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In semiarid regions, drought is the major threat to crop production, but climate change and variability often bring floods to the regions, forming seasonal wetlands causing damage to local, drought-adapted staple grains and, hence, low yields and food deficit. Introduction of the semiaquatic crop rice (Oryza spp.) to these semiarid wetlands could complement the dryland crop low yields and overcome the food shortage problem. A field experiment was carried out at the University of Namibia-Ogongo Campus during the 2016/2017 and 2017/2018 cropping seasons to assess the growth and yield of rice genotypes. Twelve short-duration rice genotypes, nine from the International Rice Research Institute (IRRI) and three locally grown upland NERICA genotypes, were used. Parametric analysis of variance was performed to test their effects on crop growth and yield characters. The results showed significant genotype by year interaction for days to heading, plant height, the number of tillers per m2, shoot biomass, the number of panicles per m2, 1000-grain weight, harvest index, and grain yield. The IRRI genotypes produced a higher number of tillers, shoot biomass, and grain yield than the NERICA ones, which were early maturing, were taller, and had higher 1000-grain weight across the years. Generally, most of the genotypes had lower grain yield and higher shoot biomass in the first year, due to the prevailing cool, rainy, and seemingly cloudy weather conditions associated with lower temperature and lower solar radiation. Grain yield was positively correlated with most characters but negatively correlated with the 1000-grain weight. These results demonstrate the yield superiority of IRRI genotypes over their early-maturing NERICA counterparts. However, further studies on morphological characters and drought tolerance of the IRRI genotypes are warranted to ascertain production sustainability under semiarid environments.

Ecosystem Approach to Fisheries (EAF) management is a concept aimed at the conservation and sustainable use of the entire ecosystem. While EAF is a noble approach, its implementation has been challenging. Although Namibia has committed to the implementation of EAF, only limited assessment has been done of Namibian fisheries management processes and instruments concerning EAF. This assessment aimed to qualitatively ascertain if the Namibian fisheries management processes and instruments conform to the EAF principles. Although this assessment found that Namibian fisheries management processes and instruments largely conform to the EAF principles, it also identified notable areas needing improvements. The conformities were pronounced in the total allowable catch setting, rebuilding depleted stocks, minimizing bycatch, and fishing impact minimization. The polluter pays, and user pays principles were also applied. Areas that were found lacking in this study included setting the indicators for EAF and ecosystem integrity. The assessment also noted the absence of guidelines for the precautionary approach principle and a transparent policy for quota and right allocation processes. The strategies for managing transboundary fish species are also not formulated. Overall, this assessment showed the complexities and challenges of the fisheries management instruments that Namibia and other countries need to overcome to implement EAF successfully.

In recent years, serious drought and flooding become more frequent than before, affecting semi-arid regions of Sub-Saharan Africa due to the climate change. The research project was conducted to develop a “flood- and drought-adaptive cropping system” which can preserve water resources and cope with the yearly fluctuation of flood and drought in a semi-arid densely populated region of north-central Namibia. The crop science team proposed six cultivation techniques adapted to both flood and drought environments. Hydrology team explored that origin of surface and subsurface water was from local rainfall that was pooled temporary on the surface of small wetland formed in a farm field. The wetland can be easily affected by direct evaporation; however, rice cropping has no significant effect on the water environment of these wetlands. Shallow groundwater could be protected from drought weather conditions, and the recharge rate to the shallow groundwater could be enough only from the local rainfall in spite of recent drought weather conditions. The development studies team established seven methods for understanding the changing attitudes and perceptions of farmers and the socioeconomic impact on farmers through the introduction of the rice-pearl millet mixed cropping system. By using these methods, we found four aspects of socioeconomic impact and examined the socioeconomic sustainability of mixed cropping from four perspectives (incentive, independence, accessibility, and systematization). In this article, the results of the crop science team and the possible list of the cultivation techniques are described in detail.

Land use changes in wetland areas can alter evapotranspiration, a major component of the water balance, which eventually affects the water cycle and ecosystem. This study assessed the effect of introduced rice-cropping on evapotranspiration in seasonal wetlands of northern Namibia. By using the Bowen ratio–energy balance method, measurements of evapotranspiration were performed over a period of 2.5 years at two wetland sites—a rice field (RF) and a natural vegetation field (NVF)—and at one upland field (UF) devoid of surface water. The mean evapotranspiration rates of RF (1.9 mm daytime−1) and NVF (1.8 mm daytime−1) were greater than that in UF (1.0 mm daytime−1). RF and NVF showed a slight difference in seasonal variations in evapotranspiration rates. During the dry season, RF evapotranspiration was less than the NVF evapotranspiration. The net radiation in RF was less in this period because of the higher albedo of the non-vegetated surface after rice harvesting. In the early growth period of rice during the wet season, evapotranspiration in RF was higher than that in NVF, which was attributed to a difference in the evaporation efficiency and the transfer coefficient for latent heat that were both affected by leaf area index (LAI). Evapotranspiration sharply negatively responded to an increase in LAI when surface water is present according to sensitivity analysis, probably because a higher LAI over a surface suppresses evaporation. The control of LAI is therefore a key for reducing evaporation and conserving water. Copyright © 2013 John Wiley & Sons, Ltd.

UNLABELLED The survival of bifidobacteria in simulated conditions of the gastrointestinal (GI) tract was studied based on the D- and z-value concept. Some Bifidobacterium spp. are probiotics that improve microbial balance in the human GI tract. Because they are sensitive to low pH and bile salt concentrations, their viability in the GI tract is limited. The D- and z-value approach was therefore adopted as a result of observing constant log-cell reduction (90%) when Bifidobacterium spp. were exposed to these 2 different stressing factors. Survivals of one strain each or 4 species of Bifidobacterium was studied at pH between 3.0 and 4.5 and in ox-bile between 0.15% and 0.60% for times up to 41 h. From the D(acid)- and D(bile)-values, the order of resistance to acid and bile was B. bifidum > B. infantis > B. longum > B. adolescentis. While the former 3 strains retained high cell viability at pH 3.5 (>5.5 log CFU/mL after 5 h) and at elevated bile salt concentration of 0.6% (>4.5 log CFU/mL after 3 h), B. adolescentis was less resistant (

No Abstract. Discovery and Innovation Vol. 17(1&2) 2005: 1-7