连续施用有机肥下设施土壤碳氮磷化学计量学特征及其与土壤有效磷的关系

Stoichiometric characteristics of soil carbon,nitrogen and phosphorus and their relationship with soil available phosphorus under continuous application of organic fertilizer for vegetable cultivation in greenhouse

为阐明设施土壤中连续施用有机肥条件下土壤碳氮磷化学计量学特征的动态变化,并探讨碳氮磷化学计量比对土壤磷素有效性的影响,通过定位试验研究连续5季大棚辣椒栽培中不同处理(CK,空白对照;CF,单施化肥;OCF1,有机肥替代49%磷肥;OCF2,有机肥替代63%磷肥;OCF3,有机肥替代73%磷肥)对土壤碳氮磷化学计量比及不同形态磷的影响。结果表明,与单施化肥相比,3个施用有机肥处理均显著增加了土壤全碳、全氮和全磷含量。OCF1处理的土壤碳氮比在5季辣椒栽培中都显著高于CF处理,OCF3处理的土壤碳磷比仅在第5季中显著高于CF处理。不同处理间的土壤氮磷比差异不显著。此外,与CF处理相比,OCF3处理在第1季和第2季显著增加了土壤有效磷含量,在第5季中OCF2处理显著降低了土壤有效磷含量。相关性分析结果表明,土壤全磷含量、无机磷含量及其占比、总碳含量、全氮含量与有效磷含量呈极显著正相关关系(P<0.01),而有机磷占比、碳磷比和氮磷比与有效磷含量呈极显著负相关关系(P<0.01)。结果说明在设施蔬菜栽培中长期施用有机肥替代磷肥可能会降低土壤有效磷含量,其原因可能是提高了土壤的碳磷比,造成土壤中有效磷的生物固持。

In order to clarify the dynamic changes of the stoichiometric characteristics of soil carbon,nitrogen and phosphorus under the condition of continuous application of organic fertilizer for vegetable cultivation soil in greenhouse,and to discuss the effect of stoichiometric ratio of carbon,nitrogen and phosphorus on the availability of soil phosphorus,a positioning experiment was conducted to study the effect of different treatments(CK,blank control;CF,single application of chemical fertilizer;OCF1,organic fertilizer instead of 49%phosphate fertilizer;OCF2,organic fertilizer instead of 63%phosphate fertilizer;OCF3,organic fertilizer instead of 73%phosphate fertilizer)on the stoichiometric ratio of soil carbon,nitrogen and phosphorus and different forms of phosphorus during pepper cultivation in the greenhouse for five consecutive seasons.The results showed that,compared with single application of chemical fertilizer,three organic fertilizer treatments all increased the contents of total carbon,total nitrogen and total phosphorus in the soil significantly.The soil carbon-nitrogen ratio of OCF1 treatment was significantly higher than that of CF treatment in all the five cultivation seasons of pepper,and the soil carbon-phosphorus ratio of OCF3 treatment was significantly higher than that of CF treatment only in the fifth season.There was no significant difference in soil nitrogen-phosphorus ratio among different treatments.In addition,compared with CF treatment,soil available phosphorus content increased significantly in the first and second seasons under OCF3 treatment,and decreased significantly in the fifth season under OCF2 treatment.Results of correlation analysis showed that,the total phosphorus content,inorganic phosphorus content and proportion,total carbon content,total nitrogen content in the soil were in extreme significant positive correlation(P<0.01)with soil available phosphorus content,while the proportion of organic phosphorus,carbon-phosphorus ratio and nitrogen-phosphorus ratio were in extreme significant negative correlation(P<0.01)with the soil available phosphorus content.The results indicate that,long-term application of organic fertilizer instead of phosphate fertilizer during vegetable cultivation in the greenhouse may reduce the soil available phosphorus content.The reason may be that the soil carbon-phosphorus ratio is improved,resulting in the biological fixation of soil available phosphorus.