Effect of different sources organic fertilizers and nitrogen on some physiological, quantitive and qualitive characteristics of rice

In order to investigate the effect of different sources of organic fertilizers and nitrogen on some of the physiological, quantitive and qualitive characteristics under direct cultivation, a field experiment in the crop season 2020-2021, in a split plot experiment based on a randomized complete block design with three replications were implemented in Ahvaz. the main factor at three levels (humic acid, fulvic acid and control) and the use of nitrogen fertilizer at 6 levels (granulated urea fertilizer, sulfur coated urea, ammonium sulfate fertilizer, urea and ammonium nitrate, sulfur coated urea and granulated urea fertilizer and no application of nitrogen fertilizer as a control) were a secondary factor. Mean comparison of simple effects showed that the highest percentage of total protein of leaf, rice yield, hectoliter weight, rice grain length, white grain width after cooking and the lowest percentage of grain crushing after bleaching were observed by humic acid application. The increase in rice yield, rice grain length and white grain width after cooking in humic acid application treatment compared to the control was 19.4, 5.4 and 5.6 percentage respectively. The highest percentage of total protein of leaf, rice grain length, white grain width after cooking and the lowest percentage of grain crushing after bleaching were obtained by applying sulfur coated urea or sulfur coated urea with granular urea. The mean comparison of interaction effect of the factors on other studied traits showed that the highest leaf area index was observed with the application of sulfur coated urea or the application of sulfur coated urea with granular urea × application of fulvic acid and the highest amount of chlorophyll a, b, carotenoids and white grain length after cooking belonged to the treatment of application of sulfur coated urea along with granular urea × application of humic acid. It seems that the supply and availability of nitrogen in the soil at different growth stages of rice under the application of nitrogen fertilizer treatments and the improvement of soil characteristics due to the use of organic fertilizers and as a result of sufficient access to nutrients at different stages of plant growth and development, improvement of physiological characteristics, has affected the quantity and quality of rice. Based on the results of this experiment, it seems that the combined application of humic acid or fulvic acid with sulfur coated urea fertilizer or sulfur coated urea with granulated urea is recommended in similar conditions.