Sowíng systems of annual medie pastures

Carlos Ovalle M.1, Alejandro del Pozo L.1 y Julia Avendaño R.2

The rotation of annual medic (Medicago polymorpha L.) and wheat (Triticum aestivum L.), called ley-farming system, is promising new production strategy for the interior dryland (secano interior) of the subhumid mediterranean area of Chile, The aim of this study was to asses the effect of different sowing methods on the establishment and production in the first three years of medicago in granitic soils of the interior dryland of Cauquenes, Seeds of medicago were sown pure or associated with falaris (Phalaris aquatica cv, Sirolán), or with both wheat (cv, Patagua) and falaris. Additionally medicago pods were sown with wheat. The best establishment and greatest biomass production wereobtained with medicago sown pureo in the first year the medicago contribution was low in all plots (4.4 to 15%), due to a lack of nodulation that led to a high mortality of seedlings. In the second year, the contribution of medicago was even lower (2 to 3%). However, in the third year this percenlage reached 60% in plots where medicago was sown alone, and between 26 and 46% in plots where medicago was associated with wheat or falaris. Using pods instead of seeds, il would probably take more than year for medicago to reach an adecuate percenlage in the pasture. Seed production was 126 kg/ha and 450 kg/ha in the first and third year, respectively, in plots where medicago was sown alone. The process of building up an adequate seed pool is discussed in terms of seed production and rate of seed softening.

Keywords: annual medic, ley farming, Medicago polymorpha, sowing systems, dryland zone, mediterranean pastures, wheal.
1 Estación Experimental Quilamapu (INIA), Casilla 426, Chillán. Chile.
2 Subestación Experimental Cauquenes (INIA), Casilla 165, Cauquenes, Chile.