Browsing by Author "Marzouk, Said H"

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An overview of underutilized benefits derived from Azolla as a promising biofertilizer in lowland rice production
(cell press, 2023) Marzouk, Said H; Tindwa, Hamis J; Amuri, Nyambilila A; Semoka, Johnson M
Currently, there is no doubt that Azolla can compensate for the nitrogen requirements of rice in different agroecological zones. Compared to synthetic N-fertilizers, Azolla has various positive impacts on lowland rice production, including improving soil fertility, minimizing weeds, increasing soil organic carbon, improving microbial biomass, and thus nutrient cycling and enhancing rice growth and yield. However, Azolla has not been accepted globally by rice farmers for field use and so far, farmers are relying on increasing rates of synthetic N fertilizers instead of taking advantage of Azolla which will improve long-term soil fertility and health. This systematic literature review and scientific evidence could help policymakers, scientists and researchers to understand the benefits, limitations, and innovative ways of utilizing Azolla as a cost-effective and eco-friendly amendment in rice production. The paper uses Preferred Reporting Items for Sys tematic Review and Meta-Analysis (PRISMA) method to review the hidden potential of Azolla as a biofertilizer in paddy and summarizes its benefits and problems by collecting information from different sources and presenting under different subheadings such as critical factors affecting Azolla growth and nitrogen fixation, nitrogen fixation of Anabaena Azollae and their contribution in soil health, release and availability of Azolla-N to rice, amounts and time of Azolla inoculation, influence of Azolla on ammonia volatilization, contribution of Azolla to yield and yield compo nents of rice, and impact of Azolla on weed emergence in rice cropping system. Literature indi cated that the use of Azolla as green manure incorporated before rice transplanting or grown together with rice and left until a few days of harvest alone or in combinations with other syn thetic fertilizers in the lowland rice production saved the nitrogen requirement of rice up to 60 kg N ha− 1 , it enhances the availability of nutrients, improves physiochemical properties of soils, minimizes soil salinity, reduces the soil pH, and minimize weed germination. However, it was observed that incorporating Azolla as green manure is labor-intensive, and maintaining the Azolla inocula and phosphorous requirement are major restrictions for farmers. Therefore, under standing mechanism of spore production, educating farmers on cheaper alternative ways of Azolla application, and testing different species of Azolla over different agroecological zones will help in maintaining Azolla biomass and applying it at low cost for further environmental conservation.
Pedological characterization and soil fertility assessment of the selected rice irrigation schemes, Tanzania
(Frontiers, 2023) Marzouk, Said H; Tindwa, Hamis J; Massawe, Boniface H. J; Amur, Nyambilila A; Semoka, Johnson M
Rice (Oryza sativa L.) is the second cereal food crop grown in Tanzania after maize (Zea mays L.) and covers approximately 18% of the agricultural land. Soil degradation due to intensive cultivation along with low organic matter input and nutrient imbalance has led to a decline in rice crop yields. This study was conducted to characterize, classify, and assess the fertility status of soils in two rice irrigation schemes of Morogoro region in Tanzania. The data obtained through this study will contribute significantly to land use planning and will facilitate the transfer of agro-technology and other development of the regions with similar ecological conditions. The studied pedons were named MKU-P1 and MKD-P1 for Mkula and Mkindo irrigation schemes, respectively. A total of seven composite soil samples (0–20 cm) were collected for soil fertility assessments. Landform, soil morphological features, parent material, natural vegetation, drainage, erosion, and laboratory data were used to classify the soils in their respective order as per the United States Department of Agriculture (USDA) Soil Taxonomy and the World Reference Base (WRB) soil classification systems. Results showed that the pedons were sandy clay loam in the topsoil and sandy clay to clay in the subsoil; soil reaction ranged from medium acid (pH 5.7) to strongly alkaline (pH 8.6). The topsoil and subsoil nutrients of the studied pedons including available K+, total N, soil organic matter, and organic carbon are low. Based on the USDA Soil Taxonomy, MKU-P1 is classified as Inceptisols cumulic humaquepts and MKD-P1 as Vertisols Fluvaquentic endoaquerts corresponding to Subaquatic fluvisols (loamic, oxyaquic) and Irragric vertisols (gleyic) in the WRB, respectively. The pedons were ranked as suitable for rice production. However, the chemical fertility of the soil is ranked as low fertile associated with deficient in total N; available P, K+, and Ca2+ with excessive iron and manganese; and likely to pose toxicity to crops. The application of organic and mineral amendments in recommended rates and timing for N and P is therefore essential to increase the nutrient content of these soils and minimize losses. Salinity in the subsurface pedon MKD-P1 needs to be taken into future consideration.