Canopy Development of Annual Legumes and Forage Sorghum Intercrops and Its Relation to Dry Matter Accumulation

Summary. A number of studies conducted in Western Australia have shown that faba bean has considerable potential as a pulse crop in the low to medium rainfall cropping regions (300–450 mm/year). However, its yield is variable and can be low in seasons when rainfall is less than average. Traits associated with the adaptation of 10 diverse faba bean genotypes to low rainfall, Mediterranean-type environments were evaluated at Merredin in south-western Australia over 2 contrasting seasons. Plant density was varied with seed size to ensure all genotypes achieved similar canopy development and dry matter production. Time to flowering appeared to be the most important trait influencing seed yield of faba bean in this environment. Seed yield was significantly correlated with time to 50% first flower in 1994 and 1995 (r2 = 0.61 and 0.82 respectively, P<0.01). In the dry 1994 season, rapid leaf area development in ACC286 allowed a greater absorption of photosynthetically active radiation resulting in more dry matter accumulation than other genotypes. ACC286 also had greater root length density at 20–30 cm depth compared with Icarus and the standard cultivar Fiord. There were no significant differences in total water use between the genotypes examined, although the pattern of water use varied markedly. The ratio of pre- to post-flowering water use was about 1:1 in the early flowering and high yielding ACC286 and 2.6 :1 for the late maturing, low yielding Icarus. Seed yield and harvest index were positively correlated with post-flowering water use (r2 = 0.75 and 0.71 respectively). Above-average rainfall in 1995 resulted in increased yield of all genotypes, particularly ACC286 which again produced the highest yields. Early flowering genotypes with rapid dry matter accumulation in the seedling stages (such as ACC286) could widen the adaptation of faba bean to low rainfall, Mediterranean-type environments and situations where sowing is delayed.

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Responses of faba bean (Vicia faba L.) to sowing rate in south-western Australia II Canopy development, radiation absorption and dry matter partitioning

Australian Journal of Agricultural Research ◽

10.1071/a98003 ◽

1998 ◽

Vol 49 (6) ◽

pp. 999 ◽

Cited By ~ 8

Author(s):

R. Jettner ◽

S. P. Loss ◽

L. D. Martin ◽

K. H. M. Siddique

Keyword(s):

Seed Yield ◽

Faba Bean ◽

Dry Matter ◽

Plant Density ◽

Radiation Absorption ◽

Dry Matter Accumulation ◽

Dry Matter Partitioning ◽

Canopy Development ◽

Green Area ◽

Matter Production

Sowing rate influences plant density, canopy development, radiation absorption, dry matter production and its partitioning, and seed yield. The canopy development, radiation interception, and dry matter partitioning of faba bean (cv. Fiord) were examined using 6 sowing rate treatments from 70 to 270 kg/ha in field experiments conducted over 3 years at Northam as part of a larger investigation of sowing rate responses in faba bean in south-western Australia. High sowing rates resulted in significantly earlier canopy closure, larger green area indexes, more radiation absorption, more dry matter accumulation particularly during the early vegetative stages, and greater seed yield than treatments where a low plant density was established. The results suggest that further increases in canopy development, radiation absorption, dry matter accumulation, and seed yield are possible by using sowing rates in excess of 270 kg/ha. The rate of node appearance was relatively constant within and across seasons (1 every 65·9 degree-days), whereas the number of branches per plant declined with increasing plant density, and less branches survived through to maturity at high density. The peak photosynthetically active radiation absorption (75-85%) measured at green area index of 2·9-3·8 in the highest sowing rate treatment in this study is similar to previous reports for other crops. The estimated radiation use efflciency (1·30 g/MJ) was constant across sowing rate treatments and seasons. High sowing rates produced tall crops with the lowest pods further from the soil surface than those at low plant density, and hence, mechanical harvesting was easier. The growth of individual plants may have been limited by the low growing season rainfall (266-441 mm) and/or low soil pH (5·0 in CaCl2) at the site, and competition between plants for radiation was probably small even at the highest sowing rate. Early canopy closure and greater dry matter production with high sowing rates may also cause greater suppression of weeds and aphids.

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Dry matter accumulation and sheep grazing preference of six winter active annual legumes

NZGA: Research and Practice Series ◽

10.33584/rps.11.2003.3006 ◽

2003 ◽

Vol 11 ◽

pp. 117-121

Author(s):

M.G. Hyslop ◽

M.W.A. Slay ◽

C.A. Moffat

Keyword(s):

Medicago Truncatula ◽

Dry Matter ◽

Seasonal Pattern ◽

Block Design ◽

Subterranean Clover ◽

Late Winter ◽

Dry Matter Accumulation ◽

Sweet Clover ◽

High Quality ◽

Annual Legumes

Winter active legumes are suited to the mild winter areas of New Zealand, where they provide high quality forage in late winter and early to mid-spring. Six winter active annual legumes, persian clover, balansa clover, sweet clover, hybrid serradella, subterranean clover, and Medicago truncatula, were sown in a randomised complete block design with four replicates. Their dry matter (DM) accumulation and grazing preference to young sheep were measured every 3-6 weeks from sowing on 6 April 2000 until 24 October 2000. Total ungrazed DM production ranged from 5 500 kg/ha (sweet clover) to 9 300 kg/ha (balansa clover) over this period. The seasonal pattern of growth varied significantly between species, as did hogget grazing preference, with persian, balansa, and subterranean clover most preferred. These six plant species are capable of producing large amounts of high quality dry matter, but at all grazings, preference was extreme (measured by the number of sheep preferring to graze any one of the species when given a choice of all six), which may indicate the limited usefulness of some species. Key words: accumulative yield, grazing preference, Medicago truncatula, Melilotus albus, Ornithopus sativus x compressus, seasonal growth, sheep, Trifolium balansae, Trifolium respinatum, Trifolium subterraneum, winter active legumes

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