Nitrogen mineralization patterns of leaf-twig mixtures from tropical leguminous trees |
| |
| Authors: | M Constantinides J H Fownes |
| |
| Institution: | (1) Department of Agronomy and Soil Science, University of Hawaii, 1910 East-West Rd, 96822 Honolulu, HI, USA |
| |
| Abstract: | Green manure applications in alley cropping systems often include twigs despite their potential to absorb (immobilize) nitrogen (N). To assess the impact of twigs on net N mineralization or immobilization from hedge row cuttings, we separated cuttings fromCalliandra calothyrsus andGliricidia sepium into leaf-only, twig-only, and mixed (leaf + twig) fractions and incubated them with moist soil in the laboratory. Soil extractable inorganic N did no differ among treatments after two weeks, but after four and eight weeks was greatest in leaf-only, and least in twig-only treatments. After two weeks, extractable N from the leaf-only treatment rose steadily, while that from the twig-only and mixed treatments was variable due to periods of net mineralization and net immobilization. The pattern of variation in mixed treatments paralleled that of twig-only, indicating that net immobilization in the mixture was largely caused by the presence of twigs. Extractable N from the mixture was somewhat lower than that predicted from the sum of leaf-only and twig-only treatments. We conclude that twigs in green manure reduce short-term N availability to associated crops in agroforestry systems. |
| |
| Keywords: | alley cropping Calliandra calothyrsus Gliricidia sepium green manure incubations nitrogen mineralization multipurpose tree |
| 本文献已被 SpringerLink 等数据库收录！ |
|
