Tree legumes in medium-term fallows: Nitrogen, fixation, nitrate recovery and effects on subsequent crops
| dc.creator | Wortmann, Charles S. | |
| dc.creator | Kaizzi, CK | |
| dc.date | 2000 | |
| dc.date | 2014-10-02T08:33:25Z | |
| dc.date | 2014-10-02T08:33:25Z | |
| dc.date.accessioned | 2026-06-27T14:28:30Z | |
| dc.description | Fallows improved with tree legumes have a potential role in soil fertility management in the sub-humid tropics. In addition to N2 fixation, deep rooting species can be used to redistribute leached nutrients to the topsoil while producing useful woody by-products. Such fallows are not very effective in improving phosphorus availability, however, and supplying P from other sources may be required to take full advantage of the improved fallows. Busumbu rock P is a potential source of P, but of low reactivity. Our objectives were to compare three tree or shrub legumes with Mucuna [Mucuna pruriens (L.) DC. var. utilis], to determine their rotation effects on subsequent crops and on P availability from Busumbu P rock. Legume effects on the fixation of atmospheric N and nitrate recovery were determined in a sub-humid, bi-modal rainfall system. Fallows improved with sesbania (Sesbania sesban) and tephrosia (Tephrosia vogellii) produced more biomass and fixed more N than those fallows improved with pigeonpea (Cajanus cajan) or mucuna. Pigeonpea derived only about 11% of plant N from the atmosphere compared to 49% for sesbania and tephrosia. The maize-bean [Zea mays (L.)]-[Phaseolus vulgaris (L.)] intercrop was most productive following sesbania and tephrosia fallow and least productive after the fallow improved with pigeonpea. All legumes and food crops failed to acquire significant amounts of P from the P rock. Sesbania and tephrosia were most efficient in recovery of nitrates from below 50 cm depth. The carbon:N ratios were low enough for the biomass of all fallows to allow early mineralisation of N, but the C:P ratios were within the critical level range for a net immobilisation of P following application. Generally, recovery by the subsequent maize-bean intercrops of N supplied in the biomass of tephrosia and sesbania was poor and the results indicate that much of the biomass N was lost. Recovery of N may be improved by transfer of a major part of the legume biomass to manure adjacent land which was continuously cropped. | |
| dc.identifier | https://hdl.handle.net/10568/44201 | |
| dc.identifier.uri | http://hdl.handle.net/123456789/79269 | |
| dc.language | en | |
| dc.rights | Open Access | |
| dc.subject | feed crops | |
| dc.subject | cajanus cajan | |
| dc.subject | mucuna pruriens | |
| dc.subject | sesbania sesban | |
| dc.subject | tephrosia vogelii | |
| dc.subject | cover crops | |
| dc.subject | fallow | |
| dc.subject | green manures | |
| dc.subject | soil fertility | |
| dc.subject | nitrogen fixation | |
| dc.subject | tphrosia vogelii | |
| dc.subject | plantas de cobertura | |
| dc.subject | barbecho | |
| dc.subject | abonos verdes | |
| dc.subject | fertilidad del suelo | |
| dc.subject | fijación del nitrógeno | |
| dc.title | Tree legumes in medium-term fallows: Nitrogen, fixation, nitrate recovery and effects on subsequent crops | |
| dc.type | Journal Article |