Assessment of variable application rates of biological amendment substances on establishment and growth characteristics of maize plants

Good plant establishment and excellent vigour constitute essential pre-requisites for successful grain production. The sowing of good viable seeds could contribute to increased productivity and ultimately lead to minimal seed cost and high return on investment. These are however dependent on such factors as the possible effects of pre- and post-seed sowing soil amendments. Hence, a greenhouse experiment was conducted in 2008 to assess the effects of variable rates (50, 75 and 100% of the recommended rates) of industrial manufactured biological amendment substances (IMBAS) (Biozone, Crop care, Gromor, Growmax, K-humate, Lanbac, Molcast, Montys and Promis) on the establishment and growth characteristics of maize seedlings. Inorganic NPK fertilizer and unamended control treatments were included as standards. Results obtained revealed a significant IMBAS as well as IMBAS x rates interaction effects on plant height, number of leaves, total biomass and leaf area. The percent plant emergence in K-humate, Montys and Promis treatments at 50% recommended rate were significantly decreased relative to the standard treatments. Application of most of the IMBAS at 100% of the recommended rate generally decreased plant establishment and phenological characteristics of maize. The study underpins the relevance of in-depth and accurate agronomic evaluation of industrially manufactured growth enhancement materials prior to recommendation for use by farmers.