EFFECT OF INORGANIC CATIONS IN ANIMAL-WASTE COMPOSTS ON WATER AND CATION ABSORPTION OF GERMINATING SORGHUM (SORGHUM-BICOLOR L MOENCH) SEEDS

The effects of soluble inorganic cations contained in some animal-waste composts on water and cation absorption and subsequent germination of sorghum (Sorghum bicolor L. Moench) seeds were investigated under laboratory conditions. The cation content of the seeds imbibed in the compost extracts showed a positive linear correlation with the water soluble cation concentration in the respective compost extracts. Water absorption of compost-imbibed sorghum seeds was well correlated with subsequent germination. However, the Na+ and K+ contents in imbibed seeds and the total soluble cation content in compost extracts did not contribute significantly to seed water absorption. Thus, it was suggested that the cation concentration in the compost medium and the cation influx during seed imbibition have a lesser impact on the control of water absorption via osmotic adjustment and subsequent germination of sorghum seeds. Some possible factors that may influence water absorption of sorghum seeds imbibed in animal-waste compost extracts are also discussed.