| Urea and diammonium phosphate are the main chemical nitrogen and phosphorus fertilizer varieties used for agriculture in China.However,their fertilizer use efficiency is low for urea has high activity,can be lost via various ways,while diammonium phosphate is easily fixed in soil.These has a great negative impact on the environment.Modifying chemical fertilizer is an important way to improve the fertilizer use efficiency.Humic acid,alginic acid and amino acid and other natural vegetal substances are usually selected as synergists to manufacture value-added fertilizers,such as value-added urea,value-added ammonium phosphate and value-added compound fertilizer,which have been generally accepted for their effects on increasing crop yield and improving fertilizer efficiency.However,there is little research using glucose,small molecular organic substance,as synergist.In this paper,we prepared urea containing glucose by combining glucose with melton urea,and diammonium phosphate containing glucose by physically blending glucose with diammonium phosphate.The soil incubation and soil column cultivation experiments were conducted to investigate the transformation of urea and diammonium phosphate containing glucose in calcareous fluvo-aquic soil and their effects on corn growth,nutrient uptake and utilization.The results could provide theoretical basis and technical support for the development of fertilizer synergists and value-added fertilizer.The main results were shown as follows:（1）When glucose was added into urea at the level of 5‰,1%,5%and 10%,urea containing glucose can decrease urea hydrolysis within 1 day in the 0-20 cm soil layer.Urea containing 5%and10%glucose showed a better performance than that containing 5‰and 1%glucose.In the 40-60 cm soil layer,urea containing glucose can promote urea hydrolysis after 3 days.Therein,the urea containing 10%glucose showed the most significant difference from the common urea.During the incubation period（21 days）,there was no significant difference about the total ammonia volatilization among common urea and urea containing glucose in the 0-20 cm soil layer,but in the 40-60 cm soil layer,the total ammonia volatilization of urea containing 10%glucose was higher than that of urea containing other glucose.Urea containing glucose can increase the contents of soil mineral nitrogen and enhance the activities of soil urease,cellobiohydrolase,β-glucosidase,N-acetyl-glucosaminidase and L-leucine aminopeptidase in both 0-20 cm and 40-60 cm soil layers.The application of urea containing5%and 10%glucose enhanced the contents of soil mineral nitrogen amd the above enzyme activities more than that containing 5‰and 1%glucose.In addition,urea showed a faster transformation in 0-20cm soil layer than that in 40-60 cm soil layer.Therefore,the urea containing 5%glucose showed the best effects on slowing urea hydrolysis and increasing the activities of related hydrolase enzymes.（2）When glucose was added into diammonium phosphate at the level of 5‰,1%,5%and 10%,compared with common diammonium phosphate,diammonium phosphate containing glucose can increase the soil available phosphorus contents by 7.27%～14.25%and 3.31%～10.13%in 0-20 cm and40-60 cm soil layers for 60 days’incubation,respectively.Diammonium phosphate containing 5%and10%glucose showed a better performance than that containing 5‰and 1%glucose.The contents of Ca8-P increased by 1.22%～5.49%and 2.67%～3.89%in 0-20 cm and 40-60 cm soil layers for 60 days’incubation,respectively.The diammonium phosphate containing 5%glucose enhanced Ca8-P more than other treatments.The activities of soil alkaline phosphatase,α-glucosidase andβ-glucosidase enhanced,and diammonium phosphate containing 5%and 10%glucose showed a higher enhancement that containing 5‰and 1%glucose.The phosphate fertilizer showed a faster transformation in 0-20 cm soil layer than that in 40-60 cm soil layer.Therefore,the diammonium phosphate containing 5%glucose showed the best effects on preventing the fixation of phosphate fertilizer and increaseing the activities of related hydrolase enzymes.（3）When the same amount of nitrogen applied,the corn yields with urea containing 5‰and 5%glucose application were higher than that with common urea by 10.31%and 12.00%,respectively.Meanwhile,urea containing 5‰and 5%glucose could enhance the nitrogen uptake and utilization.In detail,with urea containing 5‰and 5%glucose application,the apparent utilization rate of nitrogen fertilizer increased by 7.20%and 10.27%,and the 15N utilization rate increased by 4.71%and 2.04%.Urea containing 5‰and 5%glucose increased the residual amount of fertilizer nitrogen by 3.66%and18.29%in the 30-60 cm soil layer,and reduced the loss by 4.46%and 4.61%,respectively.There was no significant difference about corn yield between urea containing 5‰and 5%glucose.The urea containing 5‰glucose could promote more fertilizer nitrogen uptake by corn than urea containing 5%glucose,but there was more fertilizer nitrogen residue in soil when using urea containing 5%glucose.（4）When the same amount of phosphorus applied,the corn yields with diammonium phosphate containing 5‰and 5%glucose application were higher than that with common diammonium phosphate by 10.31%and 12.00%,respectively.Diammonium phosphate containing glucose could promote the phosphorus uptake and utilization.Compared with common diammonium phosphate,the diammonium phosphate containing 5‰and 5%glucose increased the phosphorus apparent efficiency by 4.53%and4.80%,phosphorus agronomic efficiency by 24.67%and 28.74%,and phosphorus partial factor productivity by 10.32%and 12.01%,respectively.The diammonium phosphate containing 5‰and 5%glucose increased the contents of available phosphorus by 4.66%and 6.44%respectively in 0-30 cm soil layer.In general,the diammonium phosphate containing 5%glucose had a better effects on increasing corn yield and phosphorus use efficiency. |
