Root distribution ofDactyladenia (Acioa) barteri andSenna (Cassia) Siamea in alley cropping on Ultisol. II. Impact on water regime and consequences for experimental design


Tensiometer measurements were carried out on a typic Paleudult in the humid forest zone of south eastern Nigeria in an alley cropping trial using fertilized and unfertilizedDactyladenia (Acioa) barteri andSenna (Cassia) siamea as hedgerow trees and a no-tree control. The interrow space of alley cropped and no-tree control plots were planted to maize/cassava intercrop. Water withdrawal during short dry spells and the dry season occurred fastest in the no-tree control plot and resembled the pattern in the adjacentS. siamea alley cropping. Previous root investigations showed that the whole no-tree control plot was within the range of root propagation of the adjacent hedgerow trees. Installation of a 70 cm deep root barrier led to a retarded water withdrawal in unfertilized no-tree control plots to a depth of 150 cm. In fertilized no-tree control this retardation occurred to a depth of 110 cm, while at 130 and 150 cm water withdrawal with root barriers was faster than without barriers. Results indicate thatS. siamea depleted water resources in the no-tree control plot and shortened the growing season of cassava. Restricting roots to the assigned plot size can reduce competition for water in adjacent plots even in layers below the depth of the barrier but can also induce compensative water withdrawal from layers which were not necessarily affected by the barrier. It appears that currently no standard methodology is available to conduct agroforestry trials without the risk of invalidation through root interference. Methods to determine minimum plot size in order to reduce the risk of invalidation and misinterpretation of results are suggested.

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  1. De Willingen P and Van Noordwijk M (1989) Rooting depth, synchronization, synlocalization and N-use efficiency under humid tropical conditions. In: Van der Heide, ed, Nutrient Management for Food Crop Production in Tropical Farming Systems, pp 145–156. Haren, The Netherlands

  2. Gichuru M and Kang BT (1990) Potential woody species for alley cropping on acid soils: In: More E, ed, Agroforestry Land-Use Systems. Proceedings of a Special Session of American Society of Agronomy Annual Meeting, 28–29 November, 1988. Anaheim, CA, USA

  3. Hauser S (1990) Water and nutrient dynamics under alley cropping versus monocropping in the humid-subhumid transition zone. Transaction 14. ICSS, Vol VI, pp 204–209. Kyoto, Japan

    Google Scholar 

  4. Hauser S (1993) Root distribution ofDactyladenia (Acioa) barteri andSenna (Cassia) siamea in alley cropping on ultisol. I. Implication for field experimentation. Agroforestry Systems 24: 111–121.

    Google Scholar 

  5. IITA (1984) Research Highlights of 1983, pp 22–27. International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria

    Google Scholar 

  6. IITA (1990) Annual Report for 1989 Resource and Crop Management Program, pp 17–18. International Institute of Tropical Agriculture, Ibadan, Nigeria

    Google Scholar 

  7. Kang BT and Wilson GF (1987) The development of alley cropping as a promising agroforestry technology. In: Steppler HA and Nair PKR, eds, Agroforestry: A Decade of Development, pp 227–243. ICRAF, Nairobi, Kenya

    Google Scholar 

  8. Kang BT, Wilson GF and Lawson TL (1984) Alley cropping a stable alternative to shifting cultivation. International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria

    Google Scholar 

  9. Kang BT, Grimme H and Lawson TL (1985) Alley cropping sequentially cropped maize and cowpea with Leucaena on a sandy soil in southern Nigeria. Plant and Soil 85: 267–277

    Google Scholar 

  10. Kang BT, Reynolds L and Atta-Krah AN (1990) Alley farming. Adv Agron 43: 315–359

    Google Scholar 

  11. Lal R (1991) Myths and scientific realities of agroforestry as a strategy for sustainable management for soils in the tropics. Adv Soil Sci 15: 91–137

    Google Scholar 

  12. Singh RP, Ong CK and Saharan N (1989) Above and below ground interactions in alley-cropping in semi arid India. Agroforestry Systems 9: 259–274

    Google Scholar 

  13. Wood PJ (1980) Principles of species selection for agroforestry In: MacDicken KG and Vergara NT, eds, Agroforestry: Classification and Management, pp 290–309. John Wiley & Sons, New York

    Google Scholar 

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Hauser, S., Gichuru, M.P. Root distribution ofDactyladenia (Acioa) barteri andSenna (Cassia) Siamea in alley cropping on Ultisol. II. Impact on water regime and consequences for experimental design. Agroforest Syst 26, 9–21 (1994).

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Key words

  • soil water tension
  • root barriers
  • competition
  • no-tree control
  • experimental design