01466naa a2200205 a 450000100080000000500110000800800410001910000190006024500780007926000090015752009450016665000130111165000100112465000120113465000130114665000140115965000170117365000140119077300560120411973232020-06-18       1976    bl uuuu     u00u1 u    #d1 aFAGERIA, N. K.  aCritical P, K, Ca, and Mg contents in the tops of rice and peanut plants.  c1976  aRice and peanut plants were grown in nutrient solution with varying concentrations of phosphorus, potassium, calcium, and magnesium. Growth response and concentration of the elements in the plant tops were recorded and from these critical and adequate values for P, K, Ca, and Mg were defined. These were for P at 25 days of growth of rice plants 0.70-0.80 and 0.80-0.86; at 50 days of growth 0.18-0.26 and 0.26-0.40; and at 75 days 0.26-0.36 and 0.36-0.48 per cent of dry matter respectively. For K they were 3.75-4.25 and 4.25-4.35 per cent at 25 days of growth; 3.7-4.0 and 4.0-4.62 per cent at 50 days of growth; and 3.5-3.62 and 3.62-3.99 per cent at 75 days of growth resp. At 100 days of growth the values for Ca and Mg were established as 0.36-0.45, 0.45-0.65; and 0.12-0.17, 0.17-0.30 per cent respectively. For 39 days old peanut plants values established for K and Mg were; 2.8-3.4, 3.4-3.8 and 0.25-0.30, 0.3-0.36 per cent resp.  aAmendoim  aArroz  aCálcio  aFósforo  aMagnésio  aOryza Sativa  aPotássio  tPlant and Soilgv. 45, n. 2, p. 421-431, Oct. 1976.