Studies on the plant growth regulatory effect of pyroligneous acid to turfgrasses Part 2: a case study on the effect of continuous treatment of pyroligneous acid on the growth of manilagrass (Zoysia matrella Merr.) in a field test

摘要

The effects of the continuous treatment of pyroligneous acid (PA) on the growth of manilagrass (Zoysia matrella Merr) were evaluated in a field test.1. The monthly application of PA at 0.1～5 #iota#/#alpha# for three years (36 times)from 1994 to 1997 dose-dependently increased the cumulative top fresh weight of manilagrass. Especially, marked promotive effects were observed at 1 and 5 #iota#/#alpha#.2. The increases in the root weight were observed in the surveys on 12, 24 and 36 months after the first application of PA. A. marked effect on the root growth was observed at 0.5 #iota#/#alpha#.3. The continuous application of PA induced no significant change in the soil pH of the turf, indicating that the modes of growth promotive effects of PA on manilagrass are independent of its effect on soil pH. 4. after the last application of PA, its residual effect on top growth was observed for 8～9 months at 0.1 #iota#/#alpha#, 16～20 months at 0.5 #iota#/#alpha#, 20～22 months at 1 #iota# / #alpha# and more than 23 months at 5 #iota#/#alpha#. In the survey on 13 months affter the last application, a promotive effect on root growth was also observed in every plot treated with PA.5. These results indicate that the monthly application of PA at 0.5～1 #iota#/#alpha# diluted in 50 #iota#/#alpha#of water, which is a standard applicable to turf management, exhibits beneficial and long-lasting effects on the top and root growth of manilagrass.