Mapara, Lovejoy Patrick Tambudzai2026-06-112026-06-112002https://www.suaire.sua.ac.tz/handle/20.500.14820/7661DissertationTraditional water management techniques employed in irrigated rice production are deficient, particularly in controlling moisture loss. In this study, Azolla caroliniana backed by conventional approaches (e.g soil puddling, sub-soil compaction and levee coating reinforced with lateral flow barriers) was used to suppress evapotranspiration in rice Helds under irrigation. A field experiment was carried out at Lower Moshi irrigation project in Kilimanjaro region in Tanzania between the dry season and short rainy season from September 2000 to January 2001. The study was done at the Kilimanjaro Agricultural Training Centre (KATC) experimental farm, which has medium clay soils. The aim was to evaluate the effect of Azolla caroliniana (a green manure with symbiont blue green algae) in economising irrigation water in rice cultivation. The type of rice used in the study was a local indigenous variety known as Wahiwahi. The water balances for the growing period and grain yields at harvest were determined. Yield attributes were assessed for the effect of Azolla. The experiment was conducted in a randomized complete-block design with four replications and three treatments. The plot sizes were each 5.3 m x 5.1 m. The treatments were: Wahiwahi only (Tl); Wahiwahi and Azolla (T2) and Azolla only (T3). Ridges were made around the individual plots to allow ponding. A nursery for pre-germinated rice seeds was established for 25 days after which the seedlings were transplanted. Azolla was administered in treatments T2 and T3, 7 days after transplanting. Crop water use measurements were done at 14 days post transplanting and thereafter daily for the whole growing period (three and half months). Parameters monitored in total water use were evapotranspiration and seepage and percolation. One lysimeter and one percolation cylinder were installed in each treatment to facilitate the measurements. Other data collected included measuring plant growth (plant height, straw dry weight, number of tillers, heading time and weed population); determining yield components (number of panicles and grains, percent of ripe grains and grain weight at harvest) and grain yield. The total water use obtained in treatments T2 and T3 were 8.13 mm/day and 7.05 mm/day respectively, which were not significantly different (p < 0.05). In treatment Tl, the total water use observed was 11.99 mm/day, which was significantly higher (p < 0.05) than T2 and T3. There was no significant effect (p < 0.05) of Azolla on seepage and percolation. Tlxe lowest evapotranspiration was obtained in treatment T3 with 2.24 mnv'day, wliich was significantly different (p < 0.05) from T1 and T2. Evapotranspiration was 6.48 mm/day in treatment T2 which was 23% lower and significantly dififerent (p、0.05) fiom that in Tl. Reduced dry matter weiglit of weeds was registered in T2 and T3 where the weed control efficiency was significantly higlier (p < 0.05) tlian Tl. Rice plant growth in T2 was greater and more superior throughout the growing period compared to plants in Tl. The grain yield in T2 was 7.93 t/ha which was significantly higher (p < 0.05) than 6.31 t/ha in Tl. Azolla management e俭ct gave soil-moisture retentivity of 32% that resulted in increased water use efficiency by tlie crop. The crop stand was improved and grain yield increased. The use of Azolla caroliniana in irrigated rice cultivation is recommended as a water management practice.enMoshi irrigation projectEvapotranspirationAzolla productionEvaporationThesis