Soil quality and vegetable growth as affected by organic amendments to a tropical Oxisol during transition to organic farming

摘要

Changes in soil properties and vegetable growth were quantified during the transition from conventional to organic farming. Four treatments (2 composts, urea and control) were applied to an Oxisol in Hawaii. Two crops, Chinese cabbage and eggplant were grown sequentially as test crops. Hot-water soluble carbon, dehydrogenase activity and CEC were increased by compost amendments. CO_2 respiration rate did not correlate with the soil amendments. Nitrogen nutrition was the main factor that improved growth and carotenoid content in cabbage. The urea treatment promoted better growth of cabbage, while compost was effective for eggplant, suggesting N from organic inputs requires time to mineralize and to become available to crops.