The effect of deep plowing on growth and yield of vegetable crops

Abstract

1. Influences of deep plowing on growth and yield of several vegetable crops and effects of subsoil condition which counteracts the favorable effect of deep plowing were investigated on vegetable crops comparing with some cereals and forage crops, in order to know their adaptability to the cropping systems under deep plowing.2. The studies were performed in the field of volcanic ash soil. The crops investigated were tomato, cucumber, pumpkin, Chinese cabbage, Welsh onion, Japanese radish, taro, sweet potato, soybean, upland rice, corn, and barnyard millet.3. It was recognized that deep plowing had an favorable effect on growth and yield of most vegetable crops and it was more effective with heavy application of fertilizers. The raw subsoil was unfaborable to growth and yield of cereals and forage crops, but most vegetable crops with heavy fertilization were not so sensitive to the inhibition caused by subsoil. Moreover, most vegetable crops showed excellent growth and yield on the subsoil which was improved by exposing to frost action in winter and by heavy application of fertilizers.4. In pot-cultur the growth of most vegetable crops was inhibited in the poor subsoil, but it was vigorus in the fertile subsoil with heavy fertilization. Some of them showed rather better growth in subsoil than in topsoil with the same amout of fertilizers.5. It was made clear that the crops which gained high yields under deep plowimg were not so affected by poor nutritive condition of subsoil and the yields of vegetable crops did not decrease remarkably in the raw subsoil when it was heavily fertilized.6. Moreover, it was suggested that the sensitiveness for Al toxity and deficiency of nutritive elements, especially of phosphorous, was concerned with the adaptability of crops for subsoil conditions.7. After all, it was concluded that most of vegetable crops showed a good result under deep plowimg because their roots developed well and the absorption of nutrients became active in response to good soil aeration after deep plowing, and also unfavorable conditions of raw subsoil could be overcome by the heavy application of fertilizers. It was also made clear that they were adapted to the cropping systems under deep plowing.