EFFECT OF FOLIAR APPLICATIONS OF HUMIC ACID ON GROWTH, VISUAL QUALITY, NUTRIENTS CONTENT AND ROOT PARAMETERS OF PERENNIAL RYEGRASS (LOLIUM PERENNE L.)

In recent years, applying humic acid (HA) has been common in turfgrass management. A series of experiments were conducted to evaluate the effect of HA on qualitative and quantitative characteristics of Speedygreen perennial ryegrass (Lolium perenne L.). Different concentrations of HA (0, 100, 400, and 1000 mg L-1) were applied monthly as foliar application. Results showed that leaf phosphorus (P), potassium (K), and zinc (Zn) content, fresh and dry weight, chlorophyll content, and root fresh weights were not affected by HA. Meanwhile, HA improved the root and shoot development, except for root fresh weight. While just 100 mg L-1 improved height, visual quality, nitrogen (N) content, roots length, and surface of roots, all of HA concentrations were effective on iron content. These results suggest that HA foliar application might be of benefit to enhance some nutrients uptake and root development of ryegrass possibly leading to improved drought resistance.