Quantification of the processes of gross mineralization and immobilization is very important to make full nitrogen balances. These processes were quantified in a clay loam soil (S) after application of nitrogen K15NO3 (N) and four organic amendments (two composts of domestic waste of different ages (C1 and C3), residual waste from a treatment plant (B) and farmyard manure (F) as a control). This study was carried out during a 1–2 mo incubation at a temperature of 25 °C and a moisture content of 2/3 of the field capacity. The mineralization and immobilization processes depended on the nature of the organic amendments, their degree of stability and their nitrogen content. N mineralization was correlated with C/N ratios (r = 0.936), N contents (r = 0.880), hemicellulose contents (NDF – ADF) (r = 0.869), (hemicellulose + cellulose + lignin)/N ratios (NDF/N) (r = 0.886) and (cellulose + lignin)/N ratios (ADF/N) (r = 0.869). The immobilization of N was correlated to (cellulose + lignin) contents (ADF) (r = 0.607). The amount of mineralized N (mg kg−1) during this month was in the following decreasing order: S + N + B (94.3) > S + N + F (14.3) > S + N + C3 (4.92) > S + N (− 0.31) > S + N + C1 (−20.1). Organic amendments application favored the process of N immobilization which decreased with the degree of stability of organic materials. The amount of N immobilization (mg kg−1) was in the following decreasing order: S + N + B (53.3), S + N + C1 (49.1), S + N + F (36.72), S + N + C3 (35.6) and S + N (29.1). The loss of nitrogen (between 2 and 20%) was attributed to dénitrification or volatilization. Key words: Mineralization, immobilization, organic amendments, 15N
Combined Effects of Farmyard Manure (FYM) and Elemental Sulfur (S)on Soil Chemical Properties, Growth, Yield, Leaf Water and Nutrient Contents of Corn Plant Grown on Sandy Clay Loam Soil
