The effects of different organic fertilizer applications on plant growth, yield, quality properties and nutrient content in spinach (Spinacia oleracea L.)

This study was conducted to determine the effects of different organic fertilizer applications on plant growth, yield, quality properties and nutrient content in spinach grown in ecological conditions of Bolu province. The research was carried out in the open field during the autumn growing season of 2017 and Matador spinach variety was used. Seven different applications were examined in the study. The applications was as follows: 1) Control, 2) Chicken manure, 3) Turkey manure, 4) Sheep manure, 5) Cattle manure, 6) Vermicompost and 7) Chemical fertilizer. The study was established in randomized complete block design with 3 replications. In the study, 26 properties related to plant growth, yield, quality and 24 elements were examined. According to the research findings, significant differences were found among the applications. The plant height, plant wet weight, number of marketable leaves, chlorophyll content, nitrate content, nitrogen content, phosphorus content and potassium content in spinach used different fertilizer applications ranged from 9.66 to 11.18 cm, 8.88 to 11.07 g, 7.81 to 8.57, 54.71 to 68.93 spad, 518.71 to 1182.62 mg/kg, 3.43 to 5.91%, 489.26 to 518.82 mg/kg and 20724.30 to 25066.64 mg/kg, respectively. Compared with control and chemical fertilizer, the higher values in terms of plant height, plant wet weight, plant dry weight, number of marketable leaves, dry matter content and yield were obtained from all organic fertilizer applications. The highest yield was determined in cattle manure. It was observed that cattle manure increased the yield by 88.08% compared to the control and increased the yield by 41.16% compared to the chemical fertilizer. In general, organic fertilizer applications significantly increased the nitrogen, phosphorus, sulphur and selenium content of the plant compared to control and chemical fertilizer. In the plants which organic fertilizers were applied the contents of heavy metals such as arsenic, cobalt, chromium and nickel were lower than the control and contents of aluminum and cadmium were lower than chemical fertilizer. All fertilizer applications increased nitrate content in the plant. Organic fertilizer applications did not have a significant effect on the color properties of spinach. As a result of the study, it was determined that organic fertilizers examined have positive effects on plant growth, yield, quality properties and nutrient content in spinach and organic fertilizers can be used successfully in spinach cultivation.