Growth, yield components and micronutrient nutrition of field-grown maize (Zea mays L.) as affected by nitrogen fertilization and plant density
Growth and yield components in field-grown maize (Zea mays L.) were enhanced by nitrogen fertilization ranging from 50 to 200 kg N ha−1. Ear diameter, kernel depth, grain: stover ratio, number of ears plant−1, plant height and dry matter production increased as N fertilization rate was increased up to 100 or 150 kg N ha−1. Tasselling in maize was hastened by N fertilization. Increasing plant density from 25000 to 75000 plants ha−1 increased plant height, dry matter production and delayed tasseling but reduced ear diameter, kernel depth, grain: stover ratio and number of ears plant−1. Increased N supply and plant density had no influence on the concentrations of Mn, Zn, Cu, and Fe in ear leaf; except that Mn concentration increased as N fertilization rate was increased up to 150 kg N ha−1. Nitrogen × plant density interactions on the concentrations of the micronutrients in maize ear leaf were not significant.
Growth and Productivity of Maize (Zea mays L.) as Influenced by Inter- and Intra-Row Spacing in Kombolcha, Eastern Ethiopia
Effect of intra- and inter-row spacing on growth, yield components and grain yield of maize was investigated at Kombolcha, Eastern Ethiopia in 2014. The Objective of the experiment was to investigate the influence of intra- and inter-row spacing on growth, yield components and grain yield of maize in Kombolcha, East Hararghe zone. The experiment was arranged in a factorial combination of the three intra-rows (20, 25 and 30 cm) spacing and five inter-row spacing (45, 55, 65, 75 and 85 cm) spacing which were laid out in RCBD with three replication using maize (Zea mays L.) BH 660 variety. The results obtained had shown that there was highly significant (P< 0.01) main effect of inter-row spacing on leaf area, leaf area index, number of ears per plant, above ground dry biomass yield per hectare, number of kernels per ear, 1000 kernels weight and harvest index. Thousand kernels weight and number of kernels per ear highly significantly increased with decreased inter-row spacing while above ground dry biomass yield decreased with decreased inter-row spacing. Highly significant difference due to the main effects of intra-row spacing was observed on all the above parameters except harvest index. Thousand kernels weight and number of kernels per ear highly significantly increased with decreased intra-row spacing. There was highly significant interaction effect of inter-row by intra-row spacing on stand count percent, above ground dry biomass yield per plant, grain yield per plant, and grain yield per hectare. In general, significantly higher grain yield and above ground dry biomass yield were obtained due to intermediate and closer spacing. It may therefore be concluded that spacing combinations of 65 x 25 cm responded favorably in attaining higher grain yield of maize in the area. Keywords: Density, Phenology, Population, Yield, Yield components,
Phosphate responses in relation to soil tests and organic phosphorus
Phosphate responses of wheat in a number of soil types have been correlated with the amounts of phosphate extracted by ten different methods. Of these only total organic phosphorus, and inorganic phosphorus extracted with hot 0·1N caustic soda, were significantly related to phosphate response, the former at the 1% level and the latter at the 5% level. The amount of organic phosphorus in the soil was also found to be significantly related, in each instance at the 5% level, to phosphate responses of grass and the percentage phosphate in the grass. When the amount of organic phosphorus was considered together with the phosphate retention capacity of the soil, to give a measure of available mineralized phosphate, the relationships to response (and uptake of phosphorus by grasses) was more significant than with organic phosphorus alone. The organic phosphorus fraction accounted for about 86% of the total soil phosphorus. Measurable amounts of water-soluble organic phosphorus were found with all the soils. The amounts were, however, not significantly related to phosphate response. Moreover, it was found that while the soil extract containing organic phosphorus decomposed, it did so without the production of mineral phosphate. From this, and further evidence in the literature, it is considered that the organic complex in the soil, rather than the water soluble phosphorus, is the main source for the plant.