Effects of Long-term Located Appling Calcium Superphosphate on Forms Distribution of Calcium in Facilities Soil

The effects of fertilizers application on the contents and distributions of fractions of calcium in facilities soil and soil particle sizes were investigated in a field experiment,which consisted five treatments of control no fertilizers,phosphorus fertilizers,phosphorus fertilizers plus nitrogen fertilizers,phosphorus fertilizers plus potassium fertilizers,and phosphorus fertilizers plus organic fertilizer and had continued for 23 years.The results showed that compared with the treatments of control,single application of phosphorus fertilizers,the combined application of other could significantly increase the content of different forms soil calcium.The rough ordering was phosphorus fertilizers plus manurephosphorus plus potassium fertilizersphosphorus fertilizersphosphorus plus nitrogen fertilizersno fertilizers.The distribution coefficient of un-acid soluble calcium was dominated.It was about 60%.The distribution coefficient of water soluble calcium was minimum.It was below 3%.It did not increase the distribution coefficient of un-acid soluble calcium after application of phosphorus fertilizers.The treatment of phosphorus fertilizers plus organic fertilizer increased significantly the content and the contribution rate of calcium in soil big particle sizes.The content and the contribution rate of calcium of other treatments increased with the decrease of the soil particle.