Chestnut and litterfall production and leaf nutrient concentration in chestnut groves submitted to different soil tillage systems.

The effects of several soil management systems on litterfall production (leaves, burs, chestnuts and inflorescences) and leaf nutrient concentration were studied in a 50 year-old chestnut grove, located in NorthREVISTA DE CIENCIAS AGRARIAS 246 east Portugal. The experimental trial was installed in the beginning of 1996 and it was monitored for eight years. The treatments were: chisel plow (average depth 15 cm), which corresponds to the traditional tillage (MT); disc harrowing tillage, up to 7 cm depth (GD); rainfed seeded pasture, with leguminous and grasses species (PS); and notillage with spontaneous herbaceous vegetation (NM). Results, between 1999 and 2004, showed that the average production of litterfall (leaves, burs, chestnuts and inflorescences), was greatest in NM treatment (755 g m), followed by the PS (729 g m), GD (708 g m) and MT (627 g m) treatment, although the differences were not significant. During that period, the burs (36.7%) made the greatest contribution to total litterfall, followed by the leaves (32.5%), chestnuts (24.7%) and inflorescences (6.1%). The chestnut production was significantly lower in the MT (133 g m) treatment than in the NM (193 g m) and PS (191 g m). The N, P and Mg content in leaves were significantly lower in MT treatment than in the others; the K content was significantly lower in MT and PS treatments than in GD; the Ca concentration was significantly lower in MT treatment than in GD and PS. Management practices alternatives to the traditional soil tillage revealed to be more appropriated to enhance productivity of chestnut groves and to reduce production costs.