Disease index and EC value and the mineral nutrient concentrations of dew on creeping bentgrass (Agrostis palustris Huds.) turf cvs. CY-2 and Penncross were investigated. As a result, the number of patches of the dollar spot disease at non fungicide treated plot were larger and the rate disease area of the brown patch were higher than fungicide treated plot. The patch numbers of the dollar spot disease in cv. Penncross were larger than the number of patches in cv. CY-2. EC value in dew adhering to the leaf surface of the non fungicide treated plot showed the tendency to be higher than EC value in the fungicide treated plot. EC value of cv. CY-2 tended to be lower than EC value of cv. Penncross. K, Ca, and Mg concentration in dew adhering to the turf surface of the non fungicide treated plot were all higher than the fungicide treated plot, and their concentration in dew from cv. Penncross were higher than the values of cv. CY-2. From these analysis results, concentration of K, Ca, and Mg leaching to adhering dew on the turf surface of the creeping bentgrass differ among cultivars. Moreover, it was suggested that the leaching increases in connection with the damage of stem and leaf by diseases occurrence.
The additional effects of matrix modifiers on the measurement of the mineral elements in late fall dew on two creeping bentgrass cultivars by atomic spectrometry method were observed. The calcium carbonate as matrix modifier for the determination of potassium (K) showed higher values than without modifier. The lanthanum chloride as matrix modifiers for the determination of calcium (Ca) showed significantly higher values than without modifier. The lanthanum chloride as matrix modifiers for the determination of magnesium (Mg) showed no effects on them. However, all of mineral concentration in the dew water of Penncross was higher than CY-2. The co-relationship between electric conductibility values (EC) and all mineral concentration values with matrix modifiers showed significantly high.
This study was comparison between architecture models with turf roofs covered by Manilagrass (Zoysia matrella Merr.) and Kentucky Bluegrass (Poa pratensis L.) and simulation model with slab roof. The experiment was carried out in a natural winter environment and environmental control room, under the conditions of fixed time and fixed temperature. As a result, in the slab roof, temperature rose in comparison with Manilagrass and Kentucky Bluegrass during the day and under the condition of heating, but temperature fell at night and under the condition of stop heating. Compared with this result, turf roofs stored heat and had an advantage which suppress the temperature fall at night. Therefore, it is clear that turf roofs were hardly changing of temperature.
In order to clarify the mechanism of the adaptability of Poa annua L. to putting greens where mowing stress are imposed remarkably with frequent and very low clipping, two populations of the weed derived from a putting green (PG) and an orchard (OR) were compared in terms of energy allocation to seed production. The results obtained from the present study were summarized as follows. When energy allocation to seed production were estimated as NSD [ (total number of seed/plant) / (dry weight of shoot) ] and WSD [ (total weight of seed/plant) / (dry weight of shoot) ], both NSD and WSD values of PG exceeded those of OR at 30 days after heading. However, no significant difference in NSD and WSD between PG and OR were observed at 60 days after heading, and contrary to above results, PG exceeded OR in NSD and WSD at 90 days after heading. These results indicate that although PG is slightly below to OR in the energy allocation at relatively early periods after heading, PG exceeds OR at late periods after heading; showing that an adaptability of Poa annua L. to a putting green partly depends on a high energy allocation to seed production.