Effects of ground temperature regulation on dynamic changes in turf nutrients under high-temperature stress conditions

To study the effects of ground temperature regulation on the dynamic changes in lawn nutrients under high-temperature stress conditions, we used bentgrass and the natural environment as the test material and control, respectively. The soil temperature was controlled at 27, 24, and 21 ℃ at 20 cm underground as treatments to study their effects on turfgrass nutrient absorption, turf soil nutrient dynamic changes, and soil microbial and enzyme activities. The results indicated that cooling promoted the growth of bentgrass and increased the lawn biomass. Nitrogen and phosphorus uptake by turfgrass significantly increased, and the increasing effect was strongest at 21 ℃, with the aboveground and underground biomass being increased by 44.3% and 220.7%, respectively, compared with that in the control. Nitrogen and phosphorus uptake in the underground part increased by 147.9% and 179.3%, respectively. The content of mineral nitrogen in soil decreased, and the highest decrease in the 10－20 cm soil layer was 48.45% at 24 ℃. The content of available P in soil increased, and the highest increase was 82.5% in the 0－10 cm soil layer at 21 ℃. The soil microbial biomass carbon content increased first and then decreased with an increase in the cooling range, whereas the soil microbial biomass nitrogen content decreased first and then increased in the 10－20 cm soil layer. The activities of enzymes related to soil C, N, and P cycles were generally affected by cooling treatment. In conclusion, soil temperature regulation in summer promotes the growth of bentgrass and uptake of nutrients in the soil by turfgrass, affects the activities of enzymes related to soil C, N, and P cycles, and changes the availability of corresponding nutrients. In addition, it is suggested to serve as a supplement to nitrogen fertilizer after cooling in summer.