Browsing by Author "Mvukiye, Ndimubandi Egidius"

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Rice yields as influenced by nitrogen from azolla-anabaena association supplemented with inorganic fertiliser nitrogen in the lower Moshi irrigation project, Tanzania
(Sokoine University of Agriculture, 1999) Mvukiye, Ndimubandi Egidius
A field study was conducted in the Lower Moshi Irrigation green-manurial Project, quantify Tanzania, the to potential of Azolla grown as a dual crop with irrigated rice. Parallel studies on the in situ decomposition rate of Azolla and the effect of the rice canopy on Azolla N accumulation were also undertaken. Azolla alone and in combination with 40 and 80 kg N/ha as urea (45% N) was compared with untreated control or, 160 kg N/ha as urea. These treatments were tested on Wahiwahi (indigenous) (improved)and IR54 rice varieties in a split-plot design with 3 replications. Each plot received a basal phosphate dose of 20 kg P/ha as TSP. Rice leaf chlorophyll plant content, height, tiller number, flowering and maturation time, panicle excertion, panicle number per unit area, grain number per panicle, panicle fertility, grain weight and the ultimate grain yield were recorded. An inoculation rate of 3 t/ha yielded 19.63 t/ha of fresh Azolla in 15 days and contained about 26 kg N/ha. The Azolla decomposed very fast, loosing 90% of its weight in 3 weeks of incorporation into soil. Azolla alone significantly (P = 0.05) improved rice leaf chlorophyll and most of the other parameters cited above, the improvement being comparable to that obtained with Azolla supplemented with successive amounts of urea or, 160 kg N/ha Despite itsalone. low Nas urea contribution, Azolla demonstrated considerable potential in promoting rice performance under conditions of the Lower Moshi Irrigation Project. Given the low amounts of N contributed by Azolla, studies to identify furthe rother possible rice growth-promoting in Azolla factors are suggested at the study site and in other rice growing areas in Tanzania.