Response of maize (Zea mays) and cassava (Manihot esculenta) to removal of surface soil from an alfisol in Nigeria.
1987
Lal R.
The effects of surface soil removal to varying depths and of fertilizer rates were investigated for three consecutive crops of maize and two crops of cassava. There were three depths of soil removal (20, 10 and 0 cm), and three levels of each of N (0, 60 and 120 kg/ha) and P (0, 25 and 50 kg/ha). Grain yield or maize was drastically affected by the depth of soil removed. For the 1980 first season crop, the grain yield or maize was 0.22, 0.73 and 1.199 t/ha for 20, 10 and 0 cm depth of soil removed. None of the fertilizer combinations used could compensate for the loss of soil removed. Soil moisture reserves in the 0-5 and 5-10 cm depths were greater for the undisturbed control than for soils from which 10 or 20 cm of soil had been removed. The leaf content of P and K and root weight were significantly lower for the undisturbed control. Although cassava tuber yield also decreased with increasing depth of soil removed, the effect was not as drastic as on maize. The cassava tuber yield for the 1981 crop was 14.4, 20.0 and 31.1 t/ha for 20, 10 and 0 cm depth of soil removed, respectively. At 0 level of N, cassava had a positive response to P for treatment with 20 or 10 cm depth of soil removed.
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