Amelioration of a hardsetting Alfisol through deep mouldboard ploughing, gypsum application and double cropping. 3. Crop production and profitability

arados de vertedera aradura crop yield cultivo secuencial gypse gypsum labour luvisol luvisoles luvisols mouldboard ploughs plant water relations ploughing profitability relaciones planta agua relation plante eau rendement des cultures rendimiento de cultivos rentabilidad sequential cropping sorghum arundinaceum triticum aestivum vigna unguiculata yeso