- Email: [email protected]
Early growth of Eucalyptus camaldulensis under agroforestry conditions at Mafiga, Morogoro, Tanzania
Forest Ecology and Management, 11 (1985) 241--244 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
241
EARLY GROWTH OF E UCAL YPTUS C A M A L D ULENSIS UNDER AGROFORESTRY CONDITIONS AT MAFIGA, MOROGORO, TANZANIA
T.M. CHINGAIPE
Division of Forestry, University of Dar as Salaam, Morogoro (Tanzania) Present address : National Council for Scientific Research, Box 21210, Kitwe (Zambia) Address for correspondence: T.M. Chingaipe, Dept. of Forestry and Wood Science, U.C.N.W., Bangor, Gwynedd LL57 2UW, United Kingdom (Accepted 28 February 1985)
ABSTRACT Chingaipe, T.M., 1985. Early growth of Eucalyptus camaldulensis under agroforestry conditions at Mafiga, Morogoro, Tanzania. For. Ecol. Manage., 11: 241--244. The growth of Eucalyptus camaldulensis clean weeded, spot weeded and intercropped with maize and beans was studied. At 4 m × 4 m and 5 m × 5 m spacings trees were significantly shorter after 15 months under a conventional spot weeding regime than with clean weeding or intercropping with beans. A satisfactory maize yield (683 kg ha-') was recorded from plots with trees spaced at 5 m × 5 m. Plots where trees were spaced at 4 m × 4 m and 3 m × 3 m gave significantly lower yields (444 kg ha-' and 283 kg ha-', respectively).
INTRODUCTION
In Tanzania, demand for land is a less serious problem than demand for wood: People may travel 5--10 km looking for w o o d to use as poles or fuel (L.L. Lulandala, pers. commun., 1985). In much of the semi-arid area, rainfall is n o t only low but so irregular that both farming and w o o d production are problematical. Nevertheless, the majority of the people in these areas are farmers, cultivating food crops on small patches of land. The introduction and planting o f fast-growing, drought-resistant trees could help to ameliorate the w o o d supply problem, and the potential to use them simultaneously in intercropping practices would be a major additional attraction. Eucalyptus camaldulensis Dehnh. is k n o w n to be among the species suitable for this purpose in semi-arid conditions. This account refers to an experiment at Mafiga, Morogoro, c o n d u c t e d by the Division of Forestry, University of D a r e s Salaam. The objective of the study was to evaluate the growth of E. camaldulensis planted at
242
3 m X 3 m, 4 m X 4 m and 5 m × 5 m spacing, and intercropped with maize and beans (Maghembe and Redhead, 1982). To detect any constraints under conventional afforestation, two treatments w i t h o u t intercrops -spot-weeded and clean-weeded -- were included, and to determine normal tree growth, clean-weeding was used as the control treatment. Mean annual rainfall at Mafiga is 784 m m with m o n t h l y means of daily temperature varying from 28 to 34°C (maxima) and 14 to 23°C (minima). Soils are fine loamy sands developed f r o m alluvial deposits (Chamshama and Hall, 1984). METHODS
A split plot design (Snedecor and Cochran, 1980) was used for the experiment. There were f o u r replications. Cropping treatments were intercropping with either maize or beans, and the application of clean or spot weeding. Spacings at 3 m X 3 m, 4 m X 4 m a n d 5 m X 5 m c o n s t i t u t e d the sub-plots. Planting of maize was at 75 cm X 30 cm but a circle of 50 cm radius was left unplanted with maize r o u n d every tree; planting o f beans was at 40 cm X 20 cm but with an unplanted circle of 20 cm radius left round every tree. Clean-weeding entailed complete cultivation o f the whole plot using a tractor. Spot-weeding removed competing vegetation from a circle of 50 cm radius r o u n d each tree, according to the standard Tanzanian forestry practice. Maize was fertilized with a m m o n i u m sulphate (42 kg ha -1) and triple superphosphate (40 kg ha-') at sowing time. More a m m o n i u m sulphate (42 kg ha -1) was applied when the crop began to flower (recommended by L.L. Lulandala, pets. c o m m u n . , 1985). Beans were fertilized with amm o n i u m sulphate (20 kg ha-') and triple superphosphate (40 kg ha -1) at sowing time. A m m o n i u m sulphate (20 kg ha -1) was applied again when the crop began to flower. Fertilizer was applied along the periphery of a circle of radius 5 cm r o u n d each maize or bean plant. RESULTS
In terms of height attained there was evidence after 15 m o n t h s of a significant interaction between spacing and management regime. Trees given spot-weeding were significantly shorter at the 4 m X 4 m and 5 m X 5 m spacing than trees grown clean weeded or intercropped with beans (Table 1). In terms of root collar diameter attained after 15 months, there was a less pronounced interaction effect, but the spot-weeded trees were again significantly smaller -- in this case only at the 5 m X 5 m planting -- than trees clean-weeded or intercropped with beans (Table 2). There was a satisfactory maize yield from plots with trees planted at 5 m X 5 m, but with a decrease in tree spacing the yield of maize from intercropped plots fell significantly (Table 3). No significant effects on bean yield (x = 83.7 kg h a - ' ) were detected.
243 TABLE 1 Heights ( m ) of 15 m o n t h s old Eucalyptus camaldulensis a t d i f f e r e n t e s p a c e m e n t s u n d e r d i f f e r e n t m a n a g e m e n t regimes a t Mafiga, M o r o g o r o , T a n z a n i a Spacing ( m )
3 x 3 4 × 4 5 × 5
M a n a g e m e n t regimes Monocultures
Intercropping
Clean weeded
Spot weeded
With maize
With beans
3.36 abc 3.91 a 4.09 a
2.28 c 2.55 bc 2.51 bc
3.49 a b c 3.53 a b c 3.54 a b c
3.18 a b c 3.81 a 4.20 a
Values w i t h i d e n t i c a l following letters d o n o t d i f f e r s i g n i f i c a n t l y (P < 0.05).
TABLE 2 R o o t collar d i a m e t e r s (cm) o f 15 m o n t h s old Eucalyptus camaldulensis at d i f f e r e n t e s p a c e m e n t s u n d e r d i f f e r e n t m a n a g e m e n t r e g i m e s a t Mafiga, M o r o g o r o , T a n z a n i a Spacing ( m )
3 x 3 4 X 4 5 X 5
M a n a g e m e n t regimes Monocultures
Intercropping
Clean weeded
Spot weeded
With maize
With beans
4.23 ab 5.54 ab 6.17 a
3.73 ab 3.02 b 3.21 b
4.66 ab 4.58 ab 4 . 9 3 ab
4.46 ab 5.48 ab 6.10 a
Values w i t h i d e n t i c a l following letters do n o t differ s i g n i f i c a n t l y (P < 0 . 0 5 )
TABLE 3 S e c o n d y e a r m a i z e yield (kg h a -1) u n d e r i n t e r c r o p p i n g a m o n g Eucalyptus camaldulensis at d i f f e r e n t e s p a c e m e n t s at Mafiga, M o r o g o r o , T a n z a n i a T r e e s h a -1
Spacing ( m )
Yield
1111 667 400 0 (no-tree control)
3 × 3 4 × 4 5× 5
232.5 c 443.8 b 683.1a 658.1 a
Values w i t h i d e n t i c a l f o l l o w i n g letters d o n o t d i f f e r s i g n i f i c a n t l y (P < 0 . 0 5 )
244 DISCUSSION
The better growth in height and diameter in clean-weeded plots and for trees planted at 4 m X 4 m and 5 m X 5 m compared with those at 3 m X 3 m demonstrate the potential response of individual trees to freedom from competition. The early development of these trends underlines the necessity for careful tending of Eucalyptus stands. It is particularly interesting that tree growth at the wider spacing in plots underplanted with f o o d crops was better than in spot-weeded plots at the same spacing (Tables 1 and 2). The maize yield (Table 3) from plots with trees at the 5 m X 5 m spacing indicates that at 15 months old (after the second growing season) the trees did n o t depress the growth of this f o o d crop. Significant contributions to domestic fuelwood supply could, therefore, be obtained in areas climatically suitable for maize. Intercropping maize with trees planted at 5 m X 5 m, cut after only three growing seasons w o u l d yield 6 m 3 of fuelw o o d from 1/3 ha, which is the approximate area actually cultivated by a family in a single year. Tree-growing, however, could be included in the fallow phase of the bush--fallow system (a further 2/3 ha) and a similar level of w o o d production here would then provide self-sufficiency. Only a minimal level of organization is needed for trees to be cut to a schedule to provide a steady fuel supply.
REFERENCES Chamshama, S.A.O. and Hall, J.B., 1984. Height graded Eucalyptus tereticornis seedlings: one year field performance. For. Ecol. Manage., 7: 225--232. Maghembe, J.A. and Redhead, J.F., 1982. Agroforestry: preliminary results of intercropping Acacia, Eucalyptus and Leucaena with maize and beans. In: C.L. Keswani and B.J. Ndunguru (Editors), 2nd Syrup. Intercropping in Semi-Arid Areas, 1980. IDRC/University of Dares Salaam, pp. 43--49. Snedecor, G.W. and Cochran, W.G., 1980. Statistical Methods (Seventh Edition). Iowa State University Press, Ames, 1A.
241
EARLY GROWTH OF E UCAL YPTUS C A M A L D ULENSIS UNDER AGROFORESTRY CONDITIONS AT MAFIGA, MOROGORO, TANZANIA
T.M. CHINGAIPE
Division of Forestry, University of Dar as Salaam, Morogoro (Tanzania) Present address : National Council for Scientific Research, Box 21210, Kitwe (Zambia) Address for correspondence: T.M. Chingaipe, Dept. of Forestry and Wood Science, U.C.N.W., Bangor, Gwynedd LL57 2UW, United Kingdom (Accepted 28 February 1985)
ABSTRACT Chingaipe, T.M., 1985. Early growth of Eucalyptus camaldulensis under agroforestry conditions at Mafiga, Morogoro, Tanzania. For. Ecol. Manage., 11: 241--244. The growth of Eucalyptus camaldulensis clean weeded, spot weeded and intercropped with maize and beans was studied. At 4 m × 4 m and 5 m × 5 m spacings trees were significantly shorter after 15 months under a conventional spot weeding regime than with clean weeding or intercropping with beans. A satisfactory maize yield (683 kg ha-') was recorded from plots with trees spaced at 5 m × 5 m. Plots where trees were spaced at 4 m × 4 m and 3 m × 3 m gave significantly lower yields (444 kg ha-' and 283 kg ha-', respectively).
INTRODUCTION
In Tanzania, demand for land is a less serious problem than demand for wood: People may travel 5--10 km looking for w o o d to use as poles or fuel (L.L. Lulandala, pers. commun., 1985). In much of the semi-arid area, rainfall is n o t only low but so irregular that both farming and w o o d production are problematical. Nevertheless, the majority of the people in these areas are farmers, cultivating food crops on small patches of land. The introduction and planting o f fast-growing, drought-resistant trees could help to ameliorate the w o o d supply problem, and the potential to use them simultaneously in intercropping practices would be a major additional attraction. Eucalyptus camaldulensis Dehnh. is k n o w n to be among the species suitable for this purpose in semi-arid conditions. This account refers to an experiment at Mafiga, Morogoro, c o n d u c t e d by the Division of Forestry, University of D a r e s Salaam. The objective of the study was to evaluate the growth of E. camaldulensis planted at
242
3 m X 3 m, 4 m X 4 m and 5 m × 5 m spacing, and intercropped with maize and beans (Maghembe and Redhead, 1982). To detect any constraints under conventional afforestation, two treatments w i t h o u t intercrops -spot-weeded and clean-weeded -- were included, and to determine normal tree growth, clean-weeding was used as the control treatment. Mean annual rainfall at Mafiga is 784 m m with m o n t h l y means of daily temperature varying from 28 to 34°C (maxima) and 14 to 23°C (minima). Soils are fine loamy sands developed f r o m alluvial deposits (Chamshama and Hall, 1984). METHODS
A split plot design (Snedecor and Cochran, 1980) was used for the experiment. There were f o u r replications. Cropping treatments were intercropping with either maize or beans, and the application of clean or spot weeding. Spacings at 3 m X 3 m, 4 m X 4 m a n d 5 m X 5 m c o n s t i t u t e d the sub-plots. Planting of maize was at 75 cm X 30 cm but a circle of 50 cm radius was left unplanted with maize r o u n d every tree; planting o f beans was at 40 cm X 20 cm but with an unplanted circle of 20 cm radius left round every tree. Clean-weeding entailed complete cultivation o f the whole plot using a tractor. Spot-weeding removed competing vegetation from a circle of 50 cm radius r o u n d each tree, according to the standard Tanzanian forestry practice. Maize was fertilized with a m m o n i u m sulphate (42 kg ha -1) and triple superphosphate (40 kg ha-') at sowing time. More a m m o n i u m sulphate (42 kg ha -1) was applied when the crop began to flower (recommended by L.L. Lulandala, pets. c o m m u n . , 1985). Beans were fertilized with amm o n i u m sulphate (20 kg ha-') and triple superphosphate (40 kg ha -1) at sowing time. A m m o n i u m sulphate (20 kg ha -1) was applied again when the crop began to flower. Fertilizer was applied along the periphery of a circle of radius 5 cm r o u n d each maize or bean plant. RESULTS
In terms of height attained there was evidence after 15 m o n t h s of a significant interaction between spacing and management regime. Trees given spot-weeding were significantly shorter at the 4 m X 4 m and 5 m X 5 m spacing than trees grown clean weeded or intercropped with beans (Table 1). In terms of root collar diameter attained after 15 months, there was a less pronounced interaction effect, but the spot-weeded trees were again significantly smaller -- in this case only at the 5 m X 5 m planting -- than trees clean-weeded or intercropped with beans (Table 2). There was a satisfactory maize yield from plots with trees planted at 5 m X 5 m, but with a decrease in tree spacing the yield of maize from intercropped plots fell significantly (Table 3). No significant effects on bean yield (x = 83.7 kg h a - ' ) were detected.
243 TABLE 1 Heights ( m ) of 15 m o n t h s old Eucalyptus camaldulensis a t d i f f e r e n t e s p a c e m e n t s u n d e r d i f f e r e n t m a n a g e m e n t regimes a t Mafiga, M o r o g o r o , T a n z a n i a Spacing ( m )
3 x 3 4 × 4 5 × 5
M a n a g e m e n t regimes Monocultures
Intercropping
Clean weeded
Spot weeded
With maize
With beans
3.36 abc 3.91 a 4.09 a
2.28 c 2.55 bc 2.51 bc
3.49 a b c 3.53 a b c 3.54 a b c
3.18 a b c 3.81 a 4.20 a
Values w i t h i d e n t i c a l following letters d o n o t d i f f e r s i g n i f i c a n t l y (P < 0.05).
TABLE 2 R o o t collar d i a m e t e r s (cm) o f 15 m o n t h s old Eucalyptus camaldulensis at d i f f e r e n t e s p a c e m e n t s u n d e r d i f f e r e n t m a n a g e m e n t r e g i m e s a t Mafiga, M o r o g o r o , T a n z a n i a Spacing ( m )
3 x 3 4 X 4 5 X 5
M a n a g e m e n t regimes Monocultures
Intercropping
Clean weeded
Spot weeded
With maize
With beans
4.23 ab 5.54 ab 6.17 a
3.73 ab 3.02 b 3.21 b
4.66 ab 4.58 ab 4 . 9 3 ab
4.46 ab 5.48 ab 6.10 a
Values w i t h i d e n t i c a l following letters do n o t differ s i g n i f i c a n t l y (P < 0 . 0 5 )
TABLE 3 S e c o n d y e a r m a i z e yield (kg h a -1) u n d e r i n t e r c r o p p i n g a m o n g Eucalyptus camaldulensis at d i f f e r e n t e s p a c e m e n t s at Mafiga, M o r o g o r o , T a n z a n i a T r e e s h a -1
Spacing ( m )
Yield
1111 667 400 0 (no-tree control)
3 × 3 4 × 4 5× 5
232.5 c 443.8 b 683.1a 658.1 a
Values w i t h i d e n t i c a l f o l l o w i n g letters d o n o t d i f f e r s i g n i f i c a n t l y (P < 0 . 0 5 )
244 DISCUSSION
The better growth in height and diameter in clean-weeded plots and for trees planted at 4 m X 4 m and 5 m X 5 m compared with those at 3 m X 3 m demonstrate the potential response of individual trees to freedom from competition. The early development of these trends underlines the necessity for careful tending of Eucalyptus stands. It is particularly interesting that tree growth at the wider spacing in plots underplanted with f o o d crops was better than in spot-weeded plots at the same spacing (Tables 1 and 2). The maize yield (Table 3) from plots with trees at the 5 m X 5 m spacing indicates that at 15 months old (after the second growing season) the trees did n o t depress the growth of this f o o d crop. Significant contributions to domestic fuelwood supply could, therefore, be obtained in areas climatically suitable for maize. Intercropping maize with trees planted at 5 m X 5 m, cut after only three growing seasons w o u l d yield 6 m 3 of fuelw o o d from 1/3 ha, which is the approximate area actually cultivated by a family in a single year. Tree-growing, however, could be included in the fallow phase of the bush--fallow system (a further 2/3 ha) and a similar level of w o o d production here would then provide self-sufficiency. Only a minimal level of organization is needed for trees to be cut to a schedule to provide a steady fuel supply.
REFERENCES Chamshama, S.A.O. and Hall, J.B., 1984. Height graded Eucalyptus tereticornis seedlings: one year field performance. For. Ecol. Manage., 7: 225--232. Maghembe, J.A. and Redhead, J.F., 1982. Agroforestry: preliminary results of intercropping Acacia, Eucalyptus and Leucaena with maize and beans. In: C.L. Keswani and B.J. Ndunguru (Editors), 2nd Syrup. Intercropping in Semi-Arid Areas, 1980. IDRC/University of Dares Salaam, pp. 43--49. Snedecor, G.W. and Cochran, W.G., 1980. Statistical Methods (Seventh Edition). Iowa State University Press, Ames, 1A.