ISSN:
1432-0789
Keywords:
N2 fixation
;
N-supplying ability
;
15N
;
Arachis hypogaea
;
Intercropping
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Identification of legume genotypes with high N-supplying ability is important in improving and sustaining the productivity of low-input cropping systems. Hence, 15N-aided studies were made to ascertain the relative N-supplying ability of some cultivars of groundnut, a widely grown tropical legume. The study was conducted outdoors in 1991 at Kamburupitiya, Sri Lanka, in tanks filled with 64 kg soil which had been tagged by incorporating 15N-labelled plant material. Maize cv. Badra was grown as a monocrop and as an intercrop with five genotypes of groundnut, X-14, MI-1, Red Spanish, ICGV 87127, and a non-nodulating line. All the nodulating genotypes derived over 90% of their N from the atmosphere. Significant genotypic differences in N2 fixation were observed. X-14 fixed the highest amount (1.95 g plant-1), while Red Spanish the lowest (0.88 g plant-1). Intercropping of maize with nodulating groundnut significantly decreased the 15N atom excess of maize, depending on the genotype. However, this decrease did not appear to be related to the amount of N2 fixed, based on aboveground material. The per cent N derived by maize from the intercropped groundnuts varied from 17% (X-14) to 39% (Red Spanish), indicating a marked genotypic variability in N-suppling ability. X-14, which fixed the largest amounts of N2, grew most vigorously compared to other genotypes, causing a growth depression in the maize. The genotype that fixes the most N2 may therefore not necessarily have the greatest N-supplying ability. The transfer of N from the legume and the consequent improvement of N nutrition in the associated cereal in low-fertility situations is therefore expected to be high when the growth of the legume is intermediate and does not suppress the growth of the cereal.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00361614
