Grain legumes and green manures as pre-rice crops in Northeast Thailand
- 57 Downloads
The loss of dry matter (ash corrected), nitrogen (N) and carbon (C) from residues of several tropical legume species was monitored using litter bags in the field over a three-month period in Northeast Thailand. This work was linked to an experiment in a farmers' field where the residual benefits of the same legume species grown before flooded rice were measured. Litter bags were incorporated in the flooded rice plots at the same time as residue incorporation in the field experiment. The species studied were Sesbania rostrata, Aeschynomene afraspera and a multi-purpose cowpea variety (Vigna unguiculata cv KVC-7). In the case of S. rostrata the breakdown of fresh and oven-dried residues and of residues buried at depths of 2–3 cm and 15 cm was also compared.
Although the initial N and C concentrations were similar for all the residues they exhibited differing dry matter, N and C loss patterns. With Sesbania rostrata, 80% of the N was lost from the residues after 20 days, however, there was only a 40% decline in C and weight during the same period. The rate and amount of N loss from Aeschynomene afraspera residues was much less than with S. rostrata, declining by approximately 35% during the first 40 days. There were marked differences in rates of N loss from stem and leaves of A. afraspera indicating that monitoring the decomposition of stem and leaves combined can be misleading. In multi-purpose cowpea, loss patterns of dry matter, N and C were all similar and 50–65% was lost after 40 days burial. There was little difference between breakdown of fresh and oven-dried S. rostrata residues nor were there noticeable differences between residues incorporated superficially (2–3 cm) and buried at 15 cm. Although both %N and lignin:N ratios correlated well with weight and N loss from the residues, this was only the case when leaf and stem material were analyzed separately for A. afraspera.
Despite the slower rate and smaller total amount of N released from the A. afraspera residues compared with the S. rostrata residues, a similar amount and proportion (around 20 kg N ha-1 or 22–28%) of the N was recovered from both residues by a crop of rice planted at the time of residue incorporation. This suggests a considerably higher use efficiency by rice of the N released from the A. afraspera residues (approximately 40%) compared with that for S. rostrata (30%).
Key wordsdecomposition immobilization legume residues nitrogen release
Unable to display preview. Download preview PDF.
- Amato M and Ladd J M 1980 Studies of nitrogen immobilization and mineralization in calcareous soils. V. Formation and distribution of isotope-labelled biomass during decomposition of 14C- and 15N-labelled plant material. Soil Biol. Biochem. 12, 405–411.Google Scholar
- Becker M, Ladha J K and Ottow J C G 1994a Nitrogen losses and lowland rice yield as affected by residue N release. Soil Sci. Soc. Am. J. 58, 1660–1665.Google Scholar
- Becker M, Ladha J K, Simpson I C and Ottow J C G 1994b Parameters affecting residue nitrogen mineralization inflooded soils. Sci. Soc. Am. J. 58, 1666–1671.Google Scholar
- Buresh R J, Woodhead T, Shepherd K D, Flordelis E and Cabangon R C 1989 Nitrate accumulation and loss in a mungbean/lowland rice cropping system. Soil Sci. Soc. Am. J. 53, 477–482.Google Scholar
- Dakora F D, Aboyinga R A, Mahama Y and Apaseku J 1987 Assessment of N2-fixation in groundnut (Arachis hypogaea) and cowpea (Vigna unguiculata L. Walp) and their relative N contribution to a succeeding maize crop in Northern Ghana. MIRCEN J. 3, 389–399.Google Scholar
- Frankenberger W T and Abdelmagid H M 1985 Kinetic parameters of nitrogen mineralization rates of leguminous crops incorporated into soil. Plant and Soil 87, 257–271.Google Scholar
- George T, Ladha J K, Buresh R J and Garnity D P 1993 Nitrate dynamics during the aerobic soil phase in lowland rice-based cropping systems. Soil Sci. Soc. Am. J. 57, 1526–1532.Google Scholar
- Goering H K and VanSoest P J 1970 Forage fiber analysis (apparatus, reagents, procedures and some applications). Agriculture Handbook No. 379. Agricultural Research Service, USDA, Washington DC. 20p.Google Scholar
- Handayanto E, Cadisch G and Giller K E 1994 Nitrogen release from prunings of legume hedgerow trees in relation to quality of the prunings and incubation method. Plant and Soil 160, 237–248.Google Scholar
- Haynes R J 1986 Mineral Nitrogen in the Plant-Soil System. Academic Press, Madison, WI. 483p.Google Scholar
- Ladd J N, Amato M, Jackson R B and Butler J H A 1983 Utilization by wheat crops of nitrogen from legume residues decomposing in soils in the field. Soil Biol. Biochem. 15, 231–238.Google Scholar
- McDonagh J F, Toomsan B, Limpinuntana V and Giller K E 1995 Grain legumes and green manures as pre-rice crops in Northeast Thailand: I. Legume N2-fixation, production and residual nitrogen benefits to rice. Plant and Soil 177, 111–126.Google Scholar
- Palm C A and Sanchez P A 1991 Nitrogen release from the leaves of some tropical legumes as affected by their lignin and polyphenolic contents. Soil Biol. Biochem. 23, 83–88.Google Scholar
- Sisworo W H, Mitrosuhardjo M M, Rasjid H and Myers R J K 1990 The relative roles of N fixation, fertilizer, crop residues and soil in supplying N in multiple cropping systems in a humid, tropical upland cropping system. Plant and Soil 121, 73–82.Google Scholar
- Suwanarit A, Suwannarat C and Chotechaungmanirat S 1986 Quantities of fixed N and effects of grain legumes on following maize, and N and P status of soil as indicated by isotopes. Plant and Soil 93, 249–258.Google Scholar