Yield, Leaf Growth, and Tillering in Bahiagrass by N Rate and Season1

If tiller numbers/area of Pensacola bahiagrass (Paspalum notatum, Flugge) could be correlated with yield and tillers/area is related to N fertility status, fertility and yield research would be simplified. To test the concept that a yield predictive model could be developed, an established Pensacola bahiagrass sod was fertilized with 0, 84, 168, and 336 kg/ha N in 1973 and 1974. Starting in early June and continuing until October plots were clipped monthly at heights of 2.5 and 7.5 cm. Before clipping, 1.0 tillers with mature leaves/plot were collected and numbers of clipped elongated and unclipped leaves were determined. Tillers on duplicate (15 cm)2 areas were counted after clipping. Dry forage was increased over the 0 N check by adding 84 and 168 kg/ha N. The 336 kg/ha N did not increase forage yields over 168 kg/ha N. Clipping at 2.5 cm produced almost three times as much forage as clipping at 7.5 cm. Number of leaves/stolon/season averaged between 20.2 and 22.0 and was influenced by N rate. At each of the five harvest dates, an average of 1.3 leaves/tiller (growing point) was elongating. Nitrogen application increased tiller numbers by up to 300% and the largest number of new tillers occurred in June. Some data as collected were predictive of N and leaf generation rate, but variations in tiller numbers/area and probably leaf weight/N relationships prevented the development of an effective yield prediction model. Further refinement of the data is needed. Statistical models based on tillers/area were not effective in predicting yields. The lack of an effective relationship between tillers/area and yield was believed due to many young tillers dying before contributing to yield and variations in leaf size reflecting N fertilization and tiller age.