The Effect of Soil Fertilizers on Yield and Growth Traits of Sorghum (Sorghum bicolor)

Since the use of chemical fertilizers causes environmental pollution and ecological damage, so application of biological fertilizers and selection the effective and compatible species in an special area, could be beneficial for sustainability of agroecosystems there. Nowadays, attention to the interrelation of plant-organism tended to interrelations between plant-organism-organism. Such nutritional relations, have ecological importance and important application in agriculture. The aim of this experiment was to evaluate the effect of chemical, organic and bio fertilizers on sorghum performance.
A field experiment was conducted in a randomized complete block design with three replications. The experimental treatments include three kinds of biofertilizers and their integrations and vermicompost and chemical fertilizer as follow: 1- mycorhhiza arbuscular (G.mosseae) vermicompost 2- mycorhhiza Nitroxine® (included bacteria Azospirillum sp. and Azotobacter sp.) 3- mycorhhiza arbuscular Rhizobium (Rhizobium sp.) 4-mycorhhiza arbuscular Chemical fertilizer NPK 5- mycorhhiza arbuscular 6-control. Mycorhhiza and chemical fertilizer were mixed with soil at the depth of 30 cm before planting. Seeds were inoculated with bio fertilizers and dried at shadow. First irrigation applied immediately after planting. In order to improve seedling emergence second irrigation was performed after 4 days and other irrigation was applied at regular intervals of 10 days. Studied traits were: height and percentage of root colonization, specific root length, seed yield, number of seeds in panicle, thousands seeds weight. To determine the specific root length (root length in a certain volume of soil) at the end of the growing season, plants in each plot were sampled. Then the length of root of each sample was determined.
The results showed that although the treatments did not affect the height of stem significantly, but they had significant effects on characteristics of root length colonization, specific root length, leaf area index, crop yield, number of seeds per panicle and thousand grains weight .The results demonstrated that the highest percent of root length colonization (82), specific root length (51.82 m root in 25 cm3 soil), leaf area index (5.47), seed yield (425.62 g.m-2), number of seeds in panicle (635) were obtained in mycorhhiza with Nitroxine® treatment. The highest weight of thousands seeds (29.26 g) was gained in simultaneous use of mycrhhoriza and vermicampost. On the basis of our results, the integration of mycrhhoriza with Nitroxine® is suggested as the best fertilizer treatment for sorghum.
The results showed that the application of mycorrhiza with nitroxin had the greatest effect on growth characteristics and yield of sorghum. It seems that whenever there was a source of nitrogen beside the mycorrhiza, the performance of sorghum was higher. Undoubtedly, application of bio and organic fertilizers specially in poor soils, have positive effects on soil physical and nutritional characteristics. On the other hand according to economical, environmental and social aspects, they are benefits and could be appropriate alternative for chemical fertilizers in future.