摘要
为探讨石灰性农田土壤-水稻系统根际与非根际土的氮素转化特征差异,本研究以石灰性紫色土发育而成的水稻土为研究对象,通过采集水稻分蘖期和成熟期的根际与非根际土壤,开展15N成对标记室内好氧培养试验,并计算土壤各初级氮转化速率。结果表明:水稻分蘖期根际土初级矿化速率(4.45 mg·kg^(-1)·d^(-1))和硝化速率(9.16 mg·kg^(-1)·d^(-1))均显著低于非根际土(P<0.05);水稻成熟期根际土初级矿化速率(6.75 mg·kg^(-1)·d^(-1))和硝化速率(16.86 mg·kg^(-1)·d^(-1))与非根际土无显著差异,但显著高于分蘖期根际土的初级矿化和硝化速率(P<0.05)。水稻分蘖期NH+4-N固定速率显著高于成熟期,其中,分蘖期根际土NH+4-N固定速率为19.75 mg·kg^(-1)·d^(-1),与成熟期根际土相比增加了42.21%;此外,两个生育期的水稻根际土NO-3-N固定速率均显著高于非根际土。水稻分蘖期根际土无机氮总固定速率显著大于有机氮矿化速率,有利于氮素的留存和周转,相应地,初级硝化速率显著降低,减少了土壤NO-3-N损失。研究表明,水稻不同生育期对石灰性水稻土主要氮转化速率的影响具有差异,且这种差异可能受水稻生育期内土壤水分、根系分泌物及无机氮含量变化的调控。
To better understand the differences in nitrogen transformation between the rhizosphere and bulk soil in a calcareous soil-rice system,soils were collected at the tillering stage and maturity stage of rice and differences in the gross rates of mineralization,nitrification,and immobilization were investigated in aerobic microcosmic experiments.The results showed that:The gross rates of mineralization and nitrification of the rhizosphere soil were 4.45 mg·kg^(-1)·d^(-1) and 9.16 mg·kg^(-1)·d^(-1),respectively,which are significantly lower than that of bulk soil(P<0.05).There was no significant difference in the gross mineralization rate(6.75 mg·kg^(-1)·d^(-1))and nitrification rate(16.86 mg·kg^(-1)·d^(-1))between the rhizosphere and bulk soil at the maturity stage,but these rates were significantly higher than those at the tillering stage(P<0.05).The NH+4-N immobilization rate at the tillering stage was higher than that at the maturity stage.The NH+4-N immobilization rate of rhizosphere soil was 19.75 mg·kg^(-1)·d^(-1) at the tillering stage,which is 42.21%higher than that at the maturity stage.Additionally,the NO-3-N immobilization rates of rhizosphere soil in both stages were higher than that of bulk soil.In the tillering stage,the gross mineralization rate of rhizosphere soil was significantly higher than the inorganic nitrogen immobilization rate,whereas the gross nitrification rate was decreased,enabling nitrogen retention and curbing NO-3-N loss.Our results indicate that the nitrogen transformation rates of rhizosphere soil differ in different growth stages because of variations in the water content,mineral nitrogen,and root exudation.
作者
何晓茜
刘汐霓
黄宇潇
兰婷
HE Xiaoqian;LIU Xini;HUANG Yuxiao;LAN Ting(College of Resources,Sichuan Agricultural University,Chengdu 611130,China;Key Laboratory of Investigation and Monitoring,Protection and Utilization for Cultivated Land Resources,Chengdu 611130,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2023年第2期384-392,共9页
Journal of Agro-Environment Science
基金
国家自然科学基金面上项目(42077096)
四川省科技创新人才项目(2021JDRC0034)。
关键词
石灰性水稻土
水稻根际
初级氮转化速率
15N标记
硝化作用
calcareous soil
rhizosphere of rice
gross nitrogen transformation rate
15N labeling
nitrification
