Comparison of effects of pulping black liquor and inorganic fertilizer application on the cold resistance of Poa pratensis

The physiological and biochemical indexes and apparent quality of leaves were tracedetermined in autumn to compare the effects of pulping black liquor and inorganic fertilizer application on the cold resistance of Poa pratensis. The results of this study showed that the pulping black liquor and inorganic fertilizer enhanced the cold hardening effect of P. pratensis to some degrees. The inorganic fertilizer increased the accumulation of free proline with a maximum concentration of 868.95 g/g, while the pulping black liquor increased the activity of superoxide dismutase (SOD) with 201.16 U/g and the content of soluble sugar (WSS) with 137.15 g/g. The inorganic fertilizer prolonged the turf green period for about 10 days, while the pulping black liquor did it for about 40 days. The pulping black liquor enhanced the cold resistance of P. pratensis more effectively and maintained a higher apparent quality.