Investigation of the effects of treated organic fertilizers on sandy-lime soil biological properties and plant growth during cultivation of melo (Cucumis melo L.) and watermelon (Citrullus lanatus Thunb.)

This study investigates the effects of different types of organic fertilizers (goat manure-U1, cow manure-U5, chicken manure-U4, and vermicompost-U2) on the biological properties of sandy-calcareous soil and the growth of melon (Cucumis melo L.) and watermelon (Citrullus lanatus Thunb.). Additionally, the study aims to determine how the optimal organic fertilizer doses recommended by organic fertilizer producers for plant growth impact dynamic soil quality. In this context, these fertilizers were compared in terms of their effects on soil microbial activity, chemical parameters, and plant growth parameters. Based on the results obtained from statistical analysis, the effects of the applied fertilizers on soil biological properties were evaluated. According to these results, an increase in soil urease activity (melon: U4, watermelon: U5), alkaline phosphatase activity (melon: U2), β-glucosidase activity (melon: U2), dehydrogenase activity (melon: U5), arylsulfatase activity (melon: U4, watermelon: U4), and bacterial count (melon: U1, watermelon: U1) was seen. When the effects of the applications on soil chemical properties were examined, it was determined that soil EC (melon: U5, watermelon: U4) and available P (melon: U4) values varied with organic fertilization. Regarding plant growth parameters, it was found that stem diameter (melon: U4, watermelon: U1, U4) and fruit weight (melon: U1, watermelon: U4) were positively influenced by organic fertilization. The biological properties of the soil cultivated with melon and watermelon were compared, and it was seen that urease activity in the soils with watermelon cultivation was 40% higher and dehydrogenase activity was 46% higher. On the other hand, arylsulfatase activity in the melon soil was determined to be 17% higher than that in the watermelon soil. Comparing the soil chemical properties, the EC value of the melon soil was 18% higher, and the available P value was 20% higher than those of the watermelon soil. In terms of plant growth parameters, the chlorophyll content of the melon plant was measured to be 20% higher, whereas the stem diameter of the watermelon plant was 40% greater, the fruit flesh thickness was 40% greater, and the water-soluble dry matter content was 100% higher compared to the melon plant. In conclusion, in the area cultivated with watermelon, vermicompost, chicken, and cattle manure stood out in terms of soil biological parameters; chicken and cattle manure were prominent in terms of soil chemical parameters; and vermicompost and chicken manure were superior regarding plant parameters. In the area cultivated with melons, vermicompost and chicken manure were significant for soil biological parameters, cattle manure for soil chemical parameters, and goat, chicken, and cattle manure for plant parameters. Overall, it was concluded that using vermicompost, chicken, and cattle manure would be more beneficial for improving soil properties, while chicken manure would be more advantageous for plant growth.