Summary
The perennial bunchgrass, blue grama Bouteloua gracilis is often difficult to establish from seed. It may be possible to establish by sod planting in specific localities (e.g. restoration of small areas to create patches of native grassland). Experiments were undertaken to determine how to best establish blue grama by sodding at Central Plains Experimental Range, Colorado, mid-west USA.
On abandoned dry farmland soil, plots (122 x 122 cm) were prepared by discing and hand-raking. Sod was cut from a native, nearly pure blue grama stand with an oscillating-blade sod cutter (as commonly used in commercial turf production) in strips about 5 cm deep by 30 cm wide, and cut into 30 to 37 cm lengths.
Sod was placed on plots within 1 hour of cutting and rolled to ensure good soil contact. Fifteen plots (5 replications of 3 plots each) were planted on each of eight dates (13 May-18 August) in 1976, and seven (3 May-24 August) 1977. Treatments were:
1) no irrigation;
2) irrigated with 2 cm water at transplanting;
3) irrigated with 2 cm water at transplanting and watered twice (1.3 cm) within the following 5-6 days.
Sod broke when the soil was dry. Thus on each of two dates in 1976 and 1977, part of the area from which the sod was to be removed was watered (about 2.5 cm water) the day before cutting (‘pre-wet’) and compared to sod cut from the unwatered area.
In 1977, soil cores (12 cm diameter x 60 cm deep) were taken 15-17 days after transplanting (3 May, 21 June, 27 July and 23 August) to assess root growth and number of live tillers. Establishment was rated (31 August 1978 and 6 September 1979) according to the plot area occupied by living blue grama.
Best blue gamma establishment was obtained by:
1) transplanting early in the season (May-June), when sods produced the most new roots (in general, the earlier in the season the better the establishment);
2) cutting the sod about 5 cm thick (in earlier trials, sod cut 2-3 cm deep broke apart when lifted) and keeping flat in transit;
3) pre-wetting before cutting if the soil was not already wet (although this did not always enhance establishment);
4) watering immediately after transplanting plus watering within the following 5-6 days (average stand rating for all dates with single irrigation 45% vs. 59% for three irrigations; there were only two successes (stand rating of 50% or higher) for the non-irrigated treatment).
Establishment depended mainly on development of new adventitious roots which were only produced on new developed tillers.