Tasistro Armando S, Kissel David E
University of Georgia, Agricultural and Environmental Services Laboratories, Athens, GA 30602, USA.
J Environ Sci Health B. 2006;41(6):989-1000. doi: 10.1080/03601230600808620.
More knowledge on the composition of aqueous extracts of broiler litter amended for Water Soluble P (WSP) reduction would help to understand how amendments work. We measured pH, concentrations of Ca, Mg, Fe, Al, Cu, Mn, Zn, Molybdate Reactive P (MRP), and Dissolved Unreactive P (DUP) in water extracts of broiler litter treated with aluminum sulfate (ALS), ferrous sulfate (FES), ferric chloride (FEC), and gypsum (GYP) at 0, 5, 15, and 25% w/w. In order to study the effects of acidification, the same properties were measured in aqueous extracts of broiler litter suspensions that were titrated to end-points 3, 4, or 6 with 0.5N HCl. Concentrations of MRP, DUP, Ca and Mg, were 61%, 53%, 3.8 times, and 2.6 times greater in extracts from suspensions acidified to pH 6 than at the original pH of 8.9. ALS, FES, and FEC reduced pH, and showed similar effects on WSP concentrations, which were greater than with GYP. The magnitude of the reductions in WSP by ALS, FES, and FEC is uncertain because the actual amount of WSP immobilized cannot be determined. This is because of two opposite effects: 1) Through adsorption, soluble aluminum and iron remove phosphates from solution, and 2) Through acidification, iron and aluminum compounds release phosphates to solution.
深入了解为降低水溶性磷（WSP）而改良的肉鸡粪便水提取物的成分，将有助于理解改良剂的作用原理。我们测定了用硫酸铝（ALS）、硫酸亚铁（FES）、氯化铁（FEC）和石膏（GYP）以0、5、15和25%（w/w）处理的肉鸡粪便水提取物中的pH值、钙、镁、铁、铝、铜、锰、锌、钼酸反应性磷（MRP）和溶解性非反应性磷（DUP）的浓度。为了研究酸化的影响，我们还测定了用0.5N盐酸滴定至终点3、4或6的肉鸡粪便悬浮液水提取物中的相同性质。酸化至pH 6的悬浮液提取物中MRP、DUP、钙和镁的浓度分别比初始pH值8.9时高61%、53%、3.8倍和2.6倍。ALS、FES和FEC降低了pH值，对WSP浓度的影响相似，且大于GYP。由于无法确定实际固定的WSP量，因此ALS、FES和FEC对WSP的降低幅度尚不确定。这是因为存在两种相反的作用：1）通过吸附，可溶性铝和铁从溶液中去除磷酸盐；2）通过酸化，铁和铝化合物将磷酸盐释放到溶液中。
