Evaluation of the forage potential of four Pennisetum purpureum cultivars on a Brown soil of the central region of Las Tunas

Lázaro Manuel García Torres

ABSTRACT
A trial was conducted on grayish Brown soil, belonging to the EEPF Las Tunas, with slightly acid pH, low OM content and assimilable phosphorus, in order to evaluate the productive performance of the Pennisetum purpureum cultivars (cvs. King grass, Cuba CT-169, Cuba CT-115 and Taiwán morado). For planting the above-mentioned cultivars, the soil was prepared with minimum tillage. These P. purpureum cultivars were sown using a planting distance of 0,90 m between rows and 0,60 m between plants. The size of the cuttings was 25-30 cm, each having from three to five buds per stem. The age of the seed used was 90 days and the planting depth was 15 to 20 cm. The seeds were covered with hoe with a soil thickness of 3-5 cm. The study was carried out without irrigation or fertilization. The cutting frequency was 60 days for the rainy season and 90 days for the dry season; all the cuttings were made at soil level. In a randomized block design, with five replications, the following variables were studied: plant height, green mass yield (t GM/ha/year), dry matter yield (t DM/ha/year), DM %, leaf-stem ratio, tillering per plantlet and incidence of pests and diseases. In the first as well as the second year the growth dynamics in height showed a very similar pattern for all the studied cultivars, among which Cuba CT-169 slightly stood out with higher values. In general, the biggest height was reached in May-July and the second one from July to September. Regarding the GM yield no significant differences were found among the cultivars in any of the evaluated seasons, or in the annual cumulative of the first year of study and the yields exceeded 127 t/ha/year in all cases. Although there were no significant differences, it could be observed that the cv. Cuba CT-169 showed the best result. Already in the second significant differences were detected for P<0,05 in the rainy season and annual total, in which cultivar CT-169 showed significant differences (P<0,05) with superiority over the other cultivars. In the dry season the yields of all the evaluated cultivars were similar. Regarding the DM yield no significant differences were observed for the seasons or for the P. purpureum cultivars in the first year of evaluation. Nevertheless, the cv. CT-169 showed the highest value and in the second year of evaluation, the variance analysis showed significant differences in the rainy season and the annual total, where cultivar CT-169 significantly differed over the other treatments. In the dry season all the cultivars had a similar performance. The leaf percentage of the different evaluated cultivars of this species did not show significant differences in both seasons of the first year. It could also be observed that in the rainy season the leaf content was higher (42,3 to 44,5), while in the second year of evaluation the different cultivars showed significant differences for P<0,05 only in the dry season. It was also observed that CT-169 showed higher leaf percentage, exceeding the other cultivars in 3-5 percentage units. Among the studied Pennisetum purpureum cultivars, the one with the best performance was cultivar CT-169 with marked differences in biomass production, dry matter yield, leaf percentage and number of tillers per plantlet.