Light interception and utilization of four grain legumes sown at different plant populations and depths

Abstract

Canopy development, radiation absorption and its utilization for yield was studied in four grain legume species Cicer arietinum, Lens culinaris, Lupinus angustifolius and Pisum sativum. The grain legumes were grown at different plant populations and sowing depths over two seasons in Canterbury, New Zealand. The green area index (GAI), intercepted radiation, radiation use efficiency (RUE) and total intercepted photosynthetically active radiation (PAR) increased significantly (P<0·001) with increased plant population. Narrow-leafed lupin produced the highest maximum biomass (878 and 972 g/m2, averaged over all populations during 1998/99 and 1999/2000, respectively) and intercepted more radiation (600 and 714 MJ/m2, averaged over all populations during 1998/99 and 1999/2000, respectively) than the other three legumes. In all four species, in both trials, the highest plant populations reached their peak GAI about 7–10 days earlier than legumes sown at low populations. Cumulative intercepted PAR was strongly associated with seed yield and crop harvest index (CHI).The RUE increased (from 1·10 to 1·46 and from 1·04 to 1·34 g/MJ during 1998/99 and 1999/2000, respectively) as plant population increased and was highest in the highest yielding species (e.g. 146 and 1·36 g/MJ for narrow-leafed lupin in both experiments). The larger leaf canopies produced at the higher plant populations reduced the extinction coefficient (k).The results suggest that in the subhumid temperate environment of Canterbury, grain legume species should be selected for the development of a large GAI. This should maximize PAR interception, DM production and, consequently, seed yield.

Using Light Attenuation to Estimate Leafy Spurge Impacts on Forage Production

“…Because root and shoot effects were confounded in our study, we make no claims about the relative intensities of light competition and soil resource competition. We use light readings to model leafy spurge competitive effects because light attenuation should be highly correlated with biomass (Ayaz et al 2005;Enriquez and Pantoja-reyes 2005) and because, compared to biomass, light attenuation is measured much more rapidly. The biomass that leafy spurge produces has proven to be an important predictor of this weed's competitive effect (Gylling and Arnold 1985;Sheley 2005a, 2005b).…”

Light interception and radiation use efficiency of fern- and unifoliate-leaf chickpea cultivars

“…Crop management practices often affect canopy development, LI, and RUE (Leach and Beech 1988; Ayaz et al 2004). Narrow row spacing coupled with high plant population increases the LI of chickpea.…”

“…A plant population higher than the current recommendation (38Á45 plants m (2 ) may be needed to ensure rapid canopy closure in order to improve LI. Higher plant populations usually give rise to an earlier canopy closure in chickpea (Ayaz et al 2004), soybean (Ball et al 2000;Purcell et al 2002), faba bean (Loss et al 1998), and lentil (McKenzie and Hill 1991). However, in the dry environment of northern Syria, plant population and growth habit had marginal effects on dry matter production (Hughes et al 1987).…”

“…(1 (Ayaz et al 2004;Anwar et al 2003;Thomas and Fukai 1995;Leach and Beech 1988, respectively), with a range of 0.91 to 1.53 g MJ (1 . The lowest values of RUE came from drought-stressed studies, whereas relatively high values for RUE were obtained when irrigation was applied to chickpea.…”

“…The lowest values of RUE came from drought-stressed studies, whereas relatively high values for RUE were obtained when irrigation was applied to chickpea. Ayaz et al (2004) compared the RUE among four grain legumes and found that the species with highest yield also had the highest RUE in the temperate environment of New Zealand. However, Thomson and Siddique (1997) found that RUE was poorly correlated with maximum BM in a Mediterranean-type environment.…”