[Plant protection in cereals by reduced tillage - effect on noxius organisms and yields]

cereal crops cultivos de cereales direct sowing enfermedades de las plantas harrowing hersage maladie des plantes malezas mauvaise herbe minimum tillage noruega norway pests of plants plagas de plantas plant diseases plant protection protection des plantes rastreo ravageur des plantes rendement rendimiento semis direct siembra directa spraying travail du sol minimal weeds yields