有机无机肥配合对土壤磷素吸附、解吸和迁移特性的影响

通过32P示踪、薄层层析和土柱淋洗研究了经过四季不施磷肥、施用纯无机磷肥以及有机无机磷肥3种处理对土壤磷素迁移的影响。结果表明:有机无机肥配合处理的土壤磷吸附亲和力常数和最大吸附量显著低于化肥处理,磷累积解析量高于化肥处理,而32P在薄层板的迁移距离显著高于化肥及对照处理;淋洗试验中有机无机肥配合处理土壤中的32P最先在淋洗液达到13.1mL时出现,而化肥及对照的32P则分别在淋洗液达19.0和19.8mL时出现;在淋洗液体积达到50mL时,对照、化肥及有机无机肥配合处理淋出的32P总量分别为总加入量的1.6%、8.4%和9.8%。有机无机肥配合可以减少土壤磷素的固定,增强磷在土壤中的移动,提高磷的有效性。

Interactive Effects of Combined Inorganic and Organic Fertilizers on Phosphorous Adsorption, Desorption and Mobility

A 32P-labeled experiment was conducted to investigate the mechanisms of combining inorganic and organic fertilizers affecting P availability. Results showed that the characters of soil P adsorption-desorption changed remarkably with different patterns of fertilizer application. The affinity constant (k) of soil P adsorption, the maximal P adsorption (Q) and the buffering capacity of P adsorption (MBC) of the treatment of 80/20 were lower than those of the 100/0 treatment. The thin-layer chromatography (TLC) showed that 32P of the 80/20 treatment moved faster than the 100/0 treatment. The leaching volumes collected for each treatment when 32P first was observed were 13.1 mL for the treatment 80:20, 19.0 mL for the treatment of 100:0 and 19.8 mL (0:0)mL. Total 32P recovery for the 100:0 and the 80:20 treatments increased significantly after nearly 45 mL of leachates were collected. When the leachates reached 50 mL, only 1.6%, 8.4% and 9.8% of the applied 32P leached out from the 0:0, 100:0 and 80:20 treated soils, respectively. The findings indicated that combined organic and inorganic fertilizers could suppress the decreasing of P fixation, enhance P mobility more effectively and improve P use efficiency.