Studies on the effect of farmyard manure and mineral fertiliser on the growth of maize ( Zea mays L.) in a long-term experiment. I. Using the classical form of plant growth analysis

Abstract

The classical method of growth analysis was applied to compare the effects of farmyard manure (FYM) and mineral fertiliser on the dynamics of growth and growth parameters in maize ( Zea mays L.) over a three-year period (2005–2007) in a long-term continuous maize experiment set up using the principle of active agent equivalence in 1959. The experiment included two nutrient levels: (i) the NPK active agent equivalent of 35 t ha −1 FYM in the form of FYM, FYM + mineral fertiliser or mineral fertiliser alone; (ii) the NPK active agent equivalent of 70 t ha −1 FYM in the form of FYM, FYM + mineral fertiliser or mineral fertiliser alone. The aim was to determine the mean and maximum values of the plant growth parameters AGR, ALGR, RGR, NAR and LAR and to compare the effects of FYM and mineral fertiliser on maize growth in various years in a long-term experiment. The effect of the treatments and the year were analysed in terms of the dynamics of total dry matter production, leaf area, absolute growth rate, net assimilation rate and leaf area ratio.Both the fertiliser treatments and the year had a significant influence on the mean and maximum values of the given growth parameters during the vegetative growth stage. The rate and duration of growth (AGR and ALGR) were lowest in the unfertilised control and highest in treatments given high rates of mineral fertiliser or combined FYM and mineral fertiliser. In all the treatments the significantly lowest values of maximum NAR were observed in 2005, when the weather was average, with higher values in the drier years (2006 and 2007). The maximum values of LAR were significantly the highest in the droughty year of 2007. It could be concluded from the results that the effects of FYM and mineral fertiliser and that of the year on maize growth can be reliably evaluated with the classical method of growth analysis in long-term experiments.