Characterization of Growth, Nitrogen Accumulation and Competitive Ability of Six Tropical Legumes for Potential Use in Intercropping Systems

Abstract

Legume cover crops can be successfully used as intercrop or relay crops in low‐input farming systems. To select appropriate species for intercropping, experiments were conducted in the savannah zone of Côte d’Ivoire during the wet seasons of 1997 and 1998 to determine the growth and nitrogen (N) accumulation of six cover legumes as well as the characteristics indicative of competitive ability. The species included the erect growing Crotalaria juncea and Cajanus cajan, the creeping species Mucuna pruriens var. cochinchinensis and Calopogonium mucunoides and the bushy herbaceous species Aeschynomene histrix and Stylosanthes hamata. Marked differences in phenology were observed as S. hamata and C. juncea flowered around 45–55 days after sowing (DAS) and the other species around 80–95 DAS. C. juncea and C. cajan produced close to 9 ton dry matter ha–1, whereas the other species produced less than half this amount. The average estimated amount of accumulated N, based on leaf material, was around 70 kg ha–1 for all species except S. hamata and A. histrix, which only produced around 25 kg ha–1. Based on morphological characteristics, C. juncea, C. cajan and the short‐lived M. pruriens were identified as potentially most competitive, indicating that productivity and competitive ability are strongly linked. The implications of these findings for intercropping systems in upland rice production are discussed.

Competitiveness of Three Leguminous Cover Crops with Yellow Nutsedge (Cyperus esculentus) and Smooth Pigweed (Amaranthus hybridus)

“…Iron Clay cowpea, sunn hemp, and velvetbean are already known as cover crops that provide services such as green manuring and suppressing root knot nematodes (Abdul-Baki et al 2005;Cherr et al 2006;Roberts et al 2005). There has also been strong interest recently in these cover crops for weed suppression (Adler and Chase 2007;Akanvou et al 2001;Caamal-Maldonado et al 2001;Collins 2004;Harrison et al 2006;Hill et al 2006;Hutchinson and McGiffen 2000;Wang et al 2004Wang et al , 2006. Although all three cover crop species are well-adapted to Florida conditions (Abdul-Baki et al 2005); they did not prove to be consistently more competitive than model weed species in greenhouse studies.…”

Allelopathic Effects of Sunnhemp (Crotalaria juncea L.) on Germination of Vegetables and Weeds

“…Nitrogen fixation by sunnhemp is similar to that of hairy vetch (Vicia villosa) and crimson clover (Trifolium incarnatum) (Akanvou et al 2001;Mansoer, et al, 1997;Scholberg et al, 2005). Sunnhemp could supply a significant amount of nitrogen (N) needed by either a fall/winter vegetable crop or by a spring crop (Mansoer et al, 1997;Scholberg et al, 2005).…”

Living Mulch as a Tool to Control Weeds in Agroecosystems: A Review

“…This can be explained by the combination of high initial growth rates for height and leaf area development. Additionally, the high final height of C. juncea and C. cajan may confer higher competitiveness throughout the growing season (Akanvou et al 2001). …”

“…According to Akanvou et al (2001), slow-growing species with longer duration such as Stylosanthes hamata and Aeschynomene histrix are expected to be less competitive and therefore appropriate for early establishment in rice-legume intercropping systems.…”

“…For example, tall and vigorously growing legumes with relatively large leaves and rapid leaf expansion might be detrimental to the associated crop, whereas poorly competing species will be out-competed and will therefore contribute little to improving soil fertility (Akanvou et al 2001). …”