Journal Articles

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Journal Articles (Soil Science)

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Browsing Journal Articles by Author "Adepetu, J. A."

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    A Preliminary Survey of the Fertility Status of Soils in Ondo State under Traditional Cultivation
    (Faculty of Agriculture, University of Ife, 1979) Adepetu, J. A.; Adebayo, A. A.; Aduayi, E. A.; Alofe, C. O.
    Surface and subsoil samples, as well as maize leaf samples were collected from local fields at about ten kilometers intervals along the major and minor highways across Ondo state in 1977. The samples were subsequently processed and analysed for various components in the laboratory. The surface 0-15cm soil samples showed a mean of 23; 7pp NO3 -N, 13.6ppm avail. P, 119.4ppm exch. K, 1168 ppm exch. Ca, 98.2 ppm exch. Mg, and Na-EDTA-extractable trace elements in the amount 131.9, 9.0, 319 and 1.3ppm of Fe. Zn, Mn, and Cu respectively. About 93% of the samples had a pH value between 5 and 7, while the soils had a mean 0.M content of 1.9% and C.E.C. of 11.4 meq/100g soil. About 77% of samples had a base saturation exceeding 50%. The values of these parameters generally decline down the soil profile to the 90cm depth studied. From the frequency distribution of various amounts of nutrients in the soil and plant tissue samples, it was concluded that N, P and Cu were generally deficient in the soils, while Ca. Mg, Fe. Mn, and Zn appeared adequate for optimum crop growth. However, it was difficult to make a definite statement, one way or the other, about K because of the seemingly contradictory conclusions that could be drawn from evaluating the soil and plant tissue data, which evaluations were based on what are generally believed to be the critical levels of K in soil 3nd maize plant for optimum crop yield. A further study to determine the internal and external critical nutrient requirements of crops in these soils is considered a priority.
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    Response of Two Lowland Rice Varieties to N, P and a Combination of Other Nutrients in a Flooded Soil
    (Faculty of Agriculture, University of Ife, 1984) Obi, A. O.; Adepetu, J. A.
    A 4x3x2x2 factorial experiment was conducted to evaluate the effects of N, P and a combination of some other nutrients on grain yields of two rice varieties under hydromorphic soil conditions, in the &forest of southern Nigeria. The low yielding variety (IR-20) responded better to fertilizer application than the higher yielding variety (OM). The best rates of N and P application to both rice varieties in this flooded soil were 60kg N/ha and 25kg N P/ha. Yield response to a combination of l00kg K, 40kg Mg, 5kg Cu, 2kg Zn and 2kg Fe per ha was significant during both years of cropping. Yield response to NP, and the combined application of the other nutrients were greater during the second than the first year of cropping.