After five decades and due to Chile bicentenary, the Chilean government decided to renew both the field and the infrastructure of the National Stadium Julio Martinez Prádanos (Photograph 1). Work began in September of 2009 and is expected to be completed in March 2010. In order to observe the progress of this renovation, during the second week of January we visited the stadium field for the first time. On this visit we could talk with the manager of the stadium (Ricardo Arias) and to assess the soil profile prior to the turf installation.

Photograph 1.  Establishing the soil profile, aerial view of the process. Picture courtesy of lanube360.cl

The field soil profile corresponds to a USGA profile with two horizons, an upper 30 cm of pure sand (0.93% very fine, 24.09% fine, 73.95% medium/coarse and 1.03% coarse sand) and a lower 10 cm of gravel. Photograph 2 shows how they level the ground before planting. Note that the slope is 1% from midfield to the edges. The irrigation system installed is automatic with 20 sprinklers. Fourteen of these sprinklers are on the side and goal linesl, and six are within the field.

Photograph 2.  Leveling the field before planting

We made a second visit to the stadium on January 14, the day which coincided with one of the most critical moments of the renewal process, the planting of new grass. The type of turf chosen as the base of the stadium was a hybrid bermudagrass (Cynodon transvaalensis x Cynodon dactylon) variety Tifway (Photograph 3). The reasons why this particular specie and variety was chosen are diverse. This turf has a creeping growth habit (it has stolon and rhizomes), has high resistance to traffic and recover quickly. This variety is vigorous and has a dark green. It is widely used in high performance sports fields throughout the world and as well as the beneficial properties already mention, it tolerates fairly low cutting heights.

Photograph 3.  Hybrid bermudagrass stolons ((Cynodon transvaalensis x Cynodon dactylon) variety Tifway.

Because this variety is hybrid and has no viable seed, the method of establishment is through springs (rhizomes, stolons or stems). In the National stadium the establishment of this bermudagrass was made by hand and after this process a special equipment was use to incorporate the runners in the sand (Photograph 4). Another important feature is that bermuda grass is a warm-season specie and when near-zero temperatures are present the turf starts to get dormant.

Photograph 4.  Special equipment to incorporate the runners on the sand.

Ricardo Arias, the superintendent of this field, said that he will handle this bermudagrass dormancy with a ryegrass overseeding (Lolium perenne a cool-season species) in autumn to ensure a green cover in the colder months. Lolium varieties chosen were Top Gun 2, The Fifth 2 and CaddiesHack 2. This March, Lolium will be overseed at a 750 kg / ha rate. If necessary, a second overseeding wil be made after 15 to 20 days after the first one and this process will be done with gravity-type equipment.

authors: Marcela Munoz and Alejandra Acuna (globalcesped.org)