บทบาทของหินฟอสเฟท (Phosphate Rock, PR) ในการผลิตข้าวโพดแบบอินทรีย์

Abstract

Growth of corn responded markedly to application of phosphorus from both phosphate rock and triple super phosphate. It was found that corn with application of 6 and 30 gm P/pot of PR had average plant height (at 30 and 50 days after planting) of 77 percent and 82 percent, compared to the growth of corn with 6 gm P/pot of TSP. And increasing the rate of phosphorus from PR to 60 gm P/pot resulted of 92 percent in growth, compared to that from application of triple super phosphate. No application of phosphorus resulted in only 69 percent of the growth of corn, compared to that from application of triple super phosphate. Similarly, the application of phosphorus from phosphate rock (PR) at the rates of 0, 6, 30 and 60 gm P/pot resulted 29 percent, 38 percent, 64 percent and 89 percent growth in dry weight growths of corn, compared to that of triple super phosphate. The study also revealed that a considerable portion of residual phosphorus remained in the soil due to use of phosphate rock. Moreover, discussion on use of legumes as green manure in the cropping in order to increase availability of phosphorus from phosphate rock was included.