^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.R...^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.展开更多
以粳稻武运粳23和超级杂交籼稻Y两优2号为供试品种,应用15N示踪方法研究不同时期施肥对水稻不同阶段氮肥利用率的影响,以确定不同时期施肥的最佳阶段氮肥利用率。结果表明,基肥在基肥阶段(移栽后的8 d左右)的吸收利用较低,2012年水稻基...以粳稻武运粳23和超级杂交籼稻Y两优2号为供试品种,应用15N示踪方法研究不同时期施肥对水稻不同阶段氮肥利用率的影响,以确定不同时期施肥的最佳阶段氮肥利用率。结果表明,基肥在基肥阶段(移栽后的8 d左右)的吸收利用较低,2012年水稻基肥氮(15N)吸收量不到5 kg hm–2,2013年最大为7.5 kg hm–2,回收利用率在1.5%~11.5%之间;基肥主要是在蘖肥阶段(分蘖肥与穗肥之间)被吸收,其回收利用率在6.6%~24.9%之间,平均为15.6%;穗肥阶段(穗肥后到成熟)基本不再吸收基肥。基肥氮的总体恢复利用效率不高,在9.1%~22.8%之间,品种及氮肥运筹对基肥氮的总体恢复利用效率影响不显著。蘖肥主要在蘖肥阶段发生作用,施穗肥后水稻基本不再吸收蘖肥。蘖肥的总体恢复吸收利用率和基肥相当,在17%~34%之间,Y两优2号高于武运粳23。穗肥的回收效率最高,在54.0%~82.1%之间,武运粳23低于Y两优2号。水稻在整个生育期的总体氮肥恢复效率随氮肥用量的增加而下降,变化在32%~64%之间。水稻一生中吸收积累的氮素中,基肥的贡献占4.13%~10.59%(平均6.92%),蘖肥占3.98%~11.75%(平均7.58%),穗肥占13.32%~37.56%(平均26.02%),土壤的贡献在45.71%~70.83%(平均59.91%)之间。基蘖肥用量越大,其损失也越大,总体氮肥利用率也越低。研究结果证明,在水稻氮肥管理中必须考虑水稻各阶段对不同时期施肥的吸收利用情况,从而提高水稻氮肥利用效率,保证产量的同时减少不必要的损失。展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘^15N-labelled phenolic polymers were synthesized by reactions of p-benzoquinone and 1,4-diphenol with ^15N-labelled glycine and were studied by using ^15N CP-MAS NMR technique in combination with chemical approaches.Results showed that the proportion of polymer nitrogen as N-phenyl amino acid N was not as great as expected,only accounting for 5%-15%;and most of N in polymers occurred in the forms of amide,pyrrole-and indole-like nitrogen,aliphatic amines and isonitrile.It seems that great differences existed between synthetic humic acids and soil humic acids in the type and distribution of nitrogen forms.
文摘以粳稻武运粳23和超级杂交籼稻Y两优2号为供试品种,应用15N示踪方法研究不同时期施肥对水稻不同阶段氮肥利用率的影响,以确定不同时期施肥的最佳阶段氮肥利用率。结果表明,基肥在基肥阶段(移栽后的8 d左右)的吸收利用较低,2012年水稻基肥氮(15N)吸收量不到5 kg hm–2,2013年最大为7.5 kg hm–2,回收利用率在1.5%~11.5%之间;基肥主要是在蘖肥阶段(分蘖肥与穗肥之间)被吸收,其回收利用率在6.6%~24.9%之间,平均为15.6%;穗肥阶段(穗肥后到成熟)基本不再吸收基肥。基肥氮的总体恢复利用效率不高,在9.1%~22.8%之间,品种及氮肥运筹对基肥氮的总体恢复利用效率影响不显著。蘖肥主要在蘖肥阶段发生作用,施穗肥后水稻基本不再吸收蘖肥。蘖肥的总体恢复吸收利用率和基肥相当,在17%~34%之间,Y两优2号高于武运粳23。穗肥的回收效率最高,在54.0%~82.1%之间,武运粳23低于Y两优2号。水稻在整个生育期的总体氮肥恢复效率随氮肥用量的增加而下降,变化在32%~64%之间。水稻一生中吸收积累的氮素中,基肥的贡献占4.13%~10.59%(平均6.92%),蘖肥占3.98%~11.75%(平均7.58%),穗肥占13.32%~37.56%(平均26.02%),土壤的贡献在45.71%~70.83%(平均59.91%)之间。基蘖肥用量越大,其损失也越大,总体氮肥利用率也越低。研究结果证明,在水稻氮肥管理中必须考虑水稻各阶段对不同时期施肥的吸收利用情况,从而提高水稻氮肥利用效率,保证产量的同时减少不必要的损失。
