The Effect of Chemical and Non-Chemical Nutrition Systems on Some Growth Traits, Yield and Yield Components of Hashemi Variety Rice (Oryza sativa L.) - A Case Study in Lahijan City, Gilan Province

Introduction[1] Rice is a staple and valuable grain that is the main source of food for over 50 percent of the world's population after wheat (Lopez et al., 2019; Jabran and Chauhan, 2015). Rice production should increase by over 50 percent by 2050, which can be realized by improving its cultivars and applying sound agronomic management practices (Esfahani et al., 2005; Asadi et al., 2016). Nitrogen (N) is a key macroelement that is decisive for plants, but it is deficient in most farms. N fertilizer is applied chemically, organically, and biologically (Moslehi et al., 2015).  Materials and Methods This research was conducted as a factorial experiment based on a randomized complete block design with three replications at two sites at the experimental farm of Islami Azad University of Lahijan (the village of Tustan) and Kateshal farm in 2018-2019. The study site (Lat. 36°55' N., Long. 45°20' E. (first location) and Lat. 37°21' N., Long. 50°18' E. (second location)) has a temperate and humid climate with a 10-year mean annual precipitation of 1150 mm (Guilan Meteorological Quarterly, 2020). Table 1 presents the meteorological data of the region during the experiment. Before the experiment, the physical and chemical characteristics of the soil at the study site were measured in the laboratory of the Water and Soil Department of Rice Research Center. The experimental factors included organic, chemical fertilizer, and control as the three levels of the first factor and urban waste compost, biochar, and Azolla, and control as the four levels of the second factor. Statistical analysis of data, data conversion, and drawing of graphs and charts were done using SAS 9.2 and Excel 2010 software. The averages obtained were statistically compared with each other using Tukey's test and at the probability level of 5%. Results and Discussion The simple effects of the chemical, organic, and organic nutritional systems were found to be significant (P < 0.01) on grain yield. Based on the comparison of data means for both research farms, the highest grain yield of, on average, 3699 kg/ha was obtained from the treatment of chemical fertilizer and biochar, and the lowest one of 2209 kg.ha-1 (40% lower than its maximum counterpart) from the control (unfertilized) treatment. Among the subplots, the biochar treatment was the most effective, and the control (unfertilized) was the least effective in this trait. The treatments that were fertilized with chemical N fertilizer produced more panicles per plant than the treatments that weren’t. Among the sub-plots, the highest number of panicles per plant was related to the biochar treatments under no-fertilization, ecological, and chemical conditions, and the lowest number to the control (unfertilized treatment). The plants treated chemically and ecologically in the presence of biochar were the tallest, growing to a height of 127 and 124 cm, respectively, whereas the lowest plant height was 108 cm, related to the control (unfertilized plants).   Conclusion The use of organic fertilizers alone or in combination with chemical fertilizers, in addition to improving the quantitative and qualitative characteristics of rice, has a positive effect on the sustainability of production and preservation of the environment. The results of this research showed that the application of nitrogen fertilizer and biochar, in addition to optimizing the application of fertilizer, increased the yield of rice. It was also found that the consumption of biochar caused an increase in traits related to grain yield. The role of biochar was evident in the significant change of the studied traits of Hashemi rice in the main treatments (control, ecological, and chemical). Therefore, it is recommended to use biochar along with chemical fertilizer in order to maintain yield, prevent biological pollution and increase soil and rice fertility. Acknowledgments The assistance of the esteemed personnel of the Islamic Azad University, Lahijan branch, who helped us in the implementation of this research, is gratefully acknowledged.