摘要
【目的】阐明长期施肥下我国南方典型农田土壤的酸化特征,为合理施肥缓解农田土壤酸化提供科学依据。【方法】对湖南省典型农田土壤一水稻土和红壤上设置的32个长期监测点10年间的土壤pH及相关数据进行统计分析。【结果】从整体上看水稻土在长期施肥下未呈现明显酸化;在水旱轮作模式下的水稻土出现显著酸化,其pH平均下降速率为每年0.076是持续种稻模式的10倍。化学氮肥施用量的增加是水旱轮作下土壤酸化的重要因素之一,有机肥的施用对水稻土酸化无显著影响。红壤在常规施肥10 a期间pH呈明显的阶段性变化特征,施肥4-6 a与1-3a相比土壤pH下降了0.19个单位显著酸化;持续施肥至7-10 a红壤pH保持相对稳定。起始pH相对较高（pH〉6）的红壤长期施肥下出现极显著酸化,pH平均下降速率为每年0.075,与化肥氮施用量呈显著正相关;pH相对较低（pH 4-5）的红壤长期施肥下未显著酸化。【结论】我国南方地区长期施肥下,与持续种稻模式相比水旱轮作模式加速了水稻土的酸化,化学氮肥施用量的增加是导致其酸化的重要原因;起始pH相对较高（pH〉6）的红壤显著酸化化学氮肥用量增加导致其显著酸化。因此,控制和减少化学氮肥的用量是防止水旱轮作模式下土壤及红壤旱地进一步酸化的重要措施。
[Objectives]The objective was to illustrate characteristics of soil acidification in southern China＇s croplands under long-term fertilization,which will help to reduce acidification rate in these areas by rational fertilization.[Methods]Soil acidification characteristics of typical croplands were evaluated using a 10-year monitoring data in 32 sites located in Hunan province,including paddy soils and red soils under the long-term fertilization.[Results]There is no obvious soil acidification in paddy soils,generally.Significant soil acidification is observed in the paddy-upland rotation with the acidification rate of 0.071 unit/a which is 10 times of that in the rice-rice succession cropping system.Soil acidification is mainly ascribed to the increase of chemical N fertilizer amounts in the paddy-upland rotation.Similarly,obvious soil acidification is also observed in red soils.Further,the acidification tendency with fertilization year consists of two different stages,stage I,rapid decline in rate of soil acidification after the fertilization for 1-6 years,and Stage II,slow decline or relatively stable in rate of soil acidification after the fertilization for 7-10 years.Additionally,more significant soil acidification（average rate of0.075 unit/a） is observed in red soils with initial higher pH（pH〉 6） than that with lower pH（pH 4-5）,and there is a positive correlation between the soil acidification rate and application amounts of chemical nitrogen fertilizers.[Conclusions]In southern China＇s croplands the long-term chemical nitrogen fertilization accelerates soil acidification in paddy soils under the paddy-upland rotation and red soils with higher initial pH（pH 〉6）.Therefore,controlling and reducing the application amounts of chemical nitrogen fertilizers is an effective measure for preventing further acidification in paddy-upland rotation soils and red soils.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2015年第6期1615-1621,共7页
Journal of Plant Nutrition and Fertilizers
基金
国家"973"项目(2014CB441001)
博士后基金项目(2015M571179)资助
关键词
长期施肥
土壤酸化
PH
水稻土
红壤
long-term fertilization
soil acidification
soil pH
paddy soil
red soil
