摘要：

为探明南方双季稻区长期不同施肥处理下稻田不同耕层(0~10 cm和10~20 cm)土壤酸缓冲性能的变化特征,依托长期(36 a)施肥模式稻田(无肥(CK)、化肥(MF)、秸秆还田+化肥(RF)和30%有机肥+70%化肥(OM)),系统分析长期不同施肥处理下双季稻田0~10 cm和10~20 cm土壤酸中和容量(ANC)、酸缓冲容量(ABC)、酸瞬时缓冲容量(IAC)、铵态氮和硝态氮含量变化特征,及其土壤酸缓冲性能与土壤理化性质之间的相关性。结果表明,MF、RF和OM处理均有利于增加双季稻田0~10 cm和10~20 cm土壤ANC、ABC和IAC,其大小顺序均表现为OM>RF>MF>CK。与CK处理相比,OM处理稻田0~10 cm和10~20 cm土壤ANC和ABC分别增加36.78%,33.18%,18.67%,17.84%,IAC分别增加15.22%,14.02%。稻田0~10 cm和10~20 cm,MF处理土壤铵态氮含量均显著高于OM、RF和CK处理,MF处理分别比CK处理增加48.15%,51.09%;OM处理土壤硝态氮含量均显著高于RF、MF和CK处理,OM处理分别比CK处理增加204.73%,161.94%。各施肥处理稻田0~10 cm土壤ANC、ABC、IAC、铵态氮和硝态氮含量均高于10~20 cm。土壤ANC、ABC、IAC与土壤有机碳、全氮含量、电导率均呈显著的正相关关系;土壤ANC、ABC、IAC与土壤pH值、阳离子交换量均呈极显著的正相关关系。因此,长期采取秸秆还田、30%有机肥配施化肥措施是增强南方双季稻田耕层土壤酸缓冲性能的有效措施。

关键词: 双季稻田, 长期施肥, 土壤酸化, 土壤酸缓冲性能

Abstract:

In order to explore the effects of different long-term (36 a)fertilizer treatments on characteristics of soil acid buffering capacity at different soil layers (0—10 cm and 10—20 cm)under the double-cropping rice field in Southern of China,four different fertilizer treatments were set up:without any fertilizer input as a control(CK),chemical fertilizer alone (MF),rice straw and chemical fertilizer (RF),and 30% organic manure and 70% chemical fertilizer (OM).Soil acid neutralizing capacity(ANC),acid buffering capacity(ABC),instant acid buffering capacity(IAC),ammonium nitrogen($\text{NH}_{4}^{+}$-N),nitrate nitrogen($\text{NO}_{3}^{-}$-N)contents,and its relationship between soil acid buffering capacity and soil physicochemical properties were analysis.This result indicated that soil ANC,ABC and IAC at soil 0—10 cm and 10—20 cm layer in the double-cropping rice field with MF,RF and OM treatments were increased.The order of soil ANC,ABC and IAC at soil 0—10 cm and 10—20 cm layer in paddy field with all fertilizer treatments showed OM>RF>MF>CK.Compared with CK treatment,soil ANC and ABC at 0—10 cm and 10—20 cm layer in paddy field with OM treatment increased by 36.78%,33.18% and 18.67%,17.84%,respectively.Soil IAC at 0—10 cm and 10—20 cm layer in paddy field with OM treatment increased by 15.22% and 14.02%,compared with CK treatment,respectively.This result indicated that soil $\text{NH}_{4}^{+}$-N content at 0—10 cm and 10—20 cm layer in paddy field with MF treatment were significantly higher than that of RF,OM and CK treatments.Soil $\text{NH}_{4}^{+}$-N content at 0—10 cm and 10—20 cm layer in paddy field with MF treatment increased by 48.15% and 51.09%,compared with CK treatment,respectively.This result showed that soil $\text{NO}_{3}^{-}$-N content at 0—10 cm and 10—20 cm layer in paddy field with OM treatment were significantly higher than that of MF,RF and CK treatments.Soil $\text{NO}_{3}^{-}$-N content at 0—10 cm and 10—20 cm layer in paddy field with OM treatment increased by 204.73% and 161.94%,compared with CK treatment,respectively.Soil ANC,ABC,IAC,$\text{NH}_{4}^{+}$-N and $\text{NO}_{3}^{-}$-N contents at 0—10 cm layer were obvious higher than that of 10—20 cm layer in paddy field under the same fertilizer treatment condition.It had significantly positive correlation between soil ANC,ABC,IAC and soil organic carbon,total nitrogen contents,electrical conductivity in paddy field.Meanwhile,there had extremely significantly positive correlation between soil ANC,ABC,IAC and soil pH,cation exchange capacity in paddy field.As a result,it was effective practices for increasing soil acid buffering capacity at plough layer under the double-cropping rice field in Southern of China by combined application of rice straw or 30% organic manure with chemical fertilizer managements.

Key words: Double-cropping rice field, Long-term fertilizer, Soil acidification, Soil acid buffering capacity