# Presentation: 436296

## COVER CROP EFFECTS ON SWEETGUM PRODUCTITY

- R. k. Malik*
- Alabama A&M University, Dept. of Plant & Soil Science, Huntsville (Normal) AL 35762

## INTRODUCTION

- Environmental  Crossroads
- Key  Issues
- Fossil  Fuels
- Oil Embargo 1973-74  &  recent CRISIS October, 2000 and now  September 11, 2001

## Introduction....................

- Renewable  Energy  Sources
- Biomass Energy - Important  Alternative:
- Woody  Biomass
- Herbaceous  Biomass
- Alcohol from grain

## OBJECTIVE

- Study the effects of cover crops on a
- short-rotation hardwood crop (SRWC)
- SWEETGUM (*Liquidambar  styraciflua*  L.),
- it’s growth  and biomass  production.

## MATERIALS  AND  METHODS

- LOCATION

## EXPERIMENTAL DESIGN

- Split  Plot
- Cover  Crops  -  Main  Plot
- Strip  Widths  -  Splits

## PLANT  MATERIAL

_**TREES**_
- Sweetgum transplanted  March 21-27, 1995
- Row     -  3.048  m  (10  ft)
- Trees  -  1.524  m  (5  ft)
- 35 trees per plot,  315  per block,   and 945 in 3 reps

## COVER  CROPS

**(A)**  _** GRASSES**_
- 1.  Winter  annual - Ryegrass  (*Lolium                **	**multiflorum*  L.) - Kino
- 2.  Perennial -  Tall Fescue  (*Festuca  **	**	**	**arundinacea*  L.) - Kentucky  31

## (B)  LEGUMES

1.  Winter  annual - Crimson  Clover  			(Trifolium  incarnatum   L.)  -  Bigbee

2.  Perennial - Sericea  Lespedeza  			(Lespedeza  cuneata  (Dumont) G. Don) 		- Interstate  76

- 1.  Winter  annual - Crimson  Clover  			(*Trifolium  incarnatum*   L.)  -  Bigbee
- 2.  Perennial - Sericea  Lespedeza  			(*Lespedeza  cuneata*  (Dumont) G. Don) 		- Interstate  76

## PLOT  LAYOUT

- Single  Plot - 21.3  m  (70  ft)  length
- 			      -    7.5  m  (25  ft)  width
- 9 plots per block including control, 3blocks
- Each plot surrounded by 25 cm high berm

## STRIP  WIDTHS

- Cover  crops were maintained at:
- 122  cm  (4  ft)
- 244  cm  (8  ft)
- Control

## DATA  ANALYSIS

- Data  analyzed using GLM of SAS
- ANOVAs Calculated
- Means separated by Tukey’s Studentized Range test
- Regression analysis for strip widths
- Pearson Correlation

## RESULTS

## Summary of ANOVA

## Effects of Cover Crops on Diameter Breast Height (DBH)

- _Cover Crop__	_	     _DBH (cm)__	__% of Control_
- 1. Control			6.70a
- 2. Ryegrass		6.53a		97
- 3. Crimson clover	6.37a			95
- 4. Lespedeza		5.17b			77
- 5. Tall Fescue		5.13b			76

## Effects of Cover Crops on  Volume Index (VI)

- _Cover Crop__	__	_   _VI  (cm_3_)_        _% of Control_
- 1. Control		       24497a
- 2. Ryegrass	       23464a		  95
- 3. Crimson clover     22699a		  93
- 4. Lespedeza	       14465b		  59
- 5. Tall Fescue	       14273b		  58

## Effects of Cover Crops on   Leaf Nitrogen (LN)

- _Cover Crop__	__	_      _LN  (%) __	_   _% of Control_
- 1. Control		        1.08b
- 2. Ryegrass	        1.12b		104
- 3. Crimson clover      1.23a		114
- 4. Lespedeza	        1.24a		115
- 5. Tall Fescue	        1.11b		103

## Pearson Correlation Coefficients

## Slide 19

## SUMMARY  OF  RESULTS

- _COVER  CROPS_
- During first 2 years H, GLD, and VI were   significantly reduced by all covers,  except  ryegrass.
- By end of 5 years (1999) only Lespedeza and tall fescue significantly reduced DBH, VI. Ryegrass,  crimson clover and control were not significantly different .

## SUMMARY  OF  RESULTS.........................

- Leaf N was significantly higher in sweetgum leaves from plots of crimson clover  &  lespedeza.
- _STRIP  WIDTH_
- Had no significant effect on H, DBH & VI.   However,  sweetgum leaf N, except from tall fescue plots, increased with increasing strip width.

## CONCLUSION

- SRWC Sweetgum can be successfully
- grown for bioenergy in Conservation
- Reserve Program (or under utilized land)
- with crimson clover (no re-seeding) and
- ryegrass as a choice of cover crop.

## Thank YOU very much

## LONG TERM EFFECTS OF COVER CROPS ON SWEETGUM BIOMASS PRODUCTION

- R. k. Malik  (Ravi)
- Alabama A&M University
- Department of Plant & Soil Science,
- Huntsville (Normal) AL 35762