Effects of depth and time of ploughing on yields of spring cereals and potatoes and on soil properties of a morainic loam soil

aradura cultivos de primavera culture de printemps depth estructura del suelo hordeum vulgare labour loam soils noruega norway ploughing profondeur profundidad soil structure sol sablolimoneux solanum tuberosum spring crops structure du sol suelo franco temps tiempo time triticum aestivum