Wu Juan, He Shengzhou, Liang Ying, Li Guoxue, Li Song, Chen Shili, Nadeem Faisal, Hu Jingwei
College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
Environmental Monitoring Station of Baotou, Inner Mongolia, 014060, China.
Environ Sci Pollut Res Int. 2017 Jul;24(21):17760-17768. doi: 10.1007/s11356-017-9285-x. Epub 2017 Jun 11.
Previous studies revealed that phosphate, as an additive to composting, could significantly reduce NH emission and nitrogen loss through change of pH and nitrogen fixation to form ammonium phosphate. However, few studies have explored the influence of pH change and phosphate additive on NO -N, NH-N, NH, and NO, which are dominate forms of nitrogen in composting. In this study, the equimolar HPO, HSO, and KHPO were added into pig manure composting to evaluate the effect of H and PO on nitrogen transformation. As a result, we reached the conclusion that pH displays significant influence on adsorption from PO to NH. The NH-N concentration in HPO treatment kept over 3 g kgDM (dry matter) which is obviously higher than that in HSO treatment, and NH-N concentration in KHPO treatment (pH>8.5) is lower than 0.5 g kgDM because adsorption capacity of PO is greatly weakened and NH-N rapidly transformed to NH-N influenced by high pH value. The NO emission of composting is significantly correlated with incomplete denitrification of NO -N, and PO addition could raise NO -N contents to restrict denitrification and further to promote NO emission. The study reveals the influence mechanism of phosphate additive to nitrogen transformation during composting, presents theoretical basis for additive selection in nitrogen fixation, and lays foundation for study about nitrogen circulation mechanism during composting.
先前的研究表明，磷酸盐作为堆肥添加剂，可通过改变pH值和固氮形成磷酸铵，显著减少氨气排放和氮素损失。然而，很少有研究探讨pH值变化和磷酸盐添加剂对堆肥中主要氮形态——硝态氮、铵态氮、氨气和一氧化氮的影响。本研究将等摩尔的磷酸氢二钾、硫酸氢钾和磷酸二氢钾添加到猪粪堆肥中，以评估氢离子和磷酸根对氮转化的影响。结果表明，pH值对磷酸根吸附铵态氮有显著影响。磷酸氢二钾处理中的铵态氮浓度保持在3克/千克干物质以上，明显高于硫酸氢钾处理；磷酸二氢钾处理（pH>8.5）中的铵态氮浓度低于0.5克/千克干物质，这是因为高pH值使磷酸根的吸附能力大大减弱，铵态氮迅速转化为氨气。堆肥的一氧化氮排放与硝态氮的不完全反硝化显著相关，添加磷酸根会提高硝态氮含量，从而抑制反硝化作用，进而促进一氧化氮排放。该研究揭示了磷酸盐添加剂对堆肥过程中氮转化的影响机制，为固氮添加剂的选择提供了理论依据，也为堆肥过程中氮循环机制的研究奠定了基础。
