Sand, rockwool, perlite and newly developed urethane-foam have been used as growth media to grow turfgrass (Agrostis stolonifera L. cv. Pencross) sod. Series of tests were conducted to study turfgrass seedlings growth and mechanical characteristics of the sods on the four growth media. The results showed that urethane-foam growth media had an equivalent water holding property of perlite which is much higher than that of sand, and also a better water permeability than those of sand and perlite. There was no significant difference at p<0.05 in fresh and dried shoot weight among the four growth media. The turfgrass seedings grew more dense and green in color on urethane-foam than on the others. As expected, the tensile and shearing strength of the turfgrass sod for urethane-foam had the highest value among the four growth media.
The results suggest that the urethane-foam can be used as a better growth media for turfgrass sod. And urethane-foam turfgrass sod would contribute to the handling in the process from the sod harvest to the sod transplant due to its superior mechanical flexibility.

View full abstract

This study was conducted to evaluate desorption of simazine, pendimethalin and Asulam deposited on green foliage, dead foliage and thatch of Zoysia matrella and soil. These herbicides were applied on foliage of the turfgrass in growing season and on the dead leaves in early spring season and the herbicides were also applied on thatch and soil. Desorption of herbicides was carried out by rinsing with 0.01 M of CaCl₂ on a reciprocal shaker at 120 rpm for 24 hr. These procedure were carried out 10 times 3 days after treatment.
Desorption of the herbicides deposited on foliage, thatch and soil was very varied with their physico-chemical properties. Simazin which has water solubility of 5 mg/L was readily desorbed. Pendimethalin which has very low solubility (0.3 mg/L) was little desorbed. But, asulam, as it has high solubility (5000 mg/L), was desorbed very rapidly and in large quantity.

View full abstract

We conducted greenhouse experiments to investigate the herbicidal activities of pyrazosulfuron-ethyl, flazasulfuron and imazaquin against Cyperus brevifolius var. leiolepis and side effects of these herbicides on Zoysia matrella growth. The results are summarized as follows.
1. Herbicidal activity ; Three herbicides effectively controlled C. brevifolius var. leiolepis, in the order of pyrazosulfuron-ethyl>flazasulfuron>imazaquin. Herbicidal activity of imazaquin was not affected by cutting the grass nor application time after the cutting, while, pyrazosulfuron-ethyl and flazasulfuron provided the highest activity when applied just after cutting.
2. Effects on the Zoysia matrella growth; Excessive application of pyrazosulfuron-ethyl, flazasulfuron and imazaquin at the dosage of 100, 100 and 300 g a.i./10 a, respectively, did not inhibit the growth of Zoysia matrella, while the latter two suppressed the growth of shoot and root, when the top dressing soil was thick or they were applied immediately after cutting of the turf.
These result suggest that pyrazosulfuronethyl, flazasulfuron and imazaquin applications after cutting of the weed offer an effective control of C. brevifolius var. leiolepis. However, to prevent injury of Zoysia turf, attention should be paired for the latter two when the top dressing soil is thick and/or larger dosages are applied just after cutting of the turfgrass.

View full abstract

Three lines of Japanese lawn grass, No.1, No.17 and No.35 were collected from different places in Japan and preserved by the Grassland Development Lab.. These were planted in Wagner pots and grown in green houses (25/20°C, day/night) as materials for an experiment. Line No.1 was collected in Nagasakibana, Kagoshima, line No.17 in Sugadaira, Nagano and line No.35 in Oono, Hokkaido.
These plants were grown for a week (Nov. 6-Nov.13, 1990) at 20/15°C, day/night, in order to acclimatize the plants to low temperatures. Then, the plants were divided into three groups and grown for two weeks (Nov.14-Nov.29 ) under three different conditions, i.e. control (20/15°C, day/night), low temperature (15/10°C, day/night) and, low temperature and long day (15 /10 °C, day /night, with an aditional illumination of 2.5 hours) .
We picked five 2nd-leaves and measured their photosynthetic rate 29 using portable photosynthetic measurement (SPB-1 type, ADC Co.) .
The leaf-colour differences of 2nd-cut leaves were also measured on Nov.6 and 29 using colour and colour difference meter (ND-101D, Nihon Denshoku) .
The results obtained were as follows.
1) The leaf photosynthetic ability of control treatment was maintained for most of the experimental period in all lines.
The leaf photosynthetic abilities of No.17 and No.35, wich were exposed to low temperature treatment and low temperature with long day treatment decreased rapidly after each treatments. However, the photosynthetic abilities of line No.1 remained for the first two weeks and then decreased.
These results reveal that the decrease in photosynthetic ability during the period preceding dormancy is caused by drop in air temperatures and not by leaf-aging or photoperiodic response accompanied with short day.
It is also shwn that the photosynthetic ability of Japanese lawn grass grown in high latitudes is more sensitive to low temperatures than the photosynthetic ability ability of grass grown in low latitudes.
2) The leaf-colour of Japanese lawn grass changed from yellow-green to orange, and the change of a^*was larger than L^*or b^*, during the experiment. It is clear that these colour-change and colour differences were caused by low temperatures, and these phenomena were closely connected with the change in photosynthetic ability.

View full abstract

In model plots of turf and bare soil grounds with a 15 degree inclination, simulated rainfall of 80 mm was applied for 60 minutes at 6, 24 and 72 hours after application of herbicides (simazine, pendimethalin and asu-lam ), and runoff water and soil sediments including herbicides were collected. A significant soil erosion occurred in the bare ground plots, while no erosion was observed for the turfgrass plots. The amount of surface runoff water was higher in the bare ground plots than in the turfgrass plots where it greatly reduced when the mowing height was increased from 2 cm to 5 cm. In the bare ground plots, simazine was washed out with both soil sediments and runoff water, whereas pendimethalin was moved mainly with soil sediments. In contrast, larger amount of asulam was found in runoff water than in soil sediments. In all the turfgrass plots, the extent of herbicide runoff was less than in the bare ground plots, being least in the plots of 5 cm mowing height. The amount of the herbicides in runoff was high when the simulated rainfall applied shortly after application and then it declined with time.
In the turf and bare soil ground plots with a 33 degree inclination, simazine, commercially formulated as flowable or as wettable-powder, was applied at spray volume of 200 L /10a or 400 L/10a, and the herbicide runoff after simulated rainfall of 40 mm /h was examined. The total amount of simazine in the runoff water and in the soil sediments was affected significantly neither by spray volume nor by formulation types.

View full abstract