Abstract
The consumption of corn-based foods is a good alternative for human health due to their high content of proteins, essential amino acids and polyunsaturated fatty acids of the omega-3 family. The present study evaluated the effect of two medium-term canola (Brassica napus L.)-corn (Zea mays L.) and bean (Phaseolus vulgaris L.)-corn rotations with four residue incorporation rates (0%, 50%, 100% and 200% of the preceding crop) on corn grain yield, residue production, nutrient concentration and extraction after two rotation cycles in a volcanic soil of south-central Chile. Results indicated that grain yield ranged from 17.04 to 17.40 Mg ha -1 , and residue production ranged from 16.41 to 16.50 Mg ha -1 , being unaffected by the preceding crop. Residue incorporation rates had no effect on grain yield and residue production. The preceding crop affected the concentration and extraction of some nutrients in grain and residue. Residue rate affected the concentration and extraction of some nutrients in grain only. Ca distribution in corn grain was negatively affected by the preceding bean crop and increased residue incorporation rate. Nutrient concentration in grain ranged from 1.33 to 1.36% for N, 0.33% for P, 0.53 to 0.54% for K, 0.008 to 0.011% for Ca, 0.14% for Mg, and 0.087 to 0.092% for S. The ranking of total macronutrient extraction in the corn crop was K > N > Ca > P > Mg > S. The extraction means ranged from 320.0 to 325.8, 56.0 to 57.1, 364.7 to 373.7, 86.5 to 99.3, 39.4 to 42.4, and 22.6 to 23. 7 kg ha -1 , while grain nutrient partitioning coefficients ranged from 64.5 to 66.8, 90.1 to 90.9, 23.1 to 23.7, 1.3 to 2.0, 50.8 to 57.5, and 60.3 to 60.6 for N, P, K, Ca, Mg, and S, respectively. The use of bean as a previous crop allowed an increase in grain protein content (8.56 vs. 8.30%) with respect to the canola crop.