石灰性土壤上三种磷肥不同用量的磷肥利用率及其缓效率

The Use Efficiency and Slow-Release Rate of Various P Fertilizers with Different Application Rates on Calcareous Soil

供试三种磷肥虽其性质不同,但其磷肥利用率和缓效率表现趋势一致。磷肥利用率均随磷肥用量的增高而降低,呈负相关,且随种植年限的延长而减小。磷肥缓效率随磷肥用量的增加而提高,呈正相关。磷肥利用率和缓效率,过磷酸钙的利用率最大,缓效率最小;磷酸二铵磷肥利用率最低,缓效率最高;钙镁磷肥利用率及缓效率均居上述两种磷肥之间,但其P2O5用量小于142.5kghm-2时,利用率大于缓效率,P2O5用量大于285kghm-2时,利用率小于缓效率。由此可知:P2O5含量以水溶性为主要成分的磷酸二铵和P2O5为枸溶性的钙镁磷肥对石灰性土壤均不是理想的磷肥品种。本试验结果提示:石灰性土壤施用磷肥最好的方法是水溶性磷与枸溶性磷合理搭配,其最佳的配合比例应据当地试验结果而定。

Although the 3 tested P fertilizers had different features, they had similar trend in use efficiency and slow-release rate. Their use efficiency decreased with increasing application rate, as well as with increasing cropping period. The slow-release rate increased with increasing application rate, having a positive correlation. Single super-phosphate had the greater use efficiency and lower slow-release rate. Diammonium phosphate has the least use efficiency and greater slow-release rate. When the application rate of calcium-magnesium phosphate was less than 142.5 kg P2O5 /ha, the use efficiency was greater than slow-release rate. Whereas when the application rate was greater than 285 kg P2O5 /ha, the use efficiency was less than slow-release rate. It is suggested that whether diammonium phosphate with water soluble P2O5 as the major component or calcium-magnesium phosphate with citrate soluble P205 as the whole component, were not ideal phosphate fertilizer variety for calcareous soil. The experiment indicated that the best way of P fertilization on calcareous soil was a mixture of water soluble P2O5 with citrate soluble P2O5. The best ratio should be determined by local trials.