ESTABLISHMENT, FORAGE PRODUCTION, AND NUTRITIVE-VALUE OF LEUCAENA IN CENTRAL FLORIDA

Tree and shrub legumes are increasingly being recommended for forage use in the tropics and subtropics. A forage production trial to evaluate members of the genus Leucaena varying in their level of resistance to the leucaena psyllid, Heteropsylla cubana Crawford, was conducted for 3 yr at the USDA-ARS Subtropical Agricultural Research Station in central Florida. A total of eight selections (one or more of L. leucocephala, L. pallida, or L. esculenta, and hybrids L. diversifolia x L. pallida, L. pallida x L. leucocephala, and L. diversifolia x L. leucocephala) were evaluated for establishment, winter survival, total dry matter DM), edible DM (stems < 6 mm diam. + leaves), percentage of edible DM, and N and in vitro organic matter digestibility (IVOMD) concentration of the edible DM. Seedlings were transplanted in a double hedgerow pattern (two rows 1 m apart, with 0.25 m within-row spacing) in Blichton loamy fine sand (Arenic Plinthic Paleaquult) in June 1989. Winter survival of the selections ranged from 48 to 62% and did not differ among selections. The three L. leucocephala selections had the highest edible DM yields averaging 14 Mg ha(-1) yr(-1) DM in yr 2 and 3. Nitrogen concentration ranged from 31 to 49 g kg(-1) and IVOMD concentration from 350 to 560 g kg(-1), with the L. leucocephala selections exhibiting the highest IVOMD. Leucaena esculenta had lower levels of both N and IVOMD concentration, averaging 37 and 380 g kg(-1), respectively. Based on yield and nutritive value, L. leucocephala selections K584 and K636, although having less psyllid resistance than the hybrids or other species, appear to be better suited for central Florida.