太湖地区稻麦轮作系统有机氮肥替代率的演变特征及其影响因素  

Evolution Characteristics and Influence Factors of Substitution Rate of Organic Nitrogen in Rice-wheat Rotation System in Taihu Lake Region

作　　者：施林林 柳开楼[3] 董林林[1,2] 沈园 陈培峰 沈明星 王海侯[1,2] SHI Linlin;LIU Kailou;DONG Linlin;SHEN Yuan;CHEN Peifeng;SHEN Mingxing;WANG Haihou(National Soil Quality Observation&Experiment Station in Xiangcheng,Suzhou,Jiangsu 215155;Institute of Agriculture Science in Taihu Lake District,Suzhou,Jiangsu 215155;Jiangxi Institute of Red Soil,Nanchang 330046)

机构地区：[1]国家土壤质量相城观测实验站,江苏苏州215155 [2]江苏太湖地区农业科学研究所,江苏苏州215155 [3]江西省红壤研究所,南昌330046

出　　处：《中国农学通报》2024年第1期1-6,共6页Chinese Agricultural Science Bulletin

基　　金：江苏省农业科技自主创新课题“有机物料驱动太湖地区农田土壤质量及碳库演变的长期定位观测研究”[CX(22)3005];苏州市科技计划项目“生态敏感区HDPE沼液稻田消纳适宜承载量及关键技术研究”(SNG2021015),“苏南地区稻麦周年优质丰产绿色高效技术示范”(SNG2020040)。

摘　　要：有机肥替代化肥是化肥减量的关键措施。本研究的主要目标是明确太湖地区稻麦轮作体系中有机氮肥替代率的主要限制因素,为提高有机氮肥替代率提供理论基础。依托40 a长期定位观测试验,分别选择不施肥(CK)、单施化肥(NPK)和单施有机肥(OM)3个处理,研究有机氮肥替代率与土壤碳氮关系。其中,化肥采用尿素、过磷酸钙和氯化钾,年均施氮225~300 kg/hm^(2),年均施磷(P2O5)119.4 kg/hm^(2),年均施钾(K2O)179.1 kg/hm^(2);有机肥采用猪粪和菜籽饼,年均折合施氮103.1 kg/hm^(2),折合施磷(P2O5)82.7 kg/hm^(2),折合施钾(K2O)70.1 kg/hm^(2)。测定指标包括土壤有机碳、总氮,计算有机氮肥替代率和土壤碳氮比。结果表明,长期施肥提高了土壤有机碳水平,OM、NPK和CK处理土壤有机碳含量可用米氏方程拟合,且前10 a内快速累积、后30 a趋近平衡,平均含量分别为16.8、15.8、15.1 g/kg。长期施肥处理线性提高了土壤总氮含量,OM、NPK和CK处理土壤平均总氮含量分别为1.71、1.64、1.47 g/kg。有机氮肥替代率的时序演变可用分段线性模型拟合,有机氮肥替代率前期略降低后期增加,稻麦两季有机氮肥替代率的时间拐点分别出现在第11年和第15.5年。线性回归分析表明,有机氮肥替代率与土壤总有机碳无显著关系,但与土壤总氮和碳氮比显著线性相关。在太湖地区稻麦轮作系统中,长期施用有机肥可有效提高土壤碳氮库容,具有较高水平土壤有机碳(>17.0 g/kg)是提升有机氮肥替代率的前提,但在有机碳趋近饱和后,土壤总氮和碳氮比是限制有机氮肥替代率提升的主要因素。Substitution of chemical fertilizer with organic fertilizer is the key strategy for chemical fertilizer reduction.The main aims are to clarify the main limiting factors of substitution rate of chemical nitrogen with organic nitrogen(SR)in rice-wheat rotation system in Taihu Lake region,and to provide theoretical basis for SR promoting.This study based on the 40 years long-term field experiment,and three treatments were chosen,including no fertilization treatment(CK),chemical fertilization treatment(NPK)and organic fertilization treatment(OM).Urea,superphosphate and potassium chloride were applied in NPK treatment,and the annual average amounts of pure N,P2O5 and K2O were 225-300,119.4 and 179.1 kg/hm^(2),respectively.Pig manure or oil cake was used in OM treatment,which equaled to 103.1,82.7 and 70.1 kg/hm^(2).The soil organic carbon(SOC),soil total nitrogen(TN)and SR and soil C/N ratio were calculated as well.The results showed that long-term fertilization promoted SOC level,and the SOC contents of the above three treatments could be fitted by Michaelis-Menten equation.The SOC content in the first decade accumulated rapidly and tended to equilibrate in the last 30 years.The average SOC content was 16.8 g/kg for OM,15.8 g/kg for NPK and 15.1 g/kg for CK treatment.TN contents of OM,NPK and CK linearly increased with years,and the average TN contents were 1.71,1.64 and 1.47 g/kg.The dynamics of the SR could be fitted by a piecewise linear model,where the SR decreased slightly at early times but increased at late times,with the threshold years being the 11th and 15.5th years of the rice and wheat seasons,respectively.Linear regulation analysis showed no relationship between SR and SOC,but SR was significantly correlated with TN and C/N ratio.In rice-wheat rotation system in Taihu Lake region,long-term organic fertilization can effectively promote soil carbon and nitrogen pools,and a high level of SOC(>17.0 g/kg)is the premise of improving SR.When the SOC approaches saturation,soil TN and C/N ratio are the main facto

关 键 词：长期施肥 稻麦轮作 有机氮肥替代率 土壤有机碳 土壤总氮 

分 类 号：S14-35[农业科学—肥料学]