Document Type : Applicable
Authors
1 MS.c. graduate, Department of Plant Production and Genetics, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
2 Associate Professor, Department of Plant Production and Genetics, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
Abstract
Introduction: A decline in soil organic matter is a key facet of soil degradation, leading to the loss of soil fertility and the capacity to produce crops. The intensive use of synthetic inorganic inputs, such as chemical fertilizers, has resulted in soil organic matter depletion, groundwater contamination, air pollution, and reduced production quality in arid and semi-arid regions. Therefore, sustainable techniques, such as organic fertilizers and natural inputs, are becoming increasingly important to enhance soil organic matter and plant yield in sustainable agricultural systems. The use of organic fertilizers and soil amendment like biochar and wood vinegar can significantly improve soil organic matter. Much of the world's interest in biochar stems from the worsening condition of agricultural soils and the depletion of water resources. Additionally, biochar has attracted researchers’ interest mainly due to its long-term soil carbon sequestration potential, role in greenhouse gas mitigation, phytoremediation, and ability to improve soil fertility. Biochar and wood vinegar can be made from various biomass materials/residues such as wood waste, crop and refinery residues, animal manures, and municipal wastes. Biofertilizers also play a vital role in sustainable agriculture systems. Mycorrhiza is one of the most important biofertilizers. Mycorrhizal associations help plants obtain water and nutrients in dry and nutrient-poor conditions by increasing the root surface area for water and nutrient uptake. Castor bean (Ricinus commonis L.) is a valuable annual herb belonging to the Euphorbiaceae family. It is an important oilseed crop widely used in industry and medicine today. Numerous studies have underlined the beneficial effects of organic fertilizers on soil fertility and crop yield. However, no study has evaluated the impact of organic fertilizer, biochar, wood vinegar, and mycorrhiza on Ricinus commonis L. This research aims to discover the main effects and interactions of these treatments on the quantitative and qualitative traits of Ricinus commonis L.
Materials and Methods: The field experiment was conducted at the Research Field at the University of Kurdistan (35° 19' N, 47° 18' E) during 2022 growing season. The research was designed as a factorial experiment using a randomized complete block design with three replications. Treatment included five fertilizer types: control, organic fertilizer (800 kg ha-1), biochar (3000 kg ha-1), wood vinegar (90 kg ha-1) and chemical fertilizer (urea 200 kg ha-1, and TSP 100 kg ha-1). Additionally, two mycorrhiza levels (Rhizophagus irregularis) were tested: no-inoculation and inoculation. Each experimental plot consisted of six rows, each 6 meters long and spaced 75 cm apart. The seeds were sown on 10 May 2020. Agronomic traits such as plant height, number of capsules per plant, and 1000-seed weight were randomly measured from five plants at full maturity in each plot. In the center rows of each plot, 2.25 m2 of area was harvested at the end of each growing season to evaluate biological and seed yield. Other studied traits included harvest index, seed oil content, seed oil yield, and the nitrogen, phosphorous, and potassium concentration of the seeds.
Results and Discussion: The results showed that the effect of mycorrhiza inoculation on the plant height, capsules number per plant, seed number per plant, and 1000-seed weight was significant. Furthermore, the fertilizer impact on the mentioned traits except of 1000-seed weight was significant. Organic fertilizer, biochar, wood vinegar, and chemical fertilizer significantly increased the capsules number per plant. The highest number of capsules per plant and seed number per plant belonged to the organic fertilizer. Mycorrhiza inoculation enhanced the seed number per plant and 1000-seed weight by 16% and 23% compared to control, respectively. the interaction effects of different fertilizers and mycorrhiza inoculation improved the quantitative and qualitative traits of castor bean. The highest biological yield (3650.2 g/m2), seed oil content (50.5 %), and oil yield (588.3 g/m2) were observed in the integrated treatment of organic fertilizer and mycorrhiza inoculation. This treatment increased seed and biological yield by 36.5% and 24% compared to control, respectively. Mycorrhiza can enhance plant growth and yield by increasing the supply of phosphorus to the host plant. Mycorrhizal plants can absorb and accumulate several times more phosphate from the soil or solution than non-mycorrhizal plants. Organic fertilizer and biochar positively affected the morphological characteristics. Biochar reduces water consumption and improves soil properties under drought conditions. Compared to other amendment materials, biochar has the benefit of a large surface area and pore spaces, allowing it to absorb and retain water. The highest seed nitrogen and potassium content was observed in the organic fertilizer treatment. Organic fertilizers may promote root development by retaining more water and nutrients in the soil, secreting more plant hormones, and increasing the amount of inorganic material such as nitrogen, phosphorus, and potassium that plants can absorb.
Conclusion: Therefore, it can be said that the integrated application of organic and biofertilizers not only improve the quantitative and qualitative traits of Ricinus commonis L. but also could be a key strategy in sustainable agricultural systems by reducing the consumption of chemical fertilizers.
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