****	****	****  4446**
**1996****	****	****	****4430****	****	****4000****	****	****  8430**
**1997****	****	****	****8637****	****	****3926****	****	****12563**
**1998****	****	****	****7692****	****	****2453****	****	****10145**
**1999****	****	****	****5306****	****	****2998****	****	****  8304**
**2000****	****	****	****4437****	****	**** ----****	****	****  4437**
**2001****	****	****	****8270****	****	****5444****	****	****13714**
**___________________________________________**
- N: 1995 - 2000 @ 120 kg ha-1;  2001 @ 200 kg ha-1

## Soil Analysis 0-6 in, April 2000
___________________________________________
Crop			pH	   P	   K	    Ca	         Mg
___________________________________________
Corn			5.8	  35	 135	   1900	270
Switchgrass	5.1	  30	   77	   1135	134
T + C + N		5.4	  23	 150	   1165	170
T + C + N		5.3	  14	 175	   1140	174
T - C + N		5.3	  28	 117	   1190	182
T - C - N		5.5	  14	 145	   1205	208
___________________________________________

**___________________________________________**
**Crop****	****	****	****pH****	****   P****	****   K****	****    Ca****	****         Mg**
**___________________________________________**
**Corn****	****	****	****5.8****	****  35****	**** 135****	****   1900****	****270**
**Switchgrass****	****5.1****	****  30****	****   77****	****   1135****	****134**
**T + C + N****	****	****5.4****	****  23****	**** 150****	****   1165****	****170**
**T + C + N****	****	****5.3****	****  14****	**** 175****	****   1140****	****174**
**T - C + N****	****	****5.3****	****  28****	**** 117****	****   1190****	****182**
**T - C - N****	****	****5.5****	****  14****	**** 145****	****   1205****	****208**
**___________________________________________**

## NEEDS

1. Better chemical weed control:
Complete control in flat areas for 2 or 3 years
Strip control in sloping areas.  Use weeds for cover in center of plot instead of fescue and control weeds in tree rows
As an alternative use reseeding crimson clover in middles

**1. Better chemical weed control:**
**Complete control in flat areas for 2 or 3 years**
**Strip control in sloping areas.  Use weeds for cover in center of plot instead of fescue and control weeds in tree rows**
**As an alternative use reseeding crimson clover in middles**

## NEEDS

2. Better control of fertility; fertilizer around trees for 2 or 3 years rather than broadcast fertilization.

3. More emphasis on machinery development to apply herbicides and fertilizers in an agronomically sound and economically efficient manner. 

**2. Better control of fertility; fertilizer around trees for 2 or 3 years rather than broadcast fertilization.**
**3. More emphasis on machinery development to apply herbicides and fertilizers in an agronomically sound and economically efficient manner. **