Preliminary Study On Effect Of HA Activate CaHPO₄ In Calcareous Soil

CAFS and SRFS can improve the fertilizer utilization ratio, which is the trend of the study and development of fertilizer. In the northern area of china, phosphorus utilization ratio in calcareous soil is low, which makes production cost high. Lots of studies have proved that HA can improve the phosphorus utilization, protect available P and reduce the fixation of phosphorus in soil and improve phosphorus abstraction in roots. The experiment, adopting mung bean potted, studies initially the effects of the combination of HA and CaHPO₄ in soil available-P content and on mung bean form, physiology and bio-chemical quota, and provides scientific basis for CAFS and SRFS research and production and improvement of fertilizer utilization ratio. The following are the main conclusions:1. HA contains various active group, such as -OH, -COOH, and so on, so it shows positive physiological activeness that can reduce the fixation of phosphorus in soil and improve the effectiveness of phosphorus.2. CaHPO₄ is hard-dissolution, however, after action with HA, with the physical, chemical and biological change, phosphorus releases slowly and provides nutrients to crops steadily and lastingly; the release reaches a summit at a certain time, so its fertilization provision trend is more reasonable. Part of phosphorus in soil is absorbed and utilized by crops , and the majority is accumulated in the form of Ca₂-P, Cag-P, and A1-P. The treatment of phosphorus fertilizer is far better than The treatment of none-phosphorus fertilizer.3. HA activate CaHPO4 that can be treated CAFS and SRFS, in which reach the need of the mung. And it satisfies the needs of phosphorus during mung bean growing process, and improves the accumulation of the output of mung bean.4. In a word, CaHPO4 added HA in right amount can be used as SRFS. Because of the high degree of purity of CaHPO4 impurity content such as heavy metal is low, which decreases pollution to soil and water. On the other hand, fertilizer of CaHPCu is cheap and the high degree of purity (the content of P₂O₅ is 27 -30% )can improve phosphorus in soil, reduce production cost and promotes agricultural effectiveness. The content P in CaHPO₄ slow release in calcareous soil. Besides, the addition of HA activates phosphorus in CaHPO₄ and in soil, increases organics in soil, which promotes crops quality and yield.