Effects of different fertilizers on some soil enzymes activity and chlorophyll contents of two cotton (G. hirsutum L.) varieties grown in a saline and non-saline soil

Abstract

Cotton plant has two physiological development periods which are vegetative and generative periods. The activities of urease, dehydrogenase, glucosidase and alkaline phosphatase enzymes in the soil continue during the growth of plants. In this study, three different fertilizer sources (diammonium phosphate (DAP), vermicompost and manure) and two cotton varieties (Candia and Lima) were used in non-saline and saline soil conditions. The experimental layout was randomized plots with 3 replications. Total chlorophyll content of Candia and Lima cotton (Gossypium hirsutum L.) cultivars and urease, dehydrogenase, glucosidase and alkaline phosphate enzyme activities of the soil were determined. The chlorophyll content of cotton plants was significantly (p < 0.01) different in fertilizer treatments applied in non-saline and saline soils. The lowest chlorophyll value (17.83) in non-saline soil was obtained in the control, while the highest chlorophyll value (32.64) was recorded in the DAP fertilizer treatments. The lowest chlorophyll value (20.33) in saline soil was obtained from DAP fertilizer, while the highest chlorophyll value (24.11) was obtained in the vermicompost application. The fertilizer treatment significantly affected the urease activity in non-saline (p < 0.01) and saline (p < 0.05) soils. The highest mean urease enzyme activity in non-saline (102.74 µg N g−1 dry soil h−1) and saline (120.23 µg N g−1 dry soil h−1) soils was obtained in the DAP treatments. The highest mean dehydrogenase enzyme activity in non-saline (35.99 µg TPF g−1 dry soil 24 h−1) and saline (48.63 µg TPF g−1 dry soil 24 h−1) soils was obtained in cattle manure application. The difference between fertilizer applications was significant at p < 0.01 level in both soils.