A test turf-green (Pencross bentgrass) was set up on the sand dunes of suburban Niigata during 1990-1991. Experiments were made to determine the relationship between the quantities of underdrainage and the released contents of agricultural chemicals by rain water or overhead irrigation. The chemicals used were; acephate, flutoluanil, chloroneb, isoxathion, chlorothalonil, isoprothiolane, trichlorofon, metalaxyl, isofenphos, thiram and tolclophosmethyl. The results were as follows ;
1. The amount of drained water in 1991 depended on the amount of precipitation in each month rather than sprinkler irrigation. The quantity of under-drained water by precipitation did not show much difference between 1990 and 1991.
2. The chronological changes of agricultural chemicals in the drained water through the Test-Green sward were tested using acephate, flutoluanil and chloroneb. The amount of flutoluanil increased in the drained water in 1991 rather than in 1990. The other chemicals, acephate and chloroneb were also detected in the drained water in 1990. Although acephate was recovered at a higher level than other chemicals and acephate and chloroneb were not detected in the drained water in 1991.
3. The additional agricultural chemicals used in 1991 were isoxation, chlorothalonil, isoprothiolane, trichlorofon, metalaxyl, isofenphos, thiram and tolclophosmethyl. The recovery was highest in trichlorfon, followed by metalaxyl and isoprothiolane. Other chemi-cals were detected in small amount or not detected.

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Insecticidal activities of an insect growth regulator, tefurubenzuron against the important turfgrass insects, the japanese lawn grass cutworm (LGC), Spodoptera depravata, the bluegrass webworm (BWW), Parapediasia teterrella, the oriental beetle (OB), Blitopertha orientalisand the cupreous chafer (CC), Anomala cuprea, were evaluated by laboratory and field tests.
(1) Laboratory tests
Tefurubenzuron showed high insecticidal activity against larvae of LGC, BWW, OB and CC. Complete death were observed by application of 25 or 50ppm (active ingreditent) of tefurubenzuron, against young or middlestage larvae of the LGC, respectively.
Mortalities of 1st or 2nd instar larvae of the BWW treated by 50ppm of tefurubenzuron were 100%.
Mortalities of 1st or 2nd instar larvae of the OB, and of 2nd instar larvae of the CC, treated by 25 or 50ppm of tefurubenzuron were 90% or much more.
According to the results of this experiments against 2nd instar larvae of the CC, feeding activity of the insects which were poisoned by sublethal dose of tefurubenzuron, were strongly suppressed.
Short-term (4 days) application of tefurubenzuron was also effective against the CC, which may indicated that tefurubenzuron are relatively stable in the insect body, and can be expected sure controlling effects against the beetles.
The speed of action of tefurubenzuron against beetle larvae is much more slow than lepidopterous larvae, and terms enough to complete the toxic action of the chemical were estimated about 15-30days.
(1) Field tests
Results of the field experiment indicated that LGG and BWW were effectively controlled by spraying of diluents, 3000-4000 times of tefurubenzuron 10% emulsifiable conscentrate, at rate of 300ml/m².
It was recognized in a test of the BWW, that the controlling effect of tefurubenzuron came out more slowly than that of an organophosphate insecticide, fenitrothion.

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Two sets of experiments in summer and winter were conducted to clarify the effect of air-pruning on turf (Agrostis stolonifearL. cv. Pencross) sod culture.
For shoot growth, there was no significant differences in germination rate, on the other hand, it was clear that conventional nusery produced a faster germination speed than air-pruning nursery. In winter, conventional nursery resulted in a better shoot growth with 1.4-2.0 times more than air-pruning, but in summer, the differences in shoot growth was not significant between two nursery methods.
For the root growth, severl advantages of air-pruning nursery, such as eliminating roottangling or root-binding, promoting properly oriented root-branching and better root growth after transplanting were demonstrated in this study.
During turf seedling culture period, the maximum root lengths for air-pruning nursery were much shorter than conventional nursery both in winter and in summer. However, the root number for one plant of air-pruning nursery was 1.4-1.6 times more than that of conventional nursery. Also root-tangling or root-binding at tray bottom were not observed.
The air-pruned seedling kept a greater root number continuously, and its maximum root length got longer than the conventional nursery seedling in six months after transplanting. This result implied that the air-pruned seedling's roots grow faster, and this point is one of the most important factors for producing turf.

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The sod-transplanter RG609 developed by KUBOTA Inc. was incorporated to this research's sod production system. After investigating the application of the sod-transplanter RG609 on conventional sods, the transplanting experiments of Urethane-foam sods by RG609 were conducted. The experimental results showed clearly several advantages of urethane-foam sod comparing to the conven-tional one.
(1) Transplantation precision has been improved.
(2) Labor strength of sod-providing operators was lowered.
(3) Labor environment was improved.
One problem that should be solved was of a sod-roll on the landing plate of the sodtransplanter. The stickness measurement's results showed that Teflon had the smallest stickiness and Stainless steel had the greatest one for the same sod, and the urethane-foam sod had greater stickiness than conventional sod for the same material. Furthermore, the date suggested that attention should be paid to the urethane-foam characteristics, when designing a sod transplanter or the other machines handling urethane-foam sod.
It can be concluded that several constructive suggestions have been obtained from this study. Thus, it could be expected that this study's results would contribute to develop a more efficient sod producing and transplanting system.

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