Input of dry matter and nutrients to the soil from cover plants cultivated between rows of perennial crops and their effects on soil reaction

The total input of dry matter, N, P, K, Ca, and Mg to the soil from cover crops planted between rows of coffee and apple trees was measured in six separated field sites in the State of Parana, Brazil. The following cover crops were evaluated: Avena strigosa, Stizolobium cinereum, Stizolobium deeringianum, Lollium multiflorum, Crotalaria mucronata Crotalaria spectabilis, Crotalaria breviflora Vigna unguiculata, Arachis hypogaea. and Leucaena leucocephala. Annual cover crops were sown between tree rows and the shoots cut off at the flowering stage. For Leucaena, a perennial crop, three cuttings had been applied per year. The cutted plant materials were allowed to dry and decompose on the soil surface as mulch. The total input of above ground dry matter ranged from 2.0 Mg ha(-1)y(-1) (Crotalaria spectabilis) to 15.7 Mg ha(-1)y(-1) (Leucaena leucocephala). Estimated N, P, K, Ca, and Mg contents in the residues ranged from 31.0 to 400.2; 2.2 to 26.2, 22.0 to 223.6, 20.6 to 273.1, and 4.0 to 37.9 kg ha(-1)y(-1), respectively. Plant residues were found to decrease soil acidity. Cover crops are recommended as an important management strategy for coffee and apple production because they provide large quantities of dry mater and plant nutrients to improve soil fertility of the degraded acid soils in Parana.