Germination response and viability of an endangered tropical conifer Widdringtonia whytei seeds to temperature and light

AgriwetenskappeBos-en HoutkundePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Integration of legume trees in maize-based cropping systems improves rain use efficiency and yield stability under rain-fed agriculture

Water availability is a major constraint to crop production in sub-Saharan Africa (SSA) where agriculture is predominantly rain-fed. This study aimed to investigate the effect of the nitrogen-fixing legume tree Leucaena (Leucaena leucocephala) and inorganic fertilizer on rain use efficiency (RUE), a robust measure of productivity and land degradation, in three long-term (11–12 years) experiments conducted in Zambia and Nigeria. On the two Zambian sites, sole maize (Zea mays) grown continuously (for 11–12 years) with the recommended fertilizer achieved the highest RUE (3.9–4.6 kg ha−1mm−1) followed by maize intercropped with Leucaena (2.5–3.4 kg ha−1mm−1). This translated to 192–383% increase in RUE over the control (maize grown without nutrient inputs), which is the de facto resource-poor farmers’ practice. RUE was more stable in fully fertilized sole maize on the first Zambian site and not statistically different from the maize–Leucaena associations on the second site. On the Nigerian site, RUE was higher in maize planted between Leucaena hedgerows supplemented with 50% of the recommended fertilizer (3.9 kg ha−1mm−1), maize grown between Leucaena hedgerows without fertilizer (3.0 kg ha−1mm−1) and sole maize receiving the recommended fertilizer (2.8 kg ha−1mm−1), which translated to increases in RUE of 202%, 139% and 85%, respectively, over the control. RUE was more stable in the maize grown between Leucaena hedgerows than in the fully fertilized maize. On all sites RUE was least stable in the control. Yield stability in the maize–Leucaena association was not significantly different from the fully fertilized maize on the Zambian sites. On the Nigerian site, maize yields were more stable in maize grown in Leucaena hedgerows than in fully fertilized sole maize. Supplementation of maize grown in Leucaena hedgerows with 50% of the recommended fertilizers resulted in greater yield stability. It is concluded that intercropping cereals with legume trees and supplementation with inorganic fertilizer can increase rain use efficiency and yield stability in rain-fed agriculture in SSA.status: publishe

Understanding the multidimensionality of climate-smartness: Examples from agroforestry in Tanzania

Climate-smart agriculture (CSA) has three goals—productivity, resilience and mitigation. Rarely are these accounted for in CSA programming or the scientific evidence that supports it. Here, we evaluate the climate smartness of CSA-based agroforestry practices in Tabora and Dodoma, Tanzania using unpublished data from earlier studies. Firstly, a study of on-farm wood production and its use with the improved cook stove (ICS) was used to ascertain the productivity and mitigation effects of CSA. Next, intercropping experiments of maize or cassava with pigeonpea and/or G. sepium provided information on the production and resilience benefits of CSA. It was found that agroforestry practices (shelterbelt, trees on contours and intercropping) supplied up eight tons per hectare (t ha−1) of wood—enough to support a five-member family for up to 6 years when using ICS. Employing ICS also reduced the time spent in cooking (20%) and fuelwood collection (32%), and reduced gas emissions by 62%. Generally, intercropping pigeonpea or G. sepium enhanced farm production (as noted by a land equivalent ratio greater than 1) and agroecosystem resilience through crop diversification by using suitable intercropping arrangements and including a drought-resistant crop. Using the latter two in semi-arid Dodoma enhanced crop production across seasons and sites. Our analysis shows that adopting CSA-based agroforestry and intercropping practices is beneficial. However, these benefits are not universal. It also illustrates other key principles for understanding multidimensionality of CSA objectives, including the need to: select appropriate indicators, ensure designs are robust for heterogeneity, examine trade-offs, and conduct participatory evaluation of CSA