A primary concern in managing warm‐season turfgrasses within the transition zone is the lengthy dormant period, during which these swards lack green color. The objectives of this study were to determine the effects of three N fertilization schedules on spring green‐up and fall color retention of bermudagrass [Cynodon dactylon (L.) Pers.] and seashore paspalum (Paspalum vaginatum Sw.). A field trial was performed at the agricultural experimental farm of Padova University (northeastern Italy). Bermudagrass cultivars Princess‐77, Riviera, SWI 1014, and Yukon and seashore paspalum ‘Sea Spray’ were compared under three N fertilization schedules: (i) 6.7 g N m−2 on 15 May, 15 June, and 15 August, (ii) 5 g N m−2 on 15 May, 15 June, 15 August, and 15 October, and (iii) 4 g N m−2 on 15 May, 15 June, 15 August, 15 September, and 15 October. Spring green‐up was estimated weekly as a percent green turfgrass coverage from 15 March to 15 June of 2010 and 2011. Fall color retention was visually rated from September to November of 2010 and 2011. Sea Spray seashore paspalum had later spring green‐up and better fall color than the bermudagrass cultivars, which differed widely in terms of spring green‐up and fall color retention. Fall‐applied N enhanced green‐up of all the grasses tested and extended fall color retention of bermudagrass cultivars. This study revealed that protracting applications of N fertilizer until late season may improve quality performance of warm‐season grasses without increasing annual N applied.

In the transition zone, a primary concern in managing warm‐season turfgrasses is turf survival under low temperatures. The objectives of this study were to determine the effects of three N fertilization schedules on stolon carbohydrates and crude protein (CP) reserves of four bermudagrasses [Cynodon dactylon (L.) Pers.] and a seashore paspalum (Paspalum vaginatum Sw.). A field trial was performed at the agricultural experimental farm of Padova University (northeastern Italy). Bermudagrass cultivars Princess‐77, Riviera, SWI 1014, and Yukon and seashore paspalum ‘Sea Spray’ were compared under three N fertilization schedules: (i) 6.7 g N m–2 on 15 May, 15 June, and 15 August, (ii) 5 g N m–2 on 15 May, 15 June, 15 August, and 15 October, and (iii) 4 g N m–2 on 15 May, 15 June, 15 August, 15 September, and 15 October. Turf samples measuring 20 by 20 by 4 (depth) cm were collected monthly from September to April 2009 to 2010 and 2010 to 2011. The stolons were separated from the remainder of the samples and starch, water‐soluble carbohydrates (WSC), and CP were determined on a dry matter basis. The bermudagrass cultivar Riviera was characterized by high stolon density and showed highest carbohydrates (starch and WSC) content along with Yukon. Late‐season applications of N had limited influence on carbohydrates content but increased the concentrations of CP from November through April.

Fertilization strategies for high‐yielding alfalfa (Medicago sativa L.) should take in account the increase in soil nutritional status that occurred during the last decades in areas with intensive agricultural use. A field study was conducted at the University of Padova, northeastern Italy, to determine the response of alfalfa yield and nutritive value to various combinations of P and K rates in a soil lacking nutrient deficiency. Alfalfa cultivar Delta was seeded in March 2005 on a silt loam soil having 38 mg kg–1 available P and 178 mg kg–1 exchangeable K. Nine treatments deriving from the combination of three P fertilization rates (0, 100, and 200 kg ha–1 P2O5) and three K rates (0, 300, and 600 kg ha–1 K2O) were compared in a randomized complete block design. Plots were harvested at bud stage during three growing seasons (2005–2007) and dry matter (DM) yield, forage nutritive value, P and K contents, canopy height, and stem density were measured at each harvest. Soil samples were collected at the end of the research period for determination of available P and exchangeable K. The results demonstrated that P application had no impact on yield and did not interact with K in determining productivity, while K had a positive effect on yield. However, the 300 kg ha–1 K2O rate appeared sufficient to maximize yield, without adverse effects on the forage nutritive value. Data from soil analyses showed that alfalfa has a high K uptake even when it is fertilized at high rates.

Alfalfa (Medicago sativa L.) is the most important hay crop used in the dairy industry of the Po Valley, Italy, characterized by a subtropical climate with hot, humid summers and cool winters. Information is lacking as to selecting fall dormancy (FD) varieties adapted to the region and their response to intense harvest regimes. A 3-yr study was conducted to investigate the effect of two harvest regimes based on phenological stage (early bud and early flower) and three FD categories on productivity, canopy height, and leaf to stem proportion. Cultivars with FD ratings of 7.5 (less nondormant), 8.5 (nondormant), and 10.5 (very nondormant) were seeded in April 2005 at the experimental farm of Padova University in Legnaro, Italy. The experimental design was a randomized complete block in a split-plot arrangement. Canopy height and dry matter (DM) yield were measured at each harvest. Subsamples were collected to determine leaf area index (LAI), stem silhouette area index (SAI), and leaf dry matter to stem dry matter ratios (LSR). Nondormant cultivars had higher DM yield (18.2 Mg ha−1) than less nondormant (17.1 Mg ha−1) and very nondormant cultivars (16.9 Mg ha−1). Harvesting at early bud decreased DM yield by 11% compared to early flower. The FD categories had no effect on LAI/SAI and LSR ratios, however harvesting at early bud increased both ratios by 12.0 to 12.5%. Producers in subtropical climates may obtain alfalfa hay with a high portion of leaves at a reasonable yield from the three tested FD categories by cutting alfalfa at early bud stage

In transitional environments, turf managers and sod producers of warm-season grasses face the issue of winter annual weeds that can dominate dormant turf stands through the winter until late spring. The use of glyphosate to control weeds in dormant bermudagrass (Cynodon dactylon) has been well documented, but information is lacking about its effect on spring green-up of other warm-season grasses. A field study was conducted on two commercial sod farms in northern Italy (Expt. 1) to evaluate the effects of glyphosate applied on two different winter dates on weed control and spring green-up of ‘Zeon’ manilagrass (Zoysia matrella). A second study was carried out at the experimental agricultural farm of Padova University (Expt. 2) to assess the effects of a winter application of glyphosate on weed control and spring green-up of ‘Yukon’ bermudagrass and ‘Companion’ zoysiagrass (Zoysia japonica). Each experiment was conducted from Jan. to June 2011, and glyphosate was applied at 1.1 kg·ha−1 on 8 and 21 Feb. in Expt. 1 and on 8 Feb. in Expt. 2. Spring recovery was evaluated by periodical visual ratings of green turf cover and by collecting normalized difference vegetation indices (NDVIs). Weed injury was visually evaluated on all plots 7 weeks after the 8 Feb. glyphosate application. The visual ratings of green cover were strongly and positively correlated with NDVI measurements. Glyphosate applied in February as a single treatment effectively controlled winter weeds in ‘Zeon’ manilagrass (Expt. 1) and ‘Yukon’ bermudagrass (Expt. 2) without negatively affecting spring green-up. In contrast, spring green-up of ‘Companion’ zoysiagrass (Expt. 2) was delayed by the application of glyphosate.