The Effect of Organic, Biofertilizer and Chemical Fertilizer on Growth and Yield of Castor Bean (Ricinus communis)

Background and objectives: Application of chemical fertilizers besides contaminating the water and soil resources, and reducing the quality of agricultural and medicinal products has created serious environmental issues. Plant nutrients management is an important factor for increasing growth and yield of plants. In sustainable agriculture, biological and organic fertilizers are an alternative to chemical fertilizers that they can improve the quality and quantity of plants. Based on this, due to the importance of castor and its extensive use in various industries, an integrated nutrition system assessment was carried out on Ricinus communis L. for simultaneous use of biofertilizer, vermicompost fertilizer and nitrogen fertilizer.
Materials and methods: The experiment was included nitrogen fertilization at three levels 0 (N0), 75 (N1), 150 (N2), kg ha-1, vermicompost at three levels of application 0 (V0), 5 (V1) and 10 (V2) t ha-1 and biofertilizer in two levels of non-inoculation (P1) and inoculation with biofertilizer (P2). The experiment was performed in a factorial base on randomized complete block design with three replications was conducted at experimental farm of Faculty of Agriculture, Azarbaijan Shahid Madani University in 2017. Parameters such as plant fresh and dry weight, height, number of leaves, leaf area, pigments content, inflorescence length and diameter, number of capsules per plant, number of seed per capsules, 1000 seeds weight, seed and oil yield and oil content were measured.
Results: The results showed that combination of non-inoculation+ vermicompost 10 t ha-1+nitrogen 150, kg ha-1 was the most effective treatment for increasing the plant height, number of branches, stem diameter, weight and dry weight of the plant. Also, the highest seed and oil yield were obtained in non-inoculation+ vermicompost 0 t ha-1+nitrogen 150, kg ha-1 and inoculation+ vermicompost 10 t ha-1+nitrogen 150, kg ha-1 treatments with 2824 and 1185.1 kg ha-1, respectively. The highest and lowest oil content were 43.31% and 36%, in the non-inoculation + vermicompost 10 t ha-1+nitrogen 150, kg ha-1 and control (non-application of fertilizer) treatments, respectively. The Oil yield per plant was positively correlated with number of seeds per plant (r = 0.74). The maximum coefficient of determination for stepwise regression was obtained for the number of seeds per plant (0.68).
Conclusion: The number of seeds per plant can be the suitable trait to achieve a higher oil yield per plant. The treatment combination of inoculation+ vermicompost 10 t ha-1+nitrogen 150, kg ha-1 through increasing the number of seeds per plant and the treatment combination of inoculation+ vermicompost 10 t ha-1+nitrogen 0 kg ha-1 through increasing the 1000 seed weight showed higher oil yield per hectare compared to other treatment combination. Therefore, the treatment combination inoculation+ vermicompost 10 t ha-1+nitrogen 0, kg ha-1 can be a good choice for achieving the highest oil yield per hectare in sustainable agriculture and reducing the consumption of nitrogen from chemical sources.