Effect of mixed application of growth regulators and fertilizers on the growth, cold-resistance and physiology of turfgrass Zoysia matrella in wintering period

In addressing the problem of warm-season turfgrass withering during winter, the turfgrass species Zoysia matrella was treated with growth regulators, fast-released fertilizers and organic fertilizers in L₉(3⁴ orthogonal test. Compared with the control, leaf LAI, chlorophyll, free proline and soluble sugar of the treatments significantly improve. Also, the activities of root and of antioxidant enzymes of SOD, POD and CAT improve, whereas malondialdehyde (MDA) content decreases significantly. Hence the growth, cold-resistance ability and landscape quality of turfgrass during winter under the treatments are significantly enhanced. Range analysis indicates that the effective factors vary with different test indexes, implying that plant growth regulators and fertilizers are complementary in promoting growth and enhancing physiological functions of turfgrass in winter. For an improved integrated quality of Z. matrella turfgrass in winter, an optimum formula is proposed based on comprehensive analysis of the growth and cold-resistance stress indexes. The proposed optimum formula is: liquid fertilizer, containing paclobutrazol, triacontanol, sulphate-potassium magnesium, urea and chitosan at 300 mg·L^-1, 2 mg·L^-1, 1 500 mg·L^-1, 1 000 mg·L^-1 and 1 000 mg·L^-1 respectively. This should be applied to the turfgrass by foliage spray at 200 mL·m^-2, and then peanut cake broadcasted at 90 g·m^-2.