Multistrata Agroforestry with Beans, Bananas and Grevillea robusta in the Highlands of Burundi

Abstract

Some agronomic, economic and ecological aspects of an agroforestry system combining Grevillea robusta trees, bananas (Musa spp.) and beans (Phaseolus vulgaris) were studied in the subhumid highlands of Burundi. Three densities of G. robusta, 208, 313 and 625 trees ha 71 were interplanted in plots of bananas, beans and a banana±bean mixture. When G. robusta was interplanted with bananas, the tree had a positive eect on banana yield with maximum yield occurring at 300 trees ha 71 . In the presence of beans, banana yield was not in¯uenced by the densities of the tree. Under low fertility regimes, the yields of beans interplanted with G. robusta were equal to or greater than those of the no-tree plots. Maximum bean yields were observed at between 283 and 295 trees ha 71 , representing a 25±135% yield increase above the no-tree control. When soil fertility was raised by the application of fertilizers, bean yields declined with an increasing density of G. robusta. Three years after planting, the growth of G. robusta was not aected by tree density. Mean height and mean basal diameter were 7.1 m and 13.2 cm respectively. Below ground competition between beans on the one hand, and bananas or bananas and G. robusta on the other, was more important than competition for light. Compared with the crops alone treatments, cumulative net present values of tree plots improved from being negative in the ®rst year to being positive in the third year. Net present value was highest in two of three instances when the density of G. robusta was 625 trees ha 71 . A multistrata arrangement of bananas and beans with G. robusta is viable for the low input agriculture system of the highlands of Burundi.

Intercropping of climbing bean (Phaseolus vulgaris, L.) and East African highland banana (Musa spp.) in the Ugandan highlands

“…However, Ntamwira et al (2013;2014) found similar (small) effects of pruning on bush and climbing bean yields. A fraction of 0.70 of total PAR transmitted did not affect bean yields in a study by Akyeampong et al (1999), and this fraction is similar to the fraction found in the non-covered measurement positions ( Figure 2). However, at a more severe pruning regime with only four banana leaves remaining, Ntamwira et al (2013) and Ocimati et al (2019) found that banana yields significantly reduced, and in the latter study even pruning up to seven leaves remaining reduced banana yields.…”

“…Our findings suggest that pruning may not have been severe enough to enhance climbing bean yields. The fraction of PAR transmitted through the banana canopy on the pruned plots was 0.43, whereas Akyeampong et al (1999) concluded that a similar fraction of 0.42 of PAR transmitted decreased bush bean yields by 27% compared to a non-shaded control. For climbing bean, internal shading of the bean plants could have reduced light availability even more than is expected in bush bean, which could have contributed to a limited effect of pruning on yield.…”

Modifying forestry and agroforestry to increase water productivity in the semi-arid tropics.

“…These observations suggest that there was complementarity of resource use between A. acuminata and maize at Thika but neutral or competitive interactions were apparent in all other treatments. The enhanced crop growth adjacent to A. acuminata at Thika is analogous to that reported in Uganda [78,79]. Although G. robusta is popular with farmers in semi-arid and sub-humid areas of Kenya, and has been reported to increase crop yield [80], the results from the Thika and Naru Moru sites clearly indicate otherwise, as has been found in other studies [40,81,82].…”

Integrated evaluation of soil fertility in Ginkgo (Ginkgo biloba L.) agroforestry systems in Jiangsu, China

“…It is generally agreed that perennial cropping systems are more suitable for maintenance of soil fertility than annual crop system (van Wambeke 1992). For this reason, multi-strata agroforestry with perennial crops is a promising option for long-term land use (Tomich et al 1998;Akyeampong et al 1999), however, these agroforestry systems require proper species selection and adequate management (Schroth et al 2000). The objective of the present study was to analyze the effects of different Ginkgo and crop combinations on soil chemical properties and enzyme activities, and soil fertility quality.…”