Tillage Effects on Botanical Composition of Bluepea (Clitoria ternatea)-Guineagrass (Panicum maximum Jacq.) Pastures.

Incorporation of perennial seeded legumes (e.g., bluepea; Clitoria ternatea) may benefit the nutritive value of guineagrass (Panicum maximum Jacq.) in forage conservation systems, but little information is available on means of incorporating this seeded legume on existing guineagrass stands.  Field studies were conducted in 2006 and 2007 to assess seedbed management [SBM; conventional tillage (CT), minimum tillage (MT) and no-till (NT)] effects on seedling emergence of bluepea.  In addition, botanical composition, total dry matter yield, and nutritive value [crude protein (CP) and neutral detergent fiber (NDF)] were determined at 120-d after planting.  Soil type was a San Antón (fine loamy, mixed, superactive, isohyperthermic Cummulic Haplustolls). There was no SBM x year interaction.  There was a SBM effect (P<0.05) on seedling emergence (67, 80, and 62 plants m², for CT, MT and NT, respectively).  There were no SBM effects (P>0.05) on plant height at 90-d, because at this point, all the plants reached their optimum height (average of 40-cm).  At harvest, there was a SBM effect on botanical composition.  Legume percentage was 6% higher for CT (67%; 1978 kg ha^-1) compared to MT (62%; 1317 kg ha^-1).  The higher percentage composition of legume in CT and MT was also reflected in total dry matter yield.   Dry matter yield averaged 2859, 2280 and 1978 kg ha^-1 for CT, MT and NT, respectively.  There was an increase in grass CP as a result of increasing legume percentage in CT  [2.7 percentage unit difference in CP for CT (6.6%) compared to NT (3.9%)].  In conclusion, bluepea can be incorporated in existing guineagrass stands by CT and MT, but legume proportion would be lower in a NT planting.