Browsing by Author "Bebeley, Jenneh Fatima"

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    Rate and Time of Nitrogen Fertilizer Application on the Growth, Nitrogen Remobilization and Yield of Soybean (Glycine max (L) Merrill
    (2013-12-09) Bebeley, Jenneh Fatima
    Two field experiments were conducted in 2012 at the Plantation Crops Section of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, to investigate the effect of N availability on the growth, nodulation, nitrogen fixation, N remobilization and grain yield of soybean. The design used in both studies was a 3×4 factorial arranged in randomized complete block design. Each treatment was replicated three times. The factors studied were rate and time of N fertilizer application. The N rates were 0, 20, 40 and 60 kgN/ha and the time of application were early vegetative, late vegetative and early flowering phases. `The soybean variety used was Anidaso an improved variety released by the CSIR- Crops Research Institute, with a maturity period of 110 days. The land was ploughed, harrowed and plots were laid out. Plot length was 3×3m. Each plot consisted of five rows in both seasons and planting was done at the beginning of the rains in May at a spacing of 50×5cm. All required cultural practices were observed. The results indicated that soybean growth indices were not significantly (P>0.05) affected by rate and time of N application. Nodulation was also not significantly (P>0.05) affected by N rate and time of application. However, there was a positive correlation between nodule numbers and nodule dry weight, as well as between nitrogen fixation and grain yield in the minor season. Nitrogen fixation was significantly (P<0.05) affected by time of N application in the minor season. Harvest index was significantly affected by time of N application in the major season. Grain vii yield was also significantly affected by time of N application in both seasons. Furthermore, the study demonstrated that N remobilization occurs in soybean during grain filling although rate and time of application used did not significantly (P>0.05) affect N remobilization. It is recommended that in future work, isotope N should be applied and soil samples should be collected alongside with plant samples during the growth stages of the plant to assess how much of the N in the harvested plant comes from the fertilizer and how much was taken up by the plant from N stored in the soil. Also, further work should be done in a more N-deficient soil to study this phenomenon of N remobilization.