Spectral Reflectance of Tall Fescue (Festuca Arundinacea Schreb.) Under Different Irrigation and Nitrogen Conditions

The issue of water and climate change is present in many countries. Drought stress is one of the main abiotic stresses influencing turfgrass growth and quality. Tall fescue is the most suitable cool-season turfgrass for the Mediterranean region. This species has a better heat tolerance than perennial ryegrass and Kentucky bluegrass. The analysis of radiation reflected by turfgrass can supply precious information on drought stress and nutritional status. In this study a Linear Gradient Irrigation System (LGIS) was adopted on a Festuca arundinacea turf with 9 water replenishment levels and 2 nitrogen conditions, to evaluate the proximity sensed spectral reflectance. ET0 was estimated using the Hargreaves and Samani method. The following parameters were determined: turf quality, drought tolerance, pest problems, temperature of the surface, clippings weight and relative nitrogen content, turf growth and soil moisture. Spectral reflectance data were acquired using a LICOR 1800 spectroradiometer. Pearson correlation coefficients were studied among all parameters and vegetation indices. Nitrogen fertilization influenced significantly turf quality, clippings weight, nitrogen content and turf growth. Water replenishment influenced significantly all parameters except nitrogen content. Among all parameters the highest correlation coefficient was registered relating drought tolerance with turf quality (r = 0.88) and with surface temperature (r = - 0.88). Among vegetation indices results showed that Water Index (WI) and Normalized Difference Water Index (NDWI), are the most suitable to discriminate between different levels of water replenishment. Comparing WI with NDWI, the correlation coefficients were higher for Water Index in all the parameters, in particular the highest WI value was registered for drought tolerance (r = 0.91). This preliminary research demonstrates that spectral remote sensing can be a useful diagnostic tool to detect water stress in turfgrasses

The effect of increasing application rates of nine plant growth regulators on the turf and Stolon characteristics of pot-grown ‘patriot’ hybrid bermudagrass

Vegetatively propagated warm-season turfgrasses are established with methods that rely on large quantities of propagation material and subsequent plant growth support. The precision seeding adopted for some seed propagated crops controls the depth and spacing at which seeds are placed in the soil. Sprigs that are reduced in length could potentially be suitable for existing machinery, and precision planting could enhance the efficiency of use of the propagation material. The aim of the present study was to carry out a preliminary screening on products known to act as plant growth regulators to explore their potential use for controlling stolon development and elongation of ‘Patriot’ hybrid bermudagrass (Cynodon dactylon x C. transvaalensis) grown in pots for propagation purposes. Trinexapac-ethyl (TE), chlormequat chloride (CM), paclobutrazol (PB), propiconazole (PPC), diquat (DQ), flazasulfuron (FS), glyphosate (GP), ethephon (EP), and gibberellic acid (GA) were applied to pot-grown ‘Patriot’ hybrid bermudagrass turf in eight different application rates, ranging for each product from the minimum expected effective rate to a potentially harmful rate. Of the tested treatments, TE applied at 2.0 kg·ha-1 and PB applied at 1.0 kg· ha-1 reduced stolon and internode length without causing a reduction in the stolon number or turf quality. PPC was also effective in reducing stolon length, but the effect on internode length was not statistically significant. Stolon length was unaffected by CM, while DQ and GP induced stolon elongation. FS, EP, and GA affected stolon length without a consistent relation between stolon length and application rate. The chemical suppression of stolon elongation in pot-grown ‘Patriot’ hybrid bermudagrass can contribute to controlling sprig size for use with precision seeding machinery