A Study of the Effects of Soil Moisture Stress and Fertility Levels on Hydrocyanic Acid Formation in Sorghum

Pot culture studies were conducted to determine the effect of different levels of nitrogen, phosphorus and soil moisture regimes on the hydrocyanic acid content of Sorghum vulgare Pers. (var. J. S, 263) grown in sandy loam soil deficient in available phosphorus. Significant differences in hydrocyanic acid content developed in plant tops that received different levels of nitrogen High (80 kglha) and medium (40 kg/ha) levels of N when associated with either low (no added phosphorus) or medium (20 kg/ha) levels of P₂O₅ caused significant increase in HCN content after 35 days of sowing, i.e., before heading as compared to low N (as added nitrogen) and high P₂O₅ levels (40 kg/ha). High levels of P₂O₅ (40 kg/ha) tended to limit the production of cy-nide regardless of the associated levels of nitrogen. There was no consistent response to soil moisture regimes.