Eradication of Dichrostachys cinerea through clearing, introduction and establishment of Pennisetum purpureum var. king grass

Sergio Montesinos Pérez

ABSTRACT
In order to establish the eradication of Dichrostachys cinerea in an area of cattle production with Gley Brown soil without carbonate classified as unusable, two control methods were applied: clearing and introduction and establishment of Pennisetum purpureum var. king grass in areas freed of D. cinerea. The introduction to grazing was programmed 6, 9 and 12 months after being planted and as requisite P. purpureum should have at least 160 cm of height. The clearing and burning of D. cinerea allowed the production of 30 t of coal whose incomes covered 70 % of the expenses and also produced $ 27 000 USD. Six months after being planted, P. purpureum showed 250 cm of average height and more than 70 % of prevalence in the floristic composition. The performance at 9 and 12 months determined a lower population of D. cinerea in grazing. Pennisetum purpureum var. king grass showed average values of 8,7 % of crude protein, good leaf:stem percentages, of 45:55 and 40:60 % at 6 and 9 months, and yields of 12,5; 29,4 and 29,5 t DM/ha of edible biomass at 6, 9 and 12 months after the start of grazing. The quantity of D. cinerea seeds at 20 cm of depth in the soil from the second year decreased and became zero since the third year, which corroborates the initial work hypothesis that P. purpureum var. king grass is an effective control method in high-density areas of D. cinerea that grows on Brown Gley soil without carbonate. Other outputs were the economic impact that is achieved, having a higher area for cattle exploitation, a feed biomass production for the animals over 20 t DM/ha/year and the improvement of the animal welfare. It is recommended to generalize the evaluated method in those areas with similar characteristics, emphasizing Gley Brown soil without carbonate and to perform similar works in other soils. The introduction of the animals in the system when P. purpureum has a height equal to or higher than 160 cm and the clearing of D. cinerea after each grazing, are recommended.