High density banana/rubber intercrops have no negative effects on component crops under the smallholder conditions

ACCLIMATION OF PHOTOSYNTHESIS AND GROWTH OF BANANA (MUSA SP.) TO NATURAL SHADE IN THE HUMID TROPICS

“…0, 33 ± 1.0, 55 ± 0.5 and 77 ± 0.7% reduction in full sunlight and hereinafter referred to as unshaded control, low, medium and high shade treatments, respectively. Natural shade was imposed by selecting existing mature rubber plantations, and the different shade levels were achieved as a result of the age and inter-row spacing of rubber, and by selective pruning of branches of the mature rubber trees (Senevirathna, 2001). An open area close to the shaded sites was selected for the unshaded control treatment.…”

“…Soil pits were excavated to a depth of 1 m and to a diameter of 1.8 m. All particles greater than 15 cm 3 were removed from the excavated soil, and the pits were refilled according to the original soil profile. Fertilizer was applied according to recommendations, and manual weeding was undertaken when required (Senevirathna, 2001).…”

“…Prior to each set of F v / F m measurements, leaves from five replicate plants in each treatment were dark adapted for 25 min using the leaf clips provided. The saturating light intensity of the PEA (flash used to reduce fully the primary electron acceptor) was adjusted to 50%, as determined for banana leaves during preliminary experiments (Senevirathna, 2001). Measurements were taken on clear days (maximum PPFD of ca.…”

“…Banana is commonly grown in plantations as a monocrop, or in mixed cropping systems, under tropical and subtropical conditions. In mixed and high density cropping systems (Robinson and Nel, 1988; Rodrigo et al ., 1997; 2001), banana may experience mutual shading, and so benefit from changes in microclimate such as small reductions in photosynthetic photon flux density (PPFD), air temperature, turbulence and evaporative demand (Barradas and Fanjul, 1986). One of the most common companion crops grown with rubber in Sri Lanka is banana.…”

“…One of the most common companion crops grown with rubber in Sri Lanka is banana. Previous studies showed that banana growth improved when intercropped at high densities with rubber, with an increase in light interception and radiation use efficiency, possibly due to the benefits conferred by greater mutual shading in dense canopies (Rodrigo et al ., 1997; 2001). Other studies have reported negative impacts of shade on growth and photosynthetic productivity of banana (Israeli et al ., 1996; Robinson and Nel, 1988).…”