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This study aims to characterize soil chemical properties and microbial biomass, greenhouse gas production, and organic matter dynamics in upland rice field as affected by the long-term fertilizer managements in Uganda. Soil total C (TC) and N (TN) contents were in the relatively smaller range under different fertilizer treatments, even after 20 crop seasons. However, available phosphate contents showed positive correlation with average yield of upland rice. Incubation experiments were conducted under aerobic or under flooding conditions to measure CO2, methane, and nitrous oxide productions. After the incubation, soil samples were extracted to quantify nitrification rate for aerobic condition and ammonification rate for flooding condition. Soil microbial biomass carbon (MBC) and nitrogen were measured. Stable isotope ratio of 13C and 15N were also determined for the soil samples. CO2 production potential under aerobic condition was higher than the flooding condition. The qCO2 (CO2/MBC) in the treatment applied with compost tended to be higher than the other treatments. Positive correlation between nitrous oxide production and nitrification was found. The delta 13C values of the soil samples indicated that the effect of C4 plants before rice cultivation still remained, while the contribution of biological N2 fixation was little according to delta 15N values. These results indicate that soil microbial biomass in upland rice field of the long-term fertilizer experiment in Uganda was characterized with higher qCO2. Greenhouse gas production was affected by fertilizer management, while soil organic C before the long-term experiment still remained in the experiment. [ABSTRACT FROM AUTHOR]

Using data obtained from a series of nation-wide market surveys in Uganda, this article attempts to document and assess the domestic rice market at all stages in the post-harvest marketing chain from the farm gate to metropolitan area retail outlets. The criteria used are quantities marketed, prices, marketing margins, marketing costs and net returns to traders. The results show that the regional rice markets are integrated into the national market and that on average little surplus is left for rice traders at all market stages if marketing costs are accounted for. The spontaneously developed indigenous crop market works reasonably well. [ABSTRACT FROM AUTHOR]

We investigated the occurrence of insect pests and natural enemies on rice plants and weeds around rice fields in Uganda, East Africa, during 2010 and 2013. The following pest arthropods were collected with an insect net: large-sized stalk-eyed fly (Diopsis longicornis), small-sized stalk-eyed fly (D. apicalis), plant bugs (Pentatomidae and Alydidae), planthoppers and leafhoppers (Delphacidae and Cicadellidae), leaf beetles (Chaetocnema spp., Chrysispa viridicyanea and Altica spp.), short-horned grasshoppers (Coryphosima spp. etc.) and long-horned grasshoppers (Tettigoniidae). Small-sized natural enemies, such as parasitic wasps (Hymenoptera: Eulophidae, Cynipoidea, Braconidae and Ichneumonidae), were also captured. [ABSTRACT FROM AUTHOR]