[Preliminary studies on optimum combination of agronomical measures for gyrotillaged and shallowly drilled wheat]. [Chinese]

agronomia agronomie agronomy crop yield cultivadores rotativos cultivateur rotatif cultivation cultivo date de semis drilling espacement espaciamiento fecha de siembra fertilizers modele modelos models optimization methods pratique culturale rendement des cultures rendimiento de cultivos rotary cultivators sowing date spacing trigo wheats