Nitrogen fixation capacity in the component species of contour hedgerows: how important?
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The choice of an appropriate hedgerow species is one of the most critical decisions in exploiting the value of a contour hedgerow system. The implications of hedgerow species with nitrogen (N)-fixation capacity on hedgerow-crop competition and crop productivity have been widely debated. We examined the agronomic significance of N-fixation by comparing the performance of species representing three classes of hedgerow vegetation: A nitrogen-fixing tree legumeGliricidia sepium), a non-nitrogen fixing tree (Senna spectabilis syn.Cassia spectabilis), and a forage grass (Pennisetum purpureum). The 4-year study investigated the hedgerow biomass and nutrient yields, and their relative effects on the performance of two annual crops commonly grown in alley farming systems, with emphasis on hedgerow-crop interference. The work was done on an Ultic Haplorthox (pH 4.8, organic C 1.9%, total N 0.18%).Senna produced 46% more pruning biomass on an annual basis than didGliricidia; N supplied to the alley crops was similar toGliricidia in the first year of observation, but 20–30% higher in the succeeding years. Upland rice and maize grain yields and total dry matter were unaffected by tree species, but the nitrogen-fixing tree exerted less competitive effects on the annual crops growing in adjacent rows. Grass hedgerows reduced maize yields 86% by the second year, indicating an unsustainable drawdown of nutrients and water. We conclude that hedgerow systems composed of a nitrogen-fixing tree did not exert significant advantages compared to a non-fixing tree species, and that factors other than N-fixation were more important determinants for the choice of hedgerow species.
Key wordsGliricidia sepium Senna spectabilis Cassia spectabilis Pennisetum purpureum tree legume alley cropping
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- Agus F (1993) Soil processes and crop production under contour hedgerow systems on sloping oxisols. PhD thesis. North Carolina State University, Raleigh, NC, 141 ppGoogle Scholar
- Garrity DP (1993) Sustainable land use systems for the sloping uplands of Southeast Asia. In: Technologies for Sustainable Agriculture in the Tropics, pp 41–66. American Society of Agronomy, Madison, WIGoogle Scholar
- Garrity DP, Kummer DM and Guiang FS (1993) The Philippines. In: Agricultural Sustainability and the Environment in the Humid Tropics, pp 549–624. National Academy Press, Washington DCGoogle Scholar
- ICRAF (1994) Annual Report for 1993. International Center for Research in Agroforestry. Nairobi, KenyaGoogle Scholar
- Kang BT, Reynolds L and Atta-Krah AN (1990) Alley farming. Adv Agron 43: 315–359Google Scholar
- Ladha JK, Peoples MB, Garrity DP, Capuno VT and Dart PJ (1993) Estimating dinitrogen fixation of hedgerow vegetation using the nitrogen-15 natural abundance method. Soil Sci Soc Am J 57: 732–737Google Scholar
- Maclean RH, Litsinger JA, Moody K and Watson AK (1992) IncreasingGliricidia sepium andCassia spectabilis biomass production. Agroforestry Systems 20: 199–212Google Scholar
- Mercado AR Jr, Furoc R, Tumacas A, Mateo N and Garrity DP (1991) Coffee as a crop component in hedgerow farming systems in acid upland soils. Agronomy, Plant Physiology and Agroecology Division, International Rice Research Institute, Los Baños, Philippines, 24 ppGoogle Scholar
- Mercado AR Jr, Montecalvo A, Garrity DP and Basri I (1992) Upland rice and maize response in a contour hedgerow systems in sloping acid upland soils. Paper presented at the Annual Scientific Meeting of the Federation of Crop Science Societies of the Philippines held at Zamboanga City, 24–28, May, 1992.Google Scholar
- SAS (1988), SAS/STAT User's Guide. Statistical Analysis System Institute, Cary, NC, 620 ppGoogle Scholar