Effects of Biochar Application as a Carbon Substrate on Cotton Plant Growth and Some Soil Enzymes

Biochar is a soil amendment that can influence many biotic processes in the soil. When applied to soil with low organic matter content, it improves the physical, chemical, and biological properties of the soil, thereby enhancing soil quality. This study was conducted to examine the potential effects of different ratios of biochar applied to a calcareous soil on the growth of cotton plants and soil biology. The study comprised four treatments: a control group without biochar application and three different levels of biochar application (3%, 6%, 9%). As a result, biochar application increased the uptake of nitrogen, potassium, iron, and boron in cotton plants. It significantly increased the NDVI (Normalized Difference Vegetation Index) and SPAD values used to assess the plant's nitrogen status. By triggering an increase in the activity of nitrate reductase enzymes in the plant leaves, biochar application notably hindered nitrate accumulation, particularly in the case of the 6% biochar application. Additionally, biochar significantly increased the soil enzymes dehydrogenase and urease, contributing positively to the C and N cycles in the soil. The study results demonstrate that biochar application can enhance the uptake of plant nutrient elements from the soil and increase soil enzyme activity in cotton plants.