ACCUMULATION OF DRY-MATTER AND EVOLUTION OF NUTRITIVE-VALUE IN SERRADELLA (ORNITHOPUS-SATIVUS BROT.)

Development of efficient forage management and utilization is facilita ted by knowledge of nutrititive value evolution and dry matter (DM) di stribution patterns within plants. The objectives of this experiment w ere to determine the patterns of DM accumulation and the evolution of nutritive value from the vegetative stage to the ripe seed stage of se rradella (Ornithopus sativus Brot.), a cool-season annual forage legum e adapted to acid soils. Serradella was established on a Dystric Eutro chrept soil with pH 5.4 in Mabegondo, northwestern Spain, for three co nsecutive years (1990-1992). Shoot samples were taken at approximately biweekly intervals in the spring and summer following autumn seeding, and were separated into stems, leaves, and seed pods. Dry matter (DM) accumulation, crude protein (CP), acid-detergent fiber (ADF), and in vitro organic matter digestibility (IVOMD) were determined for each pl ant part at each stage. Average annual DM production at initial flower ing was 5.1 Mg ha(-1), and the CP, ADF, and IVOMD concentrations were 163, 279, and 750 g kg(-1), respectively. The rates of nutritive value decline with age coincided with a reduction in leaf-to-stem ratio (fr om a range of 1.91 to 2.85 at vegetative stage to 0.2 at ripe seed sta ge) and appear lower than the rates reported for other legumes, possib ly because of the long indeterminate flowering period. We concluded th at the nutritive value parameters of serradella indicate that this leg ume has a forage quality comparable to other leguminous crops and, if seeded in double-cropping systems (as is done in some Atlantic coastal areas of southern Europe, where it is harvested around initial flower ing), it can provide forage of good quality.