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Agronomy Journal Abstract -

Sorghum Growth and Nutrient Uptake in Relation to Soil Fertility, II. N, P, and K Uptake Pattern by Various Plant Parts1


This article in AJ

  1. Vol. 66 No. 1, p. 5-10
    Received: May 13, 1972

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  1. R. N. Roy and
  2. B. C. Wright2



An understanding of seasonal nutrient accumulation patterns under varying fertility levels is important for planning an efficient fertilization program. Field experiments were conducted to determine the effects of varying rates of N (0, 60, and 120 kg/ha) and P (0 and 26 kg/ha) on the N, P, and K accumulation pattern by various plant parts of a sorghum [Sorghum bicolor (L.) Moench] hybrid. Plant samples were collected at weekly intervals, partitioned into plant parts, and analyzed for N, P, and K.

Nitrogen and P accumulation by whole plants increased almost linearly until maturity, but K accumulation was more rapid early in the season. A significant loss of K from the whole plant (and head) occurred during the last week. Nitrogen, P, and K accumulation rates were higher during the 35th to 42nd day and 70th to 91st day which coincided with the peak vegetative growth period and the grain-filling stage, respectively. In unfertilized plants relatively higher translocation of N and P from the vegetative parts to the developing grain occurred. Little K was translocated. A much smaller percentage of total K was found in the head and more K accumulated in the stem than N and P.

Application of 60 kg N/ha significantly increased N, P, and K yields of whole plant by 60.9, 49.4, and 19.1%, respectively. Further respective increases were 19.0, 18.9, and 12.3%, with 120 kg N/ha. Respective increases were 28.6, 49.0, and 17.1% with 26 kg P/ha over no phosphorus.

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