The decomposition of winter cover plants on the soil surface can increase nitrogen (N) availability during the onion crop cycle. The objective of this study was to evaluate N mineralization of cover plant litter, intercropeed or not, in a soil with a history of onion plantation. Soil was collected, prepared, placed in acrylic containers. Dry mass of black oats, rye, oilseed radish, black oats + oilseed radish and rye + oilseed radish were added into soil surface and incubated for 90 days. Soil was sampled and contents of total N, NO3--N and NH4+-N were determined at time zero and at 18, 36, 54, 72 and 90 days after incubation. Values of mineral N, net mineral N, mineralized N and total N - mineralized N were calculated. The highest contents of NH4+-N were found in the soil with the deposition of oilseed radish litter and rye + oilseed radish intercrop. The greatest contents of NO3--N and mineral N from 36 to 90 days after incubation and of mineralized N from 18 to 92 DAI were found in the soil with the rye + oilseed radish litter deposition. Mineralization rate was positive in all soil samples with deposition of rye and oilseed radish litter, and black oats + oilseed radish and rye + oilseed radish intercrops, and negative on 18 and 72 days after incubation in the soil with deposition of black oats litter. The oilseed radish litter and rye + oilseed radish intercrop displayed the greatest potential for mineralization.
Allium cepa L.; decomposition; mineral N
