Decomposition and release of nutrients from leaves and pruned stems in vineyard.

The aim of this study was to evaluate the decomposition and release of nutrients and carbon from leaves and pruned stems deposited in the rows and in the spacing between rows of vineyards, throughout the vegetative and productive cycle of the grapevines in a vineyard in Santana do Livramento, Southern Brazil, from May to November 2009. Senescent leaves and new stems that were pruned and enriched with 15N were collected, analyzed chemically and biochemically, and placed in litter bags, which were deposited in the vine rows and in the spacing between them. After 0, 30, 60, 90, 120, 150, 180, and 210 days of the deposition of the litter bags, these residues were collected, dry matter was determined, and the residues were analyzed for total contents of N, 15N, P, K, and C. The rate of decomposition and release of C and nutrients from the leaves and pruned stems deposited on the soil surface was not affected by the place of deposition, row or spacing between rows, of the grapevines. The rate of decomposition and release of C and nutrients from the leaves deposited in the row and in between rows of the vineyard was greater than that of the pruned stems throughout the period evaluated.