RAIMUNDO, Fernando; COUTINHO, João; MARTINS, Afonso    MADEIRA, Manuel. Soil management system effects on N availability and tree productivity in chestnut plantations under Mediterranean conditions. []. , 38, 4, pp.547-562. ISSN 0871-018X.  https://doi.org/10.19084/RCA15139.

Soil tillage with chisel ploughing is the conventional soil management system in chestnut stands for fruit production in Northern Portugal. A study was developed to assess the effects of three soil management systems on in situ soil N mineralization dynamics, tree nutrition status and fruit productivity, in a 50-yr old chestnut stand. The treatments were: conventional tillage with a chisel ploughing twice a year (CT), no-tillage with rainfed improved pasture with leguminous and grasses plants (NIP), and no-tillage with spontaneous herbaceous vegetation - natural pasture (NP). The CT treatment showed a strong increase of the soil N mineral concentration following soil disturbance by tillage, but the cumulative net N mineralized along the year was significantly lower (51.8 kg ha^-1) than in the NIP (85.1 kg ha^-1) treatment. The NP treatment (65.9 kg ha^-1) did not cause a reduction in the soil N mineralization when compared to the CT treatment. The mineralization rate (g mineralized N kg^-1 total N) in 2004 was about 26, 30 and 38 in the treatments CT, NP and NIP, respectively. Treatments showed different soil N dynamics, the proportion of mineralized NO₃^--N being lower in the NP (10-48%) than in CT and NIP treatments (53-74%). Our study indicates that no-tillage systems improve the tree nutrition status and enhance productivity.

: NH₄⁺-N; NO₃^--N; N mineralization; No-tillage; phosphorous; tree nutrition.

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