Search

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 P 2 O 5 ) and three K rates (0, 300, and 600 kg ha -1 K 2 O) 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 K 2 O 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.

The widespread use of warm-season turfgrasses in transition zones of Europe, such as northern Italy, has been hampered by the long dormancy periods. To encourage the conversion from cool- to warm-season grasses, research is needed to identify cultivars that exhibit early spring green-up. A 2-year study was conducted at the agricultural experimental farm of Padova University from November 2006 to October 2008 to compare water-soluble carbohydrate and protein content in stolons of four bermudagrass [Cynodon dactylon (L.) Pers.] cultivars and determine their effect on spring green-up. Samples of ‘La Paloma’, ‘NuMex Sahara’, ‘Princess 77’ and ‘Yukon’ were collected monthly, and water-soluble carbohydrates (WSC) and crude protein (CP) content of stolons were measured. Dry weight values of WSC and CP for each cultivar were regressed against days needed to reach 80 % green cover in spring (D80). ‘Yukon’ exhibited the highest rhizome dry weight and WSC content during the winter months and was the fastest to reach 80 % green cover. Conversely, ‘Princess 77’ was the slowest cultivar to green-up in both years. Regression analysis revealed a stronger relationship between D80 and WSC than between CP content and D80.

Warm season turfgrasses are increasingly used throughout the transitional areas of Mediterranean countries due to their low water requirements. A two-year field study was carried out in north-eastern Italy to evaluate the turf canopy quality and root system architecture of three seeded bermudagrass cultivars (La Paloma, Princess-77 and Yukon), and a zoysiagrass (Companion) under non-irrigated conditions. Plots (1.6×4.5 m) were established in July 2005 and arranged in a randomized complete block with three replicates. Visual quality ratings were assessed weekly from April to November in 2006 and 2007. Soil cores were collected at depths of 0–3, 3–8, 8–15, 15–25 and 25–40 cm in August 2006, January 2007, May 2007 and September 2007 to measure main rooting characteristics: root length density (RLD), root mass density (RMD) and root diameter. Companion zoysiagrass had higher canopy quality than bermudagrass cultivars in early spring and in the late growing season, while it displayed poorest quality f...

Alfalfa (Medicago sativa L.) annual yield is not strongly related to fall dormancy (FD) rating in regions with mild winters, but nutritive value might be, especially when accounting for harvest management. The objective of this study was to compare the forage quality of alfalfa having three FD ratings, all within the nondormant group, under the effect of two phenologically based harvest regimes in a humid subtropical climate. 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, northeastern Italy. Plots were harvested at early bud or early flower from 2005 to 2007 and were subsampled at each harvest for nutritive value analyses. Differences were observed between FD ratings for weighted annual average (weighted by yield) neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), crude protein (CP), ash, and ether extract (EE). For example, less nondormant cultivars had higher CP (193 g kg⁻¹) than nondormant cultivars (190 g kg⁻¹), and very nondormant cultivars (187 g kg⁻¹). Harvesting more frequently improved forage nutritive value regardless of the FD rating used. Alfalfa harvested at early flower had NDF concentrations 18 g kg⁻¹ higher than when harvested at early bud. All the chemical components studied were better correlated to the height of canopy than to the leaf to stem ratio (LSR). Results suggest that forage nutritive value was more impacted by stage of maturity than by FD rating or LSR.

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.

To have more insight into the vegetation dynamics of the mountain pastures after their abandon, two areas in the Massiccio del Grappa where abandoned and still grazed pastures have been studied. The results show that such type of pasture, when abandoned, can evolve in two different ways. If the soil is shallow, after at least 15 years, a « sward with Nardus stricta » with abundant presence of Calluna vulgaris was established. After a further 15-years period some trees appeared. Where the soil was deeper, at the beginning of the succession, Veratrum album invaded the pastures reducing the number of species of about one third. Then Vaccinium myrtillus become also very abundant. The two above species delayed the reconstruction of the climax forest.

Winter dormancy is the main impediment to a wide acceptance of warm-season turfgrasses in the Mediterranean countries of Europe due to a loss of color during the winter months. Scalping during late winter or early spring has been recommended anecdotally to enhance spring green-up of bermudagrass (Cynodon dactylon); however, information is lacking on the effectiveness of this practice. A study was conducted to investigate the effects of spring scalping on spring green-up of eight bermudagrass cultivars (Barbados, Contessa, La Paloma, Mohawk, NuMex Sahara, Princess-77, SR 9554, and Yukon) grown in a transition zone environment. The trial was carried out in Spring of 2009 and 2010 on plots established in July 2005 at the experimental farm of the University of Padova (northeastern Italy). Half of the plots for each cultivar were subjected to spring scalping, which was applied in both years on 13 Mar. with a rotary mower set at a height of 28 mm. Soil temperatures were recorded hourly during the research period at a depth of 2.5 cm. The percentage of green cover was estimated weekly from 0 to 98 days after spring scalping (DASS). Soil temperatures in scalped plots were greater than in unscalped plots. Among the cultivars tested, ‘Yukon’ showed earliest spring green-up, with no difference between the scalping treatments, reaching 80% green cover by the end of April. For all other cultivars, scalped plots reached 80% green cover 10 to 18 days earlier than unscalped plots. Results showed that scalping enhanced spring green-up, primarily for cultivars that recover slowly from winter dormancy.

Warm-season grasses are not widely accepted in Mediterranean countries because they lose color during the winter months. A study was conducted at the University of Padova (Padova, Italy) to determine whether fall and spring water-soluble carbohydrate (WSC) content in stolons of seeded bermudagrass cultivars (Cynodon dactylon) influenced spring green-up in the first year of establishment. Nine bermudagrass cultivars (La Paloma, Mohawk, NuMex Sahara, Princess 77, Riviera, SR 9554, Barbados, Contessa, and Yukon) were seeded in July 2005, and dry weight and WSC content in stolons were measured in Fall 2005 and again in Spring 2006. The percentage of green cover and days needed to achieve 80% green cover (D80) were regressed against November and March values of stolon dry weight and WSC content to determine if they were good predictors of D80. ‘Yukon’ showed earliest spring green-up by end of April, and ‘Princess 77’ and ‘Riviera’ were slowest, needing 43 to 46 days more than ‘Yukon’ to reach D80. There was a significant inverse relationship between November (r2 = 0.57) and March (r2 = 0.77) WSC content in stolons and D80 for all nine bermudagrass cultivars. These results suggest that bermudagrass cultivars with high WSC in stolons recover more rapidly from dormancy during establishment than those with low WSC content.